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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-07-01 11:26:57 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-09-07 16:27:20 -0700
commitbde6c3aa993066acb0d6ce32ecabe03b9d5df92d (patch)
tree09ec78a9cfa751ce36288c32c4e5112f34af8582 /mm
parent8315f42295d2667a7f942f154b73a86fd7cb2227 (diff)
downloadblackbird-op-linux-bde6c3aa993066acb0d6ce32ecabe03b9d5df92d.tar.gz
blackbird-op-linux-bde6c3aa993066acb0d6ce32ecabe03b9d5df92d.zip
rcu: Provide cond_resched_rcu_qs() to force quiescent states in long loops
RCU-tasks requires the occasional voluntary context switch from CPU-bound in-kernel tasks. In some cases, this requires instrumenting cond_resched(). However, there is some reluctance to countenance unconditionally instrumenting cond_resched() (see http://lwn.net/Articles/603252/), so this commit creates a separate cond_resched_rcu_qs() that may be used in place of cond_resched() in locations prone to long-duration in-kernel looping. This commit currently instruments only RCU-tasks. Future possibilities include also instrumenting RCU, RCU-bh, and RCU-sched in order to reduce IPI usage. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'mm')
-rw-r--r--mm/mlock.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/mlock.c b/mm/mlock.c
index ce84cb0b83ef..ab3150c26711 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -789,7 +789,7 @@ static int do_mlockall(int flags)
/* Ignore errors */
mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags);
- cond_resched();
+ cond_resched_rcu_qs();
}
out:
return 0;
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