linux-kernel - [PATCH AUTOSEL 5.16 17/34] mm: io_uring: allow oom-killer from io_uring

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Date:   Tue, 15 Feb 2022 10:26:40 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Shakeel Butt <shakeelb@...gle.com>, Jens Axboe <axboe@...nel.dk>,
        Sasha Levin <sashal@...nel.org>, io-uring@...r.kernel.org
Subject: [PATCH AUTOSEL 5.16 17/34] mm: io_uring: allow oom-killer from io_uring_setup

From: Shakeel Butt <shakeelb@...gle.com>

[ Upstream commit 0a3f1e0beacf6cc8ae5f846b0641c1df476e83d6 ]

On an overcommitted system which is running multiple workloads of
varying priorities, it is preferred to trigger an oom-killer to kill a
low priority workload than to let the high priority workload receiving
ENOMEMs. On our memory overcommitted systems, we are seeing a lot of
ENOMEMs instead of oom-kills because io_uring_setup callchain is using
__GFP_NORETRY gfp flag which avoids the oom-killer. Let's remove it and
allow the oom-killer to kill a lower priority job.

Signed-off-by: Shakeel Butt <shakeelb@...gle.com>
Link: https://lore.kernel.org/r/20220125051736.2981459-1-shakeelb@google.com
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/io_uring.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 698db7fb62e06..a92f276f21d9c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8872,10 +8872,9 @@ static void io_mem_free(void *ptr)
 
 static void *io_mem_alloc(size_t size)
 {
-	gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP |
-				__GFP_NORETRY | __GFP_ACCOUNT;
+	gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP;
 
-	return (void *) __get_free_pages(gfp_flags, get_order(size));
+	return (void *) __get_free_pages(gfp, get_order(size));
 }
 
 static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries,
-- 
2.34.1