From: Mikulas Patocka Date: Wed, 13 Jul 2022 11:09:04 +0000 (-0400) Subject: dm writecache: set a default MAX_WRITEBACK_JOBS X-Git-Tag: v4.19.256~89 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=0dd4d4297a82ba82b7fe23d3dbdcd52de846ecca;p=thirdparty%2Fkernel%2Fstable.git dm writecache: set a default MAX_WRITEBACK_JOBS commit ca7dc242e358e46d963b32f9d9dd829785a9e957 upstream. 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 Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c index 3ca8627c2f1de..af5af0b78022b 100644 --- a/drivers/md/dm-writecache.c +++ b/drivers/md/dm-writecache.c @@ -20,7 +20,7 @@ #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