From: Mikulas Patocka <mpatocka@redhat.com>
[ 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@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/md/dm-writecache.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index d74c5a7a0ab4..d572135cd43f 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
--
2.35.1