This is a note to let you know that I've just added the patch titled
kasan: resched in quarantine_remove_cache()
to the 4.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kasan-resched-in-quarantine_remove_cache.patch
and it can be found in the queue-4.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 68fd814a3391c7e017ae6ace8855788748edd981 Mon Sep 17 00:00:00 2001
From: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Date: Thu, 9 Mar 2017 16:17:28 -0800
Subject: kasan: resched in quarantine_remove_cache()
From: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
commit 68fd814a3391c7e017ae6ace8855788748edd981 upstream.
We see reported stalls/lockups in quarantine_remove_cache() on machines
with large amounts of RAM. quarantine_remove_cache() needs to scan
whole quarantine in order to take out all objects belonging to the
cache. Quarantine is currently 1/32-th of RAM, e.g. on a machine with
256GB of memory that will be 8GB. Moreover quarantine scanning is a
walk over uncached linked list, which is slow.
Add cond_resched() after scanning of each non-empty batch of objects.
Batches are specifically kept of reasonable size for quarantine_put().
On a machine with 256GB of RAM we should have ~512 non-empty batches,
each with 16MB of objects.
Link: http://lkml.kernel.org/r/20170308154239.25440-1-dvyukov@xxxxxxxxxx
Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Acked-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Greg Thelen <gthelen@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/kasan/quarantine.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
--- a/mm/kasan/quarantine.c
+++ b/mm/kasan/quarantine.c
@@ -282,8 +282,15 @@ void quarantine_remove_cache(struct kmem
on_each_cpu(per_cpu_remove_cache, cache, 1);
spin_lock_irqsave(&quarantine_lock, flags);
- for (i = 0; i < QUARANTINE_BATCHES; i++)
+ for (i = 0; i < QUARANTINE_BATCHES; i++) {
+ if (qlist_empty(&global_quarantine[i]))
+ continue;
qlist_move_cache(&global_quarantine[i], &to_free, cache);
+ /* Scanning whole quarantine can take a while. */
+ spin_unlock_irqrestore(&quarantine_lock, flags);
+ cond_resched();
+ spin_lock_irqsave(&quarantine_lock, flags);
+ }
spin_unlock_irqrestore(&quarantine_lock, flags);
qlist_free_all(&to_free, cache);
Patches currently in stable-queue which might be from dvyukov@xxxxxxxxxx are
queue-4.10/kasan-resched-in-quarantine_remove_cache.patch