The patch titled
oom: select_bad_process(): never choose tasks with badness == 0
has been added to the -mm tree. Its filename is
oom-select_bad_process-never-choose-tasks-with-badness-==-0.patch
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------------------------------------------------------
Subject: oom: select_bad_process(): never choose tasks with badness == 0
From: Oleg Nesterov <oleg@xxxxxxxxxx>
As David pointed out, we should fix select_bad_process() which currently
always selects the first process which was not filtered out before
oom_badness(), no matter what oom_badness() returns.
Change the code to ignore the process if oom_badness() returns 0, this
matters Documentation/filesystems/proc.txt and this merely looks better.
This also allows us to do more cleanups:
- no need to check OOM_SCORE_ADJ_MIN in select_bad_process(),
oom_badness() returns 0 in this case.
- oom_badness() can simply return 0 instead of -1 if the task
has no ->mm.
Now we can make it "unsigned" again, the signness and the
special "points >= 0" in select_bad_process() was added to
preserve the current behaviour.
Suggested-by: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/oom.h | 3 ++-
mm/oom_kill.c | 11 ++++-------
2 files changed, 6 insertions(+), 8 deletions(-)
diff -puN include/linux/oom.h~oom-select_bad_process-never-choose-tasks-with-badness-==-0 include/linux/oom.h
--- a/include/linux/oom.h~oom-select_bad_process-never-choose-tasks-with-badness-==-0
+++ a/include/linux/oom.h
@@ -40,7 +40,8 @@ enum oom_constraint {
CONSTRAINT_MEMORY_POLICY,
};
-extern int oom_badness(struct task_struct *p, unsigned long totalpages);
+extern unsigned int oom_badness(struct task_struct *p,
+ unsigned long totalpages);
extern int try_set_zone_oom(struct zonelist *zonelist, gfp_t gfp_flags);
extern void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_flags);
diff -puN mm/oom_kill.c~oom-select_bad_process-never-choose-tasks-with-badness-==-0 mm/oom_kill.c
--- a/mm/oom_kill.c~oom-select_bad_process-never-choose-tasks-with-badness-==-0
+++ a/mm/oom_kill.c
@@ -154,7 +154,7 @@ static unsigned long oom_forkbomb_penalt
* predictable as possible. The goal is to return the highest value for the
* task consuming the most memory to avoid subsequent oom conditions.
*/
-int oom_badness(struct task_struct *p, unsigned long totalpages)
+unsigned int oom_badness(struct task_struct *p, unsigned long totalpages)
{
int points;
@@ -174,7 +174,7 @@ int oom_badness(struct task_struct *p, u
p = find_lock_task_mm(p);
if (!p)
- return -1;
+ return 0;
/*
* The baseline for the badness score is the proportion of RAM that each
* task's rss and swap space use.
@@ -295,7 +295,7 @@ static struct task_struct *select_bad_pr
*ppoints = 0;
for_each_process(p) {
- int points;
+ unsigned int points;
/* skip the init task and kthreads */
if (is_global_init(p) || (p->flags & PF_KTHREAD))
@@ -337,11 +337,8 @@ static struct task_struct *select_bad_pr
*ppoints = 1000;
}
- if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
- continue;
-
points = oom_badness(p, totalpages);
- if (points >= 0 && (points > *ppoints || !chosen)) {
+ if (points > *ppoints) {
chosen = p;
*ppoints = points;
}
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
linux-next.patch
cpu-timers-simplify-rlimit_cpu-handling.patch
cpu-timers-cleanup-arm_timer.patch
cpu-timers-return-correct-previous-timer-reload-value.patch
cpu-timers-change-sigev_none-timer-implementation.patch
cpu-timers-assure-to-not-iterate-over-all-threads-in-fastpath_timer_check.patch
cpu-timers-optimize-run_posix_cpu_timers.patch
oom-select_bad_process-check-pf_kthread-instead-of-mm-to-skip-kthreads.patch
oom-select_bad_process-pf_exiting-check-should-take-mm-into-account.patch
oom-introduce-find_lock_task_mm-to-fix-mm-false-positives.patch
oom-oom_forkbomb_penalty-move-thread_group_cputime-out-of-task_lock.patch
oom-hold-tasklist_lock-when-dumping-tasks.patch
oom-give-current-access-to-memory-reserves-if-it-has-been-killed.patch
oom-avoid-sending-exiting-tasks-a-sigkill.patch
oom-clean-up-oom_kill_task.patch
oom-clean-up-oom_badness.patch
oom-select_bad_process-never-choose-tasks-with-badness-==-0.patch
kmod-add-init-function-to-usermodehelper.patch
exec-replace-call_usermodehelper_pipe-with-use-of-umh-init-function-and-resolve-limit.patch
umh-creds-convert-call_usermodehelper_keys-to-use-subprocess_info-init.patch
umh-creds-kill-subprocess_info-cred-logic.patch
call_usermodehelper-no-need-to-unblock-signals.patch
wait_for_helper-sigchld-from-user-space-can-lead-to-use-after-free.patch
call_usermodehelper-simplify-fix-umh_no_wait-case.patch
call_usermodehelper-umh_wait_exec-ignores-kernel_thread-failure.patch
coredump-factor-out-the-not-ispipe-file-checks.patch
coredump-cleanup-ispipe-code.patch
coredump-factor-out-put_cred-calls.patch
coredump-shift-down_writemmap_sem-into-coredump_wait.patch
exit-exit_notify-can-trust-signal-notify_count-0.patch
exit-change-zap_other_threads-to-count-sub-threads.patch
exit-avoid-sig-count-in-de_thread-__exit_signal-synchronization.patch
exit-avoid-sig-count-in-__exit_signal-to-detect-the-group-dead-case.patch
posix-cpu-timers-avoid-task-signal-=-null-checks.patch
ia64-ptrace_attach_sync_user_rbs-avoid-task-signal-=-null-checks.patch
fork-exit-move-tty_kref_put-outside-of-__cleanup_signal.patch
signals-make-task_struct-signal-immutable-refcountable.patch
signals-clear-signal-tty-when-the-last-thread-exits.patch
signals-clear-signal-tty-when-the-last-thread-exits-fix.patch
signals-kill-the-awful-task_rq_unlock_wait-hack.patch
exit-__exit_signal-use-thread_group_leader-consistently.patch
kill-the-obsolete-thread_group_cputime_free-and-taskstats_tgid_init-helpers.patch
exit-move-taskstats_tgid_free-from-__exit_signal-to-free_signal_struct.patch
check_unshare_flags-kill-the-bogus-clone_sighand-sig-count-check.patch
proc-get_nr_threads-doesnt-need-siglock-any-longer.patch
proc-make-collect_sigign_sigcatch-rcu-safe.patch
proc-make-task_sig-lockless.patch
proc_sched_show_task-use-get_nr_threads.patch
keyctl_session_to_parent-use-thread_group_empty-to-check-singlethreadness.patch
proc-turn-signal_struct-count-into-int-nr_threads.patch
proc-turn-signal_struct-count-into-int-nr_threads-checkpatch-fixes.patch
proc-cleanup-remove-unused-assignments.patch
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