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.

Link: https://lkml.kernel.org/r/20230508073538.1168-1-haifeng.xu@shopee.com
Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 044e1eed720eedab7374fcf2f37de34b80ea6980..612b5597d3af44610efde5474823298836de686d 100644 (file)
--- 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;
 
        /*