2023-05-08 08:01:14

by Haifeng Xu

Subject: [PATCH] mm, oom: do not check 0 mask in out_of_memory()

Since commit 60e2793d440a ("mm, oom: do not trigger out_of_memory
from the #PF"), no user sets gfp_mask to 0. Remove the 0 mask check
and update the comments.

Signed-off-by: Haifeng Xu <[email protected]>
---
mm/oom_kill.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 044e1eed720e..612b5597d3af 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -1130,12 +1130,10 @@ bool out_of_memory(struct oom_control *oc)

/*
* The OOM killer does not compensate for IO-less reclaim.
- * pagefault_out_of_memory lost its gfp context so we have to
- * make sure exclude 0 mask - all other users should have at least
- * ___GFP_DIRECT_RECLAIM to get here. But mem_cgroup_oom() has to
- * invoke the OOM killer even if it is a GFP_NOFS allocation.
+ * But mem_cgroup_oom() has to invoke the OOM killer even
+ * if it is a GFP_NOFS allocation.
*/
- if (oc->gfp_mask && !(oc->gfp_mask & __GFP_FS) && !is_memcg_oom(oc))
+ if (!(oc->gfp_mask & __GFP_FS) && !is_memcg_oom(oc))
return true;

/*
--
2.25.1

2023-05-08 14:34:23

by Michal Hocko

Subject: Re: [PATCH] mm, oom: do not check 0 mask in out_of_memory()

On Mon 08-05-23 07:35:38, Haifeng Xu wrote:
> Since commit 60e2793d440a ("mm, oom: do not trigger out_of_memory
> from the #PF"), no user sets gfp_mask to 0. Remove the 0 mask check
> and update the comments.
>
> Signed-off-by: Haifeng Xu <[email protected]>

Acked-by: Michal Hocko <[email protected]>
Thanks!

> ---
> mm/oom_kill.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> index 044e1eed720e..612b5597d3af 100644
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -1130,12 +1130,10 @@ bool out_of_memory(struct oom_control *oc)
>
> /*
> * The OOM killer does not compensate for IO-less reclaim.
> - * pagefault_out_of_memory lost its gfp context so we have to
> - * make sure exclude 0 mask - all other users should have at least
> - * ___GFP_DIRECT_RECLAIM to get here. But mem_cgroup_oom() has to
> - * invoke the OOM killer even if it is a GFP_NOFS allocation.
> + * But mem_cgroup_oom() has to invoke the OOM killer even
> + * if it is a GFP_NOFS allocation.
> */
> - if (oc->gfp_mask && !(oc->gfp_mask & __GFP_FS) && !is_memcg_oom(oc))
> + if (!(oc->gfp_mask & __GFP_FS) && !is_memcg_oom(oc))
> return true;
>
> /*
> --
> 2.25.1

--
Michal Hocko
SUSE Labs