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authorTejun Heo <tj@kernel.org>2010-06-29 10:07:12 +0200
committerTejun Heo <tj@kernel.org>2010-06-29 10:07:12 +0200
commitdb7bccf45cb87522096b8f43144e31ca605a9f24 (patch)
treed16cc764243fb6feaa4c9dea5398e139c8012124 /include/linux/cpu.h
parentc8e55f360210c1bc49bea5d62bc3939b7ee13483 (diff)
workqueue: reimplement CPU hotplugging support using trustee
Reimplement CPU hotplugging support using trustee thread. On CPU down, a trustee thread is created and each step of CPU down is executed by the trustee and workqueue_cpu_callback() simply drives and waits for trustee state transitions. CPU down operation no longer waits for works to be drained but trustee sticks around till all pending works have been completed. If CPU is brought back up while works are still draining, workqueue_cpu_callback() tells trustee to step down and tell workers to rebind to the cpu. As it's difficult to tell whether cwqs are empty if it's freezing or frozen, trustee doesn't consider draining to be complete while a gcwq is freezing or frozen (tracked by new GCWQ_FREEZING flag). Also, workers which get unbound from their cpu are marked with WORKER_ROGUE. Trustee based implementation doesn't bring any new feature at this point but it will be used to manage worker pool when dynamic shared worker pool is implemented. Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'include/linux/cpu.h')
-rw-r--r--include/linux/cpu.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index de6b1722cdc..4823af64e9d 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -71,6 +71,8 @@ enum {
/* migration should happen before other stuff but after perf */
CPU_PRI_PERF = 20,
CPU_PRI_MIGRATION = 10,
+ /* prepare workqueues for other notifiers */
+ CPU_PRI_WORKQUEUE = 5,
};
#ifdef CONFIG_SMP