linux-kernel - [PATCH] zram_drv: add __GFP_NOWARN flag on call to zs

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Message-Id: <20220330052502.26072-1-jaewon31.kim@samsung.com>
Date:   Wed, 30 Mar 2022 14:25:02 +0900
From:   Jaewon Kim <jaewon31.kim@...sung.com>
To:     minchan@...nel.org, ngupta@...are.org, senozhatsky@...omium.org,
        akpm@...ux-foundation.org
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        s.suk@...sung.com, jaewon31.kim@...il.com,
        Jaewon Kim <jaewon31.kim@...sung.com>
Subject: [PATCH] zram_drv: add __GFP_NOWARN flag on call to zs_malloc

The page allocation with GFP_NOIO may fail. And zram can handle this
allocation failure. We do not need to print log for this.

Actually warn_alloc was more restricted by commit 1be334e5c088
("mm/page_alloc.c: ratelimit allocation failure warnings more
aggressively"). To catch other allocation failure, zram can use
__GFP_NOWARN.

This is what I got.

kswapd0: page allocation failure: order:0, mode:0x140000a(GFP_NOIO|__GFP_HIGHMEM|__GFP_MOVABLE), nodemask=(null)
kswapd0 cpuset=/ mems_allowed=0
Call trace:
 dump_backtrace+0x0/0x218
 show_stack+0x14/0x1c
 dump_stack+0xb8/0xf0
 warn_alloc+0x110/0x234
 __alloc_pages_nodemask+0x11c0/0x12a0
 zs_malloc+0x1ac/0x50c
 zram_bvec_rw+0x1a4/0x6a8
 zram_make_request+0x23c/0x328
 generic_make_request+0xe4/0x270
 submit_bio+0x64/0x2a8
 __swap_writepage+0x3a8/0x404
 swap_writepage+0x40/0x4c
 shrink_page_list.llvm.15153564514306699876+0xffc/0x13a0
 shrink_inactive_list+0x2dc/0x710
 shrink_node_memcg+0x394/0x940
 shrink_node+0x194/0x380

Signed-off-by: Jaewon Kim <jaewon31.kim@...sung.com>
---
 drivers/block/zram/zram_drv.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index e9474b02012d..c22201da25bb 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1405,6 +1405,7 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
 		atomic64_inc(&zram->stats.writestall);
 		handle = zs_malloc(zram->mem_pool, comp_len,
 				GFP_NOIO | __GFP_HIGHMEM |
+				__GFP_NOWARN |
 				__GFP_MOVABLE);
 		if (handle)
 			goto compress_again;
-- 
2.17.1