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authorIngo Molnar <mingo@kernel.org>2014-12-12 09:09:03 +0100
committerIngo Molnar <mingo@kernel.org>2014-12-12 09:09:03 +0100
commit3459f0d78ffe27a1b341c22eb158b622eaaea3fc (patch)
tree715b0575eec541d0181876ad367ca5480cdcecf3 /kernel/cpu.c
parent9fc81d87420d0d3fd62d5e5529972c0ad9eab9cc (diff)
parentbee2782f30f66898be3f74ad02e4d1f87a969694 (diff)
Merge branch 'linus' into perf/urgent, to pick up the upstream merged bits
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/cpu.c')
-rw-r--r--kernel/cpu.c19
1 files changed, 13 insertions, 6 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 90a3d017b90..5d220234b3c 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -86,6 +86,16 @@ static struct {
#define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map)
#define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map)
+static void apply_puts_pending(int max)
+{
+ int delta;
+
+ if (atomic_read(&cpu_hotplug.puts_pending) >= max) {
+ delta = atomic_xchg(&cpu_hotplug.puts_pending, 0);
+ cpu_hotplug.refcount -= delta;
+ }
+}
+
void get_online_cpus(void)
{
might_sleep();
@@ -93,6 +103,7 @@ void get_online_cpus(void)
return;
cpuhp_lock_acquire_read();
mutex_lock(&cpu_hotplug.lock);
+ apply_puts_pending(65536);
cpu_hotplug.refcount++;
mutex_unlock(&cpu_hotplug.lock);
}
@@ -105,6 +116,7 @@ bool try_get_online_cpus(void)
if (!mutex_trylock(&cpu_hotplug.lock))
return false;
cpuhp_lock_acquire_tryread();
+ apply_puts_pending(65536);
cpu_hotplug.refcount++;
mutex_unlock(&cpu_hotplug.lock);
return true;
@@ -161,12 +173,7 @@ void cpu_hotplug_begin(void)
cpuhp_lock_acquire();
for (;;) {
mutex_lock(&cpu_hotplug.lock);
- if (atomic_read(&cpu_hotplug.puts_pending)) {
- int delta;
-
- delta = atomic_xchg(&cpu_hotplug.puts_pending, 0);
- cpu_hotplug.refcount -= delta;
- }
+ apply_puts_pending(1);
if (likely(!cpu_hotplug.refcount))
break;
__set_current_state(TASK_UNINTERRUPTIBLE);