[3.16.y-ckt stable] Patch "dm bufio: when done scanning return from __scan immediately" has been added to staging queue
Luis Henriques
luis.henriques at canonical.com
Mon Nov 24 15:03:42 UTC 2014
This is a note to let you know that I have just added a patch titled
dm bufio: when done scanning return from __scan immediately
to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue
This patch is scheduled to be released in version 3.16.7-ckt2.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Luis
------
>From 397c6bba5bcc9d0f779e536e8171c73e030ddf7f Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka at redhat.com>
Date: Wed, 1 Oct 2014 13:29:48 -0400
Subject: 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 at redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka at redhat.com>
Signed-off-by: Mike Snitzer <snitzer at redhat.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
drivers/md/dm-bufio.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index da2ebac231b9..598ba99d2e15 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;
}
--
2.1.0
More information about the kernel-team
mailing list