This is a note to let you know that I've just added the patch titled
dm writecache: set a default MAX_WRITEBACK_JOBS
to the 5.18-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:
dm-writecache-set-a-default-max_writeback_jobs.patch
and it can be found in the queue-5.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 36bc440738ef1c764c40ac40f0a1d699ee8d1d3f
Author: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Date: Wed Jul 13 07:09:04 2022 -0400
dm writecache: set a default MAX_WRITEBACK_JOBS
[ Upstream commit ca7dc242e358e46d963b32f9d9dd829785a9e957 ]
dm-writecache has the capability to limit the number of writeback jobs
in progress. However, this feature was off by default. As such there
were some out-of-memory crashes observed when lowering the low
watermark while the cache is full.
This commit enables writeback limit by default. It is set to 256MiB or
1/16 of total system memory, whichever is smaller.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index e5acb393f70b..27557b852c94 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -22,7 +22,7 @@
#define HIGH_WATERMARK 50
#define LOW_WATERMARK 45
-#define MAX_WRITEBACK_JOBS 0
+#define MAX_WRITEBACK_JOBS min(0x10000000 / PAGE_SIZE, totalram_pages() / 16)
#define ENDIO_LATENCY 16
#define WRITEBACK_LATENCY 64
#define AUTOCOMMIT_BLOCKS_SSD 65536
