The patch titled
Subject: mm: oom_kill: add trace logs in process_mrelease() system call
has been added to the -mm mm-unstable branch. Its filename is
mm-oom_kill-add-trace-logs-in-process_mrelease-system-call.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-oom_kill-add-trace-logs-in-process_mrelease-system-call.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Charan Teja Kalla <quic_charante@xxxxxxxxxxx>
Subject: mm: oom_kill: add trace logs in process_mrelease() system call
Date: Tue, 16 Aug 2022 11:30:17 +0530
The process_mrelease() system call is used to release the memory of a
dying process from the context of the caller, which is similar to and uses
the functions of the oom reaper logic. There exist trace logs for a
process when reaped by the oom reaper. Just extend the same to when done
by the process_mrelease() system call.
This patch provides information on how much memory is freed from a process
which is being reaped. Adding trace events in the process_mrelease() path
when process is being reaped would enable more holistic debug as it
happens in oom_reap_task_mm() currently.
This extends the debug functionality for the events as described in [1] to
the process_mrelease() system call. Now the coverage of trace events is
complete.
[1] https://lore.kernel.org/all/20170530185231.GA13412@castle/T/#u
Link: https://lkml.kernel.org/r/20220816060017.17996-1-pbrahma@xxxxxxxxxxxxxxxx
Signed-off-by: Charan Teja Kalla <quic_charante@xxxxxxxxxxx>
Signed-off-by: Pratyush Brahma <quic_pbrahma@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/oom_kill.c | 24 ++++++++++++++++++++----
1 file changed, 20 insertions(+), 4 deletions(-)
--- a/mm/oom_kill.c~mm-oom_kill-add-trace-logs-in-process_mrelease-system-call
+++ a/mm/oom_kill.c
@@ -995,7 +995,6 @@ static void __oom_kill_process(struct ta
mmdrop(mm);
put_task_struct(victim);
}
-#undef K
/*
* Kill provided task unless it's secured by setting
@@ -1241,17 +1240,33 @@ SYSCALL_DEFINE2(process_mrelease, int, p
goto drop_mm;
if (mmap_read_lock_killable(mm)) {
+ trace_skip_task_reaping(task->pid);
ret = -EINTR;
- goto drop_mm;
+ goto read_unlock;
}
/*
* Check MMF_OOM_SKIP again under mmap_read_lock protection to ensure
* possible change in exit_mmap is seen
*/
- if (!test_bit(MMF_OOM_SKIP, &mm->flags) && !__oom_reap_task_mm(mm))
+ if (test_bit(MMF_OOM_SKIP, &mm->flags)) {
+ trace_skip_task_reaping(task->pid);
+ goto read_unlock;
+ }
+
+ trace_start_task_reaping(task->pid);
+
+ if (!__oom_reap_task_mm(mm))
ret = -EAGAIN;
- mmap_read_unlock(mm);
+ pr_debug("process_mrelease: reaped process %d (%s), now anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB\n",
+ task_pid_nr(task), task->comm,
+ K(get_mm_counter(mm, MM_ANONPAGES)),
+ K(get_mm_counter(mm, MM_FILEPAGES)),
+ K(get_mm_counter(mm, MM_SHMEMPAGES)));
+ trace_finish_task_reaping(task->pid);
+
+read_unlock:
+ mmap_read_unlock(mm);
drop_mm:
mmdrop(mm);
put_task:
@@ -1261,3 +1276,4 @@ put_task:
return -ENOSYS;
#endif /* CONFIG_MMU */
}
+#undef K
_
Patches currently in -mm which might be from quic_charante@xxxxxxxxxxx are
mm-page_ext-remove-unused-variable-in-offline_page_ext.patch
mm-fix-use-after-free-of-page_ext-after-race-with-memory-offline.patch
mm-cma_debug-show-complete-cma-name-in-debugfs-directories.patch
mm-oom_kill-add-trace-logs-in-process_mrelease-system-call.patch
