The patch titled
block: don't count_vm_events for discard bio in submit_bio.
has been added to the -mm tree. Its filename is
block-dont-count_vm_events-for-discard-bio-in-submit_bio.patch
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------------------------------------------------------
Subject: block: don't count_vm_events for discard bio in submit_bio.
From: Tao Ma <tao.ma@xxxxxxxxxx>
In submit_bio() we count vm events by checking READ/WRITE. But actually
DISCARD_NOBARRIER also has the WRITE flag set. It looks as if in
blkdev_issue_discard(), we also add a page as the payload and the
bio_has_data check isn't enough. So add another check for discard bio.
Signed-off-by: Tao Ma <tao.ma@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
block/blk-core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN block/blk-core.c~block-dont-count_vm_events-for-discard-bio-in-submit_bio block/blk-core.c
--- a/block/blk-core.c~block-dont-count_vm_events-for-discard-bio-in-submit_bio
+++ a/block/blk-core.c
@@ -1598,7 +1598,7 @@ void submit_bio(int rw, struct bio *bio)
* If it's a regular read/write or a barrier with data attached,
* go through the normal accounting stuff before submission.
*/
- if (bio_has_data(bio)) {
+ if (bio_has_data(bio) && !(rw & BIO_RW_DISCARD)) {
if (rw & WRITE) {
count_vm_events(PGPGOUT, count);
} else {
_
Patches currently in -mm which might be from tao.ma@xxxxxxxxxx are
linux-next.patch
block-dont-count_vm_events-for-discard-bio-in-submit_bio.patch
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