FEX-Emu/linux
1
0
Fork 0
mirror of https://github.com/FEX-Emu/linux.git synced 2024-12-23 01:40:30 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Btrfs: add branch prediction hints in the read page end IO function

Browse Source 
This patch add some branch prediction hints into the end IO function
of the read page, it reduced the percentage of the branch misses from
5.5% to 4.9%.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
This commit is contained in:
Miao Xie 2013-07-25 19:22:33 +08:00 committed by Chris Mason
parent 09a7f7a289
commit f2a09da9d0
1 changed files with 9 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
fs/btrfs/extent_io.c
View File

@ -2502,7 +2502,7 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
spin_lock(&tree->lock);
state = find_first_extent_bit_state(tree, start, EXTENT_LOCKED);
if (state && state->start == start) {
if (likely(state && state->start == start)) {
/*
* take a reference on the state, unlock will drop
* the ref
@ -2512,7 +2512,8 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
spin_unlock(&tree->lock);
mirror = io_bio->mirror_num;
if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
if (likely(uptodate && tree->ops &&
tree->ops->readpage_end_io_hook)) {
ret = tree->ops->readpage_end_io_hook(page, start, end,
state, mirror);
if (ret)
@ -2521,12 +2522,15 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
clean_io_failure(start, page);
}
if (!uptodate && tree->ops && tree->ops->readpage_io_failed_hook) {
if (likely(uptodate))
goto readpage_ok;
if (tree->ops && tree->ops->readpage_io_failed_hook) {
ret = tree->ops->readpage_io_failed_hook(page, mirror);
if (!ret && !err &&
test_bit(BIO_UPTODATE, &bio->bi_flags))
uptodate = 1;
} else if (!uptodate) {
} else {
/*
* The generic bio_readpage_error handles errors the
* following way: If possible, new read requests are
@ -2547,7 +2551,7 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
continue;
}
}
readpage_ok:
if (uptodate && tree->track_uptodate) {
set_extent_uptodate(tree, start, end, &cached,
GFP_ATOMIC);