[dm-devel] [PATCH] dm-writecache: set MAX_WRITEBACK_JOBS

[Mikulas Patocka]

On Wed, 13 Jul 2022, Mikulas Patocka wrote:

> This commit enables writeback limit by default. It is set to 1GiB or 1/16

The limit is really 256MiB, not 1GiB. I think that 1GiB is too much.

Mikulas

> of total system memory, whichever is smaller.
> 
> Signed-off-by: Mikulas Patocka <mpatocka at redhat.com>
> 
> ---
>  drivers/md/dm-writecache.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Index: linux-2.6/drivers/md/dm-writecache.c
> ===================================================================
> --- linux-2.6.orig/drivers/md/dm-writecache.c	2022-07-13 13:07:52.000000000 +0200
> +++ linux-2.6/drivers/md/dm-writecache.c	2022-07-13 13:08:19.000000000 +0200
> @@ -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
>