* [PATCH v5 01/11] block: make generic_make_request handle arbitrarily sized bios
2015-07-06 7:11 [PATCH v5 00/11] simplify block layer based on immutable biovecs mlin
@ 2015-07-06 7:11 ` mlin
2015-07-06 7:11 ` [PATCH v5 02/11] block: simplify bio_add_page() mlin
` (10 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: mlin @ 2015-07-06 7:11 UTC (permalink / raw)
To: linux-kernel
Cc: Christoph Hellwig, Jens Axboe, Kent Overstreet, Dongsu Park,
Mike Snitzer, Ming Lin
From: Kent Overstreet <kent.overstreet@gmail.com>
The way the block layer is currently written, it goes to great lengths
to avoid having to split bios; upper layer code (such as bio_add_page())
checks what the underlying device can handle and tries to always create
bios that don't need to be split.
But this approach becomes unwieldy and eventually breaks down with
stacked devices and devices with dynamic limits, and it adds a lot of
complexity. If the block layer could split bios as needed, we could
eliminate a lot of complexity elsewhere - particularly in stacked
drivers. Code that creates bios can then create whatever size bios are
convenient, and more importantly stacked drivers don't have to deal with
both their own bio size limitations and the limitations of the
(potentially multiple) devices underneath them. In the future this will
let us delete merge_bvec_fn and a bunch of other code.
We do this by adding calls to blk_queue_split() to the various
make_request functions that need it - a few can already handle arbitrary
size bios. Note that we add the call _after_ any call to
blk_queue_bounce(); this means that blk_queue_split() and
blk_recalc_rq_segments() don't need to be concerned with bouncing
affecting segment merging.
Some make_request_fn() callbacks were simple enough to audit and verify
they don't need blk_queue_split() calls. The skipped ones are:
* nfhd_make_request (arch/m68k/emu/nfblock.c)
* axon_ram_make_request (arch/powerpc/sysdev/axonram.c)
* simdisk_make_request (arch/xtensa/platforms/iss/simdisk.c)
* brd_make_request (ramdisk - drivers/block/brd.c)
* mtip_submit_request (drivers/block/mtip32xx/mtip32xx.c)
* loop_make_request
* null_queue_bio
* bcache's make_request fns
Some others are almost certainly safe to remove now, but will be left
for future patches.
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ming Lei <ming.lei@canonical.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: drbd-user@lists.linbit.com
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Jim Paris <jim@jtan.com>
Cc: Joshua Morris <josh.h.morris@us.ibm.com>
Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Oleg Drokin <oleg.drokin@intel.com>
Cc: Andreas Dilger <andreas.dilger@intel.com>
Acked-by: NeilBrown <neilb@suse.de> (for the 'md/md.c' bits)
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[dpark: skip more mq-based drivers, resolve merge conflicts, etc.]
Signed-off-by: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
---
block/blk-core.c | 19 ++--
block/blk-merge.c | 159 ++++++++++++++++++++++++++--
block/blk-mq.c | 4 +
block/blk-sysfs.c | 3 +
drivers/block/drbd/drbd_req.c | 2 +
drivers/block/pktcdvd.c | 6 +-
drivers/block/ps3vram.c | 2 +
drivers/block/rsxx/dev.c | 2 +
drivers/block/umem.c | 2 +
drivers/block/zram/zram_drv.c | 2 +
drivers/md/dm.c | 2 +
drivers/md/md.c | 2 +
drivers/s390/block/dcssblk.c | 2 +
drivers/s390/block/xpram.c | 2 +
drivers/staging/lustre/lustre/llite/lloop.c | 2 +
include/linux/blkdev.h | 3 +
16 files changed, 192 insertions(+), 22 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 82819e6..cecf80c 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -645,6 +645,10 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
if (q->id < 0)
goto fail_q;
+ q->bio_split = bioset_create(BIO_POOL_SIZE, 0);
+ if (!q->bio_split)
+ goto fail_id;
+
q->backing_dev_info.ra_pages =
(VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
q->backing_dev_info.capabilities = BDI_CAP_CGROUP_WRITEBACK;
@@ -653,7 +657,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
err = bdi_init(&q->backing_dev_info);
if (err)
- goto fail_id;
+ goto fail_split;
setup_timer(&q->backing_dev_info.laptop_mode_wb_timer,
laptop_mode_timer_fn, (unsigned long) q);
@@ -695,6 +699,8 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
fail_bdi:
bdi_destroy(&q->backing_dev_info);
+fail_split:
+ bioset_free(q->bio_split);
fail_id:
ida_simple_remove(&blk_queue_ida, q->id);
fail_q:
@@ -1612,6 +1618,8 @@ static void blk_queue_bio(struct request_queue *q, struct bio *bio)
struct request *req;
unsigned int request_count = 0;
+ blk_queue_split(q, &bio, q->bio_split);
+
/*
* low level driver can indicate that it wants pages above a
* certain limit bounced to low memory (ie for highmem, or even
@@ -1832,15 +1840,6 @@ generic_make_request_checks(struct bio *bio)
goto end_io;
}
- if (likely(bio_is_rw(bio) &&
- nr_sectors > queue_max_hw_sectors(q))) {
- printk(KERN_ERR "bio too big device %s (%u > %u)\n",
- bdevname(bio->bi_bdev, b),
- bio_sectors(bio),
- queue_max_hw_sectors(q));
- goto end_io;
- }
-
part = bio->bi_bdev->bd_part;
if (should_fail_request(part, bio->bi_iter.bi_size) ||
should_fail_request(&part_to_disk(part)->part0,
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 30a0d9f..3707f30 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -9,12 +9,158 @@
#include "blk.h"
+static struct bio *blk_bio_discard_split(struct request_queue *q,
+ struct bio *bio,
+ struct bio_set *bs)
+{
+ unsigned int max_discard_sectors, granularity;
+ int alignment;
+ sector_t tmp;
+ unsigned split_sectors;
+
+ /* Zero-sector (unknown) and one-sector granularities are the same. */
+ granularity = max(q->limits.discard_granularity >> 9, 1U);
+
+ max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
+ max_discard_sectors -= max_discard_sectors % granularity;
+
+ if (unlikely(!max_discard_sectors)) {
+ /* XXX: warn */
+ return NULL;
+ }
+
+ if (bio_sectors(bio) <= max_discard_sectors)
+ return NULL;
+
+ split_sectors = max_discard_sectors;
+
+ /*
+ * If the next starting sector would be misaligned, stop the discard at
+ * the previous aligned sector.
+ */
+ alignment = (q->limits.discard_alignment >> 9) % granularity;
+
+ tmp = bio->bi_iter.bi_sector + split_sectors - alignment;
+ tmp = sector_div(tmp, granularity);
+
+ if (split_sectors > tmp)
+ split_sectors -= tmp;
+
+ return bio_split(bio, split_sectors, GFP_NOIO, bs);
+}
+
+static struct bio *blk_bio_write_same_split(struct request_queue *q,
+ struct bio *bio,
+ struct bio_set *bs)
+{
+ if (!q->limits.max_write_same_sectors)
+ return NULL;
+
+ if (bio_sectors(bio) <= q->limits.max_write_same_sectors)
+ return NULL;
+
+ return bio_split(bio, q->limits.max_write_same_sectors, GFP_NOIO, bs);
+}
+
+static struct bio *blk_bio_segment_split(struct request_queue *q,
+ struct bio *bio,
+ struct bio_set *bs)
+{
+ struct bio *split;
+ struct bio_vec bv, bvprv;
+ struct bvec_iter iter;
+ unsigned seg_size = 0, nsegs = 0;
+ int prev = 0;
+
+ struct bvec_merge_data bvm = {
+ .bi_bdev = bio->bi_bdev,
+ .bi_sector = bio->bi_iter.bi_sector,
+ .bi_size = 0,
+ .bi_rw = bio->bi_rw,
+ };
+
+ bio_for_each_segment(bv, bio, iter) {
+ if (q->merge_bvec_fn &&
+ q->merge_bvec_fn(q, &bvm, &bv) < (int) bv.bv_len)
+ goto split;
+
+ bvm.bi_size += bv.bv_len;
+
+ if (bvm.bi_size >> 9 > queue_max_sectors(q))
+ goto split;
+
+ /*
+ * If the queue doesn't support SG gaps and adding this
+ * offset would create a gap, disallow it.
+ */
+ if (q->queue_flags & (1 << QUEUE_FLAG_SG_GAPS) &&
+ prev && bvec_gap_to_prev(&bvprv, bv.bv_offset))
+ goto split;
+
+ if (prev && blk_queue_cluster(q)) {
+ if (seg_size + bv.bv_len > queue_max_segment_size(q))
+ goto new_segment;
+ if (!BIOVEC_PHYS_MERGEABLE(&bvprv, &bv))
+ goto new_segment;
+ if (!BIOVEC_SEG_BOUNDARY(q, &bvprv, &bv))
+ goto new_segment;
+
+ seg_size += bv.bv_len;
+ bvprv = bv;
+ prev = 1;
+ continue;
+ }
+new_segment:
+ if (nsegs == queue_max_segments(q))
+ goto split;
+
+ nsegs++;
+ bvprv = bv;
+ prev = 1;
+ seg_size = bv.bv_len;
+ }
+
+ return NULL;
+split:
+ split = bio_clone_bioset(bio, GFP_NOIO, bs);
+
+ split->bi_iter.bi_size -= iter.bi_size;
+ bio->bi_iter = iter;
+
+ if (bio_integrity(bio)) {
+ bio_integrity_advance(bio, split->bi_iter.bi_size);
+ bio_integrity_trim(split, 0, bio_sectors(split));
+ }
+
+ return split;
+}
+
+void blk_queue_split(struct request_queue *q, struct bio **bio,
+ struct bio_set *bs)
+{
+ struct bio *split;
+
+ if ((*bio)->bi_rw & REQ_DISCARD)
+ split = blk_bio_discard_split(q, *bio, bs);
+ else if ((*bio)->bi_rw & REQ_WRITE_SAME)
+ split = blk_bio_write_same_split(q, *bio, bs);
+ else
+ split = blk_bio_segment_split(q, *bio, q->bio_split);
+
+ if (split) {
+ bio_chain(split, *bio);
+ generic_make_request(*bio);
+ *bio = split;
+ }
+}
+EXPORT_SYMBOL(blk_queue_split);
+
static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
struct bio *bio,
bool no_sg_merge)
{
struct bio_vec bv, bvprv = { NULL };
- int cluster, high, highprv = 1;
+ int cluster, prev = 0;
unsigned int seg_size, nr_phys_segs;
struct bio *fbio, *bbio;
struct bvec_iter iter;
@@ -36,7 +182,6 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
cluster = blk_queue_cluster(q);
seg_size = 0;
nr_phys_segs = 0;
- high = 0;
for_each_bio(bio) {
bio_for_each_segment(bv, bio, iter) {
/*
@@ -46,13 +191,7 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
if (no_sg_merge)
goto new_segment;
- /*
- * the trick here is making sure that a high page is
- * never considered part of another segment, since
- * that might change with the bounce page.
- */
- high = page_to_pfn(bv.bv_page) > queue_bounce_pfn(q);
- if (!high && !highprv && cluster) {
+ if (prev && cluster) {
if (seg_size + bv.bv_len
> queue_max_segment_size(q))
goto new_segment;
@@ -72,8 +211,8 @@ new_segment:
nr_phys_segs++;
bvprv = bv;
+ prev = 1;
seg_size = bv.bv_len;
- highprv = high;
}
bbio = bio;
}
diff --git a/block/blk-mq.c b/block/blk-mq.c
index f537796..40d08e3 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1291,6 +1291,8 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
blk_attempt_plug_merge(q, bio, &request_count, &same_queue_rq))
return;
+ blk_queue_split(q, &bio, q->bio_split);
+
rq = blk_mq_map_request(q, bio, &data);
if (unlikely(!rq))
return;
@@ -1376,6 +1378,8 @@ static void blk_sq_make_request(struct request_queue *q, struct bio *bio)
blk_attempt_plug_merge(q, bio, &request_count, NULL))
return;
+ blk_queue_split(q, &bio, q->bio_split);
+
rq = blk_mq_map_request(q, bio, &data);
if (unlikely(!rq))
return;
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 6264b38..9a25db3 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -523,6 +523,9 @@ static void blk_release_queue(struct kobject *kobj)
blk_trace_shutdown(q);
+ if (q->bio_split)
+ bioset_free(q->bio_split);
+
ida_simple_remove(&blk_queue_ida, q->id);
call_rcu(&q->rcu_head, blk_free_queue_rcu);
}
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 3907202..a6265bc 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -1497,6 +1497,8 @@ void drbd_make_request(struct request_queue *q, struct bio *bio)
struct drbd_device *device = (struct drbd_device *) q->queuedata;
unsigned long start_jif;
+ blk_queue_split(q, &bio, q->bio_split);
+
start_jif = jiffies;
/*
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 4c20c22..05a81ae 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2447,6 +2447,10 @@ static void pkt_make_request(struct request_queue *q, struct bio *bio)
char b[BDEVNAME_SIZE];
struct bio *split;
+ blk_queue_bounce(q, &bio);
+
+ blk_queue_split(q, &bio, q->bio_split);
+
pd = q->queuedata;
if (!pd) {
pr_err("%s incorrect request queue\n",
@@ -2477,8 +2481,6 @@ static void pkt_make_request(struct request_queue *q, struct bio *bio)
goto end_io;
}
- blk_queue_bounce(q, &bio);
-
do {
sector_t zone = get_zone(bio->bi_iter.bi_sector, pd);
sector_t last_zone = get_zone(bio_end_sector(bio) - 1, pd);
diff --git a/drivers/block/ps3vram.c b/drivers/block/ps3vram.c
index b1612eb..748c63c 100644
--- a/drivers/block/ps3vram.c
+++ b/drivers/block/ps3vram.c
@@ -605,6 +605,8 @@ static void ps3vram_make_request(struct request_queue *q, struct bio *bio)
dev_dbg(&dev->core, "%s\n", __func__);
+ blk_queue_split(q, &bio, q->bio_split);
+
spin_lock_irq(&priv->lock);
busy = !bio_list_empty(&priv->list);
bio_list_add(&priv->list, bio);
diff --git a/drivers/block/rsxx/dev.c b/drivers/block/rsxx/dev.c
index ac8c62c..50ef199 100644
--- a/drivers/block/rsxx/dev.c
+++ b/drivers/block/rsxx/dev.c
@@ -148,6 +148,8 @@ static void rsxx_make_request(struct request_queue *q, struct bio *bio)
struct rsxx_bio_meta *bio_meta;
int st = -EINVAL;
+ blk_queue_split(q, &bio, q->bio_split);
+
might_sleep();
if (!card)
diff --git a/drivers/block/umem.c b/drivers/block/umem.c
index 4cf81b5..13d577c 100644
--- a/drivers/block/umem.c
+++ b/drivers/block/umem.c
@@ -531,6 +531,8 @@ static void mm_make_request(struct request_queue *q, struct bio *bio)
(unsigned long long)bio->bi_iter.bi_sector,
bio->bi_iter.bi_size);
+ blk_queue_split(q, &bio, q->bio_split);
+
spin_lock_irq(&card->lock);
*card->biotail = bio;
bio->bi_next = NULL;
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index fb655e8..44e3b89 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -901,6 +901,8 @@ static void zram_make_request(struct request_queue *queue, struct bio *bio)
if (unlikely(!zram_meta_get(zram)))
goto error;
+ blk_queue_split(queue, &bio, queue->bio_split);
+
if (!valid_io_request(zram, bio->bi_iter.bi_sector,
bio->bi_iter.bi_size)) {
atomic64_inc(&zram->stats.invalid_io);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index f331d88..530fc9a 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1800,6 +1800,8 @@ static void dm_make_request(struct request_queue *q, struct bio *bio)
map = dm_get_live_table(md, &srcu_idx);
+ blk_queue_split(q, &bio, q->bio_split);
+
generic_start_io_acct(rw, bio_sectors(bio), &dm_disk(md)->part0);
/* if we're suspended, we have to queue this io for later */
diff --git a/drivers/md/md.c b/drivers/md/md.c
index d429c30..10bf6d4 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -257,6 +257,8 @@ static void md_make_request(struct request_queue *q, struct bio *bio)
unsigned int sectors;
int cpu;
+ blk_queue_split(q, &bio, q->bio_split);
+
if (mddev == NULL || mddev->pers == NULL
|| !mddev->ready) {
bio_io_error(bio);
diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index da21281..267ca3a 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -826,6 +826,8 @@ dcssblk_make_request(struct request_queue *q, struct bio *bio)
unsigned long source_addr;
unsigned long bytes_done;
+ blk_queue_split(q, &bio, q->bio_split);
+
bytes_done = 0;
dev_info = bio->bi_bdev->bd_disk->private_data;
if (dev_info == NULL)
diff --git a/drivers/s390/block/xpram.c b/drivers/s390/block/xpram.c
index 7d4e939..1305ed3 100644
--- a/drivers/s390/block/xpram.c
+++ b/drivers/s390/block/xpram.c
@@ -190,6 +190,8 @@ static void xpram_make_request(struct request_queue *q, struct bio *bio)
unsigned long page_addr;
unsigned long bytes;
+ blk_queue_split(q, &bio, q->bio_split);
+
if ((bio->bi_iter.bi_sector & 7) != 0 ||
(bio->bi_iter.bi_size & 4095) != 0)
/* Request is not page-aligned. */
diff --git a/drivers/staging/lustre/lustre/llite/lloop.c b/drivers/staging/lustre/lustre/llite/lloop.c
index cc00fd1..1e33d54 100644
--- a/drivers/staging/lustre/lustre/llite/lloop.c
+++ b/drivers/staging/lustre/lustre/llite/lloop.c
@@ -340,6 +340,8 @@ static void loop_make_request(struct request_queue *q, struct bio *old_bio)
int rw = bio_rw(old_bio);
int inactive;
+ blk_queue_split(q, &old_bio, q->bio_split);
+
if (!lo)
goto err;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index d4068c1..dc89cc8 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -462,6 +462,7 @@ struct request_queue {
struct blk_mq_tag_set *tag_set;
struct list_head tag_set_list;
+ struct bio_set *bio_split;
};
#define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
@@ -782,6 +783,8 @@ extern void blk_rq_unprep_clone(struct request *rq);
extern int blk_insert_cloned_request(struct request_queue *q,
struct request *rq);
extern void blk_delay_queue(struct request_queue *, unsigned long);
+extern void blk_queue_split(struct request_queue *, struct bio **,
+ struct bio_set *);
extern void blk_recount_segments(struct request_queue *, struct bio *);
extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
--
1.9.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH v5 02/11] block: simplify bio_add_page()
2015-07-06 7:11 [PATCH v5 00/11] simplify block layer based on immutable biovecs mlin
2015-07-06 7:11 ` [PATCH v5 01/11] block: make generic_make_request handle arbitrarily sized bios mlin
@ 2015-07-06 7:11 ` mlin
2015-07-06 7:11 ` [PATCH v5 03/11] bcache: remove driver private bio splitting code mlin
` (9 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: mlin @ 2015-07-06 7:11 UTC (permalink / raw)
To: linux-kernel
Cc: Christoph Hellwig, Jens Axboe, Kent Overstreet, Dongsu Park,
Mike Snitzer, Ming Lin
From: Kent Overstreet <kent.overstreet@gmail.com>
Since generic_make_request() can now handle arbitrary size bios, all we
have to do is make sure the bvec array doesn't overflow.
__bio_add_page() doesn't need to call ->merge_bvec_fn(), where
we can get rid of unnecessary code paths.
Removing the call to ->merge_bvec_fn() is also fine, as no driver that
implements support for BLOCK_PC commands even has a ->merge_bvec_fn()
method.
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[dpark: rebase and resolve merge conflicts, change a couple of comments,
make bio_add_page() warn once upon a cloned bio.]
Signed-off-by: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
---
block/bio.c | 135 +++++++++++++++++++++++++-----------------------------------
1 file changed, 55 insertions(+), 80 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 2a00d34..da15e9a 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -714,9 +714,23 @@ int bio_get_nr_vecs(struct block_device *bdev)
}
EXPORT_SYMBOL(bio_get_nr_vecs);
-static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
- *page, unsigned int len, unsigned int offset,
- unsigned int max_sectors)
+/**
+ * bio_add_pc_page - attempt to add page to bio
+ * @q: the target queue
+ * @bio: destination bio
+ * @page: page to add
+ * @len: vec entry length
+ * @offset: vec entry offset
+ *
+ * Attempt to add a page to the bio_vec maplist. This can fail for a
+ * number of reasons, such as the bio being full or target block device
+ * limitations. The target block device must allow bio's up to PAGE_SIZE,
+ * so it is always possible to add a single page to an empty bio.
+ *
+ * This should only be used by REQ_PC bios.
+ */
+int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page
+ *page, unsigned int len, unsigned int offset)
{
int retried_segments = 0;
struct bio_vec *bvec;
@@ -727,7 +741,7 @@ static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
if (unlikely(bio_flagged(bio, BIO_CLONED)))
return 0;
- if (((bio->bi_iter.bi_size + len) >> 9) > max_sectors)
+ if (((bio->bi_iter.bi_size + len) >> 9) > queue_max_hw_sectors(q))
return 0;
/*
@@ -740,28 +754,7 @@ static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
if (page == prev->bv_page &&
offset == prev->bv_offset + prev->bv_len) {
- unsigned int prev_bv_len = prev->bv_len;
prev->bv_len += len;
-
- if (q->merge_bvec_fn) {
- struct bvec_merge_data bvm = {
- /* prev_bvec is already charged in
- bi_size, discharge it in order to
- simulate merging updated prev_bvec
- as new bvec. */
- .bi_bdev = bio->bi_bdev,
- .bi_sector = bio->bi_iter.bi_sector,
- .bi_size = bio->bi_iter.bi_size -
- prev_bv_len,
- .bi_rw = bio->bi_rw,
- };
-
- if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len) {
- prev->bv_len -= len;
- return 0;
- }
- }
-
bio->bi_iter.bi_size += len;
goto done;
}
@@ -804,27 +797,6 @@ static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
blk_recount_segments(q, bio);
}
- /*
- * if queue has other restrictions (eg varying max sector size
- * depending on offset), it can specify a merge_bvec_fn in the
- * queue to get further control
- */
- if (q->merge_bvec_fn) {
- struct bvec_merge_data bvm = {
- .bi_bdev = bio->bi_bdev,
- .bi_sector = bio->bi_iter.bi_sector,
- .bi_size = bio->bi_iter.bi_size - len,
- .bi_rw = bio->bi_rw,
- };
-
- /*
- * merge_bvec_fn() returns number of bytes it can accept
- * at this offset
- */
- if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len)
- goto failed;
- }
-
/* If we may be able to merge these biovecs, force a recount */
if (bio->bi_vcnt > 1 && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
bio->bi_flags &= ~(1 << BIO_SEG_VALID);
@@ -841,28 +813,6 @@ static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
blk_recount_segments(q, bio);
return 0;
}
-
-/**
- * bio_add_pc_page - attempt to add page to bio
- * @q: the target queue
- * @bio: destination bio
- * @page: page to add
- * @len: vec entry length
- * @offset: vec entry offset
- *
- * Attempt to add a page to the bio_vec maplist. This can fail for a
- * number of reasons, such as the bio being full or target block device
- * limitations. The target block device must allow bio's up to PAGE_SIZE,
- * so it is always possible to add a single page to an empty bio.
- *
- * This should only be used by REQ_PC bios.
- */
-int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
- unsigned int len, unsigned int offset)
-{
- return __bio_add_page(q, bio, page, len, offset,
- queue_max_hw_sectors(q));
-}
EXPORT_SYMBOL(bio_add_pc_page);
/**
@@ -872,22 +822,47 @@ EXPORT_SYMBOL(bio_add_pc_page);
* @len: vec entry length
* @offset: vec entry offset
*
- * Attempt to add a page to the bio_vec maplist. This can fail for a
- * number of reasons, such as the bio being full or target block device
- * limitations. The target block device must allow bio's up to PAGE_SIZE,
- * so it is always possible to add a single page to an empty bio.
+ * Attempt to add a page to the bio_vec maplist. This will only fail
+ * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio.
*/
-int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
- unsigned int offset)
+int bio_add_page(struct bio *bio, struct page *page,
+ unsigned int len, unsigned int offset)
{
- struct request_queue *q = bdev_get_queue(bio->bi_bdev);
- unsigned int max_sectors;
+ struct bio_vec *bv;
- max_sectors = blk_max_size_offset(q, bio->bi_iter.bi_sector);
- if ((max_sectors < (len >> 9)) && !bio->bi_iter.bi_size)
- max_sectors = len >> 9;
+ /*
+ * cloned bio must not modify vec list
+ */
+ if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
+ return 0;
- return __bio_add_page(q, bio, page, len, offset, max_sectors);
+ /*
+ * For filesystems with a blocksize smaller than the pagesize
+ * we will often be called with the same page as last time and
+ * a consecutive offset. Optimize this special case.
+ */
+ if (bio->bi_vcnt > 0) {
+ bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
+
+ if (page == bv->bv_page &&
+ offset == bv->bv_offset + bv->bv_len) {
+ bv->bv_len += len;
+ goto done;
+ }
+ }
+
+ if (bio->bi_vcnt >= bio->bi_max_vecs)
+ return 0;
+
+ bv = &bio->bi_io_vec[bio->bi_vcnt];
+ bv->bv_page = page;
+ bv->bv_len = len;
+ bv->bv_offset = offset;
+
+ bio->bi_vcnt++;
+done:
+ bio->bi_iter.bi_size += len;
+ return len;
}
EXPORT_SYMBOL(bio_add_page);
--
1.9.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH v5 03/11] bcache: remove driver private bio splitting code
2015-07-06 7:11 [PATCH v5 00/11] simplify block layer based on immutable biovecs mlin
2015-07-06 7:11 ` [PATCH v5 01/11] block: make generic_make_request handle arbitrarily sized bios mlin
2015-07-06 7:11 ` [PATCH v5 02/11] block: simplify bio_add_page() mlin
@ 2015-07-06 7:11 ` mlin
2015-07-06 7:11 ` [PATCH v5 04/11] btrfs: remove bio splitting and merge_bvec_fn() calls mlin
` (8 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: mlin @ 2015-07-06 7:11 UTC (permalink / raw)
To: linux-kernel
Cc: Christoph Hellwig, Jens Axboe, Kent Overstreet, Dongsu Park,
Mike Snitzer, Ming Lin
From: Kent Overstreet <kent.overstreet@gmail.com>
The bcache driver has always accepted arbitrarily large bios and split
them internally. Now that every driver must accept arbitrarily large
bios this code isn't nessecary anymore.
Cc: linux-bcache@vger.kernel.org
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[dpark: add more description in commit message]
Signed-off-by: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
---
drivers/md/bcache/bcache.h | 18 --------
drivers/md/bcache/io.c | 100 +-----------------------------------------
drivers/md/bcache/journal.c | 4 +-
drivers/md/bcache/request.c | 16 +++----
drivers/md/bcache/super.c | 32 +-------------
drivers/md/bcache/util.h | 5 ++-
drivers/md/bcache/writeback.c | 4 +-
7 files changed, 18 insertions(+), 161 deletions(-)
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 04f7bc2..6b420a5 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -243,19 +243,6 @@ struct keybuf {
DECLARE_ARRAY_ALLOCATOR(struct keybuf_key, freelist, KEYBUF_NR);
};
-struct bio_split_pool {
- struct bio_set *bio_split;
- mempool_t *bio_split_hook;
-};
-
-struct bio_split_hook {
- struct closure cl;
- struct bio_split_pool *p;
- struct bio *bio;
- bio_end_io_t *bi_end_io;
- void *bi_private;
-};
-
struct bcache_device {
struct closure cl;
@@ -288,8 +275,6 @@ struct bcache_device {
int (*cache_miss)(struct btree *, struct search *,
struct bio *, unsigned);
int (*ioctl) (struct bcache_device *, fmode_t, unsigned, unsigned long);
-
- struct bio_split_pool bio_split_hook;
};
struct io {
@@ -454,8 +439,6 @@ struct cache {
atomic_long_t meta_sectors_written;
atomic_long_t btree_sectors_written;
atomic_long_t sectors_written;
-
- struct bio_split_pool bio_split_hook;
};
struct gc_stat {
@@ -873,7 +856,6 @@ void bch_bbio_endio(struct cache_set *, struct bio *, int, const char *);
void bch_bbio_free(struct bio *, struct cache_set *);
struct bio *bch_bbio_alloc(struct cache_set *);
-void bch_generic_make_request(struct bio *, struct bio_split_pool *);
void __bch_submit_bbio(struct bio *, struct cache_set *);
void bch_submit_bbio(struct bio *, struct cache_set *, struct bkey *, unsigned);
diff --git a/drivers/md/bcache/io.c b/drivers/md/bcache/io.c
index cb64e64a..86a0bb8 100644
--- a/drivers/md/bcache/io.c
+++ b/drivers/md/bcache/io.c
@@ -11,104 +11,6 @@
#include <linux/blkdev.h>
-static unsigned bch_bio_max_sectors(struct bio *bio)
-{
- struct request_queue *q = bdev_get_queue(bio->bi_bdev);
- struct bio_vec bv;
- struct bvec_iter iter;
- unsigned ret = 0, seg = 0;
-
- if (bio->bi_rw & REQ_DISCARD)
- return min(bio_sectors(bio), q->limits.max_discard_sectors);
-
- bio_for_each_segment(bv, bio, iter) {
- struct bvec_merge_data bvm = {
- .bi_bdev = bio->bi_bdev,
- .bi_sector = bio->bi_iter.bi_sector,
- .bi_size = ret << 9,
- .bi_rw = bio->bi_rw,
- };
-
- if (seg == min_t(unsigned, BIO_MAX_PAGES,
- queue_max_segments(q)))
- break;
-
- if (q->merge_bvec_fn &&
- q->merge_bvec_fn(q, &bvm, &bv) < (int) bv.bv_len)
- break;
-
- seg++;
- ret += bv.bv_len >> 9;
- }
-
- ret = min(ret, queue_max_sectors(q));
-
- WARN_ON(!ret);
- ret = max_t(int, ret, bio_iovec(bio).bv_len >> 9);
-
- return ret;
-}
-
-static void bch_bio_submit_split_done(struct closure *cl)
-{
- struct bio_split_hook *s = container_of(cl, struct bio_split_hook, cl);
-
- s->bio->bi_end_io = s->bi_end_io;
- s->bio->bi_private = s->bi_private;
- bio_endio(s->bio, 0);
-
- closure_debug_destroy(&s->cl);
- mempool_free(s, s->p->bio_split_hook);
-}
-
-static void bch_bio_submit_split_endio(struct bio *bio, int error)
-{
- struct closure *cl = bio->bi_private;
- struct bio_split_hook *s = container_of(cl, struct bio_split_hook, cl);
-
- if (error)
- clear_bit(BIO_UPTODATE, &s->bio->bi_flags);
-
- bio_put(bio);
- closure_put(cl);
-}
-
-void bch_generic_make_request(struct bio *bio, struct bio_split_pool *p)
-{
- struct bio_split_hook *s;
- struct bio *n;
-
- if (!bio_has_data(bio) && !(bio->bi_rw & REQ_DISCARD))
- goto submit;
-
- if (bio_sectors(bio) <= bch_bio_max_sectors(bio))
- goto submit;
-
- s = mempool_alloc(p->bio_split_hook, GFP_NOIO);
- closure_init(&s->cl, NULL);
-
- s->bio = bio;
- s->p = p;
- s->bi_end_io = bio->bi_end_io;
- s->bi_private = bio->bi_private;
- bio_get(bio);
-
- do {
- n = bio_next_split(bio, bch_bio_max_sectors(bio),
- GFP_NOIO, s->p->bio_split);
-
- n->bi_end_io = bch_bio_submit_split_endio;
- n->bi_private = &s->cl;
-
- closure_get(&s->cl);
- generic_make_request(n);
- } while (n != bio);
-
- continue_at(&s->cl, bch_bio_submit_split_done, NULL);
-submit:
- generic_make_request(bio);
-}
-
/* Bios with headers */
void bch_bbio_free(struct bio *bio, struct cache_set *c)
@@ -138,7 +40,7 @@ void __bch_submit_bbio(struct bio *bio, struct cache_set *c)
bio->bi_bdev = PTR_CACHE(c, &b->key, 0)->bdev;
b->submit_time_us = local_clock_us();
- closure_bio_submit(bio, bio->bi_private, PTR_CACHE(c, &b->key, 0));
+ closure_bio_submit(bio, bio->bi_private);
}
void bch_submit_bbio(struct bio *bio, struct cache_set *c,
diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c
index ce64fc8..54c02da 100644
--- a/drivers/md/bcache/journal.c
+++ b/drivers/md/bcache/journal.c
@@ -61,7 +61,7 @@ reread: left = ca->sb.bucket_size - offset;
bio->bi_private = &cl;
bch_bio_map(bio, data);
- closure_bio_submit(bio, &cl, ca);
+ closure_bio_submit(bio, &cl);
closure_sync(&cl);
/* This function could be simpler now since we no longer write
@@ -646,7 +646,7 @@ static void journal_write_unlocked(struct closure *cl)
spin_unlock(&c->journal.lock);
while ((bio = bio_list_pop(&list)))
- closure_bio_submit(bio, cl, c->cache[0]);
+ closure_bio_submit(bio, cl);
continue_at(cl, journal_write_done, NULL);
}
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index 4afb2d2..41e06da 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -711,7 +711,7 @@ static void cached_dev_read_error(struct closure *cl)
/* XXX: invalidate cache */
- closure_bio_submit(bio, cl, s->d);
+ closure_bio_submit(bio, cl);
}
continue_at(cl, cached_dev_cache_miss_done, NULL);
@@ -834,7 +834,7 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s,
s->cache_miss = miss;
s->iop.bio = cache_bio;
bio_get(cache_bio);
- closure_bio_submit(cache_bio, &s->cl, s->d);
+ closure_bio_submit(cache_bio, &s->cl);
return ret;
out_put:
@@ -842,7 +842,7 @@ out_put:
out_submit:
miss->bi_end_io = request_endio;
miss->bi_private = &s->cl;
- closure_bio_submit(miss, &s->cl, s->d);
+ closure_bio_submit(miss, &s->cl);
return ret;
}
@@ -907,7 +907,7 @@ static void cached_dev_write(struct cached_dev *dc, struct search *s)
if (!(bio->bi_rw & REQ_DISCARD) ||
blk_queue_discard(bdev_get_queue(dc->bdev)))
- closure_bio_submit(bio, cl, s->d);
+ closure_bio_submit(bio, cl);
} else if (s->iop.writeback) {
bch_writeback_add(dc);
s->iop.bio = bio;
@@ -922,12 +922,12 @@ static void cached_dev_write(struct cached_dev *dc, struct search *s)
flush->bi_end_io = request_endio;
flush->bi_private = cl;
- closure_bio_submit(flush, cl, s->d);
+ closure_bio_submit(flush, cl);
}
} else {
s->iop.bio = bio_clone_fast(bio, GFP_NOIO, dc->disk.bio_split);
- closure_bio_submit(bio, cl, s->d);
+ closure_bio_submit(bio, cl);
}
closure_call(&s->iop.cl, bch_data_insert, NULL, cl);
@@ -943,7 +943,7 @@ static void cached_dev_nodata(struct closure *cl)
bch_journal_meta(s->iop.c, cl);
/* If it's a flush, we send the flush to the backing device too */
- closure_bio_submit(bio, cl, s->d);
+ closure_bio_submit(bio, cl);
continue_at(cl, cached_dev_bio_complete, NULL);
}
@@ -987,7 +987,7 @@ static void cached_dev_make_request(struct request_queue *q, struct bio *bio)
!blk_queue_discard(bdev_get_queue(dc->bdev)))
bio_endio(bio, 0);
else
- bch_generic_make_request(bio, &d->bio_split_hook);
+ generic_make_request(bio);
}
}
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 94980bf..db70c9e 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -59,29 +59,6 @@ struct workqueue_struct *bcache_wq;
#define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE)
-static void bio_split_pool_free(struct bio_split_pool *p)
-{
- if (p->bio_split_hook)
- mempool_destroy(p->bio_split_hook);
-
- if (p->bio_split)
- bioset_free(p->bio_split);
-}
-
-static int bio_split_pool_init(struct bio_split_pool *p)
-{
- p->bio_split = bioset_create(4, 0);
- if (!p->bio_split)
- return -ENOMEM;
-
- p->bio_split_hook = mempool_create_kmalloc_pool(4,
- sizeof(struct bio_split_hook));
- if (!p->bio_split_hook)
- return -ENOMEM;
-
- return 0;
-}
-
/* Superblock */
static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
@@ -537,7 +514,7 @@ static void prio_io(struct cache *ca, uint64_t bucket, unsigned long rw)
bio->bi_private = ca;
bch_bio_map(bio, ca->disk_buckets);
- closure_bio_submit(bio, &ca->prio, ca);
+ closure_bio_submit(bio, &ca->prio);
closure_sync(cl);
}
@@ -757,7 +734,6 @@ static void bcache_device_free(struct bcache_device *d)
put_disk(d->disk);
}
- bio_split_pool_free(&d->bio_split_hook);
if (d->bio_split)
bioset_free(d->bio_split);
kvfree(d->full_dirty_stripes);
@@ -804,7 +780,6 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size,
return minor;
if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio))) ||
- bio_split_pool_init(&d->bio_split_hook) ||
!(d->disk = alloc_disk(1))) {
ida_simple_remove(&bcache_minor, minor);
return -ENOMEM;
@@ -1793,8 +1768,6 @@ void bch_cache_release(struct kobject *kobj)
ca->set->cache[ca->sb.nr_this_dev] = NULL;
}
- bio_split_pool_free(&ca->bio_split_hook);
-
free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca)));
kfree(ca->prio_buckets);
vfree(ca->buckets);
@@ -1839,8 +1812,7 @@ static int cache_alloc(struct cache_sb *sb, struct cache *ca)
ca->sb.nbuckets)) ||
!(ca->prio_buckets = kzalloc(sizeof(uint64_t) * prio_buckets(ca) *
2, GFP_KERNEL)) ||
- !(ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca)) ||
- bio_split_pool_init(&ca->bio_split_hook))
+ !(ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca)))
return -ENOMEM;
ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
diff --git a/drivers/md/bcache/util.h b/drivers/md/bcache/util.h
index 1d04c48..cf2cbc2 100644
--- a/drivers/md/bcache/util.h
+++ b/drivers/md/bcache/util.h
@@ -4,6 +4,7 @@
#include <linux/blkdev.h>
#include <linux/errno.h>
+#include <linux/blkdev.h>
#include <linux/kernel.h>
#include <linux/llist.h>
#include <linux/ratelimit.h>
@@ -570,10 +571,10 @@ static inline sector_t bdev_sectors(struct block_device *bdev)
return bdev->bd_inode->i_size >> 9;
}
-#define closure_bio_submit(bio, cl, dev) \
+#define closure_bio_submit(bio, cl) \
do { \
closure_get(cl); \
- bch_generic_make_request(bio, &(dev)->bio_split_hook); \
+ generic_make_request(bio); \
} while (0)
uint64_t bch_crc64_update(uint64_t, const void *, size_t);
diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index f1986bc..ca38362 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -188,7 +188,7 @@ static void write_dirty(struct closure *cl)
io->bio.bi_bdev = io->dc->bdev;
io->bio.bi_end_io = dirty_endio;
- closure_bio_submit(&io->bio, cl, &io->dc->disk);
+ closure_bio_submit(&io->bio, cl);
continue_at(cl, write_dirty_finish, system_wq);
}
@@ -208,7 +208,7 @@ static void read_dirty_submit(struct closure *cl)
{
struct dirty_io *io = container_of(cl, struct dirty_io, cl);
- closure_bio_submit(&io->bio, cl, &io->dc->disk);
+ closure_bio_submit(&io->bio, cl);
continue_at(cl, write_dirty, system_wq);
}
--
1.9.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH v5 04/11] btrfs: remove bio splitting and merge_bvec_fn() calls
2015-07-06 7:11 [PATCH v5 00/11] simplify block layer based on immutable biovecs mlin
` (2 preceding siblings ...)
2015-07-06 7:11 ` [PATCH v5 03/11] bcache: remove driver private bio splitting code mlin
@ 2015-07-06 7:11 ` mlin
2015-07-06 7:11 ` [PATCH v5 05/11] block: remove split code in blkdev_issue_discard mlin
` (7 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: mlin @ 2015-07-06 7:11 UTC (permalink / raw)
To: linux-kernel
Cc: Christoph Hellwig, Jens Axboe, Kent Overstreet, Dongsu Park,
Mike Snitzer, Ming Lin
From: Kent Overstreet <kent.overstreet@gmail.com>
Btrfs has been doing bio splitting from btrfs_map_bio(), by checking
device limits as well as calling ->merge_bvec_fn() etc. That is not
necessary any more, because generic_make_request() is now able to
handle arbitrarily sized bios. So clean up unnecessary code paths.
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: linux-btrfs@vger.kernel.org
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Chris Mason <clm@fb.com>
[dpark: add more description in commit message]
Signed-off-by: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
---
fs/btrfs/volumes.c | 72 ------------------------------------------------------
1 file changed, 72 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 4b438b4..fd25b81 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5833,34 +5833,6 @@ static noinline void btrfs_schedule_bio(struct btrfs_root *root,
&device->work);
}
-static int bio_size_ok(struct block_device *bdev, struct bio *bio,
- sector_t sector)
-{
- struct bio_vec *prev;
- struct request_queue *q = bdev_get_queue(bdev);
- unsigned int max_sectors = queue_max_sectors(q);
- struct bvec_merge_data bvm = {
- .bi_bdev = bdev,
- .bi_sector = sector,
- .bi_rw = bio->bi_rw,
- };
-
- if (WARN_ON(bio->bi_vcnt == 0))
- return 1;
-
- prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
- if (bio_sectors(bio) > max_sectors)
- return 0;
-
- if (!q->merge_bvec_fn)
- return 1;
-
- bvm.bi_size = bio->bi_iter.bi_size - prev->bv_len;
- if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len)
- return 0;
- return 1;
-}
-
static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
struct bio *bio, u64 physical, int dev_nr,
int rw, int async)
@@ -5894,38 +5866,6 @@ static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
btrfsic_submit_bio(rw, bio);
}
-static int breakup_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
- struct bio *first_bio, struct btrfs_device *dev,
- int dev_nr, int rw, int async)
-{
- struct bio_vec *bvec = first_bio->bi_io_vec;
- struct bio *bio;
- int nr_vecs = bio_get_nr_vecs(dev->bdev);
- u64 physical = bbio->stripes[dev_nr].physical;
-
-again:
- bio = btrfs_bio_alloc(dev->bdev, physical >> 9, nr_vecs, GFP_NOFS);
- if (!bio)
- return -ENOMEM;
-
- while (bvec <= (first_bio->bi_io_vec + first_bio->bi_vcnt - 1)) {
- if (bio_add_page(bio, bvec->bv_page, bvec->bv_len,
- bvec->bv_offset) < bvec->bv_len) {
- u64 len = bio->bi_iter.bi_size;
-
- atomic_inc(&bbio->stripes_pending);
- submit_stripe_bio(root, bbio, bio, physical, dev_nr,
- rw, async);
- physical += len;
- goto again;
- }
- bvec++;
- }
-
- submit_stripe_bio(root, bbio, bio, physical, dev_nr, rw, async);
- return 0;
-}
-
static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)
{
atomic_inc(&bbio->error);
@@ -5998,18 +5938,6 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
continue;
}
- /*
- * Check and see if we're ok with this bio based on it's size
- * and offset with the given device.
- */
- if (!bio_size_ok(dev->bdev, first_bio,
- bbio->stripes[dev_nr].physical >> 9)) {
- ret = breakup_stripe_bio(root, bbio, first_bio, dev,
- dev_nr, rw, async_submit);
- BUG_ON(ret);
- continue;
- }
-
if (dev_nr < total_devs - 1) {
bio = btrfs_bio_clone(first_bio, GFP_NOFS);
BUG_ON(!bio); /* -ENOMEM */
--
1.9.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH v5 05/11] block: remove split code in blkdev_issue_discard
2015-07-06 7:11 [PATCH v5 00/11] simplify block layer based on immutable biovecs mlin
` (3 preceding siblings ...)
2015-07-06 7:11 ` [PATCH v5 04/11] btrfs: remove bio splitting and merge_bvec_fn() calls mlin
@ 2015-07-06 7:11 ` mlin
2015-07-06 7:11 ` [PATCH v5 06/11] md/raid5: split bio for chunk_aligned_read mlin
` (6 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: mlin @ 2015-07-06 7:11 UTC (permalink / raw)
To: linux-kernel
Cc: Christoph Hellwig, Jens Axboe, Kent Overstreet, Dongsu Park,
Mike Snitzer, Ming Lin
From: Ming Lin <ming.l@ssi.samsung.com>
The split code in blkdev_issue_discard() can go away now
that any driver that cares does the split.
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
---
block/blk-lib.c | 73 +++++++++++----------------------------------------------
1 file changed, 14 insertions(+), 59 deletions(-)
diff --git a/block/blk-lib.c b/block/blk-lib.c
index 7688ee3..3bf3c4a 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -43,34 +43,17 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
DECLARE_COMPLETION_ONSTACK(wait);
struct request_queue *q = bdev_get_queue(bdev);
int type = REQ_WRITE | REQ_DISCARD;
- unsigned int max_discard_sectors, granularity;
- int alignment;
struct bio_batch bb;
struct bio *bio;
int ret = 0;
struct blk_plug plug;
- if (!q)
+ if (!q || !nr_sects)
return -ENXIO;
if (!blk_queue_discard(q))
return -EOPNOTSUPP;
- /* Zero-sector (unknown) and one-sector granularities are the same. */
- granularity = max(q->limits.discard_granularity >> 9, 1U);
- alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
-
- /*
- * Ensure that max_discard_sectors is of the proper
- * granularity, so that requests stay aligned after a split.
- */
- max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
- max_discard_sectors -= max_discard_sectors % granularity;
- if (unlikely(!max_discard_sectors)) {
- /* Avoid infinite loop below. Being cautious never hurts. */
- return -EOPNOTSUPP;
- }
-
if (flags & BLKDEV_DISCARD_SECURE) {
if (!blk_queue_secdiscard(q))
return -EOPNOTSUPP;
@@ -82,52 +65,24 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
bb.wait = &wait;
blk_start_plug(&plug);
- while (nr_sects) {
- unsigned int req_sects;
- sector_t end_sect, tmp;
- bio = bio_alloc(gfp_mask, 1);
- if (!bio) {
- ret = -ENOMEM;
- break;
- }
+ bio = bio_alloc(gfp_mask, 1);
+ if (!bio) {
+ ret = -ENOMEM;
+ goto out;
+ }
- req_sects = min_t(sector_t, nr_sects, max_discard_sectors);
-
- /*
- * If splitting a request, and the next starting sector would be
- * misaligned, stop the discard at the previous aligned sector.
- */
- end_sect = sector + req_sects;
- tmp = end_sect;
- if (req_sects < nr_sects &&
- sector_div(tmp, granularity) != alignment) {
- end_sect = end_sect - alignment;
- sector_div(end_sect, granularity);
- end_sect = end_sect * granularity + alignment;
- req_sects = end_sect - sector;
- }
+ bio->bi_iter.bi_sector = sector;
+ bio->bi_end_io = bio_batch_end_io;
+ bio->bi_bdev = bdev;
+ bio->bi_private = &bb;
- bio->bi_iter.bi_sector = sector;
- bio->bi_end_io = bio_batch_end_io;
- bio->bi_bdev = bdev;
- bio->bi_private = &bb;
+ bio->bi_iter.bi_size = nr_sects << 9;
- bio->bi_iter.bi_size = req_sects << 9;
- nr_sects -= req_sects;
- sector = end_sect;
+ atomic_inc(&bb.done);
+ submit_bio(type, bio);
- atomic_inc(&bb.done);
- submit_bio(type, bio);
-
- /*
- * We can loop for a long time in here, if someone does
- * full device discards (like mkfs). Be nice and allow
- * us to schedule out to avoid softlocking if preempt
- * is disabled.
- */
- cond_resched();
- }
+out:
blk_finish_plug(&plug);
/* Wait for bios in-flight */
--
1.9.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH v5 06/11] md/raid5: split bio for chunk_aligned_read
2015-07-06 7:11 [PATCH v5 00/11] simplify block layer based on immutable biovecs mlin
` (4 preceding siblings ...)
2015-07-06 7:11 ` [PATCH v5 05/11] block: remove split code in blkdev_issue_discard mlin
@ 2015-07-06 7:11 ` mlin
2015-07-06 7:11 ` [PATCH v5 07/11] md/raid5: get rid of bio_fits_rdev() mlin
` (5 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: mlin @ 2015-07-06 7:11 UTC (permalink / raw)
To: linux-kernel
Cc: Christoph Hellwig, Jens Axboe, Kent Overstreet, Dongsu Park,
Mike Snitzer, Ming Lin
From: Ming Lin <ming.l@ssi.samsung.com>
If a read request fits entirely in a chunk, it will be passed directly to the
underlying device (providing it hasn't failed of course). If it doesn't fit,
the slightly less efficient path that uses the stripe_cache is used.
Requests that get to the stripe cache are always completely split up as
necessary.
So with RAID5, ripping out the merge_bvec_fn doesn't cause it to stop work,
but could cause it to take the less efficient path more often.
All that is needed to manage this is for 'chunk_aligned_read' do some bio
splitting, much like the RAID0 code does.
Cc: Neil Brown <neilb@suse.de>
Cc: linux-raid@vger.kernel.org
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
---
drivers/md/raid5.c | 37 ++++++++++++++++++++++++++++++++-----
1 file changed, 32 insertions(+), 5 deletions(-)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 59e44e9..8377e72 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4799,7 +4799,7 @@ static int bio_fits_rdev(struct bio *bi)
return 1;
}
-static int chunk_aligned_read(struct mddev *mddev, struct bio * raid_bio)
+static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
{
struct r5conf *conf = mddev->private;
int dd_idx;
@@ -4808,7 +4808,7 @@ static int chunk_aligned_read(struct mddev *mddev, struct bio * raid_bio)
sector_t end_sector;
if (!in_chunk_boundary(mddev, raid_bio)) {
- pr_debug("chunk_aligned_read : non aligned\n");
+ pr_debug("%s: non aligned\n", __func__);
return 0;
}
/*
@@ -4885,6 +4885,31 @@ static int chunk_aligned_read(struct mddev *mddev, struct bio * raid_bio)
}
}
+static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
+{
+ struct bio *split;
+
+ do {
+ sector_t sector = raid_bio->bi_iter.bi_sector;
+ unsigned chunk_sects = mddev->chunk_sectors;
+ unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
+
+ if (sectors < bio_sectors(raid_bio)) {
+ split = bio_split(raid_bio, sectors, GFP_NOIO, fs_bio_set);
+ bio_chain(split, raid_bio);
+ } else
+ split = raid_bio;
+
+ if (!raid5_read_one_chunk(mddev, split)) {
+ if (split != raid_bio)
+ generic_make_request(raid_bio);
+ return split;
+ }
+ } while (split != raid_bio);
+
+ return NULL;
+}
+
/* __get_priority_stripe - get the next stripe to process
*
* Full stripe writes are allowed to pass preread active stripes up until
@@ -5162,9 +5187,11 @@ static void make_request(struct mddev *mddev, struct bio * bi)
* data on failed drives.
*/
if (rw == READ && mddev->degraded == 0 &&
- mddev->reshape_position == MaxSector &&
- chunk_aligned_read(mddev,bi))
- return;
+ mddev->reshape_position == MaxSector) {
+ bi = chunk_aligned_read(mddev, bi);
+ if (!bi)
+ return;
+ }
if (unlikely(bi->bi_rw & REQ_DISCARD)) {
make_discard_request(mddev, bi);
--
1.9.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH v5 07/11] md/raid5: get rid of bio_fits_rdev()
2015-07-06 7:11 [PATCH v5 00/11] simplify block layer based on immutable biovecs mlin
` (5 preceding siblings ...)
2015-07-06 7:11 ` [PATCH v5 06/11] md/raid5: split bio for chunk_aligned_read mlin
@ 2015-07-06 7:11 ` mlin
2015-07-06 7:11 ` [PATCH v5 08/11] block: kill merge_bvec_fn() completely mlin
` (4 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: mlin @ 2015-07-06 7:11 UTC (permalink / raw)
To: linux-kernel
Cc: Christoph Hellwig, Jens Axboe, Kent Overstreet, Dongsu Park,
Mike Snitzer, Ming Lin
From: Kent Overstreet <kent.overstreet@gmail.com>
Remove bio_fits_rdev() as sufficient merge_bvec_fn() handling is now
performed by blk_queue_split() in md_make_request().
Cc: Neil Brown <neilb@suse.de>
Cc: linux-raid@vger.kernel.org
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[dpark: add more description in commit message]
Signed-off-by: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
---
drivers/md/raid5.c | 23 +----------------------
1 file changed, 1 insertion(+), 22 deletions(-)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 8377e72..8bdf81a 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4780,25 +4780,6 @@ static void raid5_align_endio(struct bio *bi, int error)
add_bio_to_retry(raid_bi, conf);
}
-static int bio_fits_rdev(struct bio *bi)
-{
- struct request_queue *q = bdev_get_queue(bi->bi_bdev);
-
- if (bio_sectors(bi) > queue_max_sectors(q))
- return 0;
- blk_recount_segments(q, bi);
- if (bi->bi_phys_segments > queue_max_segments(q))
- return 0;
-
- if (q->merge_bvec_fn)
- /* it's too hard to apply the merge_bvec_fn at this stage,
- * just just give up
- */
- return 0;
-
- return 1;
-}
-
static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
{
struct r5conf *conf = mddev->private;
@@ -4852,11 +4833,9 @@ static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
align_bi->bi_bdev = rdev->bdev;
__clear_bit(BIO_SEG_VALID, &align_bi->bi_flags);
- if (!bio_fits_rdev(align_bi) ||
- is_badblock(rdev, align_bi->bi_iter.bi_sector,
+ if (is_badblock(rdev, align_bi->bi_iter.bi_sector,
bio_sectors(align_bi),
&first_bad, &bad_sectors)) {
- /* too big in some way, or has a known bad block */
bio_put(align_bi);
rdev_dec_pending(rdev, mddev);
return 0;
--
1.9.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH v5 08/11] block: kill merge_bvec_fn() completely
2015-07-06 7:11 [PATCH v5 00/11] simplify block layer based on immutable biovecs mlin
` (6 preceding siblings ...)
2015-07-06 7:11 ` [PATCH v5 07/11] md/raid5: get rid of bio_fits_rdev() mlin
@ 2015-07-06 7:11 ` mlin
2015-07-06 7:11 ` [PATCH v5 09/11] fs: use helper bio_add_page() instead of open coding on bi_io_vec mlin
` (3 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: mlin @ 2015-07-06 7:11 UTC (permalink / raw)
To: linux-kernel
Cc: Christoph Hellwig, Jens Axboe, Kent Overstreet, Dongsu Park,
Mike Snitzer, Ming Lin
From: Kent Overstreet <kent.overstreet@gmail.com>
As generic_make_request() is now able to handle arbitrarily sized bios,
it's no longer necessary for each individual block driver to define its
own ->merge_bvec_fn() callback. Remove every invocation completely.
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: drbd-user@lists.linbit.com
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Yehuda Sadeh <yehuda@inktank.com>
Cc: Sage Weil <sage@inktank.com>
Cc: Alex Elder <elder@kernel.org>
Cc: ceph-devel@vger.kernel.org
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: Neil Brown <neilb@suse.de>
Cc: linux-raid@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: NeilBrown <neilb@suse.de> (for the 'md' bits)
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[dpark: also remove ->merge_bvec_fn() in dm-thin as well as
dm-era-target, and resolve merge conflicts]
Signed-off-by: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
---
block/blk-merge.c | 17 +-----
block/blk-settings.c | 22 -------
drivers/block/drbd/drbd_int.h | 1 -
drivers/block/drbd/drbd_main.c | 1 -
drivers/block/drbd/drbd_req.c | 35 ------------
drivers/block/pktcdvd.c | 21 -------
drivers/block/rbd.c | 47 ---------------
drivers/md/dm-cache-target.c | 21 -------
drivers/md/dm-crypt.c | 16 ------
drivers/md/dm-era-target.c | 15 -----
drivers/md/dm-flakey.c | 16 ------
drivers/md/dm-linear.c | 16 ------
drivers/md/dm-log-writes.c | 16 ------
drivers/md/dm-raid.c | 19 ------
drivers/md/dm-snap.c | 15 -----
drivers/md/dm-stripe.c | 21 -------
drivers/md/dm-table.c | 8 ---
drivers/md/dm-thin.c | 31 ----------
drivers/md/dm-verity.c | 16 ------
drivers/md/dm.c | 127 +----------------------------------------
drivers/md/dm.h | 2 -
drivers/md/linear.c | 43 --------------
drivers/md/md.c | 26 ---------
drivers/md/md.h | 12 ----
drivers/md/multipath.c | 21 -------
drivers/md/raid0.c | 56 ------------------
drivers/md/raid0.h | 2 -
drivers/md/raid1.c | 58 +------------------
drivers/md/raid10.c | 121 +--------------------------------------
drivers/md/raid5.c | 32 -----------
include/linux/blkdev.h | 10 ----
include/linux/device-mapper.h | 4 --
32 files changed, 9 insertions(+), 859 deletions(-)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 3707f30..1f5dfa0 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -69,24 +69,13 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
struct bio *split;
struct bio_vec bv, bvprv;
struct bvec_iter iter;
- unsigned seg_size = 0, nsegs = 0;
+ unsigned seg_size = 0, nsegs = 0, sectors = 0;
int prev = 0;
- struct bvec_merge_data bvm = {
- .bi_bdev = bio->bi_bdev,
- .bi_sector = bio->bi_iter.bi_sector,
- .bi_size = 0,
- .bi_rw = bio->bi_rw,
- };
-
bio_for_each_segment(bv, bio, iter) {
- if (q->merge_bvec_fn &&
- q->merge_bvec_fn(q, &bvm, &bv) < (int) bv.bv_len)
- goto split;
-
- bvm.bi_size += bv.bv_len;
+ sectors += bv.bv_len >> 9;
- if (bvm.bi_size >> 9 > queue_max_sectors(q))
+ if (sectors > queue_max_sectors(q))
goto split;
/*
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 12600bf..e90d477 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -53,28 +53,6 @@ void blk_queue_unprep_rq(struct request_queue *q, unprep_rq_fn *ufn)
}
EXPORT_SYMBOL(blk_queue_unprep_rq);
-/**
- * blk_queue_merge_bvec - set a merge_bvec function for queue
- * @q: queue
- * @mbfn: merge_bvec_fn
- *
- * Usually queues have static limitations on the max sectors or segments that
- * we can put in a request. Stacking drivers may have some settings that
- * are dynamic, and thus we have to query the queue whether it is ok to
- * add a new bio_vec to a bio at a given offset or not. If the block device
- * has such limitations, it needs to register a merge_bvec_fn to control
- * the size of bio's sent to it. Note that a block device *must* allow a
- * single page to be added to an empty bio. The block device driver may want
- * to use the bio_split() function to deal with these bio's. By default
- * no merge_bvec_fn is defined for a queue, and only the fixed limits are
- * honored.
- */
-void blk_queue_merge_bvec(struct request_queue *q, merge_bvec_fn *mbfn)
-{
- q->merge_bvec_fn = mbfn;
-}
-EXPORT_SYMBOL(blk_queue_merge_bvec);
-
void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn)
{
q->softirq_done_fn = fn;
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index efd19c2..7ac66f3 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1450,7 +1450,6 @@ extern void do_submit(struct work_struct *ws);
extern void __drbd_make_request(struct drbd_device *, struct bio *, unsigned long);
extern void drbd_make_request(struct request_queue *q, struct bio *bio);
extern int drbd_read_remote(struct drbd_device *device, struct drbd_request *req);
-extern int drbd_merge_bvec(struct request_queue *q, struct bvec_merge_data *bvm, struct bio_vec *bvec);
extern int is_valid_ar_handle(struct drbd_request *, sector_t);
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index a151853..74d97f4 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2774,7 +2774,6 @@ enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsig
This triggers a max_bio_size message upon first attach or connect */
blk_queue_max_hw_sectors(q, DRBD_MAX_BIO_SIZE_SAFE >> 8);
blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
- blk_queue_merge_bvec(q, drbd_merge_bvec);
q->queue_lock = &resource->req_lock;
device->md_io.page = alloc_page(GFP_KERNEL);
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index a6265bc..7523f00 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -1510,41 +1510,6 @@ void drbd_make_request(struct request_queue *q, struct bio *bio)
__drbd_make_request(device, bio, start_jif);
}
-/* This is called by bio_add_page().
- *
- * q->max_hw_sectors and other global limits are already enforced there.
- *
- * We need to call down to our lower level device,
- * in case it has special restrictions.
- *
- * We also may need to enforce configured max-bio-bvecs limits.
- *
- * As long as the BIO is empty we have to allow at least one bvec,
- * regardless of size and offset, so no need to ask lower levels.
- */
-int drbd_merge_bvec(struct request_queue *q, struct bvec_merge_data *bvm, struct bio_vec *bvec)
-{
- struct drbd_device *device = (struct drbd_device *) q->queuedata;
- unsigned int bio_size = bvm->bi_size;
- int limit = DRBD_MAX_BIO_SIZE;
- int backing_limit;
-
- if (bio_size && get_ldev(device)) {
- unsigned int max_hw_sectors = queue_max_hw_sectors(q);
- struct request_queue * const b =
- device->ldev->backing_bdev->bd_disk->queue;
- if (b->merge_bvec_fn) {
- bvm->bi_bdev = device->ldev->backing_bdev;
- backing_limit = b->merge_bvec_fn(b, bvm, bvec);
- limit = min(limit, backing_limit);
- }
- put_ldev(device);
- if ((limit >> 9) > max_hw_sectors)
- limit = max_hw_sectors << 9;
- }
- return limit;
-}
-
void request_timer_fn(unsigned long data)
{
struct drbd_device *device = (struct drbd_device *) data;
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 05a81ae..190d7d7 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2506,26 +2506,6 @@ end_io:
-static int pkt_merge_bvec(struct request_queue *q, struct bvec_merge_data *bmd,
- struct bio_vec *bvec)
-{
- struct pktcdvd_device *pd = q->queuedata;
- sector_t zone = get_zone(bmd->bi_sector, pd);
- int used = ((bmd->bi_sector - zone) << 9) + bmd->bi_size;
- int remaining = (pd->settings.size << 9) - used;
- int remaining2;
-
- /*
- * A bio <= PAGE_SIZE must be allowed. If it crosses a packet
- * boundary, pkt_make_request() will split the bio.
- */
- remaining2 = PAGE_SIZE - bmd->bi_size;
- remaining = max(remaining, remaining2);
-
- BUG_ON(remaining < 0);
- return remaining;
-}
-
static void pkt_init_queue(struct pktcdvd_device *pd)
{
struct request_queue *q = pd->disk->queue;
@@ -2533,7 +2513,6 @@ static void pkt_init_queue(struct pktcdvd_device *pd)
blk_queue_make_request(q, pkt_make_request);
blk_queue_logical_block_size(q, CD_FRAMESIZE);
blk_queue_max_hw_sectors(q, PACKET_MAX_SECTORS);
- blk_queue_merge_bvec(q, pkt_merge_bvec);
q->queuedata = pd;
}
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index d94529d..055f9fa 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -3462,52 +3462,6 @@ static int rbd_queue_rq(struct blk_mq_hw_ctx *hctx,
return BLK_MQ_RQ_QUEUE_OK;
}
-/*
- * a queue callback. Makes sure that we don't create a bio that spans across
- * multiple osd objects. One exception would be with a single page bios,
- * which we handle later at bio_chain_clone_range()
- */
-static int rbd_merge_bvec(struct request_queue *q, struct bvec_merge_data *bmd,
- struct bio_vec *bvec)
-{
- struct rbd_device *rbd_dev = q->queuedata;
- sector_t sector_offset;
- sector_t sectors_per_obj;
- sector_t obj_sector_offset;
- int ret;
-
- /*
- * Find how far into its rbd object the partition-relative
- * bio start sector is to offset relative to the enclosing
- * device.
- */
- sector_offset = get_start_sect(bmd->bi_bdev) + bmd->bi_sector;
- sectors_per_obj = 1 << (rbd_dev->header.obj_order - SECTOR_SHIFT);
- obj_sector_offset = sector_offset & (sectors_per_obj - 1);
-
- /*
- * Compute the number of bytes from that offset to the end
- * of the object. Account for what's already used by the bio.
- */
- ret = (int) (sectors_per_obj - obj_sector_offset) << SECTOR_SHIFT;
- if (ret > bmd->bi_size)
- ret -= bmd->bi_size;
- else
- ret = 0;
-
- /*
- * Don't send back more than was asked for. And if the bio
- * was empty, let the whole thing through because: "Note
- * that a block device *must* allow a single page to be
- * added to an empty bio."
- */
- rbd_assert(bvec->bv_len <= PAGE_SIZE);
- if (ret > (int) bvec->bv_len || !bmd->bi_size)
- ret = (int) bvec->bv_len;
-
- return ret;
-}
-
static void rbd_free_disk(struct rbd_device *rbd_dev)
{
struct gendisk *disk = rbd_dev->disk;
@@ -3806,7 +3760,6 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
q->limits.max_discard_sectors = segment_size / SECTOR_SIZE;
q->limits.discard_zeroes_data = 1;
- blk_queue_merge_bvec(q, rbd_merge_bvec);
disk->queue = q;
q->queuedata = rbd_dev;
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 1b4e175..256e54c 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -3769,26 +3769,6 @@ static int cache_iterate_devices(struct dm_target *ti,
return r;
}
-/*
- * We assume I/O is going to the origin (which is the volume
- * more likely to have restrictions e.g. by being striped).
- * (Looking up the exact location of the data would be expensive
- * and could always be out of date by the time the bio is submitted.)
- */
-static int cache_bvec_merge(struct dm_target *ti,
- struct bvec_merge_data *bvm,
- struct bio_vec *biovec, int max_size)
-{
- struct cache *cache = ti->private;
- struct request_queue *q = bdev_get_queue(cache->origin_dev->bdev);
-
- if (!q->merge_bvec_fn)
- return max_size;
-
- bvm->bi_bdev = cache->origin_dev->bdev;
- return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
-}
-
static void set_discard_limits(struct cache *cache, struct queue_limits *limits)
{
/*
@@ -3832,7 +3812,6 @@ static struct target_type cache_target = {
.status = cache_status,
.message = cache_message,
.iterate_devices = cache_iterate_devices,
- .merge = cache_bvec_merge,
.io_hints = cache_io_hints,
};
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 0f48fed..a1f1d09 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -2035,21 +2035,6 @@ error:
return -EINVAL;
}
-static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
- struct bio_vec *biovec, int max_size)
-{
- struct crypt_config *cc = ti->private;
- struct request_queue *q = bdev_get_queue(cc->dev->bdev);
-
- if (!q->merge_bvec_fn)
- return max_size;
-
- bvm->bi_bdev = cc->dev->bdev;
- bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector);
-
- return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
-}
-
static int crypt_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data)
{
@@ -2070,7 +2055,6 @@ static struct target_type crypt_target = {
.preresume = crypt_preresume,
.resume = crypt_resume,
.message = crypt_message,
- .merge = crypt_merge,
.iterate_devices = crypt_iterate_devices,
};
diff --git a/drivers/md/dm-era-target.c b/drivers/md/dm-era-target.c
index ad913cd..0119ebf 100644
--- a/drivers/md/dm-era-target.c
+++ b/drivers/md/dm-era-target.c
@@ -1673,20 +1673,6 @@ static int era_iterate_devices(struct dm_target *ti,
return fn(ti, era->origin_dev, 0, get_dev_size(era->origin_dev), data);
}
-static int era_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
- struct bio_vec *biovec, int max_size)
-{
- struct era *era = ti->private;
- struct request_queue *q = bdev_get_queue(era->origin_dev->bdev);
-
- if (!q->merge_bvec_fn)
- return max_size;
-
- bvm->bi_bdev = era->origin_dev->bdev;
-
- return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
-}
-
static void era_io_hints(struct dm_target *ti, struct queue_limits *limits)
{
struct era *era = ti->private;
@@ -1717,7 +1703,6 @@ static struct target_type era_target = {
.status = era_status,
.message = era_message,
.iterate_devices = era_iterate_devices,
- .merge = era_merge,
.io_hints = era_io_hints
};
diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
index b257e46..d955b3e 100644
--- a/drivers/md/dm-flakey.c
+++ b/drivers/md/dm-flakey.c
@@ -387,21 +387,6 @@ static int flakey_ioctl(struct dm_target *ti, unsigned int cmd, unsigned long ar
return r ? : __blkdev_driver_ioctl(dev->bdev, dev->mode, cmd, arg);
}
-static int flakey_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
- struct bio_vec *biovec, int max_size)
-{
- struct flakey_c *fc = ti->private;
- struct request_queue *q = bdev_get_queue(fc->dev->bdev);
-
- if (!q->merge_bvec_fn)
- return max_size;
-
- bvm->bi_bdev = fc->dev->bdev;
- bvm->bi_sector = flakey_map_sector(ti, bvm->bi_sector);
-
- return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
-}
-
static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
{
struct flakey_c *fc = ti->private;
@@ -419,7 +404,6 @@ static struct target_type flakey_target = {
.end_io = flakey_end_io,
.status = flakey_status,
.ioctl = flakey_ioctl,
- .merge = flakey_merge,
.iterate_devices = flakey_iterate_devices,
};
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index 53e848c..7dd5fc8 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -130,21 +130,6 @@ static int linear_ioctl(struct dm_target *ti, unsigned int cmd,
return r ? : __blkdev_driver_ioctl(dev->bdev, dev->mode, cmd, arg);
}
-static int linear_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
- struct bio_vec *biovec, int max_size)
-{
- struct linear_c *lc = ti->private;
- struct request_queue *q = bdev_get_queue(lc->dev->bdev);
-
- if (!q->merge_bvec_fn)
- return max_size;
-
- bvm->bi_bdev = lc->dev->bdev;
- bvm->bi_sector = linear_map_sector(ti, bvm->bi_sector);
-
- return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
-}
-
static int linear_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data)
{
@@ -162,7 +147,6 @@ static struct target_type linear_target = {
.map = linear_map,
.status = linear_status,
.ioctl = linear_ioctl,
- .merge = linear_merge,
.iterate_devices = linear_iterate_devices,
};
diff --git a/drivers/md/dm-log-writes.c b/drivers/md/dm-log-writes.c
index ad1b049..883595c 100644
--- a/drivers/md/dm-log-writes.c
+++ b/drivers/md/dm-log-writes.c
@@ -728,21 +728,6 @@ static int log_writes_ioctl(struct dm_target *ti, unsigned int cmd,
return r ? : __blkdev_driver_ioctl(dev->bdev, dev->mode, cmd, arg);
}
-static int log_writes_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
- struct bio_vec *biovec, int max_size)
-{
- struct log_writes_c *lc = ti->private;
- struct request_queue *q = bdev_get_queue(lc->dev->bdev);
-
- if (!q->merge_bvec_fn)
- return max_size;
-
- bvm->bi_bdev = lc->dev->bdev;
- bvm->bi_sector = dm_target_offset(ti, bvm->bi_sector);
-
- return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
-}
-
static int log_writes_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn,
void *data)
@@ -796,7 +781,6 @@ static struct target_type log_writes_target = {
.end_io = normal_end_io,
.status = log_writes_status,
.ioctl = log_writes_ioctl,
- .merge = log_writes_merge,
.message = log_writes_message,
.iterate_devices = log_writes_iterate_devices,
.io_hints = log_writes_io_hints,
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 2daa677..97e1651 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -1717,24 +1717,6 @@ static void raid_resume(struct dm_target *ti)
mddev_resume(&rs->md);
}
-static int raid_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
- struct bio_vec *biovec, int max_size)
-{
- struct raid_set *rs = ti->private;
- struct md_personality *pers = rs->md.pers;
-
- if (pers && pers->mergeable_bvec)
- return min(max_size, pers->mergeable_bvec(&rs->md, bvm, biovec));
-
- /*
- * In case we can't request the personality because
- * the raid set is not running yet
- *
- * -> return safe minimum
- */
- return rs->md.chunk_sectors;
-}
-
static struct target_type raid_target = {
.name = "raid",
.version = {1, 7, 0},
@@ -1749,7 +1731,6 @@ static struct target_type raid_target = {
.presuspend = raid_presuspend,
.postsuspend = raid_postsuspend,
.resume = raid_resume,
- .merge = raid_merge,
};
static int __init dm_raid_init(void)
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 7c82d3c..eabc805 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -2330,20 +2330,6 @@ static void origin_status(struct dm_target *ti, status_type_t type,
}
}
-static int origin_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
- struct bio_vec *biovec, int max_size)
-{
- struct dm_origin *o = ti->private;
- struct request_queue *q = bdev_get_queue(o->dev->bdev);
-
- if (!q->merge_bvec_fn)
- return max_size;
-
- bvm->bi_bdev = o->dev->bdev;
-
- return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
-}
-
static int origin_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data)
{
@@ -2362,7 +2348,6 @@ static struct target_type origin_target = {
.resume = origin_resume,
.postsuspend = origin_postsuspend,
.status = origin_status,
- .merge = origin_merge,
.iterate_devices = origin_iterate_devices,
};
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index a672a15..c7c8ced 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -412,26 +412,6 @@ static void stripe_io_hints(struct dm_target *ti,
blk_limits_io_opt(limits, chunk_size * sc->stripes);
}
-static int stripe_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
- struct bio_vec *biovec, int max_size)
-{
- struct stripe_c *sc = ti->private;
- sector_t bvm_sector = bvm->bi_sector;
- uint32_t stripe;
- struct request_queue *q;
-
- stripe_map_sector(sc, bvm_sector, &stripe, &bvm_sector);
-
- q = bdev_get_queue(sc->stripe[stripe].dev->bdev);
- if (!q->merge_bvec_fn)
- return max_size;
-
- bvm->bi_bdev = sc->stripe[stripe].dev->bdev;
- bvm->bi_sector = sc->stripe[stripe].physical_start + bvm_sector;
-
- return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
-}
-
static struct target_type stripe_target = {
.name = "striped",
.version = {1, 5, 1},
@@ -443,7 +423,6 @@ static struct target_type stripe_target = {
.status = stripe_status,
.iterate_devices = stripe_iterate_devices,
.io_hints = stripe_io_hints,
- .merge = stripe_merge,
};
int __init dm_stripe_init(void)
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 16ba55a..afb4ad3 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -440,14 +440,6 @@ static int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
q->limits.alignment_offset,
(unsigned long long) start << SECTOR_SHIFT);
- /*
- * Check if merge fn is supported.
- * If not we'll force DM to use PAGE_SIZE or
- * smaller I/O, just to be safe.
- */
- if (dm_queue_merge_is_compulsory(q) && !ti->type->merge)
- blk_limits_max_hw_sectors(limits,
- (unsigned int) (PAGE_SIZE >> 9));
return 0;
}
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index c33f61a..37ef8b8 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -3840,20 +3840,6 @@ static int pool_iterate_devices(struct dm_target *ti,
return fn(ti, pt->data_dev, 0, ti->len, data);
}
-static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
- struct bio_vec *biovec, int max_size)
-{
- struct pool_c *pt = ti->private;
- struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
-
- if (!q->merge_bvec_fn)
- return max_size;
-
- bvm->bi_bdev = pt->data_dev->bdev;
-
- return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
-}
-
static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits)
{
struct pool_c *pt = ti->private;
@@ -3930,7 +3916,6 @@ static struct target_type pool_target = {
.resume = pool_resume,
.message = pool_message,
.status = pool_status,
- .merge = pool_merge,
.iterate_devices = pool_iterate_devices,
.io_hints = pool_io_hints,
};
@@ -4257,21 +4242,6 @@ err:
DMEMIT("Error");
}
-static int thin_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
- struct bio_vec *biovec, int max_size)
-{
- struct thin_c *tc = ti->private;
- struct request_queue *q = bdev_get_queue(tc->pool_dev->bdev);
-
- if (!q->merge_bvec_fn)
- return max_size;
-
- bvm->bi_bdev = tc->pool_dev->bdev;
- bvm->bi_sector = dm_target_offset(ti, bvm->bi_sector);
-
- return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
-}
-
static int thin_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data)
{
@@ -4315,7 +4285,6 @@ static struct target_type thin_target = {
.presuspend = thin_presuspend,
.postsuspend = thin_postsuspend,
.status = thin_status,
- .merge = thin_merge,
.iterate_devices = thin_iterate_devices,
.io_hints = thin_io_hints,
};
diff --git a/drivers/md/dm-verity.c b/drivers/md/dm-verity.c
index bb9c6a0..4f2cdd9 100644
--- a/drivers/md/dm-verity.c
+++ b/drivers/md/dm-verity.c
@@ -648,21 +648,6 @@ static int verity_ioctl(struct dm_target *ti, unsigned cmd,
cmd, arg);
}
-static int verity_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
- struct bio_vec *biovec, int max_size)
-{
- struct dm_verity *v = ti->private;
- struct request_queue *q = bdev_get_queue(v->data_dev->bdev);
-
- if (!q->merge_bvec_fn)
- return max_size;
-
- bvm->bi_bdev = v->data_dev->bdev;
- bvm->bi_sector = verity_map_sector(v, bvm->bi_sector);
-
- return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
-}
-
static int verity_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data)
{
@@ -995,7 +980,6 @@ static struct target_type verity_target = {
.map = verity_map,
.status = verity_status,
.ioctl = verity_ioctl,
- .merge = verity_merge,
.iterate_devices = verity_iterate_devices,
.io_hints = verity_io_hints,
};
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 530fc9a..c5d0d19 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -124,9 +124,8 @@ EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
#define DMF_FREEING 3
#define DMF_DELETING 4
#define DMF_NOFLUSH_SUSPENDING 5
-#define DMF_MERGE_IS_OPTIONAL 6
-#define DMF_DEFERRED_REMOVE 7
-#define DMF_SUSPENDED_INTERNALLY 8
+#define DMF_DEFERRED_REMOVE 6
+#define DMF_SUSPENDED_INTERNALLY 7
/*
* A dummy definition to make RCU happy.
@@ -1726,67 +1725,6 @@ static void __split_and_process_bio(struct mapped_device *md,
* CRUD END
*---------------------------------------------------------------*/
-static int dm_merge_bvec(struct request_queue *q,
- struct bvec_merge_data *bvm,
- struct bio_vec *biovec)
-{
- struct mapped_device *md = q->queuedata;
- struct dm_table *map = dm_get_live_table_fast(md);
- struct dm_target *ti;
- sector_t max_sectors, max_size = 0;
-
- if (unlikely(!map))
- goto out;
-
- ti = dm_table_find_target(map, bvm->bi_sector);
- if (!dm_target_is_valid(ti))
- goto out;
-
- /*
- * Find maximum amount of I/O that won't need splitting
- */
- max_sectors = min(max_io_len(bvm->bi_sector, ti),
- (sector_t) queue_max_sectors(q));
- max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
-
- /*
- * FIXME: this stop-gap fix _must_ be cleaned up (by passing a sector_t
- * to the targets' merge function since it holds sectors not bytes).
- * Just doing this as an interim fix for stable@ because the more
- * comprehensive cleanup of switching to sector_t will impact every
- * DM target that implements a ->merge hook.
- */
- if (max_size > INT_MAX)
- max_size = INT_MAX;
-
- /*
- * merge_bvec_fn() returns number of bytes
- * it can accept at this offset
- * max is precomputed maximal io size
- */
- if (max_size && ti->type->merge)
- max_size = ti->type->merge(ti, bvm, biovec, (int) max_size);
- /*
- * If the target doesn't support merge method and some of the devices
- * provided their merge_bvec method (we know this by looking for the
- * max_hw_sectors that dm_set_device_limits may set), then we can't
- * allow bios with multiple vector entries. So always set max_size
- * to 0, and the code below allows just one page.
- */
- else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9)
- max_size = 0;
-
-out:
- dm_put_live_table_fast(md);
- /*
- * Always allow an entire first page
- */
- if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
- max_size = biovec->bv_len;
-
- return max_size;
-}
-
/*
* The request function that just remaps the bio built up by
* dm_merge_bvec.
@@ -2509,59 +2447,6 @@ static void __set_size(struct mapped_device *md, sector_t size)
}
/*
- * Return 1 if the queue has a compulsory merge_bvec_fn function.
- *
- * If this function returns 0, then the device is either a non-dm
- * device without a merge_bvec_fn, or it is a dm device that is
- * able to split any bios it receives that are too big.
- */
-int dm_queue_merge_is_compulsory(struct request_queue *q)
-{
- struct mapped_device *dev_md;
-
- if (!q->merge_bvec_fn)
- return 0;
-
- if (q->make_request_fn == dm_make_request) {
- dev_md = q->queuedata;
- if (test_bit(DMF_MERGE_IS_OPTIONAL, &dev_md->flags))
- return 0;
- }
-
- return 1;
-}
-
-static int dm_device_merge_is_compulsory(struct dm_target *ti,
- struct dm_dev *dev, sector_t start,
- sector_t len, void *data)
-{
- struct block_device *bdev = dev->bdev;
- struct request_queue *q = bdev_get_queue(bdev);
-
- return dm_queue_merge_is_compulsory(q);
-}
-
-/*
- * Return 1 if it is acceptable to ignore merge_bvec_fn based
- * on the properties of the underlying devices.
- */
-static int dm_table_merge_is_optional(struct dm_table *table)
-{
- unsigned i = 0;
- struct dm_target *ti;
-
- while (i < dm_table_get_num_targets(table)) {
- ti = dm_table_get_target(table, i++);
-
- if (ti->type->iterate_devices &&
- ti->type->iterate_devices(ti, dm_device_merge_is_compulsory, NULL))
- return 0;
- }
-
- return 1;
-}
-
-/*
* Returns old map, which caller must destroy.
*/
static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
@@ -2570,7 +2455,6 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
struct dm_table *old_map;
struct request_queue *q = md->queue;
sector_t size;
- int merge_is_optional;
size = dm_table_get_size(t);
@@ -2596,17 +2480,11 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
__bind_mempools(md, t);
- merge_is_optional = dm_table_merge_is_optional(t);
-
old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
rcu_assign_pointer(md->map, t);
md->immutable_target_type = dm_table_get_immutable_target_type(t);
dm_table_set_restrictions(t, q, limits);
- if (merge_is_optional)
- set_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
- else
- clear_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
if (old_map)
dm_sync_table(md);
@@ -2887,7 +2765,6 @@ int dm_setup_md_queue(struct mapped_device *md)
case DM_TYPE_BIO_BASED:
dm_init_old_md_queue(md);
blk_queue_make_request(md->queue, dm_make_request);
- blk_queue_merge_bvec(md->queue, dm_merge_bvec);
break;
}
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 4e98499..7edcf97 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -78,8 +78,6 @@ bool dm_table_mq_request_based(struct dm_table *t);
void dm_table_free_md_mempools(struct dm_table *t);
struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t);
-int dm_queue_merge_is_compulsory(struct request_queue *q);
-
void dm_lock_md_type(struct mapped_device *md);
void dm_unlock_md_type(struct mapped_device *md);
void dm_set_md_type(struct mapped_device *md, unsigned type);
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index fa7d577..8721ef9 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -52,48 +52,6 @@ static inline struct dev_info *which_dev(struct mddev *mddev, sector_t sector)
return conf->disks + lo;
}
-/**
- * linear_mergeable_bvec -- tell bio layer if two requests can be merged
- * @q: request queue
- * @bvm: properties of new bio
- * @biovec: the request that could be merged to it.
- *
- * Return amount of bytes we can take at this offset
- */
-static int linear_mergeable_bvec(struct mddev *mddev,
- struct bvec_merge_data *bvm,
- struct bio_vec *biovec)
-{
- struct dev_info *dev0;
- unsigned long maxsectors, bio_sectors = bvm->bi_size >> 9;
- sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
- int maxbytes = biovec->bv_len;
- struct request_queue *subq;
-
- dev0 = which_dev(mddev, sector);
- maxsectors = dev0->end_sector - sector;
- subq = bdev_get_queue(dev0->rdev->bdev);
- if (subq->merge_bvec_fn) {
- bvm->bi_bdev = dev0->rdev->bdev;
- bvm->bi_sector -= dev0->end_sector - dev0->rdev->sectors;
- maxbytes = min(maxbytes, subq->merge_bvec_fn(subq, bvm,
- biovec));
- }
-
- if (maxsectors < bio_sectors)
- maxsectors = 0;
- else
- maxsectors -= bio_sectors;
-
- if (maxsectors <= (PAGE_SIZE >> 9 ) && bio_sectors == 0)
- return maxbytes;
-
- if (maxsectors > (maxbytes >> 9))
- return maxbytes;
- else
- return maxsectors << 9;
-}
-
static int linear_congested(struct mddev *mddev, int bits)
{
struct linear_conf *conf;
@@ -338,7 +296,6 @@ static struct md_personality linear_personality =
.size = linear_size,
.quiesce = linear_quiesce,
.congested = linear_congested,
- .mergeable_bvec = linear_mergeable_bvec,
};
static int __init linear_init (void)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 10bf6d4..a4aa6e5 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -352,29 +352,6 @@ static int md_congested(void *data, int bits)
return mddev_congested(mddev, bits);
}
-static int md_mergeable_bvec(struct request_queue *q,
- struct bvec_merge_data *bvm,
- struct bio_vec *biovec)
-{
- struct mddev *mddev = q->queuedata;
- int ret;
- rcu_read_lock();
- if (mddev->suspended) {
- /* Must always allow one vec */
- if (bvm->bi_size == 0)
- ret = biovec->bv_len;
- else
- ret = 0;
- } else {
- struct md_personality *pers = mddev->pers;
- if (pers && pers->mergeable_bvec)
- ret = pers->mergeable_bvec(mddev, bvm, biovec);
- else
- ret = biovec->bv_len;
- }
- rcu_read_unlock();
- return ret;
-}
/*
* Generic flush handling for md
*/
@@ -5188,7 +5165,6 @@ int md_run(struct mddev *mddev)
if (mddev->queue) {
mddev->queue->backing_dev_info.congested_data = mddev;
mddev->queue->backing_dev_info.congested_fn = md_congested;
- blk_queue_merge_bvec(mddev->queue, md_mergeable_bvec);
}
if (pers->sync_request) {
if (mddev->kobj.sd &&
@@ -5317,7 +5293,6 @@ static void md_clean(struct mddev *mddev)
mddev->degraded = 0;
mddev->safemode = 0;
mddev->private = NULL;
- mddev->merge_check_needed = 0;
mddev->bitmap_info.offset = 0;
mddev->bitmap_info.default_offset = 0;
mddev->bitmap_info.default_space = 0;
@@ -5514,7 +5489,6 @@ static int do_md_stop(struct mddev *mddev, int mode,
__md_stop_writes(mddev);
__md_stop(mddev);
- mddev->queue->merge_bvec_fn = NULL;
mddev->queue->backing_dev_info.congested_fn = NULL;
/* tell userspace to handle 'inactive' */
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 7da6e9c..ab33957 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -134,10 +134,6 @@ enum flag_bits {
Bitmap_sync, /* ..actually, not quite In_sync. Need a
* bitmap-based recovery to get fully in sync
*/
- Unmerged, /* device is being added to array and should
- * be considerred for bvec_merge_fn but not
- * yet for actual IO
- */
WriteMostly, /* Avoid reading if at all possible */
AutoDetected, /* added by auto-detect */
Blocked, /* An error occurred but has not yet
@@ -374,10 +370,6 @@ struct mddev {
int degraded; /* whether md should consider
* adding a spare
*/
- int merge_check_needed; /* at least one
- * member device
- * has a
- * merge_bvec_fn */
atomic_t recovery_active; /* blocks scheduled, but not written */
wait_queue_head_t recovery_wait;
@@ -532,10 +524,6 @@ struct md_personality
/* congested implements bdi.congested_fn().
* Will not be called while array is 'suspended' */
int (*congested)(struct mddev *mddev, int bits);
- /* mergeable_bvec is use to implement ->merge_bvec_fn */
- int (*mergeable_bvec)(struct mddev *mddev,
- struct bvec_merge_data *bvm,
- struct bio_vec *biovec);
};
struct md_sysfs_entry {
diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index ac3ede2..7ee27fb 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -257,18 +257,6 @@ static int multipath_add_disk(struct mddev *mddev, struct md_rdev *rdev)
disk_stack_limits(mddev->gendisk, rdev->bdev,
rdev->data_offset << 9);
- /* as we don't honour merge_bvec_fn, we must never risk
- * violating it, so limit ->max_segments to one, lying
- * within a single page.
- * (Note: it is very unlikely that a device with
- * merge_bvec_fn will be involved in multipath.)
- */
- if (q->merge_bvec_fn) {
- blk_queue_max_segments(mddev->queue, 1);
- blk_queue_segment_boundary(mddev->queue,
- PAGE_CACHE_SIZE - 1);
- }
-
spin_lock_irq(&conf->device_lock);
mddev->degraded--;
rdev->raid_disk = path;
@@ -432,15 +420,6 @@ static int multipath_run (struct mddev *mddev)
disk_stack_limits(mddev->gendisk, rdev->bdev,
rdev->data_offset << 9);
- /* as we don't honour merge_bvec_fn, we must never risk
- * violating it, not that we ever expect a device with
- * a merge_bvec_fn to be involved in multipath */
- if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
- blk_queue_max_segments(mddev->queue, 1);
- blk_queue_segment_boundary(mddev->queue,
- PAGE_CACHE_SIZE - 1);
- }
-
if (!test_bit(Faulty, &rdev->flags))
working_disks++;
}
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index efb654e..c853331 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -192,9 +192,6 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
disk_stack_limits(mddev->gendisk, rdev1->bdev,
rdev1->data_offset << 9);
- if (rdev1->bdev->bd_disk->queue->merge_bvec_fn)
- conf->has_merge_bvec = 1;
-
if (!smallest || (rdev1->sectors < smallest->sectors))
smallest = rdev1;
cnt++;
@@ -351,58 +348,6 @@ static struct md_rdev *map_sector(struct mddev *mddev, struct strip_zone *zone,
+ sector_div(sector, zone->nb_dev)];
}
-/**
- * raid0_mergeable_bvec -- tell bio layer if two requests can be merged
- * @mddev: the md device
- * @bvm: properties of new bio
- * @biovec: the request that could be merged to it.
- *
- * Return amount of bytes we can accept at this offset
- */
-static int raid0_mergeable_bvec(struct mddev *mddev,
- struct bvec_merge_data *bvm,
- struct bio_vec *biovec)
-{
- struct r0conf *conf = mddev->private;
- sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
- sector_t sector_offset = sector;
- int max;
- unsigned int chunk_sectors = mddev->chunk_sectors;
- unsigned int bio_sectors = bvm->bi_size >> 9;
- struct strip_zone *zone;
- struct md_rdev *rdev;
- struct request_queue *subq;
-
- if (is_power_of_2(chunk_sectors))
- max = (chunk_sectors - ((sector & (chunk_sectors-1))
- + bio_sectors)) << 9;
- else
- max = (chunk_sectors - (sector_div(sector, chunk_sectors)
- + bio_sectors)) << 9;
- if (max < 0)
- max = 0; /* bio_add cannot handle a negative return */
- if (max <= biovec->bv_len && bio_sectors == 0)
- return biovec->bv_len;
- if (max < biovec->bv_len)
- /* too small already, no need to check further */
- return max;
- if (!conf->has_merge_bvec)
- return max;
-
- /* May need to check subordinate device */
- sector = sector_offset;
- zone = find_zone(mddev->private, §or_offset);
- rdev = map_sector(mddev, zone, sector, §or_offset);
- subq = bdev_get_queue(rdev->bdev);
- if (subq->merge_bvec_fn) {
- bvm->bi_bdev = rdev->bdev;
- bvm->bi_sector = sector_offset + zone->dev_start +
- rdev->data_offset;
- return min(max, subq->merge_bvec_fn(subq, bvm, biovec));
- } else
- return max;
-}
-
static sector_t raid0_size(struct mddev *mddev, sector_t sectors, int raid_disks)
{
sector_t array_sectors = 0;
@@ -727,7 +672,6 @@ static struct md_personality raid0_personality=
.takeover = raid0_takeover,
.quiesce = raid0_quiesce,
.congested = raid0_congested,
- .mergeable_bvec = raid0_mergeable_bvec,
};
static int __init raid0_init (void)
diff --git a/drivers/md/raid0.h b/drivers/md/raid0.h
index 05539d9..7127a62 100644
--- a/drivers/md/raid0.h
+++ b/drivers/md/raid0.h
@@ -12,8 +12,6 @@ struct r0conf {
struct md_rdev **devlist; /* lists of rdevs, pointed to
* by strip_zone->dev */
int nr_strip_zones;
- int has_merge_bvec; /* at least one member has
- * a merge_bvec_fn */
};
#endif
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index f80f1af..bb90edb 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -557,7 +557,6 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
rdev = rcu_dereference(conf->mirrors[disk].rdev);
if (r1_bio->bios[disk] == IO_BLOCKED
|| rdev == NULL
- || test_bit(Unmerged, &rdev->flags)
|| test_bit(Faulty, &rdev->flags))
continue;
if (!test_bit(In_sync, &rdev->flags) &&
@@ -708,38 +707,6 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
return best_disk;
}
-static int raid1_mergeable_bvec(struct mddev *mddev,
- struct bvec_merge_data *bvm,
- struct bio_vec *biovec)
-{
- struct r1conf *conf = mddev->private;
- sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
- int max = biovec->bv_len;
-
- if (mddev->merge_check_needed) {
- int disk;
- rcu_read_lock();
- for (disk = 0; disk < conf->raid_disks * 2; disk++) {
- struct md_rdev *rdev = rcu_dereference(
- conf->mirrors[disk].rdev);
- if (rdev && !test_bit(Faulty, &rdev->flags)) {
- struct request_queue *q =
- bdev_get_queue(rdev->bdev);
- if (q->merge_bvec_fn) {
- bvm->bi_sector = sector +
- rdev->data_offset;
- bvm->bi_bdev = rdev->bdev;
- max = min(max, q->merge_bvec_fn(
- q, bvm, biovec));
- }
- }
- }
- rcu_read_unlock();
- }
- return max;
-
-}
-
static int raid1_congested(struct mddev *mddev, int bits)
{
struct r1conf *conf = mddev->private;
@@ -1268,8 +1235,7 @@ read_again:
break;
}
r1_bio->bios[i] = NULL;
- if (!rdev || test_bit(Faulty, &rdev->flags)
- || test_bit(Unmerged, &rdev->flags)) {
+ if (!rdev || test_bit(Faulty, &rdev->flags)) {
if (i < conf->raid_disks)
set_bit(R1BIO_Degraded, &r1_bio->state);
continue;
@@ -1614,7 +1580,6 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
struct raid1_info *p;
int first = 0;
int last = conf->raid_disks - 1;
- struct request_queue *q = bdev_get_queue(rdev->bdev);
if (mddev->recovery_disabled == conf->recovery_disabled)
return -EBUSY;
@@ -1622,11 +1587,6 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
if (rdev->raid_disk >= 0)
first = last = rdev->raid_disk;
- if (q->merge_bvec_fn) {
- set_bit(Unmerged, &rdev->flags);
- mddev->merge_check_needed = 1;
- }
-
for (mirror = first; mirror <= last; mirror++) {
p = conf->mirrors+mirror;
if (!p->rdev) {
@@ -1658,19 +1618,6 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
break;
}
}
- if (err == 0 && test_bit(Unmerged, &rdev->flags)) {
- /* Some requests might not have seen this new
- * merge_bvec_fn. We must wait for them to complete
- * before merging the device fully.
- * First we make sure any code which has tested
- * our function has submitted the request, then
- * we wait for all outstanding requests to complete.
- */
- synchronize_sched();
- freeze_array(conf, 0);
- unfreeze_array(conf);
- clear_bit(Unmerged, &rdev->flags);
- }
md_integrity_add_rdev(rdev, mddev);
if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
@@ -2807,8 +2754,6 @@ static struct r1conf *setup_conf(struct mddev *mddev)
goto abort;
disk->rdev = rdev;
q = bdev_get_queue(rdev->bdev);
- if (q->merge_bvec_fn)
- mddev->merge_check_needed = 1;
disk->head_position = 0;
disk->seq_start = MaxSector;
@@ -3173,7 +3118,6 @@ static struct md_personality raid1_personality =
.quiesce = raid1_quiesce,
.takeover = raid1_takeover,
.congested = raid1_congested,
- .mergeable_bvec = raid1_mergeable_bvec,
};
static int __init raid_init(void)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 940f2f3..84cb6bc 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -672,93 +672,6 @@ static sector_t raid10_find_virt(struct r10conf *conf, sector_t sector, int dev)
return (vchunk << geo->chunk_shift) + offset;
}
-/**
- * raid10_mergeable_bvec -- tell bio layer if a two requests can be merged
- * @mddev: the md device
- * @bvm: properties of new bio
- * @biovec: the request that could be merged to it.
- *
- * Return amount of bytes we can accept at this offset
- * This requires checking for end-of-chunk if near_copies != raid_disks,
- * and for subordinate merge_bvec_fns if merge_check_needed.
- */
-static int raid10_mergeable_bvec(struct mddev *mddev,
- struct bvec_merge_data *bvm,
- struct bio_vec *biovec)
-{
- struct r10conf *conf = mddev->private;
- sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
- int max;
- unsigned int chunk_sectors;
- unsigned int bio_sectors = bvm->bi_size >> 9;
- struct geom *geo = &conf->geo;
-
- chunk_sectors = (conf->geo.chunk_mask & conf->prev.chunk_mask) + 1;
- if (conf->reshape_progress != MaxSector &&
- ((sector >= conf->reshape_progress) !=
- conf->mddev->reshape_backwards))
- geo = &conf->prev;
-
- if (geo->near_copies < geo->raid_disks) {
- max = (chunk_sectors - ((sector & (chunk_sectors - 1))
- + bio_sectors)) << 9;
- if (max < 0)
- /* bio_add cannot handle a negative return */
- max = 0;
- if (max <= biovec->bv_len && bio_sectors == 0)
- return biovec->bv_len;
- } else
- max = biovec->bv_len;
-
- if (mddev->merge_check_needed) {
- struct {
- struct r10bio r10_bio;
- struct r10dev devs[conf->copies];
- } on_stack;
- struct r10bio *r10_bio = &on_stack.r10_bio;
- int s;
- if (conf->reshape_progress != MaxSector) {
- /* Cannot give any guidance during reshape */
- if (max <= biovec->bv_len && bio_sectors == 0)
- return biovec->bv_len;
- return 0;
- }
- r10_bio->sector = sector;
- raid10_find_phys(conf, r10_bio);
- rcu_read_lock();
- for (s = 0; s < conf->copies; s++) {
- int disk = r10_bio->devs[s].devnum;
- struct md_rdev *rdev = rcu_dereference(
- conf->mirrors[disk].rdev);
- if (rdev && !test_bit(Faulty, &rdev->flags)) {
- struct request_queue *q =
- bdev_get_queue(rdev->bdev);
- if (q->merge_bvec_fn) {
- bvm->bi_sector = r10_bio->devs[s].addr
- + rdev->data_offset;
- bvm->bi_bdev = rdev->bdev;
- max = min(max, q->merge_bvec_fn(
- q, bvm, biovec));
- }
- }
- rdev = rcu_dereference(conf->mirrors[disk].replacement);
- if (rdev && !test_bit(Faulty, &rdev->flags)) {
- struct request_queue *q =
- bdev_get_queue(rdev->bdev);
- if (q->merge_bvec_fn) {
- bvm->bi_sector = r10_bio->devs[s].addr
- + rdev->data_offset;
- bvm->bi_bdev = rdev->bdev;
- max = min(max, q->merge_bvec_fn(
- q, bvm, biovec));
- }
- }
- }
- rcu_read_unlock();
- }
- return max;
-}
-
/*
* This routine returns the disk from which the requested read should
* be done. There is a per-array 'next expected sequential IO' sector
@@ -821,12 +734,10 @@ retry:
disk = r10_bio->devs[slot].devnum;
rdev = rcu_dereference(conf->mirrors[disk].replacement);
if (rdev == NULL || test_bit(Faulty, &rdev->flags) ||
- test_bit(Unmerged, &rdev->flags) ||
r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
rdev = rcu_dereference(conf->mirrors[disk].rdev);
if (rdev == NULL ||
- test_bit(Faulty, &rdev->flags) ||
- test_bit(Unmerged, &rdev->flags))
+ test_bit(Faulty, &rdev->flags))
continue;
if (!test_bit(In_sync, &rdev->flags) &&
r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
@@ -1326,11 +1237,9 @@ retry_write:
blocked_rdev = rrdev;
break;
}
- if (rdev && (test_bit(Faulty, &rdev->flags)
- || test_bit(Unmerged, &rdev->flags)))
+ if (rdev && (test_bit(Faulty, &rdev->flags)))
rdev = NULL;
- if (rrdev && (test_bit(Faulty, &rrdev->flags)
- || test_bit(Unmerged, &rrdev->flags)))
+ if (rrdev && (test_bit(Faulty, &rrdev->flags)))
rrdev = NULL;
r10_bio->devs[i].bio = NULL;
@@ -1777,7 +1686,6 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
int mirror;
int first = 0;
int last = conf->geo.raid_disks - 1;
- struct request_queue *q = bdev_get_queue(rdev->bdev);
if (mddev->recovery_cp < MaxSector)
/* only hot-add to in-sync arrays, as recovery is
@@ -1790,11 +1698,6 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
if (rdev->raid_disk >= 0)
first = last = rdev->raid_disk;
- if (q->merge_bvec_fn) {
- set_bit(Unmerged, &rdev->flags);
- mddev->merge_check_needed = 1;
- }
-
if (rdev->saved_raid_disk >= first &&
conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
mirror = rdev->saved_raid_disk;
@@ -1833,19 +1736,6 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
rcu_assign_pointer(p->rdev, rdev);
break;
}
- if (err == 0 && test_bit(Unmerged, &rdev->flags)) {
- /* Some requests might not have seen this new
- * merge_bvec_fn. We must wait for them to complete
- * before merging the device fully.
- * First we make sure any code which has tested
- * our function has submitted the request, then
- * we wait for all outstanding requests to complete.
- */
- synchronize_sched();
- freeze_array(conf, 0);
- unfreeze_array(conf);
- clear_bit(Unmerged, &rdev->flags);
- }
md_integrity_add_rdev(rdev, mddev);
if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
@@ -2394,7 +2284,6 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
d = r10_bio->devs[sl].devnum;
rdev = rcu_dereference(conf->mirrors[d].rdev);
if (rdev &&
- !test_bit(Unmerged, &rdev->flags) &&
test_bit(In_sync, &rdev->flags) &&
is_badblock(rdev, r10_bio->devs[sl].addr + sect, s,
&first_bad, &bad_sectors) == 0) {
@@ -2448,7 +2337,6 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
d = r10_bio->devs[sl].devnum;
rdev = rcu_dereference(conf->mirrors[d].rdev);
if (!rdev ||
- test_bit(Unmerged, &rdev->flags) ||
!test_bit(In_sync, &rdev->flags))
continue;
@@ -3642,8 +3530,6 @@ static int run(struct mddev *mddev)
disk->rdev = rdev;
}
q = bdev_get_queue(rdev->bdev);
- if (q->merge_bvec_fn)
- mddev->merge_check_needed = 1;
diff = (rdev->new_data_offset - rdev->data_offset);
if (!mddev->reshape_backwards)
diff = -diff;
@@ -4697,7 +4583,6 @@ static struct md_personality raid10_personality =
.start_reshape = raid10_start_reshape,
.finish_reshape = raid10_finish_reshape,
.congested = raid10_congested,
- .mergeable_bvec = raid10_mergeable_bvec,
};
static int __init raid_init(void)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 8bdf81a..5f938c0 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4662,35 +4662,6 @@ static int raid5_congested(struct mddev *mddev, int bits)
return 0;
}
-/* We want read requests to align with chunks where possible,
- * but write requests don't need to.
- */
-static int raid5_mergeable_bvec(struct mddev *mddev,
- struct bvec_merge_data *bvm,
- struct bio_vec *biovec)
-{
- sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
- int max;
- unsigned int chunk_sectors = mddev->chunk_sectors;
- unsigned int bio_sectors = bvm->bi_size >> 9;
-
- /*
- * always allow writes to be mergeable, read as well if array
- * is degraded as we'll go through stripe cache anyway.
- */
- if ((bvm->bi_rw & 1) == WRITE || mddev->degraded)
- return biovec->bv_len;
-
- if (mddev->new_chunk_sectors < mddev->chunk_sectors)
- chunk_sectors = mddev->new_chunk_sectors;
- max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
- if (max < 0) max = 0;
- if (max <= biovec->bv_len && bio_sectors == 0)
- return biovec->bv_len;
- else
- return max;
-}
-
static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
{
sector_t sector = bio->bi_iter.bi_sector + get_start_sect(bio->bi_bdev);
@@ -7763,7 +7734,6 @@ static struct md_personality raid6_personality =
.quiesce = raid5_quiesce,
.takeover = raid6_takeover,
.congested = raid5_congested,
- .mergeable_bvec = raid5_mergeable_bvec,
};
static struct md_personality raid5_personality =
{
@@ -7787,7 +7757,6 @@ static struct md_personality raid5_personality =
.quiesce = raid5_quiesce,
.takeover = raid5_takeover,
.congested = raid5_congested,
- .mergeable_bvec = raid5_mergeable_bvec,
};
static struct md_personality raid4_personality =
@@ -7812,7 +7781,6 @@ static struct md_personality raid4_personality =
.quiesce = raid5_quiesce,
.takeover = raid4_takeover,
.congested = raid5_congested,
- .mergeable_bvec = raid5_mergeable_bvec,
};
static int __init raid5_init(void)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index dc89cc8..56cf082 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -213,14 +213,6 @@ typedef int (prep_rq_fn) (struct request_queue *, struct request *);
typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
struct bio_vec;
-struct bvec_merge_data {
- struct block_device *bi_bdev;
- sector_t bi_sector;
- unsigned bi_size;
- unsigned long bi_rw;
-};
-typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
- struct bio_vec *);
typedef void (softirq_done_fn)(struct request *);
typedef int (dma_drain_needed_fn)(struct request *);
typedef int (lld_busy_fn) (struct request_queue *q);
@@ -305,7 +297,6 @@ struct request_queue {
make_request_fn *make_request_fn;
prep_rq_fn *prep_rq_fn;
unprep_rq_fn *unprep_rq_fn;
- merge_bvec_fn *merge_bvec_fn;
softirq_done_fn *softirq_done_fn;
rq_timed_out_fn *rq_timed_out_fn;
dma_drain_needed_fn *dma_drain_needed;
@@ -991,7 +982,6 @@ extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
-extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
extern void blk_queue_dma_alignment(struct request_queue *, int);
extern void blk_queue_update_dma_alignment(struct request_queue *, int);
extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 51cc1de..76d23fa 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -82,9 +82,6 @@ typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,
unsigned long arg);
-typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
- struct bio_vec *biovec, int max_size);
-
/*
* These iteration functions are typically used to check (and combine)
* properties of underlying devices.
@@ -160,7 +157,6 @@ struct target_type {
dm_status_fn status;
dm_message_fn message;
dm_ioctl_fn ioctl;
- dm_merge_fn merge;
dm_busy_fn busy;
dm_iterate_devices_fn iterate_devices;
dm_io_hints_fn io_hints;
--
1.9.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH v5 09/11] fs: use helper bio_add_page() instead of open coding on bi_io_vec
2015-07-06 7:11 [PATCH v5 00/11] simplify block layer based on immutable biovecs mlin
` (7 preceding siblings ...)
2015-07-06 7:11 ` [PATCH v5 08/11] block: kill merge_bvec_fn() completely mlin
@ 2015-07-06 7:11 ` mlin
2015-07-06 7:11 ` [PATCH v5 10/11] block: remove bio_get_nr_vecs() mlin
` (2 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: mlin @ 2015-07-06 7:11 UTC (permalink / raw)
To: linux-kernel
Cc: Christoph Hellwig, Jens Axboe, Kent Overstreet, Dongsu Park,
Mike Snitzer, Ming Lin
From: Kent Overstreet <kent.overstreet@gmail.com>
Call pre-defined helper bio_add_page() instead of open coding for
iterating through bi_io_vec[]. Doing that, it's possible to make some
parts in filesystems and mm/page_io.c simpler than before.
Acked-by: Dave Kleikamp <shaggy@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[dpark: add more description in commit message]
Signed-off-by: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
---
fs/buffer.c | 7 ++-----
fs/jfs/jfs_logmgr.c | 14 ++++----------
mm/page_io.c | 8 +++-----
3 files changed, 9 insertions(+), 20 deletions(-)
diff --git a/fs/buffer.c b/fs/buffer.c
index 1cf7a53..95996ba 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -3046,12 +3046,9 @@ static int submit_bh_wbc(int rw, struct buffer_head *bh,
bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
bio->bi_bdev = bh->b_bdev;
- bio->bi_io_vec[0].bv_page = bh->b_page;
- bio->bi_io_vec[0].bv_len = bh->b_size;
- bio->bi_io_vec[0].bv_offset = bh_offset(bh);
- bio->bi_vcnt = 1;
- bio->bi_iter.bi_size = bh->b_size;
+ bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh));
+ BUG_ON(bio->bi_iter.bi_size != bh->b_size);
bio->bi_end_io = end_bio_bh_io_sync;
bio->bi_private = bh;
diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index bc462dc..46fae06 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -1999,12 +1999,9 @@ static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp)
bio->bi_iter.bi_sector = bp->l_blkno << (log->l2bsize - 9);
bio->bi_bdev = log->bdev;
- bio->bi_io_vec[0].bv_page = bp->l_page;
- bio->bi_io_vec[0].bv_len = LOGPSIZE;
- bio->bi_io_vec[0].bv_offset = bp->l_offset;
- bio->bi_vcnt = 1;
- bio->bi_iter.bi_size = LOGPSIZE;
+ bio_add_page(bio, bp->l_page, LOGPSIZE, bp->l_offset);
+ BUG_ON(bio->bi_iter.bi_size != LOGPSIZE);
bio->bi_end_io = lbmIODone;
bio->bi_private = bp;
@@ -2145,12 +2142,9 @@ static void lbmStartIO(struct lbuf * bp)
bio = bio_alloc(GFP_NOFS, 1);
bio->bi_iter.bi_sector = bp->l_blkno << (log->l2bsize - 9);
bio->bi_bdev = log->bdev;
- bio->bi_io_vec[0].bv_page = bp->l_page;
- bio->bi_io_vec[0].bv_len = LOGPSIZE;
- bio->bi_io_vec[0].bv_offset = bp->l_offset;
- bio->bi_vcnt = 1;
- bio->bi_iter.bi_size = LOGPSIZE;
+ bio_add_page(bio, bp->l_page, LOGPSIZE, bp->l_offset);
+ BUG_ON(bio->bi_iter.bi_size != LOGPSIZE);
bio->bi_end_io = lbmIODone;
bio->bi_private = bp;
diff --git a/mm/page_io.c b/mm/page_io.c
index 520baa4..194081b 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -33,12 +33,10 @@ static struct bio *get_swap_bio(gfp_t gfp_flags,
if (bio) {
bio->bi_iter.bi_sector = map_swap_page(page, &bio->bi_bdev);
bio->bi_iter.bi_sector <<= PAGE_SHIFT - 9;
- bio->bi_io_vec[0].bv_page = page;
- bio->bi_io_vec[0].bv_len = PAGE_SIZE;
- bio->bi_io_vec[0].bv_offset = 0;
- bio->bi_vcnt = 1;
- bio->bi_iter.bi_size = PAGE_SIZE;
bio->bi_end_io = end_io;
+
+ bio_add_page(bio, page, PAGE_SIZE, 0);
+ BUG_ON(bio->bi_iter.bi_size != PAGE_SIZE);
}
return bio;
}
--
1.9.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH v5 10/11] block: remove bio_get_nr_vecs()
2015-07-06 7:11 [PATCH v5 00/11] simplify block layer based on immutable biovecs mlin
` (8 preceding siblings ...)
2015-07-06 7:11 ` [PATCH v5 09/11] fs: use helper bio_add_page() instead of open coding on bi_io_vec mlin
@ 2015-07-06 7:11 ` mlin
2015-07-06 7:11 ` [PATCH v5 11/11] Documentation: update notes in biovecs about arbitrarily sized bios mlin
2015-07-13 5:12 ` [PATCH v5 00/11] simplify block layer based on immutable biovecs Ming Lin
11 siblings, 0 replies; 22+ messages in thread
From: mlin @ 2015-07-06 7:11 UTC (permalink / raw)
To: linux-kernel
Cc: Christoph Hellwig, Jens Axboe, Kent Overstreet, Dongsu Park,
Mike Snitzer, Ming Lin
From: Kent Overstreet <kent.overstreet@gmail.com>
We can always fill up the bio now, no need to estimate the possible
size based on queue parameters.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[hch: rebased and wrote a changelog]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
---
block/bio.c | 23 -----------------------
drivers/md/dm-io.c | 2 +-
fs/btrfs/compression.c | 5 +----
fs/btrfs/extent_io.c | 9 ++-------
fs/btrfs/inode.c | 3 +--
fs/btrfs/scrub.c | 18 ++----------------
fs/direct-io.c | 2 +-
fs/ext4/page-io.c | 3 +--
fs/ext4/readpage.c | 2 +-
fs/f2fs/data.c | 2 +-
fs/gfs2/lops.c | 9 +--------
fs/logfs/dev_bdev.c | 4 ++--
fs/mpage.c | 4 ++--
fs/nilfs2/segbuf.c | 2 +-
fs/xfs/xfs_aops.c | 3 +--
include/linux/bio.h | 1 -
16 files changed, 18 insertions(+), 74 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index da15e9a..f28ca16 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -692,29 +692,6 @@ integrity_clone:
EXPORT_SYMBOL(bio_clone_bioset);
/**
- * bio_get_nr_vecs - return approx number of vecs
- * @bdev: I/O target
- *
- * Return the approximate number of pages we can send to this target.
- * There's no guarantee that you will be able to fit this number of pages
- * into a bio, it does not account for dynamic restrictions that vary
- * on offset.
- */
-int bio_get_nr_vecs(struct block_device *bdev)
-{
- struct request_queue *q = bdev_get_queue(bdev);
- int nr_pages;
-
- nr_pages = min_t(unsigned,
- queue_max_segments(q),
- queue_max_sectors(q) / (PAGE_SIZE >> 9) + 1);
-
- return min_t(unsigned, nr_pages, BIO_MAX_PAGES);
-
-}
-EXPORT_SYMBOL(bio_get_nr_vecs);
-
-/**
* bio_add_pc_page - attempt to add page to bio
* @q: the target queue
* @bio: destination bio
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index 74adcd2..7d64272 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -314,7 +314,7 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
if ((rw & REQ_DISCARD) || (rw & REQ_WRITE_SAME))
num_bvecs = 1;
else
- num_bvecs = min_t(int, bio_get_nr_vecs(where->bdev),
+ num_bvecs = min_t(int, BIO_MAX_PAGES,
dm_sector_div_up(remaining, (PAGE_SIZE >> SECTOR_SHIFT)));
bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, io->client->bios);
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index ce62324..449c752 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -97,10 +97,7 @@ static inline int compressed_bio_size(struct btrfs_root *root,
static struct bio *compressed_bio_alloc(struct block_device *bdev,
u64 first_byte, gfp_t gfp_flags)
{
- int nr_vecs;
-
- nr_vecs = bio_get_nr_vecs(bdev);
- return btrfs_bio_alloc(bdev, first_byte >> 9, nr_vecs, gfp_flags);
+ return btrfs_bio_alloc(bdev, first_byte >> 9, BIO_MAX_PAGES, gfp_flags);
}
static int check_compressed_csum(struct inode *inode,
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 02d0581..ba89efd 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2802,9 +2802,7 @@ static int submit_extent_page(int rw, struct extent_io_tree *tree,
{
int ret = 0;
struct bio *bio;
- int nr;
int contig = 0;
- int this_compressed = bio_flags & EXTENT_BIO_COMPRESSED;
int old_compressed = prev_bio_flags & EXTENT_BIO_COMPRESSED;
size_t page_size = min_t(size_t, size, PAGE_CACHE_SIZE);
@@ -2829,12 +2827,9 @@ static int submit_extent_page(int rw, struct extent_io_tree *tree,
return 0;
}
}
- if (this_compressed)
- nr = BIO_MAX_PAGES;
- else
- nr = bio_get_nr_vecs(bdev);
- bio = btrfs_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
+ bio = btrfs_bio_alloc(bdev, sector, BIO_MAX_PAGES,
+ GFP_NOFS | __GFP_HIGH);
if (!bio)
return -ENOMEM;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 855935f..d66b9a3 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7959,8 +7959,7 @@ out:
static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
u64 first_sector, gfp_t gfp_flags)
{
- int nr_vecs = bio_get_nr_vecs(bdev);
- return btrfs_bio_alloc(bdev, first_sector, nr_vecs, gfp_flags);
+ return btrfs_bio_alloc(bdev, first_sector, BIO_MAX_PAGES, gfp_flags);
}
static inline int btrfs_lookup_and_bind_dio_csum(struct btrfs_root *root,
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 9f2feab..aab0b9a 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -454,27 +454,14 @@ struct scrub_ctx *scrub_setup_ctx(struct btrfs_device *dev, int is_dev_replace)
struct scrub_ctx *sctx;
int i;
struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
- int pages_per_rd_bio;
int ret;
- /*
- * the setting of pages_per_rd_bio is correct for scrub but might
- * be wrong for the dev_replace code where we might read from
- * different devices in the initial huge bios. However, that
- * code is able to correctly handle the case when adding a page
- * to a bio fails.
- */
- if (dev->bdev)
- pages_per_rd_bio = min_t(int, SCRUB_PAGES_PER_RD_BIO,
- bio_get_nr_vecs(dev->bdev));
- else
- pages_per_rd_bio = SCRUB_PAGES_PER_RD_BIO;
sctx = kzalloc(sizeof(*sctx), GFP_NOFS);
if (!sctx)
goto nomem;
atomic_set(&sctx->refs, 1);
sctx->is_dev_replace = is_dev_replace;
- sctx->pages_per_rd_bio = pages_per_rd_bio;
+ sctx->pages_per_rd_bio = SCRUB_PAGES_PER_RD_BIO;
sctx->curr = -1;
sctx->dev_root = dev->dev_root;
for (i = 0; i < SCRUB_BIOS_PER_SCTX; ++i) {
@@ -3895,8 +3882,7 @@ static int scrub_setup_wr_ctx(struct scrub_ctx *sctx,
return 0;
WARN_ON(!dev->bdev);
- wr_ctx->pages_per_wr_bio = min_t(int, SCRUB_PAGES_PER_WR_BIO,
- bio_get_nr_vecs(dev->bdev));
+ wr_ctx->pages_per_wr_bio = SCRUB_PAGES_PER_WR_BIO;
wr_ctx->tgtdev = dev;
atomic_set(&wr_ctx->flush_all_writes, 0);
return 0;
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 745d234..89baebe 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -653,7 +653,7 @@ static inline int dio_new_bio(struct dio *dio, struct dio_submit *sdio,
if (ret)
goto out;
sector = start_sector << (sdio->blkbits - 9);
- nr_pages = min(sdio->pages_in_io, bio_get_nr_vecs(map_bh->b_bdev));
+ nr_pages = min(sdio->pages_in_io, BIO_MAX_PAGES);
BUG_ON(nr_pages <= 0);
dio_bio_alloc(dio, sdio, map_bh->b_bdev, sector, nr_pages);
sdio->boundary = 0;
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 5602450..e678ad3 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -375,10 +375,9 @@ void ext4_io_submit_init(struct ext4_io_submit *io,
static int io_submit_init_bio(struct ext4_io_submit *io,
struct buffer_head *bh)
{
- int nvecs = bio_get_nr_vecs(bh->b_bdev);
struct bio *bio;
- bio = bio_alloc(GFP_NOIO, min(nvecs, BIO_MAX_PAGES));
+ bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
if (!bio)
return -ENOMEM;
bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
index ec3ef93..37c886c 100644
--- a/fs/ext4/readpage.c
+++ b/fs/ext4/readpage.c
@@ -284,7 +284,7 @@ int ext4_mpage_readpages(struct address_space *mapping,
goto set_error_page;
}
bio = bio_alloc(GFP_KERNEL,
- min_t(int, nr_pages, bio_get_nr_vecs(bdev)));
+ min_t(int, nr_pages, BIO_MAX_PAGES));
if (!bio) {
if (ctx)
ext4_release_crypto_ctx(ctx);
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 9bedfa8..53866ce 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1552,7 +1552,7 @@ submit_and_realloc:
}
bio = bio_alloc(GFP_KERNEL,
- min_t(int, nr_pages, bio_get_nr_vecs(bdev)));
+ min_t(int, nr_pages, BIO_MAX_PAGES));
if (!bio) {
if (ctx)
f2fs_release_crypto_ctx(ctx);
diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index 2c1ae86..64d3116 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -261,18 +261,11 @@ void gfs2_log_flush_bio(struct gfs2_sbd *sdp, int rw)
static struct bio *gfs2_log_alloc_bio(struct gfs2_sbd *sdp, u64 blkno)
{
struct super_block *sb = sdp->sd_vfs;
- unsigned nrvecs = bio_get_nr_vecs(sb->s_bdev);
struct bio *bio;
BUG_ON(sdp->sd_log_bio);
- while (1) {
- bio = bio_alloc(GFP_NOIO, nrvecs);
- if (likely(bio))
- break;
- nrvecs = max(nrvecs/2, 1U);
- }
-
+ bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
bio->bi_iter.bi_sector = blkno * (sb->s_blocksize >> 9);
bio->bi_bdev = sb->s_bdev;
bio->bi_end_io = gfs2_end_log_write;
diff --git a/fs/logfs/dev_bdev.c b/fs/logfs/dev_bdev.c
index 76279e1..fbb5f95 100644
--- a/fs/logfs/dev_bdev.c
+++ b/fs/logfs/dev_bdev.c
@@ -83,7 +83,7 @@ static int __bdev_writeseg(struct super_block *sb, u64 ofs, pgoff_t index,
unsigned int max_pages;
int i;
- max_pages = min(nr_pages, (size_t) bio_get_nr_vecs(super->s_bdev));
+ max_pages = min(nr_pages, BIO_MAX_PAGES);
bio = bio_alloc(GFP_NOFS, max_pages);
BUG_ON(!bio);
@@ -175,7 +175,7 @@ static int do_erase(struct super_block *sb, u64 ofs, pgoff_t index,
unsigned int max_pages;
int i;
- max_pages = min(nr_pages, (size_t) bio_get_nr_vecs(super->s_bdev));
+ max_pages = min(nr_pages, BIO_MAX_PAGES);
bio = bio_alloc(GFP_NOFS, max_pages);
BUG_ON(!bio);
diff --git a/fs/mpage.c b/fs/mpage.c
index ca0244b..4b92133 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -277,7 +277,7 @@ alloc_new:
goto out;
}
bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),
- min_t(int, nr_pages, bio_get_nr_vecs(bdev)),
+ min_t(int, nr_pages, BIO_MAX_PAGES),
GFP_KERNEL);
if (bio == NULL)
goto confused;
@@ -602,7 +602,7 @@ alloc_new:
}
}
bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),
- bio_get_nr_vecs(bdev), GFP_NOFS|__GFP_HIGH);
+ BIO_MAX_PAGES, GFP_NOFS|__GFP_HIGH);
if (bio == NULL)
goto confused;
diff --git a/fs/nilfs2/segbuf.c b/fs/nilfs2/segbuf.c
index 42468e5..4b59031 100644
--- a/fs/nilfs2/segbuf.c
+++ b/fs/nilfs2/segbuf.c
@@ -415,7 +415,7 @@ static void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
{
wi->bio = NULL;
wi->rest_blocks = segbuf->sb_sum.nblocks;
- wi->max_pages = bio_get_nr_vecs(wi->nilfs->ns_bdev);
+ wi->max_pages = BIO_MAX_PAGES;
wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
wi->start = wi->end = 0;
wi->blocknr = segbuf->sb_pseg_start;
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 3859f5e..89a8c15 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -382,8 +382,7 @@ STATIC struct bio *
xfs_alloc_ioend_bio(
struct buffer_head *bh)
{
- int nvecs = bio_get_nr_vecs(bh->b_bdev);
- struct bio *bio = bio_alloc(GFP_NOIO, nvecs);
+ struct bio *bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
ASSERT(bio->bi_private == NULL);
bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 5e963a6..1608b89 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -440,7 +440,6 @@ void bio_chain(struct bio *, struct bio *);
extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
unsigned int, unsigned int);
-extern int bio_get_nr_vecs(struct block_device *);
struct rq_map_data;
extern struct bio *bio_map_user_iov(struct request_queue *,
const struct iov_iter *, gfp_t);
--
1.9.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH v5 11/11] Documentation: update notes in biovecs about arbitrarily sized bios
2015-07-06 7:11 [PATCH v5 00/11] simplify block layer based on immutable biovecs mlin
` (9 preceding siblings ...)
2015-07-06 7:11 ` [PATCH v5 10/11] block: remove bio_get_nr_vecs() mlin
@ 2015-07-06 7:11 ` mlin
2015-07-13 5:12 ` [PATCH v5 00/11] simplify block layer based on immutable biovecs Ming Lin
11 siblings, 0 replies; 22+ messages in thread
From: mlin @ 2015-07-06 7:11 UTC (permalink / raw)
To: linux-kernel
Cc: Christoph Hellwig, Jens Axboe, Kent Overstreet, Dongsu Park,
Mike Snitzer, Ming Lin
From: Dongsu Park <dpark@posteo.net>
Update block/biovecs.txt so that it includes a note on what kind of
effects arbitrarily sized bios would bring to the block layer.
Also fix a trivial typo, bio_iter_iovec.
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Signed-off-by: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
---
Documentation/block/biovecs.txt | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/Documentation/block/biovecs.txt b/Documentation/block/biovecs.txt
index 74a32ad..2568958 100644
--- a/Documentation/block/biovecs.txt
+++ b/Documentation/block/biovecs.txt
@@ -24,7 +24,7 @@ particular, presenting the illusion of partially completed biovecs so that
normal code doesn't have to deal with bi_bvec_done.
* Driver code should no longer refer to biovecs directly; we now have
- bio_iovec() and bio_iovec_iter() macros that return literal struct biovecs,
+ bio_iovec() and bio_iter_iovec() macros that return literal struct biovecs,
constructed from the raw biovecs but taking into account bi_bvec_done and
bi_size.
@@ -109,3 +109,11 @@ Other implications:
over all the biovecs in the new bio - which is silly as it's not needed.
So, don't use bi_vcnt anymore.
+
+ * The current interface allows the block layer to split bios as needed, so we
+ could eliminate a lot of complexity particularly in stacked drivers. Code
+ that creates bios can then create whatever size bios are convenient, and
+ more importantly stacked drivers don't have to deal with both their own bio
+ size limitations and the limitations of the underlying devices. Thus
+ there's no need to define ->merge_bvec_fn() callbacks for individual block
+ drivers.
--
1.9.1
^ permalink raw reply related [flat|nested] 22+ messages in thread* Re: [PATCH v5 00/11] simplify block layer based on immutable biovecs
2015-07-06 7:11 [PATCH v5 00/11] simplify block layer based on immutable biovecs mlin
` (10 preceding siblings ...)
2015-07-06 7:11 ` [PATCH v5 11/11] Documentation: update notes in biovecs about arbitrarily sized bios mlin
@ 2015-07-13 5:12 ` Ming Lin
2015-07-13 15:35 ` Mike Snitzer
11 siblings, 1 reply; 22+ messages in thread
From: Ming Lin @ 2015-07-13 5:12 UTC (permalink / raw)
To: linux-kernel
Cc: Christoph Hellwig, Jens Axboe, Kent Overstreet, Dongsu Park,
Mike Snitzer, NeilBrown
On Mon, 2015-07-06 at 00:11 -0700, mlin@kernel.org wrote:
> Hi Mike,
>
> On Wed, 2015-06-10 at 17:46 -0400, Mike Snitzer wrote:
> > I've been busy getting DM changes for the 4.2 merge window finalized.
> > As such I haven't connected with others on the team to discuss this
> > issue.
> >
> > I'll see if we can make time in the next 2 days. But I also have
> > RHEL-specific kernel deadlines I'm coming up against.
> >
> > Seems late to be staging this extensive a change for 4.2... are you
> > pushing for this code to land in the 4.2 merge window? Or do we have
> > time to work this further and target the 4.3 merge?
> >
>
> 4.2-rc1 was out.
> Would you have time to work together for 4.3 merge?
Ping ...
What can I do to move forward?
This patchset not only simplify block layer a lot, it's also a
prerequisite of the direct IO rewrite patches, which I saw 40%
performance improvement for null_blk and 10% improvement for NVMe
drives. I have been fixing bugs for the direct IO patches. I'll post it
once it passes xfstests.
Mike,
Can I have your ACK? Or do you have other test plan?
Thanks,
Ming
>
> Fio test results(4.1-rc4/rc7) showed no performance regressions
> for HW/SW RAID6 and DM stripe tests.
> http://minggr.net/pub/20150608/fio_results/summary.log
>
> v5:
> - rebase on top of 4.2-rc1
> - reorder patch 6,7
> - add NeilBrown's ACKs
> - fix memory leak: free "bio_split" bioset in blk_release_queue()
>
> v4:
> - rebase on top of 4.1-rc4
> - use BIO_POOL_SIZE instead of number 4 for bioset_create()
> - call blk_queue_split() in blk_mq_make_request()
> - call blk_queue_split() in zram_make_request()
> - add patch "block: remove bio_get_nr_vecs()"
> - remove split code in blkdev_issue_discard()
> - drop patch "md/raid10: make sync_request_write() call bio_copy_data()".
> NeilBrown queued it.
> - drop patch "block: allow __blk_queue_bounce() to handle bios larger than BIO_MAX_PAGES".
> Will send it seperately
>
> v3:
> - rebase on top of 4.1-rc2
> - support for QUEUE_FLAG_SG_GAPS
> - update commit logs of patch 2&4
> - split bio for chunk_aligned_read
>
> v2: https://lkml.org/lkml/2015/4/28/28
> v1: https://lkml.org/lkml/2014/12/22/128
>
> This is the 5th attempt of simplifying block layer based on immutable
> biovecs. Immutable biovecs, implemented by Kent Overstreet, have been
> available in mainline since v3.14. Its original goal was actually making
> generic_make_request() accept arbitrarily sized bios, and pushing the
> splitting down to the drivers or wherever it's required. See also
> discussions in the past, [1] [2] [3].
>
> This will bring not only performance improvements, but also a great amount
> of reduction in code complexity all over the block layer. Performance gain
> is possible due to the fact that bio_add_page() does not have to check
> unnecesary conditions such as queue limits or if biovecs are mergeable.
> Those will be delegated to the driver level. Kent already said that he
> actually benchmarked the impact of this with fio on a micron p320h, which
> showed definitely a positive impact.
>
> Moreover, this patchset also allows a lot of code to be deleted, mainly
> because of removal of merge_bvec_fn() callbacks. We have been aware that
> it has been always a delicate issue for stacking block drivers (e.g. md
> and bcache) to handle merging bio consistently. This simplication will
> help every individual block driver avoid having such an issue.
>
> Patches are against 4.2-rc1. These are also available in my git repo at:
>
> https://git.kernel.org/cgit/linux/kernel/git/mlin/linux.git/log/?h=block-generic-req
> git://git.kernel.org/pub/scm/linux/kernel/git/mlin/linux.git block-generic-req
>
> This patchset is a prerequisite of other consecutive patchsets, e.g.
> multipage biovecs, rewriting plugging, or rewriting direct-IO, which are
> excluded this time. That means, this patchset should not bring any
> regression to end-users.
>
> Comments are welcome.
> Ming
>
> [1] https://lkml.org/lkml/2014/11/23/263
> [2] https://lkml.org/lkml/2013/11/25/732
> [3] https://lkml.org/lkml/2014/2/26/618
>
> Dongsu Park (1):
> Documentation: update notes in biovecs about arbitrarily sized bios
>
> Kent Overstreet (8):
> block: make generic_make_request handle arbitrarily sized bios
> block: simplify bio_add_page()
> bcache: remove driver private bio splitting code
> btrfs: remove bio splitting and merge_bvec_fn() calls
> md/raid5: get rid of bio_fits_rdev()
> block: kill merge_bvec_fn() completely
> fs: use helper bio_add_page() instead of open coding on bi_io_vec
> block: remove bio_get_nr_vecs()
>
> Ming Lin (2):
> block: remove split code in blkdev_issue_discard
> md/raid5: split bio for chunk_aligned_read
>
> Documentation/block/biovecs.txt | 10 +-
> block/bio.c | 152 ++++++++++------------------
> block/blk-core.c | 19 ++--
> block/blk-lib.c | 73 +++----------
> block/blk-merge.c | 148 +++++++++++++++++++++++++--
> block/blk-mq.c | 4 +
> block/blk-settings.c | 22 ----
> block/blk-sysfs.c | 3 +
> drivers/block/drbd/drbd_int.h | 1 -
> drivers/block/drbd/drbd_main.c | 1 -
> drivers/block/drbd/drbd_req.c | 37 +------
> drivers/block/pktcdvd.c | 27 +----
> drivers/block/ps3vram.c | 2 +
> drivers/block/rbd.c | 47 ---------
> drivers/block/rsxx/dev.c | 2 +
> drivers/block/umem.c | 2 +
> drivers/block/zram/zram_drv.c | 2 +
> drivers/md/bcache/bcache.h | 18 ----
> drivers/md/bcache/io.c | 100 +-----------------
> drivers/md/bcache/journal.c | 4 +-
> drivers/md/bcache/request.c | 16 +--
> drivers/md/bcache/super.c | 32 +-----
> drivers/md/bcache/util.h | 5 +-
> drivers/md/bcache/writeback.c | 4 +-
> drivers/md/dm-cache-target.c | 21 ----
> drivers/md/dm-crypt.c | 16 ---
> drivers/md/dm-era-target.c | 15 ---
> drivers/md/dm-flakey.c | 16 ---
> drivers/md/dm-io.c | 2 +-
> drivers/md/dm-linear.c | 16 ---
> drivers/md/dm-log-writes.c | 16 ---
> drivers/md/dm-raid.c | 19 ----
> drivers/md/dm-snap.c | 15 ---
> drivers/md/dm-stripe.c | 21 ----
> drivers/md/dm-table.c | 8 --
> drivers/md/dm-thin.c | 31 ------
> drivers/md/dm-verity.c | 16 ---
> drivers/md/dm.c | 129 +----------------------
> drivers/md/dm.h | 2 -
> drivers/md/linear.c | 43 --------
> drivers/md/md.c | 28 +----
> drivers/md/md.h | 12 ---
> drivers/md/multipath.c | 21 ----
> drivers/md/raid0.c | 56 ----------
> drivers/md/raid0.h | 2 -
> drivers/md/raid1.c | 58 +----------
> drivers/md/raid10.c | 121 +---------------------
> drivers/md/raid5.c | 92 ++++++-----------
> drivers/s390/block/dcssblk.c | 2 +
> drivers/s390/block/xpram.c | 2 +
> drivers/staging/lustre/lustre/llite/lloop.c | 2 +
> fs/btrfs/compression.c | 5 +-
> fs/btrfs/extent_io.c | 9 +-
> fs/btrfs/inode.c | 3 +-
> fs/btrfs/scrub.c | 18 +---
> fs/btrfs/volumes.c | 72 -------------
> fs/buffer.c | 7 +-
> fs/direct-io.c | 2 +-
> fs/ext4/page-io.c | 3 +-
> fs/ext4/readpage.c | 2 +-
> fs/f2fs/data.c | 2 +-
> fs/gfs2/lops.c | 9 +-
> fs/jfs/jfs_logmgr.c | 14 +--
> fs/logfs/dev_bdev.c | 4 +-
> fs/mpage.c | 4 +-
> fs/nilfs2/segbuf.c | 2 +-
> fs/xfs/xfs_aops.c | 3 +-
> include/linux/bio.h | 1 -
> include/linux/blkdev.h | 13 +--
> include/linux/device-mapper.h | 4 -
> mm/page_io.c | 8 +-
> 71 files changed, 340 insertions(+), 1358 deletions(-)
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: [PATCH v5 00/11] simplify block layer based on immutable biovecs
2015-07-13 5:12 ` [PATCH v5 00/11] simplify block layer based on immutable biovecs Ming Lin
@ 2015-07-13 15:35 ` Mike Snitzer
2015-07-14 20:51 ` Ming Lin
` (2 more replies)
0 siblings, 3 replies; 22+ messages in thread
From: Mike Snitzer @ 2015-07-13 15:35 UTC (permalink / raw)
To: Ming Lin
Cc: linux-kernel, Christoph Hellwig, Jens Axboe, Kent Overstreet,
Dongsu Park, NeilBrown, Alasdair G. Kergon, Jeff Moyer, dm-devel
On Mon, Jul 13 2015 at 1:12am -0400,
Ming Lin <mlin@kernel.org> wrote:
> On Mon, 2015-07-06 at 00:11 -0700, mlin@kernel.org wrote:
> > Hi Mike,
> >
> > On Wed, 2015-06-10 at 17:46 -0400, Mike Snitzer wrote:
> > > I've been busy getting DM changes for the 4.2 merge window finalized.
> > > As such I haven't connected with others on the team to discuss this
> > > issue.
> > >
> > > I'll see if we can make time in the next 2 days. But I also have
> > > RHEL-specific kernel deadlines I'm coming up against.
> > >
> > > Seems late to be staging this extensive a change for 4.2... are you
> > > pushing for this code to land in the 4.2 merge window? Or do we have
> > > time to work this further and target the 4.3 merge?
> > >
> >
> > 4.2-rc1 was out.
> > Would you have time to work together for 4.3 merge?
>
> Ping ...
>
> What can I do to move forward?
You can show further testing. Particularly that you've covered all the
edge cases.
Until someone can produce some perf test results where they are actually
properly controlling for the splitting, we have no useful information.
The primary concerns associated with this patchset are:
1) In the context of RAID, XFS's use of bio_add_page() used to build up
optimal IOs when the underlying block device provides striping info
via IO limits. With this patchset how large will bios become in
practice _without_ bio_add_page() being bounded by the underlying IO
limits?
2) The late splitting that occurs for the (presummably) large bios that
are sent down.. how does it cope/perform in the face of very
low/fragmented system memory?
3) More open-ended comment than question: Linux has evolved to perform
well on "enterprise" systems. We generally don't fall off a cliff on
performance like we used to. The concern associated with this
patchset is that if it goes in without _real_ due-diligence on
"enterprise" scale systems and workloads it'll be too late once we
notice the problem(s).
So we really need answers to 1 and 2 above in order to feel better about
the risks associated 3.
Alasdair's feedback to you on testing still applies (and hasn't been
done AFAIK):
https://www.redhat.com/archives/dm-devel/2015-May/msg00203.html
Particularly:
"you might need to instrument the kernels to tell you the sizes of the
bios being created and the amount of splitting actually happening."
and
"You may also want to test systems with a restricted amount of available
memory to show how the splitting via worker thread performs. (Again,
instrument to prove the extent to which the new code is being exercised.)"
> This patchset not only simplify block layer a lot, it's also a
> prerequisite of the direct IO rewrite patches, which I saw 40%
> performance improvement for null_blk and 10% improvement for NVMe
> drives. I have been fixing bugs for the direct IO patches. I'll post it
> once it passes xfstests.
>
> Mike,
> Can I have your ACK? Or do you have other test plan?
I'm not the only person with concerns. I share Alasdair's concerns.
Jeff Moyer is also concerned about the implications of this patchset.
We're all in favor of this patchset's cleanup _if and only if_ it can be
proven that we aren't going to be falling off a cliff on performance due
to some pathological workload (be it under memory pressure or whatever).
Apologies for not being able to put time to this like I hoped. But that
doesn't mean you are off the hook on showing you've done the testing and
understand the scope and implications of the changes you're pushing for.
I will do additional review to answer 1 and 2 above. And Jeff Moyer
told me he'd test the patchset on one of his testbeds.
But if you can help answer 1 and 2 above that'd go a long way.
Thanks,
Mike
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: [PATCH v5 00/11] simplify block layer based on immutable biovecs
2015-07-13 15:35 ` Mike Snitzer
@ 2015-07-14 20:51 ` Ming Lin
2015-07-24 19:50 ` Kent Overstreet
2015-07-16 7:06 ` Ming Lin
2015-07-23 18:21 ` Ming Lin
2 siblings, 1 reply; 22+ messages in thread
From: Ming Lin @ 2015-07-14 20:51 UTC (permalink / raw)
To: Mike Snitzer
Cc: linux-kernel, Christoph Hellwig, Jens Axboe, Kent Overstreet,
Dongsu Park, NeilBrown, Alasdair G. Kergon, Jeff Moyer, dm-devel
On Mon, 2015-07-13 at 11:35 -0400, Mike Snitzer wrote:
> On Mon, Jul 13 2015 at 1:12am -0400,
> Ming Lin <mlin@kernel.org> wrote:
>
> > On Mon, 2015-07-06 at 00:11 -0700, mlin@kernel.org wrote:
> > > Hi Mike,
> > >
> > > On Wed, 2015-06-10 at 17:46 -0400, Mike Snitzer wrote:
> > > > I've been busy getting DM changes for the 4.2 merge window finalized.
> > > > As such I haven't connected with others on the team to discuss this
> > > > issue.
> > > >
> > > > I'll see if we can make time in the next 2 days. But I also have
> > > > RHEL-specific kernel deadlines I'm coming up against.
> > > >
> > > > Seems late to be staging this extensive a change for 4.2... are you
> > > > pushing for this code to land in the 4.2 merge window? Or do we have
> > > > time to work this further and target the 4.3 merge?
> > > >
> > >
> > > 4.2-rc1 was out.
> > > Would you have time to work together for 4.3 merge?
> >
> > Ping ...
> >
> > What can I do to move forward?
>
> You can show further testing. Particularly that you've covered all the
> edge cases.
>
> Until someone can produce some perf test results where they are actually
> properly controlling for the splitting, we have no useful information.
>
> The primary concerns associated with this patchset are:
> 1) In the context of RAID, XFS's use of bio_add_page() used to build up
> optimal IOs when the underlying block device provides striping info
> via IO limits. With this patchset how large will bios become in
> practice _without_ bio_add_page() being bounded by the underlying IO
> limits?
>
> 2) The late splitting that occurs for the (presummably) large bios that
> are sent down.. how does it cope/perform in the face of very
> low/fragmented system memory?
>
> 3) More open-ended comment than question: Linux has evolved to perform
> well on "enterprise" systems. We generally don't fall off a cliff on
> performance like we used to. The concern associated with this
> patchset is that if it goes in without _real_ due-diligence on
> "enterprise" scale systems and workloads it'll be too late once we
> notice the problem(s).
>
> So we really need answers to 1 and 2 above in order to feel better about
> the risks associated 3.
>
> Alasdair's feedback to you on testing still applies (and hasn't been
> done AFAIK):
> https://www.redhat.com/archives/dm-devel/2015-May/msg00203.html
>
> Particularly:
> "you might need to instrument the kernels to tell you the sizes of the
> bios being created and the amount of splitting actually happening."
>
> and
>
> "You may also want to test systems with a restricted amount of available
> memory to show how the splitting via worker thread performs. (Again,
> instrument to prove the extent to which the new code is being exercised.)"
>
> > This patchset not only simplify block layer a lot, it's also a
> > prerequisite of the direct IO rewrite patches, which I saw 40%
> > performance improvement for null_blk and 10% improvement for NVMe
> > drives. I have been fixing bugs for the direct IO patches. I'll post it
> > once it passes xfstests.
> >
> > Mike,
> > Can I have your ACK? Or do you have other test plan?
>
> I'm not the only person with concerns. I share Alasdair's concerns.
> Jeff Moyer is also concerned about the implications of this patchset.
> We're all in favor of this patchset's cleanup _if and only if_ it can be
> proven that we aren't going to be falling off a cliff on performance due
> to some pathological workload (be it under memory pressure or whatever).
>
> Apologies for not being able to put time to this like I hoped. But that
> doesn't mean you are off the hook on showing you've done the testing and
> understand the scope and implications of the changes you're pushing for.
>
> I will do additional review to answer 1 and 2 above. And Jeff Moyer
> told me he'd test the patchset on one of his testbeds.
>
> But if you can help answer 1 and 2 above that'd go a long way.
Thanks for the response.
I'm working on more testing.
I'll ask if I have question about the testing.
Thanks,
Ming
>
> Thanks,
> Mike
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH v5 00/11] simplify block layer based on immutable biovecs
2015-07-14 20:51 ` Ming Lin
@ 2015-07-24 19:50 ` Kent Overstreet
0 siblings, 0 replies; 22+ messages in thread
From: Kent Overstreet @ 2015-07-24 19:50 UTC (permalink / raw)
To: Ming Lin
Cc: Mike Snitzer, linux-kernel, Christoph Hellwig, Jens Axboe,
Dongsu Park, NeilBrown, Alasdair G. Kergon, Jeff Moyer, dm-devel,
bcrl
On Tue, Jul 14, 2015 at 01:51:26PM -0700, Ming Lin wrote:
> On Mon, 2015-07-13 at 11:35 -0400, Mike Snitzer wrote:
> > On Mon, Jul 13 2015 at 1:12am -0400,
> > Ming Lin <mlin@kernel.org> wrote:
> >
> > > On Mon, 2015-07-06 at 00:11 -0700, mlin@kernel.org wrote:
> > > > Hi Mike,
> > > >
> > > > On Wed, 2015-06-10 at 17:46 -0400, Mike Snitzer wrote:
> > > > > I've been busy getting DM changes for the 4.2 merge window finalized.
> > > > > As such I haven't connected with others on the team to discuss this
> > > > > issue.
> > > > >
> > > > > I'll see if we can make time in the next 2 days. But I also have
> > > > > RHEL-specific kernel deadlines I'm coming up against.
> > > > >
> > > > > Seems late to be staging this extensive a change for 4.2... are you
> > > > > pushing for this code to land in the 4.2 merge window? Or do we have
> > > > > time to work this further and target the 4.3 merge?
> > > > >
> > > >
> > > > 4.2-rc1 was out.
> > > > Would you have time to work together for 4.3 merge?
> > >
> > > Ping ...
> > >
> > > What can I do to move forward?
> >
> > You can show further testing. Particularly that you've covered all the
> > edge cases.
> >
> > Until someone can produce some perf test results where they are actually
> > properly controlling for the splitting, we have no useful information.
> >
> > The primary concerns associated with this patchset are:
> > 1) In the context of RAID, XFS's use of bio_add_page() used to build up
> > optimal IOs when the underlying block device provides striping info
> > via IO limits. With this patchset how large will bios become in
> > practice _without_ bio_add_page() being bounded by the underlying IO
> > limits?
CCing Ben because I know he has a fair amount of experience with performance on
high end arrays
My thought here is that this only matters at all in the context of readahead -
that is, you can think of the splitting issue as being equivalent to wanting to
return partially complete results for IOs, and that's really only useful with
readahead.
But as long as readahead is pipelining (and it should be), and the window is
big enough - I don't think there'll be any issues.
But yeah we should probably have some data to back this up.
> > 2) The late splitting that occurs for the (presummably) large bios that
> > are sent down.. how does it cope/perform in the face of very
> > low/fragmented system memory?
It's all backed by mempools, and there's several other memory allocations in the
block IO path (sglists, requests, etc.) - should be a nonissue.
This patch set will help us improve performance on high end devices, by
simplifying the bio_add_page() path and not having it touch request_queue stuff
(which is behind several pointers at that point), and deferring that to the
driver - I saw a nontrivial performance boost awhile back when I converted the
mtip driver to do splitting as needed while it was mapping the sglist.
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH v5 00/11] simplify block layer based on immutable biovecs
2015-07-13 15:35 ` Mike Snitzer
2015-07-14 20:51 ` Ming Lin
@ 2015-07-16 7:06 ` Ming Lin
2015-07-16 13:13 ` Jeff Moyer
2015-07-23 18:21 ` Ming Lin
2 siblings, 1 reply; 22+ messages in thread
From: Ming Lin @ 2015-07-16 7:06 UTC (permalink / raw)
To: Mike Snitzer
Cc: linux-kernel, Christoph Hellwig, Jens Axboe, Kent Overstreet,
Dongsu Park, NeilBrown, Alasdair G. Kergon, Jeff Moyer, dm-devel
On Mon, 2015-07-13 at 11:35 -0400, Mike Snitzer wrote:
> I will do additional review to answer 1 and 2 above. And Jeff Moyer
> told me he'd test the patchset on one of his testbeds.
Hi Jeff,
FYI, here is a fix for patch 1.
Or you can pull from my tree.
https://git.kernel.org/cgit/linux/kernel/git/mlin/linux.git/log/?h=block-generic-req
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 40d08e3..181f343 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1287,12 +1287,12 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
return;
}
+ blk_queue_split(q, &bio, q->bio_split);
+
if (!is_flush_fua && !blk_queue_nomerges(q) &&
blk_attempt_plug_merge(q, bio, &request_count, &same_queue_rq))
return;
- blk_queue_split(q, &bio, q->bio_split);
-
rq = blk_mq_map_request(q, bio, &data);
if (unlikely(!rq))
return;
@@ -1374,12 +1374,12 @@ static void blk_sq_make_request(struct request_queue *q, struct bio *bio)
return;
}
+ blk_queue_split(q, &bio, q->bio_split);
+
if (!is_flush_fua && !blk_queue_nomerges(q) &&
blk_attempt_plug_merge(q, bio, &request_count, NULL))
return;
- blk_queue_split(q, &bio, q->bio_split);
-
rq = blk_mq_map_request(q, bio, &data);
if (unlikely(!rq))
return;
^ permalink raw reply related [flat|nested] 22+ messages in thread
* Re: [PATCH v5 00/11] simplify block layer based on immutable biovecs
2015-07-16 7:06 ` Ming Lin
@ 2015-07-16 13:13 ` Jeff Moyer
0 siblings, 0 replies; 22+ messages in thread
From: Jeff Moyer @ 2015-07-16 13:13 UTC (permalink / raw)
To: Ming Lin
Cc: Mike Snitzer, linux-kernel, Christoph Hellwig, Jens Axboe,
Kent Overstreet, Dongsu Park, NeilBrown, Alasdair G. Kergon,
dm-devel
Ming Lin <mlin@kernel.org> writes:
> On Mon, 2015-07-13 at 11:35 -0400, Mike Snitzer wrote:
>> I will do additional review to answer 1 and 2 above. And Jeff Moyer
>> told me he'd test the patchset on one of his testbeds.
>
> Hi Jeff,
>
> FYI, here is a fix for patch 1.
> Or you can pull from my tree.
> https://git.kernel.org/cgit/linux/kernel/git/mlin/linux.git/log/?h=block-generic-req
Thanks, Ming. I'll let you know as soon as I have results worth sharing.
Cheers,
Jeff
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 40d08e3..181f343 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -1287,12 +1287,12 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
> return;
> }
>
> + blk_queue_split(q, &bio, q->bio_split);
> +
> if (!is_flush_fua && !blk_queue_nomerges(q) &&
> blk_attempt_plug_merge(q, bio, &request_count, &same_queue_rq))
> return;
>
> - blk_queue_split(q, &bio, q->bio_split);
> -
> rq = blk_mq_map_request(q, bio, &data);
> if (unlikely(!rq))
> return;
> @@ -1374,12 +1374,12 @@ static void blk_sq_make_request(struct request_queue *q, struct bio *bio)
> return;
> }
>
> + blk_queue_split(q, &bio, q->bio_split);
> +
> if (!is_flush_fua && !blk_queue_nomerges(q) &&
> blk_attempt_plug_merge(q, bio, &request_count, NULL))
> return;
>
> - blk_queue_split(q, &bio, q->bio_split);
> -
> rq = blk_mq_map_request(q, bio, &data);
> if (unlikely(!rq))
> return;
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH v5 00/11] simplify block layer based on immutable biovecs
2015-07-13 15:35 ` Mike Snitzer
2015-07-14 20:51 ` Ming Lin
2015-07-16 7:06 ` Ming Lin
@ 2015-07-23 18:21 ` Ming Lin
2015-07-27 17:50 ` Mike Snitzer
2 siblings, 1 reply; 22+ messages in thread
From: Ming Lin @ 2015-07-23 18:21 UTC (permalink / raw)
To: Mike Snitzer
Cc: linux-kernel, Christoph Hellwig, Jens Axboe, Kent Overstreet,
Dongsu Park, NeilBrown, Alasdair G. Kergon, Jeff Moyer, dm-devel
On Mon, 2015-07-13 at 11:35 -0400, Mike Snitzer wrote:
> On Mon, Jul 13 2015 at 1:12am -0400,
> Ming Lin <mlin@kernel.org> wrote:
>
> > On Mon, 2015-07-06 at 00:11 -0700, mlin@kernel.org wrote:
> > > Hi Mike,
> > >
> > > On Wed, 2015-06-10 at 17:46 -0400, Mike Snitzer wrote:
> > > > I've been busy getting DM changes for the 4.2 merge window finalized.
> > > > As such I haven't connected with others on the team to discuss this
> > > > issue.
> > > >
> > > > I'll see if we can make time in the next 2 days. But I also have
> > > > RHEL-specific kernel deadlines I'm coming up against.
> > > >
> > > > Seems late to be staging this extensive a change for 4.2... are you
> > > > pushing for this code to land in the 4.2 merge window? Or do we have
> > > > time to work this further and target the 4.3 merge?
> > > >
> > >
> > > 4.2-rc1 was out.
> > > Would you have time to work together for 4.3 merge?
> >
> > Ping ...
> >
> > What can I do to move forward?
>
> You can show further testing. Particularly that you've covered all the
> edge cases.
>
> Until someone can produce some perf test results where they are actually
> properly controlling for the splitting, we have no useful information.
>
> The primary concerns associated with this patchset are:
> 1) In the context of RAID, XFS's use of bio_add_page() used to build up
> optimal IOs when the underlying block device provides striping info
> via IO limits. With this patchset how large will bios become in
> practice _without_ bio_add_page() being bounded by the underlying IO
> limits?
Totally new to XFS code.
Did you mean xfs_buf_ioapply_map() -> bio_add_page()?
The largest size could be BIO_MAX_PAGES pages, that is 256 pages(1M
bytes).
>
> 2) The late splitting that occurs for the (presummably) large bios that
> are sent down.. how does it cope/perform in the face of very
> low/fragmented system memory?
I tested in qemu-kvm with 1G/1100M/1200M memory.
10 HDDs were attached to qemu via virtio-blk.
Then created MD RAID6 array and mkfs.xfs on it.
I use bs=2M, so there will be a lot of bio splits.
[global]
ioengine=libaio
iodepth=64
direct=1
runtime=1200
time_based
group_reporting
numjobs=8
gtod_reduce=0
norandommap
[job1]
bs=2M
directory=/mnt
size=100M
rw=write
Here is the results:
memory 4.2-rc2 4.2-rc2-patched
------ ------- ---------------
1G OOM OOM
1100M fail OK
1200M OK OK
"fail" means it hit a page allocation failure.
http://minggr.net/pub/block_patches_tests/dmesg.4.2.0-rc2
I tested 3 times for each kernel to confirm that with 1100M memory,
4.2-rc2 always hit a page allocation failure and 4.2-rc2-patched is OK.
So the patched kernel performs better in this case.
>
> 3) More open-ended comment than question: Linux has evolved to perform
> well on "enterprise" systems. We generally don't fall off a cliff on
> performance like we used to. The concern associated with this
> patchset is that if it goes in without _real_ due-diligence on
> "enterprise" scale systems and workloads it'll be too late once we
> notice the problem(s).
>
> So we really need answers to 1 and 2 above in order to feel better about
> the risks associated 3.
>
> Alasdair's feedback to you on testing still applies (and hasn't been
> done AFAIK):
> https://www.redhat.com/archives/dm-devel/2015-May/msg00203.html
>
> Particularly:
> "you might need to instrument the kernels to tell you the sizes of the
> bios being created and the amount of splitting actually happening."
I added a debug patch to record the amount of splitting actually
happened. https://goo.gl/Iiyg4Y
In the qemu 1200M memory test case,
$ cat /sys/block/md0/queue/split
discard split: 0, write same split: 0, segment split: 27400
>
> and
>
> "You may also want to test systems with a restricted amount of available
> memory to show how the splitting via worker thread performs. (Again,
> instrument to prove the extent to which the new code is being exercised.)"
Does above test with qemu make sense?
Thanks,
Ming
>
> > This patchset not only simplify block layer a lot, it's also a
> > prerequisite of the direct IO rewrite patches, which I saw 40%
> > performance improvement for null_blk and 10% improvement for NVMe
> > drives. I have been fixing bugs for the direct IO patches. I'll post it
> > once it passes xfstests.
> >
> > Mike,
> > Can I have your ACK? Or do you have other test plan?
>
> I'm not the only person with concerns. I share Alasdair's concerns.
> Jeff Moyer is also concerned about the implications of this patchset.
> We're all in favor of this patchset's cleanup _if and only if_ it can be
> proven that we aren't going to be falling off a cliff on performance due
> to some pathological workload (be it under memory pressure or whatever).
>
> Apologies for not being able to put time to this like I hoped. But that
> doesn't mean you are off the hook on showing you've done the testing and
> understand the scope and implications of the changes you're pushing for.
>
> I will do additional review to answer 1 and 2 above. And Jeff Moyer
> told me he'd test the patchset on one of his testbeds.
>
> But if you can help answer 1 and 2 above that'd go a long way.
>
> Thanks,
> Mike
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH v5 00/11] simplify block layer based on immutable biovecs
2015-07-23 18:21 ` Ming Lin
@ 2015-07-27 17:50 ` Mike Snitzer
2015-07-27 22:11 ` Ming Lin
0 siblings, 1 reply; 22+ messages in thread
From: Mike Snitzer @ 2015-07-27 17:50 UTC (permalink / raw)
To: Ming Lin
Cc: Jens Axboe, dm-devel, linux-kernel, Christoph Hellwig,
Jeff Moyer, Dongsu Park, Kent Overstreet, Alasdair G. Kergon
On Thu, Jul 23 2015 at 2:21pm -0400,
Ming Lin <mlin@kernel.org> wrote:
> On Mon, 2015-07-13 at 11:35 -0400, Mike Snitzer wrote:
> > On Mon, Jul 13 2015 at 1:12am -0400,
> > Ming Lin <mlin@kernel.org> wrote:
> >
> > > On Mon, 2015-07-06 at 00:11 -0700, mlin@kernel.org wrote:
> > > > Hi Mike,
> > > >
> > > > On Wed, 2015-06-10 at 17:46 -0400, Mike Snitzer wrote:
> > > > > I've been busy getting DM changes for the 4.2 merge window finalized.
> > > > > As such I haven't connected with others on the team to discuss this
> > > > > issue.
> > > > >
> > > > > I'll see if we can make time in the next 2 days. But I also have
> > > > > RHEL-specific kernel deadlines I'm coming up against.
> > > > >
> > > > > Seems late to be staging this extensive a change for 4.2... are you
> > > > > pushing for this code to land in the 4.2 merge window? Or do we have
> > > > > time to work this further and target the 4.3 merge?
> > > > >
> > > >
> > > > 4.2-rc1 was out.
> > > > Would you have time to work together for 4.3 merge?
> > >
> > > Ping ...
> > >
> > > What can I do to move forward?
> >
> > You can show further testing. Particularly that you've covered all the
> > edge cases.
> >
> > Until someone can produce some perf test results where they are actually
> > properly controlling for the splitting, we have no useful information.
> >
> > The primary concerns associated with this patchset are:
> > 1) In the context of RAID, XFS's use of bio_add_page() used to build up
> > optimal IOs when the underlying block device provides striping info
> > via IO limits. With this patchset how large will bios become in
> > practice _without_ bio_add_page() being bounded by the underlying IO
> > limits?
>
> Totally new to XFS code.
> Did you mean xfs_buf_ioapply_map() -> bio_add_page()?
Yes. But there is also:
xfs_vm_writepage -> xfs_submit_ioend -> xfs_bio_add_buffer -> bio_add_page
Basically in the old code XFS sized IO accordingly based on the
bio_add_page feedback loop.
> The largest size could be BIO_MAX_PAGES pages, that is 256 pages(1M
> bytes).
Independent of this late splitting work (but related): we really should
look to fixup/extend BIO_MAX_PAGES to cover just barely "too large"
configurations, e.g. 10+2 RAID6 with 128K chunk, so 1280K for a full
stripe. Ideally we'd be able to read/reite full stripes.
> > 2) The late splitting that occurs for the (presummably) large bios that
> > are sent down.. how does it cope/perform in the face of very
> > low/fragmented system memory?
>
> I tested in qemu-kvm with 1G/1100M/1200M memory.
> 10 HDDs were attached to qemu via virtio-blk.
> Then created MD RAID6 array and mkfs.xfs on it.
>
> I use bs=2M, so there will be a lot of bio splits.
>
> [global]
> ioengine=libaio
> iodepth=64
> direct=1
> runtime=1200
> time_based
> group_reporting
> numjobs=8
> gtod_reduce=0
> norandommap
>
> [job1]
> bs=2M
> directory=/mnt
> size=100M
> rw=write
>
> Here is the results:
>
> memory 4.2-rc2 4.2-rc2-patched
> ------ ------- ---------------
> 1G OOM OOM
> 1100M fail OK
> 1200M OK OK
>
> "fail" means it hit a page allocation failure.
> http://minggr.net/pub/block_patches_tests/dmesg.4.2.0-rc2
>
> I tested 3 times for each kernel to confirm that with 1100M memory,
> 4.2-rc2 always hit a page allocation failure and 4.2-rc2-patched is OK.
>
> So the patched kernel performs better in this case.
Interesting. Seems to prove Kent's broader point that he used mempools
and handles allocations better than the old code did.
> > 3) More open-ended comment than question: Linux has evolved to perform
> > well on "enterprise" systems. We generally don't fall off a cliff on
> > performance like we used to. The concern associated with this
> > patchset is that if it goes in without _real_ due-diligence on
> > "enterprise" scale systems and workloads it'll be too late once we
> > notice the problem(s).
> >
> > So we really need answers to 1 and 2 above in order to feel better about
> > the risks associated 3.
> >
> > Alasdair's feedback to you on testing still applies (and hasn't been
> > done AFAIK):
> > https://www.redhat.com/archives/dm-devel/2015-May/msg00203.html
> >
> > Particularly:
> > "you might need to instrument the kernels to tell you the sizes of the
> > bios being created and the amount of splitting actually happening."
>
> I added a debug patch to record the amount of splitting actually
> happened. https://goo.gl/Iiyg4Y
>
> In the qemu 1200M memory test case,
>
> $ cat /sys/block/md0/queue/split
> discard split: 0, write same split: 0, segment split: 27400
>
> >
> > and
> >
> > "You may also want to test systems with a restricted amount of available
> > memory to show how the splitting via worker thread performs. (Again,
> > instrument to prove the extent to which the new code is being exercised.)"
>
> Does above test with qemu make sense?
The test is showing that systems with limited memory are performing
better but, without looking at the patchset in detail, I'm not sure what
your splitting accounting patch is showing.
Are you saying that:
1) the code only splits via worker threads
2) with 27400 splits in the 1200M case the splitting certainly isn't
making things any worse.
But for me the bigger take away is: the old merge_bvec code (no late
splitting) is more prone to allocation failure then the new code.
On that point alone I'm OK with this patchset going forward.
I'll reviewer the implementation details as they relate to DM now, but
that is just a formality. My hope is that I'll be abke to provide my
Acked-by very soon.
Mike
^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH v5 00/11] simplify block layer based on immutable biovecs
2015-07-27 17:50 ` Mike Snitzer
@ 2015-07-27 22:11 ` Ming Lin
2015-07-27 22:16 ` Ming Lin
0 siblings, 1 reply; 22+ messages in thread
From: Ming Lin @ 2015-07-27 22:11 UTC (permalink / raw)
To: Mike Snitzer
Cc: Jens Axboe, dm-devel, linux-kernel, Christoph Hellwig,
Jeff Moyer, Dongsu Park, Kent Overstreet, Alasdair G. Kergon
On Mon, 2015-07-27 at 13:50 -0400, Mike Snitzer wrote:
> On Thu, Jul 23 2015 at 2:21pm -0400,
> Ming Lin <mlin@kernel.org> wrote:
>
> > On Mon, 2015-07-13 at 11:35 -0400, Mike Snitzer wrote:
> > > On Mon, Jul 13 2015 at 1:12am -0400,
> > > Ming Lin <mlin@kernel.org> wrote:
> > >
> > > > On Mon, 2015-07-06 at 00:11 -0700, mlin@kernel.org wrote:
> > > > > Hi Mike,
> > > > >
> > > > > On Wed, 2015-06-10 at 17:46 -0400, Mike Snitzer wrote:
> > > > > > I've been busy getting DM changes for the 4.2 merge window finalized.
> > > > > > As such I haven't connected with others on the team to discuss this
> > > > > > issue.
> > > > > >
> > > > > > I'll see if we can make time in the next 2 days. But I also have
> > > > > > RHEL-specific kernel deadlines I'm coming up against.
> > > > > >
> > > > > > Seems late to be staging this extensive a change for 4.2... are you
> > > > > > pushing for this code to land in the 4.2 merge window? Or do we have
> > > > > > time to work this further and target the 4.3 merge?
> > > > > >
> > > > >
> > > > > 4.2-rc1 was out.
> > > > > Would you have time to work together for 4.3 merge?
> > > >
> > > > Ping ...
> > > >
> > > > What can I do to move forward?
> > >
> > > You can show further testing. Particularly that you've covered all the
> > > edge cases.
> > >
> > > Until someone can produce some perf test results where they are actually
> > > properly controlling for the splitting, we have no useful information.
> > >
> > > The primary concerns associated with this patchset are:
> > > 1) In the context of RAID, XFS's use of bio_add_page() used to build up
> > > optimal IOs when the underlying block device provides striping info
> > > via IO limits. With this patchset how large will bios become in
> > > practice _without_ bio_add_page() being bounded by the underlying IO
> > > limits?
> >
> > Totally new to XFS code.
> > Did you mean xfs_buf_ioapply_map() -> bio_add_page()?
>
> Yes. But there is also:
> xfs_vm_writepage -> xfs_submit_ioend -> xfs_bio_add_buffer -> bio_add_page
>
> Basically in the old code XFS sized IO accordingly based on the
> bio_add_page feedback loop.
>
> > The largest size could be BIO_MAX_PAGES pages, that is 256 pages(1M
> > bytes).
>
> Independent of this late splitting work (but related): we really should
> look to fixup/extend BIO_MAX_PAGES to cover just barely "too large"
> configurations, e.g. 10+2 RAID6 with 128K chunk, so 1280K for a full
> stripe. Ideally we'd be able to read/reite full stripes.
>
> > > 2) The late splitting that occurs for the (presummably) large bios that
> > > are sent down.. how does it cope/perform in the face of very
> > > low/fragmented system memory?
> >
> > I tested in qemu-kvm with 1G/1100M/1200M memory.
> > 10 HDDs were attached to qemu via virtio-blk.
> > Then created MD RAID6 array and mkfs.xfs on it.
> >
> > I use bs=2M, so there will be a lot of bio splits.
> >
> > [global]
> > ioengine=libaio
> > iodepth=64
> > direct=1
> > runtime=1200
> > time_based
> > group_reporting
> > numjobs=8
> > gtod_reduce=0
> > norandommap
> >
> > [job1]
> > bs=2M
> > directory=/mnt
> > size=100M
> > rw=write
> >
> > Here is the results:
> >
> > memory 4.2-rc2 4.2-rc2-patched
> > ------ ------- ---------------
> > 1G OOM OOM
> > 1100M fail OK
> > 1200M OK OK
> >
> > "fail" means it hit a page allocation failure.
> > http://minggr.net/pub/block_patches_tests/dmesg.4.2.0-rc2
> >
> > I tested 3 times for each kernel to confirm that with 1100M memory,
> > 4.2-rc2 always hit a page allocation failure and 4.2-rc2-patched is OK.
> >
> > So the patched kernel performs better in this case.
>
> Interesting. Seems to prove Kent's broader point that he used mempools
> and handles allocations better than the old code did.
>
> > > 3) More open-ended comment than question: Linux has evolved to perform
> > > well on "enterprise" systems. We generally don't fall off a cliff on
> > > performance like we used to. The concern associated with this
> > > patchset is that if it goes in without _real_ due-diligence on
> > > "enterprise" scale systems and workloads it'll be too late once we
> > > notice the problem(s).
> > >
> > > So we really need answers to 1 and 2 above in order to feel better about
> > > the risks associated 3.
> > >
> > > Alasdair's feedback to you on testing still applies (and hasn't been
> > > done AFAIK):
> > > https://www.redhat.com/archives/dm-devel/2015-May/msg00203.html
> > >
> > > Particularly:
> > > "you might need to instrument the kernels to tell you the sizes of the
> > > bios being created and the amount of splitting actually happening."
> >
> > I added a debug patch to record the amount of splitting actually
> > happened. https://goo.gl/Iiyg4Y
> >
> > In the qemu 1200M memory test case,
> >
> > $ cat /sys/block/md0/queue/split
> > discard split: 0, write same split: 0, segment split: 27400
> >
> > >
> > > and
> > >
> > > "You may also want to test systems with a restricted amount of available
> > > memory to show how the splitting via worker thread performs. (Again,
> > > instrument to prove the extent to which the new code is being exercised.)"
> >
> > Does above test with qemu make sense?
>
> The test is showing that systems with limited memory are performing
> better but, without looking at the patchset in detail, I'm not sure what
> your splitting accounting patch is showing.
>
> Are you saying that:
> 1) the code only splits via worker threads
> 2) with 27400 splits in the 1200M case the splitting certainly isn't
> making things any worse.
With this patchset, bio_add_page() always create as large as possible
bio(1M bytes max). The patch accounts how many times the bio was split
due to device limitation, for example, bio->bi_phys_segments >
queue_max_segments(q).
It's more interesting if we look at how many bios are allocated for each
application IO request.
e.g. 10+2 RAID6 with 128K chunk.
Assume we only consider device max_segments limitation.
# cat /sys/block/md0/queue/max_segments
126
So blk_queue_split() will split the bio if its size > 126 pages(504K
bytes).
Let's do a 1280K request.
# dd if=/dev/zero of=/dev/md0 bs=1280k count=1 oflag=direct
With below debug patch,
diff --git a/drivers/md/md.c b/drivers/md/md.c
index a4aa6e5..2fde2ce 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -259,6 +259,10 @@ static void md_make_request(struct request_queue *q, struct bio *bio)
blk_queue_split(q, &bio, q->bio_split);
+ if (!strcmp(current->comm, "dd") && bio_data_dir(bio) == WRITE)
+ printk("%s: bio %p, offset %lu, size %uK\n", __func__,
+ bio, bio->bi_iter.bi_sector<<9, bio->bi_iter.bi_size>>10);
+
if (mddev == NULL || mddev->pers == NULL
|| !mddev->ready) {
bio_io_error(bio);
For non-patched kernel, 10 bios were allocated.
[ 11.921775] md_make_request: bio ffff8800469c5d00, offset 0, size 128K
[ 11.945692] md_make_request: bio ffff8800471df700, offset 131072, size 128K
[ 11.946596] md_make_request: bio ffff8800471df200, offset 262144, size 128K
[ 11.947694] md_make_request: bio ffff8800471df300, offset 393216, size 128K
[ 11.949421] md_make_request: bio ffff8800471df900, offset 524288, size 128K
[ 11.956345] md_make_request: bio ffff8800471df000, offset 655360, size 128K
[ 11.957586] md_make_request: bio ffff8800471dfb00, offset 786432, size 128K
[ 11.959086] md_make_request: bio ffff8800471dfc00, offset 917504, size 128K
[ 11.964221] md_make_request: bio ffff8800471df400, offset 1048576, size 128K
[ 11.965117] md_make_request: bio ffff8800471df800, offset 1179648, size 128K
For patched kernel, only 2 bios were allocated at base case and 0 split.
[ 20.034036] md_make_request: bio ffff880046a2ee00, offset 0, size 1024K
[ 20.046104] md_make_request: bio ffff880046a2e500, offset 1048576, size 256K
4 bios allocated for worst case and 2 splits.
One of the worst case could be the memory is so segmented that 1M bio comprised
of 256 bi_phys_segments. So it needs 2 splits.
1280K = 1M + 256K
ffff880046a30900 and ffff880046a21500 are the original bios.
ffff880046a30200 and ffff880046a21e00 are the split bios.
[ 13.049323] md_make_request: bio ffff880046a30200, offset 0, size 504K
[ 13.080057] md_make_request: bio ffff880046a21e00, offset 516096, size 504K
[ 13.082857] md_make_request: bio ffff880046a30900, offset 1032192, size 16K
[ 13.084983] md_make_request: bio ffff880046a21500, offset 1048576, size 256K
# cat /sys/block/md0/queue/split
discard split: 0, write same split: 0, segment split: 2
>
> But for me the bigger take away is: the old merge_bvec code (no late
> splitting) is more prone to allocation failure then the new code.
Yes, as I showed above.
>
> On that point alone I'm OK with this patchset going forward.
>
> I'll reviewer the implementation details as they relate to DM now, but
> that is just a formality. My hope is that I'll be abke to provide my
> Acked-by very soon.
Great! Thanks.
>
> Mike
^ permalink raw reply related [flat|nested] 22+ messages in thread* Re: [PATCH v5 00/11] simplify block layer based on immutable biovecs
2015-07-27 22:11 ` Ming Lin
@ 2015-07-27 22:16 ` Ming Lin
0 siblings, 0 replies; 22+ messages in thread
From: Ming Lin @ 2015-07-27 22:16 UTC (permalink / raw)
To: Ming Lin
Cc: Mike Snitzer, Jens Axboe, dm-devel, lkml, Christoph Hellwig,
Jeff Moyer, Dongsu Park, Kent Overstreet, Alasdair G. Kergon
On Mon, Jul 27, 2015 at 3:11 PM, Ming Lin <mlin@kernel.org> wrote:
> It's more interesting if we look at how many bios are allocated for each
> application IO request.
>
> e.g. 10+2 RAID6 with 128K chunk.
>
> Assume we only consider device max_segments limitation.
>
> # cat /sys/block/md0/queue/max_segments
> 126
>
> So blk_queue_split() will split the bio if its size > 126 pages(504K
> bytes).
Fix myself.
I mean, blk_queue_split() will split the bio if bi_phys_segments > 126
^ permalink raw reply [flat|nested] 22+ messages in thread