From: Goldwyn Rodrigues <rgoldwyn@suse.de>
To: linux-fsdevel@vger.kernel.org
Cc: jack@suse.com, hch@infradead.org, linux-block@vger.kernel.org,
linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org,
linux-xfs@vger.kernel.org, sagi@grimberg.me, avi@scylladb.com,
axboe@kernel.dk, linux-api@vger.kernel.org, willy@infradead.org,
Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: [PATCH 5/8] nowait aio: return on congested block device
Date: Wed, 15 Mar 2017 16:51:04 -0500 [thread overview]
Message-ID: <20170315215107.5628-6-rgoldwyn@suse.de> (raw)
In-Reply-To: <20170315215107.5628-1-rgoldwyn@suse.de>
From: Goldwyn Rodrigues <rgoldwyn@suse.com>
A new flag BIO_NOWAIT is introduced to identify bio's
orignating from iocb with IOCB_NOWAIT. This flag indicates
to return immediately if a request cannot be made instead
of retrying.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
---
block/blk-core.c | 12 ++++++++++--
block/blk-mq-sched.c | 3 +++
block/blk-mq.c | 4 ++++
fs/direct-io.c | 11 +++++++++--
include/linux/bio.h | 6 ++++++
include/linux/blk_types.h | 1 +
6 files changed, 33 insertions(+), 4 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 0eeb99e..2e5cba2 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1232,6 +1232,11 @@ static struct request *get_request(struct request_queue *q, unsigned int op,
if (!IS_ERR(rq))
return rq;
+ if (bio && bio_flagged(bio, BIO_NOWAIT)) {
+ blk_put_rl(rl);
+ return ERR_PTR(-EAGAIN);
+ }
+
if (!gfpflags_allow_blocking(gfp_mask) || unlikely(blk_queue_dying(q))) {
blk_put_rl(rl);
return rq;
@@ -2014,7 +2019,7 @@ blk_qc_t generic_make_request(struct bio *bio)
do {
struct request_queue *q = bdev_get_queue(bio->bi_bdev);
- if (likely(blk_queue_enter(q, false) == 0)) {
+ if (likely(blk_queue_enter(q, bio_flagged(bio, BIO_NOWAIT)) == 0)) {
struct bio_list hold;
struct bio_list lower, same;
@@ -2040,7 +2045,10 @@ blk_qc_t generic_make_request(struct bio *bio)
bio_list_merge(&bio_list_on_stack, &same);
bio_list_merge(&bio_list_on_stack, &hold);
} else {
- bio_io_error(bio);
+ if (unlikely(bio_flagged(bio, BIO_NOWAIT)))
+ bio_wouldblock_error(bio);
+ else
+ bio_io_error(bio);
}
bio = bio_list_pop(current->bio_list);
} while (bio);
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 09af8ff..40e78b5 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -119,6 +119,9 @@ struct request *blk_mq_sched_get_request(struct request_queue *q,
if (likely(!data->hctx))
data->hctx = blk_mq_map_queue(q, data->ctx->cpu);
+ if (likely(bio) && bio_flagged(bio, BIO_NOWAIT))
+ data->flags |= BLK_MQ_REQ_NOWAIT;
+
if (e) {
data->flags |= BLK_MQ_REQ_INTERNAL;
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 159187a..942ce8c 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1518,6 +1518,8 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
rq = blk_mq_sched_get_request(q, bio, bio->bi_opf, &data);
if (unlikely(!rq)) {
__wbt_done(q->rq_wb, wb_acct);
+ if (bio && bio_flagged(bio, BIO_NOWAIT))
+ bio_wouldblock_error(bio);
return BLK_QC_T_NONE;
}
@@ -1642,6 +1644,8 @@ static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio)
rq = blk_mq_sched_get_request(q, bio, bio->bi_opf, &data);
if (unlikely(!rq)) {
__wbt_done(q->rq_wb, wb_acct);
+ if (bio && bio_flagged(bio, BIO_NOWAIT))
+ bio_wouldblock_error(bio);
return BLK_QC_T_NONE;
}
diff --git a/fs/direct-io.c b/fs/direct-io.c
index a04ebea..f6835d3 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -386,6 +386,9 @@ dio_bio_alloc(struct dio *dio, struct dio_submit *sdio,
else
bio->bi_end_io = dio_bio_end_io;
+ if (dio->iocb->ki_flags & IOCB_NOWAIT)
+ bio_set_flag(bio, BIO_NOWAIT);
+
sdio->bio = bio;
sdio->logical_offset_in_bio = sdio->cur_page_fs_offset;
}
@@ -480,8 +483,12 @@ static int dio_bio_complete(struct dio *dio, struct bio *bio)
unsigned i;
int err;
- if (bio->bi_error)
- dio->io_error = -EIO;
+ if (bio->bi_error) {
+ if (bio_flagged(bio, BIO_NOWAIT))
+ dio->io_error = -EAGAIN;
+ else
+ dio->io_error = -EIO;
+ }
if (dio->is_async && dio->op == REQ_OP_READ && dio->should_dirty) {
err = bio->bi_error;
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 8e52119..1a92707 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -425,6 +425,12 @@ static inline void bio_io_error(struct bio *bio)
bio_endio(bio);
}
+static inline void bio_wouldblock_error(struct bio *bio)
+{
+ bio->bi_error = -EAGAIN;
+ bio_endio(bio);
+}
+
struct request_queue;
extern int bio_phys_segments(struct request_queue *, struct bio *);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index d703acb..514c08e 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -102,6 +102,7 @@ struct bio {
#define BIO_REFFED 8 /* bio has elevated ->bi_cnt */
#define BIO_THROTTLED 9 /* This bio has already been subjected to
* throttling rules. Don't do it again. */
+#define BIO_NOWAIT 10 /* don't block over blk device congestion */
/*
* Flags starting here get preserved by bio_reset() - this includes
--
2.10.2
next prev parent reply other threads:[~2017-03-15 21:51 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-15 21:50 [PATCH 0/8 v3] No wait AIO Goldwyn Rodrigues
2017-03-15 21:51 ` [PATCH 1/8] nowait aio: Introduce IOCB_RW_FLAG_NOWAIT Goldwyn Rodrigues
2017-03-15 21:51 ` [PATCH 2/8] nowait aio: Return if cannot get hold of i_rwsem Goldwyn Rodrigues
2017-03-15 21:51 ` [PATCH 3/8] nowait aio: return if direct write will trigger writeback Goldwyn Rodrigues
2017-03-16 13:08 ` Matthew Wilcox
2017-03-16 13:46 ` Goldwyn Rodrigues
2017-03-16 13:20 ` Matthew Wilcox
[not found] ` <20170316132052.GG4033-PfSpb0PWhxZc2C7mugBRk2EX/6BAtgUQ@public.gmane.org>
2017-03-16 13:46 ` Goldwyn Rodrigues
2017-03-15 21:51 ` [PATCH 4/8] nowait-aio: Introduce IOMAP_NOWAIT Goldwyn Rodrigues
2017-03-15 21:51 ` Goldwyn Rodrigues [this message]
[not found] ` <20170315215107.5628-6-rgoldwyn-l3A5Bk7waGM@public.gmane.org>
2017-03-16 14:33 ` [PATCH 5/8] nowait aio: return on congested block device Jens Axboe
2017-03-17 2:03 ` Ming Lei
2017-03-17 12:23 ` Goldwyn Rodrigues
[not found] ` <eee4683d-9f44-434f-b97f-b0b24c7b3dab-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
2017-03-24 11:32 ` Goldwyn Rodrigues
2017-03-24 14:39 ` Jens Axboe
2017-03-16 21:31 ` Dave Chinner
2017-03-17 12:23 ` Goldwyn Rodrigues
2017-03-20 17:33 ` Jan Kara
2017-03-15 21:51 ` [PATCH 6/8] nowait aio: ext4 Goldwyn Rodrigues
2017-03-15 21:51 ` [PATCH 7/8] nowait aio: xfs Goldwyn Rodrigues
2017-03-15 21:51 ` [PATCH 8/8] nowait aio: btrfs Goldwyn Rodrigues
2017-04-03 18:52 [PATCH 0/8 v4] No wait AIO Goldwyn Rodrigues
2017-04-03 18:53 ` [PATCH 5/8] nowait aio: return on congested block device Goldwyn Rodrigues
2017-04-04 6:49 ` Christoph Hellwig
2017-04-14 12:02 [PATCH 0/8 v6] No wait AIO Goldwyn Rodrigues
2017-04-14 12:02 ` [PATCH 5/8] nowait aio: return on congested block device Goldwyn Rodrigues
2017-04-19 6:45 ` Christoph Hellwig
2017-04-19 15:21 ` Goldwyn Rodrigues
2017-04-20 13:43 ` Jan Kara
2017-04-24 21:10 ` Goldwyn Rodrigues
2017-04-25 2:28 ` Jens Axboe
2017-05-09 12:22 [PATCH 0/8 v7] No wait AIO Goldwyn Rodrigues
2017-05-09 12:22 ` [PATCH 5/8] nowait aio: return on congested block device Goldwyn Rodrigues
2017-05-11 7:44 ` Christoph Hellwig
[not found] ` <20170511074451.GD15626-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2017-05-11 18:16 ` Goldwyn Rodrigues
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