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authorPaul E. McKenney <paul.mckenney@linaro.org>2012-03-28 01:02:08 +0200
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-05-02 23:43:23 +0200
commit616c310e83b872024271c915c1b9ab505b9efad9 (patch)
tree1339bc7b3bef920b4641a5af2f182e9dfa2a6632 /kernel/sched
parentLinux 3.4-rc4 (diff)
downloadlinux-616c310e83b872024271c915c1b9ab505b9efad9.tar.xz
linux-616c310e83b872024271c915c1b9ab505b9efad9.zip
rcu: Move PREEMPT_RCU preemption to switch_to() invocation
Currently, PREEMPT_RCU readers are enqueued upon entry to the scheduler. This is inefficient because enqueuing is required only if there is a context switch, and entry to the scheduler does not guarantee a context switch. The commit therefore moves the enqueuing to immediately precede the call to switch_to() from the scheduler. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/core.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 4603b9d8f30a..5d89eb93f7e4 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2083,6 +2083,7 @@ context_switch(struct rq *rq, struct task_struct *prev,
#endif
/* Here we just switch the register state and the stack. */
+ rcu_switch_from(prev);
switch_to(prev, next, prev);
barrier();