xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

rcu: Provide cond_resched_rcu_qs() to force quiescent states in long loops

Browse Source 
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>
This commit is contained in:
Paul E. McKenney
2014-07-01 11:26:57 -07:00
parent 8315f42295
commit bde6c3aa99
6 changed files with 24 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
kernel/rcu/tree_plugin.h
View File

@@ -1848,7 +1848,7 @@ static int rcu_oom_notify(struct notifier_block *self,
get_online_cpus();
for_each_online_cpu(cpu) {
smp_call_function_single(cpu, rcu_oom_notify_cpu, NULL, 1);
cond_resched();
cond_resched_rcu_qs();
}
put_online_cpus();