The patch titled
Subject: mm, oom: remove 3% bonus for CAP_SYS_ADMIN processes
has been added to the -mm tree. Its filename is
mm-oom-remove-3%-bonus-for-cap_sys_admin-processes.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-oom-remove-3%25-bonus-for-cap_sys_admin-processes.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-oom-remove-3%25-bonus-for-cap_sys_admin-processes.patch
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------------------------------------------------------
From: David Rientjes <rientjes@xxxxxxxxxx>
Subject: mm, oom: remove 3% bonus for CAP_SYS_ADMIN processes
Since the 2.6 kernel, the oom killer has slightly biased away from
CAP_SYS_ADMIN processes by discounting some of its memory usage in
comparison to other processes.
This has always been implicit and nothing exactly relies on the behavior.
Gaurav notices that __task_cred() can dereference a potentially freed
pointer if the task under consideration is exiting because a reference to
the task_struct is not held.
Remove the CAP_SYS_ADMIN bias so that all processes are treated equally.
If any CAP_SYS_ADMIN process would like to be biased against, it is always
allowed to adjust /proc/pid/oom_score_adj.
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1803071548510.6996@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Reported-by: Gaurav Kohli <gkohli@xxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/oom_kill.c | 7 -------
1 file changed, 7 deletions(-)
diff -puN mm/oom_kill.c~mm-oom-remove-3%-bonus-for-cap_sys_admin-processes mm/oom_kill.c
--- a/mm/oom_kill.c~mm-oom-remove-3%-bonus-for-cap_sys_admin-processes
+++ a/mm/oom_kill.c
@@ -226,13 +226,6 @@ unsigned long oom_badness(struct task_st
mm_pgtables_bytes(p->mm) / PAGE_SIZE;
task_unlock(p);
- /*
- * Root processes get 3% bonus, just like the __vm_enough_memory()
- * implementation used by LSMs.
- */
- if (has_capability_noaudit(p, CAP_SYS_ADMIN))
- points -= (points * 3) / 100;
-
/* Normalize to oom_score_adj units */
adj *= totalpages / 1000;
points += adj;
_
Patches currently in -mm which might be from rientjes@xxxxxxxxxx are
mm-page_alloc-extend-kernelcore-and-movablecore-for-percent.patch
mm-page_alloc-extend-kernelcore-and-movablecore-for-percent-fix.patch
mm-page_alloc-move-mirrored_kernelcore-to-__meminitdata.patch
mm-compaction-drain-pcps-for-zone-when-kcompactd-fails.patch
mm-oom-remove-3%-bonus-for-cap_sys_admin-processes.patch
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