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Message-ID: <alpine.DEB.2.00.1205031513400.1631@chino.kir.corp.google.com>
Date: Thu, 3 May 2012 15:14:09 -0700 (PDT)
From: David Rientjes <rientjes@...gle.com>
To: Dave Jones <davej@...hat.com>, linux-mm@...ck.org,
Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: 3.4-rc4 oom killer out of control.
On Thu, 26 Apr 2012, David Rientjes wrote:
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -410,12 +410,13 @@ static const struct file_operations proc_lstats_operations = {
>
> static int proc_oom_score(struct task_struct *task, char *buffer)
> {
> + unsigned long totalpages = totalram_pages + total_swap_pages;
> unsigned long points = 0;
>
> read_lock(&tasklist_lock);
> if (pid_alive(task))
> - points = oom_badness(task, NULL, NULL,
> - totalram_pages + total_swap_pages);
> + points = oom_badness(task, NULL, NULL, totalpages) *
> + 1000 / totalpages;
> read_unlock(&tasklist_lock);
> return sprintf(buffer, "%lu\n", points);
> }
> diff --git a/include/linux/oom.h b/include/linux/oom.h
> index 3d76475..e4c29bc 100644
> --- a/include/linux/oom.h
> +++ b/include/linux/oom.h
> @@ -43,8 +43,9 @@ enum oom_constraint {
> extern void compare_swap_oom_score_adj(int old_val, int new_val);
> extern int test_set_oom_score_adj(int new_val);
>
> -extern unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
> - const nodemask_t *nodemask, unsigned long totalpages);
> +extern unsigned long oom_badness(struct task_struct *p,
> + struct mem_cgroup *memcg, const nodemask_t *nodemask,
> + unsigned long totalpages);
> extern int try_set_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_flags);
> extern void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_flags);
>
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> index 46bf2ed5..4bbf085 100644
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -180,10 +180,10 @@ static bool oom_unkillable_task(struct task_struct *p,
> * predictable as possible. The goal is to return the highest value for the
> * task consuming the most memory to avoid subsequent oom failures.
> */
> -unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
> - const nodemask_t *nodemask, unsigned long totalpages)
> +unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
> + const nodemask_t *nodemask, unsigned long totalpages)
> {
> - long points;
> + unsigned long points;
>
> if (oom_unkillable_task(p, memcg, nodemask))
> return 0;
> @@ -198,45 +198,33 @@ unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
> }
>
> /*
> - * The memory controller may have a limit of 0 bytes, so avoid a divide
> - * by zero, if necessary.
> - */
> - if (!totalpages)
> - totalpages = 1;
> -
> - /*
> * The baseline for the badness score is the proportion of RAM that each
> * task's rss, pagetable and swap space use.
> */
> - points = get_mm_rss(p->mm) + p->mm->nr_ptes;
> - points += get_mm_counter(p->mm, MM_SWAPENTS);
> -
> - points *= 1000;
> - points /= totalpages;
> + points = get_mm_rss(p->mm) + p->mm->nr_ptes +
> + get_mm_counter(p->mm, MM_SWAPENTS);
> 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 -= 30;
> + if (has_capability_noaudit(p, CAP_SYS_ADMIN) && totalpages)
> + points -= 30 * totalpages / 1000;
>
> /*
> * /proc/pid/oom_score_adj ranges from -1000 to +1000 such that it may
> * either completely disable oom killing or always prefer a certain
> * task.
> */
> - points += p->signal->oom_score_adj;
> + points += p->signal->oom_score_adj * totalpages / 1000;
>
> /*
> * Never return 0 for an eligible task that may be killed since it's
> * possible that no single user task uses more than 0.1% of memory and
> * no single admin tasks uses more than 3.0%.
> */
> - if (points <= 0)
> - return 1;
> - return (points < 1000) ? points : 1000;
> + return points <= 0 ? 1 : points;
> }
>
> /*
> @@ -314,7 +302,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
> {
> struct task_struct *g, *p;
> struct task_struct *chosen = NULL;
> - *ppoints = 0;
> + unsigned long chosen_points = 0;
>
> do_each_thread(g, p) {
> unsigned int points;
> @@ -354,7 +342,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
> */
> if (p == current) {
> chosen = p;
> - *ppoints = 1000;
> + chosen_points = ULONG_MAX;
> } else if (!force_kill) {
> /*
> * If this task is not being ptraced on exit,
> @@ -367,12 +355,13 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
> }
>
> points = oom_badness(p, memcg, nodemask, totalpages);
> - if (points > *ppoints) {
> + if (points > chosen_points) {
> chosen = p;
> - *ppoints = points;
> + chosen_points = points;
> }
> } while_each_thread(g, p);
>
> + *ppoints = chosen_points * 1000 / totalpages;
> return chosen;
> }
>
Dave, did you get a chance to test this out? It's something we'll want in
the oom killer so if I can add your Tested-by it would be great. Thanks!
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