Messages in this thread Patch in this message | | | From | "Luis R. Rodriguez" <> | Subject | [PATCH v2 1/2] sched: add cond_resched_irq() | Date | Wed, 10 Dec 2014 15:34:46 -0800 |
| |
From: "Luis R. Rodriguez" <mcgrof@suse.com>
Under special circumstances we may want to force voluntary preemption even for CONFIG_PREEMPT=n with interrupts disabled. This adds helpers to let us do that.
Cc: Borislav Petkov <bp@suse.de> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: x86@kernel.org Cc: Andy Lutomirski <luto@amacapital.net> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Jan Beulich <JBeulich@suse.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com> --- include/linux/sched.h | 7 +++++++ kernel/sched/core.c | 10 ++++++++++ 2 files changed, 17 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h index 5e344bb..92da927 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2759,6 +2759,13 @@ static inline int signal_pending_state(long state, struct task_struct *p) */ extern int _cond_resched(void); +/* + * Voluntarily preempting the kernel even for CONFIG_PREEMPT=n kernels + * on very special circumstances. This is to be used with interrupts + * disabled. + */ +extern int cond_resched_irq(void); + #define cond_resched() ({ \ __might_sleep(__FILE__, __LINE__, 0); \ _cond_resched(); \ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 89e7283..573edb1 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4239,6 +4239,16 @@ int __sched _cond_resched(void) } EXPORT_SYMBOL(_cond_resched); +int __sched cond_resched_irq(void) +{ + if (should_resched()) { + preempt_schedule_irq(); + return 1; + } + return 0; +} +EXPORT_SYMBOL_GPL(cond_resched_irq); + /* * __cond_resched_lock() - if a reschedule is pending, drop the given lock, * call schedule, and on return reacquire the lock. -- 2.1.1
| |