From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@fb.com>, Christoph Hellwig <hch@infradead.org>,
Kent Overstreet <kent.overstreet@gmail.com>
Cc: David Sterba <dsterba@suse.cz>, Huang Ying <ying.huang@intel.com>,
Mike Snitzer <snitzer@redhat.com>,
linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
Theodore Ts'o <tytso@mit.edu>,
"Darrick J . Wong" <darrick.wong@oracle.com>,
Coly Li <colyli@suse.de>, Filipe Manana <fdmanana@gmail.com>,
Randy Dunlap <rdunlap@infradead.org>,
Christoph Hellwig <hch@lst.de>
Subject: [PATCH V7 07/24] block: simplify bio_check_pages_dirty
Date: Wed, 27 Jun 2018 20:45:31 +0800 [thread overview]
Message-ID: <20180627124548.3456-8-ming.lei@redhat.com> (raw)
In-Reply-To: <20180627124548.3456-1-ming.lei@redhat.com>
From: Christoph Hellwig <hch@lst.de>
bio_check_pages_dirty currently inviolates the invariant that bv_page of
a bio_vec inside bi_vcnt shouldn't be zero, and that is going to become
really annoying with multpath biovecs. Fortunately there isn't any
all that good reason for it - once we decide to defer freeing the bio
to a workqueue holding onto a few additional pages isn't really an
issue anymore. So just check if there is a clean page that needs
dirtying in the first path, and do a second pass to free them if there
was none, while the cache is still hot.
Also use the chance to micro-optimize bio_dirty_fn a bit by not saving
irq state - we know we are called from a workqueue.
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/bio.c | 56 +++++++++++++++++++++-----------------------------------
1 file changed, 21 insertions(+), 35 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 43698bcff737..77f991688810 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1570,19 +1570,15 @@ static void bio_release_pages(struct bio *bio)
struct bio_vec *bvec;
int i;
- bio_for_each_segment_all(bvec, bio, i) {
- struct page *page = bvec->bv_page;
-
- if (page)
- put_page(page);
- }
+ bio_for_each_segment_all(bvec, bio, i)
+ put_page(bvec->bv_page);
}
/*
* bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
* If they are, then fine. If, however, some pages are clean then they must
* have been written out during the direct-IO read. So we take another ref on
- * the BIO and the offending pages and re-dirty the pages in process context.
+ * the BIO and re-dirty the pages in process context.
*
* It is expected that bio_check_pages_dirty() will wholly own the BIO from
* here on. It will run one put_page() against each page and will run one
@@ -1600,52 +1596,42 @@ static struct bio *bio_dirty_list;
*/
static void bio_dirty_fn(struct work_struct *work)
{
- unsigned long flags;
- struct bio *bio;
+ struct bio *bio, *next;
- spin_lock_irqsave(&bio_dirty_lock, flags);
- bio = bio_dirty_list;
+ spin_lock_irq(&bio_dirty_lock);
+ next = bio_dirty_list;
bio_dirty_list = NULL;
- spin_unlock_irqrestore(&bio_dirty_lock, flags);
+ spin_unlock_irq(&bio_dirty_lock);
- while (bio) {
- struct bio *next = bio->bi_private;
+ while ((bio = next) != NULL) {
+ next = bio->bi_private;
bio_set_pages_dirty(bio);
bio_release_pages(bio);
bio_put(bio);
- bio = next;
}
}
void bio_check_pages_dirty(struct bio *bio)
{
struct bio_vec *bvec;
- int nr_clean_pages = 0;
+ unsigned long flags;
int i;
bio_for_each_segment_all(bvec, bio, i) {
- struct page *page = bvec->bv_page;
-
- if (PageDirty(page) || PageCompound(page)) {
- put_page(page);
- bvec->bv_page = NULL;
- } else {
- nr_clean_pages++;
- }
+ if (!PageDirty(bvec->bv_page) && !PageCompound(bvec->bv_page))
+ goto defer;
}
- if (nr_clean_pages) {
- unsigned long flags;
-
- spin_lock_irqsave(&bio_dirty_lock, flags);
- bio->bi_private = bio_dirty_list;
- bio_dirty_list = bio;
- spin_unlock_irqrestore(&bio_dirty_lock, flags);
- schedule_work(&bio_dirty_work);
- } else {
- bio_put(bio);
- }
+ bio_release_pages(bio);
+ bio_put(bio);
+ return;
+defer:
+ spin_lock_irqsave(&bio_dirty_lock, flags);
+ bio->bi_private = bio_dirty_list;
+ bio_dirty_list = bio;
+ spin_unlock_irqrestore(&bio_dirty_lock, flags);
+ schedule_work(&bio_dirty_work);
}
EXPORT_SYMBOL_GPL(bio_check_pages_dirty);
--
2.9.5
next prev parent reply other threads:[~2018-06-27 12:45 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-27 12:45 [PATCH V7 00/24] block: support multipage bvec Ming Lei
2018-06-27 12:45 ` [PATCH V7 01/24] dm: use bio_split() when splitting out the already processed bio Ming Lei
2018-06-27 13:17 ` Mike Snitzer
2018-06-27 12:45 ` [PATCH V7 02/24] bcache: don't clone bio in bch_data_verify Ming Lei
2018-06-27 12:45 ` [PATCH V7 03/24] exofs: use bio_clone_fast in _write_mirror Ming Lei
2018-06-27 12:45 ` [PATCH V7 04/24] block: remove bio_clone_kmalloc Ming Lei
2018-06-27 12:45 ` [PATCH V7 05/24] md: remove a bogus comment Ming Lei
2018-06-27 12:45 ` [PATCH V7 06/24] block: unexport bio_clone_bioset Ming Lei
2018-06-27 12:45 ` Ming Lei [this message]
2018-06-27 12:45 ` [PATCH V7 08/24] block: bio_set_pages_dirty can't see NULL bv_page in a valid bio_vec Ming Lei
2018-06-27 12:45 ` [PATCH V7 09/24] block: use bio_add_page in bio_iov_iter_get_pages Ming Lei
2018-06-27 12:45 ` [PATCH V7 10/24] block: introduce multipage page bvec helpers Ming Lei
2018-06-27 15:59 ` kbuild test robot
2018-11-09 11:15 ` Ming Lei
2018-06-27 12:45 ` [PATCH V7 11/24] block: introduce bio_for_each_bvec() Ming Lei
2018-06-27 12:45 ` [PATCH V7 12/24] block: use bio_for_each_bvec() to compute multipage bvec count Ming Lei
2018-06-27 12:45 ` [PATCH V7 13/24] block: use bio_for_each_bvec() to map sg Ming Lei
2018-06-27 12:45 ` [PATCH V7 14/24] block: introduce bvec_last_segment() Ming Lei
2018-06-27 12:45 ` [PATCH V7 15/24] fs/buffer.c: use bvec iterator to truncate the bio Ming Lei
2018-06-27 12:45 ` [PATCH V7 16/24] btrfs: use bvec_last_segment to get bio's last page Ming Lei
2018-06-27 12:45 ` [PATCH V7 17/24] btrfs: move bio_pages_all() to btrfs Ming Lei
2018-06-27 12:45 ` [PATCH V7 18/24] block: introduce bio_bvecs() Ming Lei
2018-06-27 12:45 ` [PATCH V7 19/24] block: loop: pass multipage bvec to iov_iter Ming Lei
2018-06-27 12:45 ` [PATCH V7 20/24] bcache: avoid to use bio_for_each_segment_all() in bch_bio_alloc_pages() Ming Lei
2018-06-27 15:55 ` Coly Li
2018-06-28 1:28 ` Ming Lei
2018-06-28 2:01 ` Coly Li
2018-06-27 12:45 ` [PATCH V7 21/24] block: allow bio_for_each_segment_all() to iterate over multipage bvec Ming Lei
2018-06-27 12:45 ` [PATCH V7 22/24] block: enable multipage bvecs Ming Lei
2018-06-27 12:45 ` [PATCH V7 23/24] block: always define BIO_MAX_PAGES as 256 Ming Lei
2018-06-27 12:45 ` [PATCH V7 24/24] block: document usage of bio iterator helpers Ming Lei
2018-06-27 18:13 ` Randy Dunlap
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