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SubjectRe: [PATCH 10/11] oom: give the dying task a higher priority
Date
(cc to James)

> On Wed, 30 Jun 2010 18:33:23 +0900 (JST)
> KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> 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, &param);
> > +}
>
> 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.

ok, I've finished this works. I made two patches, for-security-tree and
for-core. diffstat is below.

I'll post the patches as reply of this mail.


KOSAKI Motohiro (2):
security: add const to security_task_setscheduler()
sched: make sched_param arugment static variables in some
sched_setscheduler() caller

include/linux/sched.h | 5 +++--
include/linux/security.h | 9 +++++----
kernel/irq/manage.c | 4 +++-
kernel/kthread.c | 2 +-
kernel/sched.c | 6 +++---
kernel/softirq.c | 4 +++-
kernel/stop_machine.c | 2 +-
kernel/trace/trace_selftest.c | 2 +-
kernel/watchdog.c | 2 +-
kernel/workqueue.c | 2 +-
security/commoncap.c | 2 +-
security/security.c | 4 ++--
security/selinux/hooks.c | 3 ++-
security/smack/smack_lsm.c | 2 +-
14 files changed, 28 insertions(+), 21 deletions(-)
- kosaki


>
>
> 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);
> _
>





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