Commit 641608f3 authored by Alexey Romanov's avatar Alexey Romanov Committed by Andrew Morton
Browse files

zram: don't retry compress incompressible page 

It doesn't make sense for us to retry to compress an uncompressible page
(comp_len == PAGE_SIZE) in zsmalloc slowpath, because we will be storing
it uncompressed anyway.  We can avoid wasting time on another compression
attempt.  It is enough to take lock (zcomp_stream_get) and execute the
code below.

Link: https://lkml.kernel.org/r/20220824113117.78849-1-avromanov@sberdevices.ru


Signed-off-by: default avatarAlexey Romanov <avromanov@sberdevices.ru>
Signed-off-by: default avatarDmitry Rokosov <ddrokosov@sberdevices.ru>
Reviewed-by: default avatarSergey Senozhatsky <senozhatsky@chromium.org>
Cc: Alexey Romanov <avromanov@sberdevices.ru>
Cc: Dmitry Rokosov <DDRokosov@sberdevices.ru>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 3083da7b

drivers/block/zram/zram_drv.c

+12 −2
Original line number Diff line number Diff line
@@ -1410,9 +1410,19 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, 
		handle = zs_malloc(zram->mem_pool, comp_len,

				GFP_NOIO | __GFP_HIGHMEM |

				__GFP_MOVABLE);

		if (!IS_ERR((void *)handle))

			goto compress_again;

		if (IS_ERR((void *)handle))

			return PTR_ERR((void *)handle);



		if (comp_len != PAGE_SIZE)

			goto compress_again;

		/*

		 * If the page is not compressible, you need to acquire the lock and

		 * execute the code below. The zcomp_stream_get() call is needed to

		 * disable the cpu hotplug and grab the zstrm buffer back.

		 * It is necessary that the dereferencing of the zstrm variable below

		 * occurs correctly.

		 */

		zstrm = zcomp_stream_get(zram->comp);

	}



	alloced_pages = zs_get_total_pages(zram->mem_pool);