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| author | Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> | 2012-09-28 20:27:49 +0800 |
|---|---|---|
| committer | Fengguang Wu <fengguang.wu@intel.com> | 2012-09-28 20:27:49 +0800 |
| commit | 2f60d628ffd042e65e0b1d3431fb3e38d6f7c1be (patch) | |
| tree | ab0abd6f9936db1441382f862028a4c22b7239e1 | |
| parent | 0e2f2b23672055e1301c11509d5b8eda7b718d8e (diff) | |
| download | linux-2f60d628ffd042e65e0b1d3431fb3e38d6f7c1be.tar.bz2 | |
CPU hotplug, writeback: Don't call writeback_set_ratelimit() too often during hotplug
The CPU hotplug callback related to writeback calls writeback_set_ratelimit()
during every state change in the hotplug sequence. This is unnecessary
since num_online_cpus() changes only once during the entire hotplug operation.
So invoke the function only once per hotplug, thereby avoiding the
unnecessary repetition of those costly calculations.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
| -rw-r--r-- | mm/page-writeback.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 5ad5ce23c1e0..830893b2b3c7 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -1602,10 +1602,18 @@ void writeback_set_ratelimit(void) } static int __cpuinit -ratelimit_handler(struct notifier_block *self, unsigned long u, void *v) +ratelimit_handler(struct notifier_block *self, unsigned long action, + void *hcpu) { - writeback_set_ratelimit(); - return NOTIFY_DONE; + + switch (action & ~CPU_TASKS_FROZEN) { + case CPU_ONLINE: + case CPU_DEAD: + writeback_set_ratelimit(); + return NOTIFY_OK; + default: + return NOTIFY_DONE; + } } static struct notifier_block __cpuinitdata ratelimit_nb = { |