diff options
| author | Oleg Nesterov | 2007-10-16 23:30:56 -0700 |
|---|---|---|
| committer | Linus Torvalds | 2007-10-17 08:43:03 -0700 |
| commit | f7b4cddcc5aca03e80e357360c9424dfba5056c2 (patch) | |
| tree | af2eae61dcd0311a4c51dc7398e9d0f049f37367 /kernel | |
| parent | cf7a44168d743ca97863b7f34ed42a45fd7b5ab0 (diff) | |
do CPU_DEAD migrating under read_lock(tasklist) instead of write_lock_irq(tasklist)
Currently move_task_off_dead_cpu() is called under
write_lock_irq(tasklist). This means it can't use task_lock() which is
needed to improve migrating to take task's ->cpuset into account.
Change the code to call move_task_off_dead_cpu() with irqs enabled, and
change migrate_live_tasks() to use read_lock(tasklist).
This all is a preparation for the futher changes proposed by Cliff Wickman, see
http://marc.info/?t=117327786100003
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Cliff Wickman <cpw@sgi.com>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 0da2b2635c54..c747bc9f3c24 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5060,6 +5060,17 @@ wait_to_die: } #ifdef CONFIG_HOTPLUG_CPU + +static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu) +{ + int ret; + + local_irq_disable(); + ret = __migrate_task(p, src_cpu, dest_cpu); + local_irq_enable(); + return ret; +} + /* * Figure out where task on dead CPU should go, use force if neccessary. * NOTE: interrupts should be disabled by the caller @@ -5098,7 +5109,7 @@ static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) "longer affine to cpu%d\n", p->pid, p->comm, dead_cpu); } - } while (!__migrate_task(p, dead_cpu, dest_cpu)); + } while (!__migrate_task_irq(p, dead_cpu, dest_cpu)); } /* @@ -5126,7 +5137,7 @@ static void migrate_live_tasks(int src_cpu) { struct task_struct *p, *t; - write_lock_irq(&tasklist_lock); + read_lock(&tasklist_lock); do_each_thread(t, p) { if (p == current) @@ -5136,7 +5147,7 @@ static void migrate_live_tasks(int src_cpu) move_task_off_dead_cpu(src_cpu, p); } while_each_thread(t, p); - write_unlock_irq(&tasklist_lock); + read_unlock(&tasklist_lock); } /* @@ -5214,11 +5225,10 @@ static void migrate_dead(unsigned int dead_cpu, struct task_struct *p) * Drop lock around migration; if someone else moves it, * that's OK. No task can be added to this CPU, so iteration is * fine. - * NOTE: interrupts should be left disabled --dev@ */ - spin_unlock(&rq->lock); + spin_unlock_irq(&rq->lock); move_task_off_dead_cpu(dead_cpu, p); - spin_lock(&rq->lock); + spin_lock_irq(&rq->lock); put_task_struct(p); } |