From: Alexey Romanov Date: Wed, 10 Aug 2022 11:28:57 +0000 (+0300) Subject: zram: don't retry compress incompressible page X-Git-Tag: howlett/maple/20220906~88 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=67461f7b6f70bca41703177af3c165a4d67bab84;p=users%2Fjedix%2Flinux-maple.git 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/20220810112857.90278-1-avromanov@sberdevices.ru Signed-off-by: Alexey Romanov Signed-off-by: Dmitry Rokosov Cc: Minchan Kim Cc: Nitin Gupta Cc: Sergey Senozhatsky Signed-off-by: Andrew Morton --- diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 226ea76cc819..0c8c211f051f 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -1410,9 +1410,20 @@ compress_again: handle = zs_malloc(zram->mem_pool, comp_len, GFP_NOIO | __GFP_HIGHMEM | __GFP_MOVABLE); - if (!IS_ERR((void *)handle)) + if (IS_ERR((void *)handle)) + return PTR_ERR((void *)handle); + + if (comp_len != PAGE_SIZE) goto compress_again; - return PTR_ERR((void *)handle); + + /* + * 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);