Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757630Ab0GBVuO (ORCPT ); Fri, 2 Jul 2010 17:50:14 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:34146 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752370Ab0GBVuL (ORCPT ); Fri, 2 Jul 2010 17:50:11 -0400 Date: Fri, 2 Jul 2010 14:49:41 -0700 From: Andrew Morton To: KOSAKI Motohiro Cc: LKML , linux-mm , Minchan Kim , David Rientjes , KAMEZAWA Hiroyuki , Ingo Molnar , Peter Zijlstra Subject: Re: [PATCH 10/11] oom: give the dying task a higher priority Message-Id: <20100702144941.8fa101c3.akpm@linux-foundation.org> In-Reply-To: <20100630183243.AA65.A69D9226@jp.fujitsu.com> References: <20100630172430.AA42.A69D9226@jp.fujitsu.com> <20100630183243.AA65.A69D9226@jp.fujitsu.com> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.9; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4571 Lines: 124 On Wed, 30 Jun 2010 18:33:23 +0900 (JST) KOSAKI Motohiro wrote: > +static void boost_dying_task_prio(struct task_struct *p, > + struct mem_cgroup *mem) > +{ > + struct sched_param param = { .sched_priority = 1 }; > + > + if (mem) > + return; > + > + if (!rt_task(p)) > + sched_setscheduler_nocheck(p, SCHED_FIFO, ¶m); > +} We can actually make `param' static here. That saves a teeny bit of code and a little bit of stack. The oom-killer can be called when we're using a lot of stack. But if we make that change we really should make the param arg to sched_setscheduler_nocheck() be const. I did that (and was able to convert lots of callers to use a static `param') but to complete the job we'd need to chase through all the security goop, fixing up security_task_setscheduler() and callees, and I got bored. include/linux/sched.h | 2 +- kernel/kthread.c | 2 +- kernel/sched.c | 4 ++-- kernel/softirq.c | 4 +++- kernel/stop_machine.c | 2 +- kernel/workqueue.c | 2 +- 6 files changed, 9 insertions(+), 7 deletions(-) diff -puN kernel/kthread.c~a kernel/kthread.c --- a/kernel/kthread.c~a +++ a/kernel/kthread.c @@ -131,7 +131,7 @@ struct task_struct *kthread_create(int ( wait_for_completion(&create.done); if (!IS_ERR(create.result)) { - struct sched_param param = { .sched_priority = 0 }; + static struct sched_param param = { .sched_priority = 0 }; va_list args; va_start(args, namefmt); diff -puN kernel/workqueue.c~a kernel/workqueue.c --- a/kernel/workqueue.c~a +++ a/kernel/workqueue.c @@ -962,7 +962,7 @@ init_cpu_workqueue(struct workqueue_stru static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) { - struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; + static struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; struct workqueue_struct *wq = cwq->wq; const char *fmt = is_wq_single_threaded(wq) ? "%s" : "%s/%d"; struct task_struct *p; diff -puN kernel/stop_machine.c~a kernel/stop_machine.c --- a/kernel/stop_machine.c~a +++ a/kernel/stop_machine.c @@ -291,7 +291,7 @@ repeat: static int __cpuinit cpu_stop_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) { - struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; + static struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; unsigned int cpu = (unsigned long)hcpu; struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu); struct task_struct *p; diff -puN kernel/sched.c~a kernel/sched.c --- a/kernel/sched.c~a +++ a/kernel/sched.c @@ -4570,7 +4570,7 @@ static bool check_same_owner(struct task } static int __sched_setscheduler(struct task_struct *p, int policy, - struct sched_param *param, bool user) + const struct sched_param *param, bool user) { int retval, oldprio, oldpolicy = -1, on_rq, running; unsigned long flags; @@ -4734,7 +4734,7 @@ EXPORT_SYMBOL_GPL(sched_setscheduler); * but our caller might not have that capability. */ int sched_setscheduler_nocheck(struct task_struct *p, int policy, - struct sched_param *param) + const struct sched_param *param) { return __sched_setscheduler(p, policy, param, false); } diff -puN kernel/softirq.c~a kernel/softirq.c --- a/kernel/softirq.c~a +++ a/kernel/softirq.c @@ -827,7 +827,9 @@ static int __cpuinit cpu_callback(struct cpumask_any(cpu_online_mask)); case CPU_DEAD: case CPU_DEAD_FROZEN: { - struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; + static struct sched_param param = { + .sched_priority = MAX_RT_PRIO-1, + }; p = per_cpu(ksoftirqd, hotcpu); per_cpu(ksoftirqd, hotcpu) = NULL; diff -puN include/linux/sched.h~a include/linux/sched.h --- a/include/linux/sched.h~a +++ a/include/linux/sched.h @@ -1924,7 +1924,7 @@ extern int task_curr(const struct task_s extern int idle_cpu(int cpu); extern int sched_setscheduler(struct task_struct *, int, struct sched_param *); extern int sched_setscheduler_nocheck(struct task_struct *, int, - struct sched_param *); + const struct sched_param *); extern struct task_struct *idle_task(int cpu); extern struct task_struct *curr_task(int cpu); extern void set_curr_task(int cpu, struct task_struct *p); _ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/