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| author | Mikulas Patocka <mpatocka@redhat.com> | 2014-10-01 13:29:48 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-11-14 08:59:51 -0800 |
| commit | 7f6c5d82bf5bb50bb3d836f5b0f207e0afeadeba (patch) | |
| tree | b234dfe4522fe48ffcfbbce5d63868c8f503250d /drivers | |
| parent | 07321b43e0a6695d39b5ebb7633960a3f89e138f (diff) | |
| download | linux-stable-7f6c5d82bf5bb50bb3d836f5b0f207e0afeadeba.tar.gz linux-stable-7f6c5d82bf5bb50bb3d836f5b0f207e0afeadeba.tar.bz2 linux-stable-7f6c5d82bf5bb50bb3d836f5b0f207e0afeadeba.zip | |
dm bufio: when done scanning return from __scan immediately
commit 0e825862f3c04cee40e25f55680333728a4ffa9b upstream.
When __scan frees the required number of buffer entries that the
shrinker requested (nr_to_scan becomes zero) it must return. Before
this fix the __scan code exited only the inner loop and continued in the
outer loop -- which could result in reduced performance due to extra
buffers being freed (e.g. unnecessarily evicted thinp metadata needing
to be synchronously re-read into bufio's cache).
Also, move dm_bufio_cond_resched to __scan's inner loop, so that
iterating the bufio client's lru lists doesn't result in scheduling
latency.
Reported-by: Joe Thornber <thornber@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/md/dm-bufio.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index 148c6f5bd8cd..ca1621b49453 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -1486,9 +1486,9 @@ static long __scan(struct dm_bufio_client *c, unsigned long nr_to_scan, list_for_each_entry_safe_reverse(b, tmp, &c->lru[l], lru_list) { freed += __cleanup_old_buffer(b, gfp_mask, 0); if (!--nr_to_scan) - break; + return freed; + dm_bufio_cond_resched(); } - dm_bufio_cond_resched(); } return freed; } |