From 6363ca57c76b7b83639ca8c83fc285fa26a7880e Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Thu, 29 May 2008 11:28:57 +0200 Subject: revert ("sched: fair-group: SMP-nice for group scheduling") Yanmin Zhang reported: Comparing with 2.6.25, volanoMark has big regression with kernel 2.6.26-rc1. It's about 50% on my 8-core stoakley, 16-core tigerton, and Itanium Montecito. With bisect, I located the following patch: | 18d95a2832c1392a2d63227a7a6d433cb9f2037e is first bad commit | commit 18d95a2832c1392a2d63227a7a6d433cb9f2037e | Author: Peter Zijlstra | Date: Sat Apr 19 19:45:00 2008 +0200 | | sched: fair-group: SMP-nice for group scheduling Revert it so that we get v2.6.25 behavior. Bisected-by: Yanmin Zhang Signed-off-by: Ingo Molnar --- include/linux/sched.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux/sched.h') diff --git a/include/linux/sched.h b/include/linux/sched.h index 5395a6176f4b..8a888499954e 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -766,7 +766,6 @@ struct sched_domain { struct sched_domain *child; /* bottom domain must be null terminated */ struct sched_group *groups; /* the balancing groups of the domain */ cpumask_t span; /* span of all CPUs in this domain */ - int first_cpu; /* cache of the first cpu in this domain */ unsigned long min_interval; /* Minimum balance interval ms */ unsigned long max_interval; /* Maximum balance interval ms */ unsigned int busy_factor; /* less balancing by factor if busy */ -- cgit v1.2.3 From 16882c1e962b4be5122fc05aaf2afc10fd9e2d15 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Sun, 8 Jun 2008 21:20:41 +0400 Subject: sched: fix TASK_WAKEKILL vs SIGKILL race schedule() has the special "TASK_INTERRUPTIBLE && signal_pending()" case, this allows us to do current->state = TASK_INTERRUPTIBLE; schedule(); without fear to sleep with pending signal. However, the code like current->state = TASK_KILLABLE; schedule(); is not right, schedule() doesn't take TASK_WAKEKILL into account. This means that mutex_lock_killable(), wait_for_completion_killable(), down_killable(), schedule_timeout_killable() can miss SIGKILL (and btw the second SIGKILL has no effect). Introduce the new helper, signal_pending_state(), and change schedule() to use it. Hopefully it will have more users, that is why the task's state is passed separately. Note this "__TASK_STOPPED | __TASK_TRACED" check in signal_pending_state(). This is needed to preserve the current behaviour (ptrace_notify). I hope this check will be removed soon, but this (afaics good) change needs the separate discussion. The fast path is "(state & (INTERRUPTIBLE | WAKEKILL)) + signal_pending(p)", basically the same that schedule() does now. However, this patch of course bloats schedule(). Signed-off-by: Oleg Nesterov Signed-off-by: Ingo Molnar --- include/linux/sched.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include/linux/sched.h') diff --git a/include/linux/sched.h b/include/linux/sched.h index ae0be3c62375..c5d3f847ca8d 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2026,6 +2026,19 @@ static inline int fatal_signal_pending(struct task_struct *p) return signal_pending(p) && __fatal_signal_pending(p); } +static inline int signal_pending_state(long state, struct task_struct *p) +{ + if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL))) + return 0; + if (!signal_pending(p)) + return 0; + + if (state & (__TASK_STOPPED | __TASK_TRACED)) + return 0; + + return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p); +} + static inline int need_resched(void) { return unlikely(test_thread_flag(TIF_NEED_RESCHED)); -- cgit v1.2.3