oom-kill: give the dying task a higher priority
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From: Minchan Kim on 31 May 2010 01:50 On Mon, May 31, 2010 at 2:04 PM, KAMEZAWA Hiroyuki <kamezawa.hiroyu(a)jp.fujitsu.com> wrote: > On Mon, 31 May 2010 14:01:03 +0900 > Minchan Kim <minchan.kim(a)gmail.com> wrote: > >> Hi, Kame. >> >> On Mon, May 31, 2010 at 9:21 AM, KAMEZAWA Hiroyuki >> <kamezawa.hiroyu(a)jp.fujitsu.com> wrote: >> > On Fri, 28 May 2010 13:48:26 -0300 >> > "Luis Claudio R. Goncalves" <lclaudio(a)uudg.org> wrote: >> >> >> >> oom-killer: give the dying task rt priority (v3) >> >> >> >> Give the dying task RT priority so that it can be scheduled quickly and die, >> >> freeing needed memory. >> >> >> >> Signed-off-by: Luis Claudio R. Gonçalves <lgoncalv(a)redhat.com> >> >> >> >> diff --git a/mm/oom_kill.c b/mm/oom_kill.c >> >> index 84bbba2..2b0204f 100644 >> >> --- a/mm/oom_kill.c >> >> +++ b/mm/oom_kill.c >> >> @@ -266,6 +266,8 @@ static struct task_struct *select_bad_process(unsigned long *ppoints) >> >> */ >> >> static void __oom_kill_task(struct task_struct *p, int verbose) >> >> { >> >> + struct sched_param param; >> >> + >> >> if (is_global_init(p)) { >> >> WARN_ON(1); >> >> printk(KERN_WARNING "tried to kill init!\n"); >> >> @@ -288,6 +290,8 @@ static void __oom_kill_task(struct task_struct *p, int verbose) >> >> * exit() and clear out its resources quickly... >> >> */ >> >> p->time_slice = HZ; >> >> + param.sched_priority = MAX_RT_PRIO-10; >> >> + sched_setscheduler(p, SCHED_FIFO, ¶m); >> >> set_tsk_thread_flag(p, TIF_MEMDIE); >> >> >> > >> > BTW, how about the other threads which share mm_struct ? >> >> Could you elaborate your intention? :) >> > > IIUC, the purpose of rising priority is to accerate dying thread to exit() > for freeing memory AFAP. But to free memory, exit, all threads which share > mm_struct should exit, too. I'm sorry if I miss something. How do we kill only some thread and what's the benefit of it? I think when if some thread receives KILL signal, the process include the thread will be killed. I think > Thanks, > -Kame > > > > -- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: KAMEZAWA Hiroyuki on 31 May 2010 02:00 On Mon, 31 May 2010 14:46:05 +0900 Minchan Kim <minchan.kim(a)gmail.com> wrote: > On Mon, May 31, 2010 at 2:04 PM, KAMEZAWA Hiroyuki > <kamezawa.hiroyu(a)jp.fujitsu.com> wrote: > > On Mon, 31 May 2010 14:01:03 +0900 > > Minchan Kim <minchan.kim(a)gmail.com> wrote: > > > >> Hi, Kame. > >> > >> On Mon, May 31, 2010 at 9:21 AM, KAMEZAWA Hiroyuki > >> <kamezawa.hiroyu(a)jp.fujitsu.com> wrote: > >> > On Fri, 28 May 2010 13:48:26 -0300 > >> > "Luis Claudio R. Goncalves" <lclaudio(a)uudg.org> wrote: > >> >> > >> >> oom-killer: give the dying task rt priority (v3) > >> >> > >> >> Give the dying task RT priority so that it can be scheduled quickly and die, > >> >> freeing needed memory. > >> >> > >> >> Signed-off-by: Luis Claudio R. Gonçalves <lgoncalv(a)redhat.com> > >> >> > >> >> diff --git a/mm/oom_kill.c b/mm/oom_kill.c > >> >> index 84bbba2..2b0204f 100644 > >> >> --- a/mm/oom_kill.c > >> >> +++ b/mm/oom_kill.c > >> >> @@ -266,6 +266,8 @@ static struct task_struct *select_bad_process(unsigned long *ppoints) > >> >> */ > >> >> static void __oom_kill_task(struct task_struct *p, int verbose) > >> >> { > >> >> + struct sched_param param; > >> >> + > >> >> if (is_global_init(p)) { > >> >> WARN_ON(1); > >> >> printk(KERN_WARNING "tried to kill init!\n"); > >> >> @@ -288,6 +290,8 @@ static void __oom_kill_task(struct task_struct *p, int verbose) > >> >> * exit() and clear out its resources quickly... > >> >> */ > >> >> p->time_slice = HZ; > >> >> + param.sched_priority = MAX_RT_PRIO-10; > >> >> + sched_setscheduler(p, SCHED_FIFO, ¶m); > >> >> set_tsk_thread_flag(p, TIF_MEMDIE); > >> >> > >> > > >> > BTW, how about the other threads which share mm_struct ? > >> > >> Could you elaborate your intention? :) > >> > > > > IIUC, the purpose of rising priority is to accerate dying thread to exit() > > for freeing memory AFAP. But to free memory, exit, all threads which share > > mm_struct should exit, too. I'm sorry if I miss something. > > How do we kill only some thread and what's the benefit of it? > I think when if some thread receives KILL signal, the process include > the thread will be killed. > yes, so, if you want a _process_ die quickly, you have to acceralte the whole threads on a process. Acceralating a thread in a process is not big help. Thanks, -Kame -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Minchan Kim on 31 May 2010 02:10 On Mon, May 31, 2010 at 2:54 PM, KAMEZAWA Hiroyuki <kamezawa.hiroyu(a)jp.fujitsu.com> wrote: > On Mon, 31 May 2010 14:46:05 +0900 > Minchan Kim <minchan.kim(a)gmail.com> wrote: > >> On Mon, May 31, 2010 at 2:04 PM, KAMEZAWA Hiroyuki >> <kamezawa.hiroyu(a)jp.fujitsu.com> wrote: >> > On Mon, 31 May 2010 14:01:03 +0900 >> > Minchan Kim <minchan.kim(a)gmail.com> wrote: >> > >> >> Hi, Kame. >> >> >> >> On Mon, May 31, 2010 at 9:21 AM, KAMEZAWA Hiroyuki >> >> <kamezawa.hiroyu(a)jp.fujitsu.com> wrote: >> >> > On Fri, 28 May 2010 13:48:26 -0300 >> >> > "Luis Claudio R. Goncalves" <lclaudio(a)uudg.org> wrote: >> >> >> >> >> >> oom-killer: give the dying task rt priority (v3) >> >> >> >> >> >> Give the dying task RT priority so that it can be scheduled quickly and die, >> >> >> freeing needed memory. >> >> >> >> >> >> Signed-off-by: Luis Claudio R. Gonçalves <lgoncalv(a)redhat.com> >> >> >> >> >> >> diff --git a/mm/oom_kill.c b/mm/oom_kill.c >> >> >> index 84bbba2..2b0204f 100644 >> >> >> --- a/mm/oom_kill.c >> >> >> +++ b/mm/oom_kill.c >> >> >> @@ -266,6 +266,8 @@ static struct task_struct *select_bad_process(unsigned long *ppoints) >> >> >> */ >> >> >> static void __oom_kill_task(struct task_struct *p, int verbose) >> >> >> { >> >> >> + struct sched_param param; >> >> >> + >> >> >> if (is_global_init(p)) { >> >> >> WARN_ON(1); >> >> >> printk(KERN_WARNING "tried to kill init!\n"); >> >> >> @@ -288,6 +290,8 @@ static void __oom_kill_task(struct task_struct *p, int verbose) >> >> >> * exit() and clear out its resources quickly... >> >> >> */ >> >> >> p->time_slice = HZ; >> >> >> + param.sched_priority = MAX_RT_PRIO-10; >> >> >> + sched_setscheduler(p, SCHED_FIFO, ¶m); >> >> >> set_tsk_thread_flag(p, TIF_MEMDIE); >> >> >> >> >> > >> >> > BTW, how about the other threads which share mm_struct ? >> >> >> >> Could you elaborate your intention? :) >> >> >> > >> > IIUC, the purpose of rising priority is to accerate dying thread to exit() >> > for freeing memory AFAP. But to free memory, exit, all threads which share >> > mm_struct should exit, too. I'm sorry if I miss something. >> >> How do we kill only some thread and what's the benefit of it? >> I think when if some thread receives KILL signal, the process include >> the thread will be killed. >> > yes, so, if you want a _process_ die quickly, you have to acceralte the whole > threads on a process. Acceralating a thread in a process is not big help. Yes. I see the code. oom_kill_process is called by 1. mem_cgroup_out_of_memory 2. __out_of_memory 3. out_of_memory (1,2) calls select_bad_process which select victim task in processes by do_each_process. But 3 isn't In case of CONSTRAINT_MEMORY_POLICY, it kills current. In only the case, couldn't we pass task of process, not one of thread? > > Thanks, > -Kame > > -- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: KOSAKI Motohiro on 31 May 2010 02:40 Hi > Hi, Kosaki. > > On Sat, May 29, 2010 at 12:59 PM, KOSAKI Motohiro > <kosaki.motohiro(a)jp.fujitsu.com> wrote: > > Hi > > > >> oom-killer: give the dying task rt priority (v3) > >> > >> Give the dying task RT priority so that it can be scheduled quickly and die, > >> freeing needed memory. > >> > >> Signed-off-by: Luis Claudio R. Gonçalves <lgoncalv(a)redhat.com> > > > > Almostly acceptable to me. but I have two requests, > > > > - need 1) force_sig() 2)sched_setscheduler() order as Oleg mentioned > > - don't boost priority if it's in mem_cgroup_out_of_memory() > > Why do you want to not boost priority if it's path of memcontrol? > > If it's path of memcontrol and CONFIG_CGROUP_MEM_RES_CTLR is enabled, > mem_cgroup_out_of_memory will select victim task in memcg. > So __oom_kill_task's target task would be in memcg, I think. Yep. But priority boost naturally makes CPU starvation for out of the group processes. It seems to break cgroup's isolation concept. > As you and memcg guys don't complain this, I would be missing something. > Could you explain it? :) So, My points are, 1) Usually priority boost is wrong idea. It have various side effect, but system wide OOM is one of exception. In such case, all tasks aren't runnable, then, the downside is acceptable. 2) memcg have OOM notification mechanism. If the admin need priority boost, they can do it by their OOM-daemon. Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: KAMEZAWA Hiroyuki on 31 May 2010 03:00
On Mon, 31 May 2010 15:09:41 +0900 Minchan Kim <minchan.kim(a)gmail.com> wrote: > On Mon, May 31, 2010 at 2:54 PM, KAMEZAWA Hiroyuki > <kamezawa.hiroyu(a)jp.fujitsu.com> wrote: > > On Mon, 31 May 2010 14:46:05 +0900 > > Minchan Kim <minchan.kim(a)gmail.com> wrote: > > > >> On Mon, May 31, 2010 at 2:04 PM, KAMEZAWA Hiroyuki > >> <kamezawa.hiroyu(a)jp.fujitsu.com> wrote: > >> > On Mon, 31 May 2010 14:01:03 +0900 > >> > Minchan Kim <minchan.kim(a)gmail.com> wrote: > >> > > >> >> Hi, Kame. > >> >> > >> >> On Mon, May 31, 2010 at 9:21 AM, KAMEZAWA Hiroyuki > >> >> <kamezawa.hiroyu(a)jp.fujitsu.com> wrote: > >> >> > On Fri, 28 May 2010 13:48:26 -0300 > >> >> > "Luis Claudio R. Goncalves" <lclaudio(a)uudg.org> wrote: > >> >> >> > >> >> >> oom-killer: give the dying task rt priority (v3) > >> >> >> > >> >> >> Give the dying task RT priority so that it can be scheduled quickly and die, > >> >> >> freeing needed memory. > >> >> >> > >> >> >> Signed-off-by: Luis Claudio R. Gonçalves <lgoncalv(a)redhat.com> > >> >> >> > >> >> >> diff --git a/mm/oom_kill.c b/mm/oom_kill.c > >> >> >> index 84bbba2..2b0204f 100644 > >> >> >> --- a/mm/oom_kill.c > >> >> >> +++ b/mm/oom_kill.c > >> >> >> @@ -266,6 +266,8 @@ static struct task_struct *select_bad_process(unsigned long *ppoints) > >> >> >> */ > >> >> >> static void __oom_kill_task(struct task_struct *p, int verbose) > >> >> >> { > >> >> >> + struct sched_param param; > >> >> >> + > >> >> >> if (is_global_init(p)) { > >> >> >> WARN_ON(1); > >> >> >> printk(KERN_WARNING "tried to kill init!\n"); > >> >> >> @@ -288,6 +290,8 @@ static void __oom_kill_task(struct task_struct *p, int verbose) > >> >> >> * exit() and clear out its resources quickly... > >> >> >> */ > >> >> >> p->time_slice = HZ; > >> >> >> + param.sched_priority = MAX_RT_PRIO-10; > >> >> >> + sched_setscheduler(p, SCHED_FIFO, ¶m); > >> >> >> set_tsk_thread_flag(p, TIF_MEMDIE); > >> >> >> > >> >> > > >> >> > BTW, how about the other threads which share mm_struct ? > >> >> > >> >> Could you elaborate your intention? :) > >> >> > >> > > >> > IIUC, the purpose of rising priority is to accerate dying thread to exit() > >> > for freeing memory AFAP. But to free memory, exit, all threads which share > >> > mm_struct should exit, too. I'm sorry if I miss something. > >> > >> How do we kill only some thread and what's the benefit of it? > >> I think when if some thread receives KILL signal, the process include > >> the thread will be killed. > >> > > yes, so, if you want a _process_ die quickly, you have to acceralte the whole > > threads on a process. Acceralating a thread in a process is not big help. > > Yes. > > I see the code. > oom_kill_process is called by > > 1. mem_cgroup_out_of_memory > 2. __out_of_memory > 3. out_of_memory > > > (1,2) calls select_bad_process which select victim task in processes > by do_each_process. > But 3 isn't In case of CONSTRAINT_MEMORY_POLICY, it kills current. > In only the case, couldn't we pass task of process, not one of thread? > Hmm, my point is that priority-acceralation is against a thread, not against a process. So, most of threads in memory-eater will not gain high priority even with this patch and works slowly. I have no objections to this patch. I just want to confirm the purpose. If this patch is for accelating exiting process by SIGKILL, it seems not enough. If an explanation as "acceralating all thread's priority in a process seems overkill" is given in changelog or comment, it's ok to me. Thanks, -Kame -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |