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. Signed-off-by: Alexey Romanov <avromanov@xxxxxxxxxxxxxx> Signed-off-by: Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxx> --- drivers/block/zram/zram_drv.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index cb253d80d72b..bb9dd8b64176 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -1413,9 +1413,20 @@ 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 (handle) + if (!handle) + return -ENOMEM; + + if (comp_len != PAGE_SIZE) goto compress_again; - return -ENOMEM; + + /* + * 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); -- 2.30.1
