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Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 

* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: 64-bit: fix arithmetics overflow
  sched: fair group: fix overflow(was: fix divide by zero)
  sched: fix TASK_WAKEKILL vs SIGKILL race
This commit is contained in:
Linus Torvalds 2008-06-12 12:55:18 -07:00
parent 14a73f5479 7a232e0350
commit 1b3cba8e60
2 changed files with 27 additions and 8 deletions
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13
include/linux/sched.h
View File

@ -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));

22
kernel/sched.c
View File

@ -312,12 +312,15 @@ static DEFINE_SPINLOCK(task_group_lock);
#endif
/*
* A weight of 0, 1 or ULONG_MAX can cause arithmetics problems.
* A weight of 0 or 1 can cause arithmetics problems.
* A weight of a cfs_rq is the sum of weights of which entities
* are queued on this cfs_rq, so a weight of a entity should not be
* too large, so as the shares value of a task group.
* (The default weight is 1024 - so there's no practical
* limitation from this.)
*/
#define MIN_SHARES 2
#define MAX_SHARES (ULONG_MAX - 1)
#define MAX_SHARES (1UL << 18)
static int init_task_group_load = INIT_TASK_GROUP_LOAD;
#endif
@ -1337,8 +1340,13 @@ calc_delta_mine(unsigned long delta_exec, unsigned long weight,
{
u64 tmp;
if (!lw->inv_weight)
lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)/(lw->weight+1);
if (!lw->inv_weight) {
if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST))
lw->inv_weight = 1;
else
lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)
/ (lw->weight+1);
}
tmp = (u64)delta_exec * weight;
/*
@ -4159,12 +4167,10 @@ need_resched_nonpreemptible:
clear_tsk_need_resched(prev);
if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
if (unlikely((prev->state & TASK_INTERRUPTIBLE) &&
signal_pending(prev))) {
if (unlikely(signal_pending_state(prev->state, prev)))
prev->state = TASK_RUNNING;
} else {
else
deactivate_task(rq, prev, 1);
}
switch_count = &prev->nvcsw;
}