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authorChristoph Lameter <clameter@sgi.com>2006-12-10 11:20:21 +0100
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-10 18:55:42 +0100
commitfe2eea3fafb3df2f5b8a55a48bcbb0d23b3b5618 (patch)
tree5376e761d21d9164985f27e8836ec2b002dad8a1 /kernel/sched.c
parent[PATCH] sched: remove staggering of load balancing (diff)
downloadlinux-fe2eea3fafb3df2f5b8a55a48bcbb0d23b3b5618.tar.xz
linux-fe2eea3fafb3df2f5b8a55a48bcbb0d23b3b5618.zip
[PATCH] sched: disable interrupts for locking in load_balance()
Interrupts must be disabled for request queue locks if we want to run load_balance() with interrupts enabled. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Peter Williams <pwil3058@bigpond.net.au> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <clameter@sgi.com> Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com> Cc: "Chen, Kenneth W" <kenneth.w.chen@intel.com> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index b5b350135002..d327511d268e 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2546,8 +2546,6 @@ static inline unsigned long minus_1_or_zero(unsigned long n)
/*
* Check this_cpu to ensure it is balanced within domain. Attempt to move
* tasks if there is an imbalance.
- *
- * Called with this_rq unlocked.
*/
static int load_balance(int this_cpu, struct rq *this_rq,
struct sched_domain *sd, enum idle_type idle)
@@ -2557,6 +2555,7 @@ static int load_balance(int this_cpu, struct rq *this_rq,
unsigned long imbalance;
struct rq *busiest;
cpumask_t cpus = CPU_MASK_ALL;
+ unsigned long flags;
/*
* When power savings policy is enabled for the parent domain, idle
@@ -2596,11 +2595,13 @@ redo:
* still unbalanced. nr_moved simply stays zero, so it is
* correctly treated as an imbalance.
*/
+ local_irq_save(flags);
double_rq_lock(this_rq, busiest);
nr_moved = move_tasks(this_rq, this_cpu, busiest,
minus_1_or_zero(busiest->nr_running),
imbalance, sd, idle, &all_pinned);
double_rq_unlock(this_rq, busiest);
+ local_irq_restore(flags);
/* All tasks on this runqueue were pinned by CPU affinity */
if (unlikely(all_pinned)) {
@@ -2617,13 +2618,13 @@ redo:
if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) {
- spin_lock(&busiest->lock);
+ spin_lock_irqsave(&busiest->lock, flags);
/* don't kick the migration_thread, if the curr
* task on busiest cpu can't be moved to this_cpu
*/
if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) {
- spin_unlock(&busiest->lock);
+ spin_unlock_irqrestore(&busiest->lock, flags);
all_pinned = 1;
goto out_one_pinned;
}
@@ -2633,7 +2634,7 @@ redo:
busiest->push_cpu = this_cpu;
active_balance = 1;
}
- spin_unlock(&busiest->lock);
+ spin_unlock_irqrestore(&busiest->lock, flags);
if (active_balance)
wake_up_process(busiest->migration_thread);