[PATCH 5.16 213/227] mm: io_uring: allow oom-killer from io_uring_setup

Greg Kroah-Hartman
2022-02-21T10:04:53Z

From: Shakeel Butt <shakeelb@google.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@google.com>
Link: https://lore.kernel.org/r/20220125051736.2981459-1-shakeelb@google.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.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