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| author | Filipe Manana <fdmanana@suse.com> | 2015-03-31 14:16:52 +0100 |
|---|---|---|
| committer | Chris Mason <clm@fb.com> | 2015-06-10 07:02:43 -0700 |
| commit | b659ef027792219b590d67a2baf1643a93727d29 (patch) | |
| tree | 648b746a44cbbdb2b27d17dc10513a87496d9b88 /fs/btrfs/ordered-data.c | |
| parent | 1ab818b137e198e4d06e987a4b089411f2e39d40 (diff) | |
| download | linux-b659ef027792219b590d67a2baf1643a93727d29.tar.bz2 | |
Btrfs: avoid syncing log in the fast fsync path when not necessary
Commit 3a8b36f37806 ("Btrfs: fix data loss in the fast fsync path") added
a performance regression for that causes an unnecessary sync of the log
trees (fs/subvol and root log trees) when 2 consecutive fsyncs are done
against a file, without no writes or any metadata updates to the inode in
between them and if a transaction is committed before the second fsync is
called.
Huang Ying reported this to lkml (https://lkml.org/lkml/2015/3/18/99)
after a test sysbench test that measured a -62% decrease of file io
requests per second for that tests' workload.
The test is:
echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
echo performance > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor
echo performance > /sys/devices/system/cpu/cpu2/cpufreq/scaling_governor
echo performance > /sys/devices/system/cpu/cpu3/cpufreq/scaling_governor
mkfs -t btrfs /dev/sda2
mount -t btrfs /dev/sda2 /fs/sda2
cd /fs/sda2
for ((i = 0; i < 1024; i++)); do fallocate -l 67108864 testfile.$i; done
sysbench --test=fileio --max-requests=0 --num-threads=4 --max-time=600 \
--file-test-mode=rndwr --file-total-size=68719476736 --file-io-mode=sync \
--file-num=1024 run
A test on kvm guest, running a debug kernel gave me the following results:
Without 3a8b36f378060d: 16.01 reqs/sec
With 3a8b36f378060d: 3.39 reqs/sec
With 3a8b36f378060d and this patch: 16.04 reqs/sec
Reported-by: Huang Ying <ying.huang@intel.com>
Tested-by: Huang, Ying <ying.huang@intel.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs/ordered-data.c')
| -rw-r--r-- | fs/btrfs/ordered-data.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c index 47966cb3d4b6..ceccd078c93d 100644 --- a/fs/btrfs/ordered-data.c +++ b/fs/btrfs/ordered-data.c @@ -837,6 +837,20 @@ out: return entry; } +bool btrfs_have_ordered_extents_in_range(struct inode *inode, + u64 file_offset, + u64 len) +{ + struct btrfs_ordered_extent *oe; + + oe = btrfs_lookup_ordered_range(inode, file_offset, len); + if (oe) { + btrfs_put_ordered_extent(oe); + return true; + } + return false; +} + /* * lookup and return any extent before 'file_offset'. NULL is returned * if none is found |