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authorBenjamin LaHaise <bcrl@kvack.org>2008-01-30 13:33:13 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-30 13:33:13 +0100
commit0723a69a63beec1ca6e792239ef75d0181387ef0 (patch)
treedf0205d10a3811084923e8f24935e400e0a81667 /arch/x86/kernel/process_32.c
parent6b8be6df7f971919622d152d144c8798ad7fd160 (diff)
x86: fix synchronize_rcu(): high latency on idle system
an otherwise idle system takes about 3 ticks per network interface in unregister_netdev() due to multiple calls to synchronize_rcu(), which adds up to quite a few seconds for tearing down thousands of interfaces. By flushing pending rcu callbacks in the idle loop, the system makes progress hundreds of times faster. If this is indeed a sane thing to, it probably needs to be done for other architectures than x86. And yes, the network stack shouldn't call synchronize_rcu() quite so much, but fixing that is a little more involved. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/kernel/process_32.c')
-rw-r--r--arch/x86/kernel/process_32.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 7a61b54649d..69a69c3f43b 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -198,6 +198,9 @@ void cpu_idle(void)
rmb();
idle = pm_idle;
+ if (rcu_pending(cpu))
+ rcu_check_callbacks(cpu, 0);
+
if (!idle)
idle = default_idle;