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authorPaul E. McKenney <paul.mckenney@linaro.org>2012-03-27 16:02:08 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-05-02 14:43:23 -0700
commit616c310e83b872024271c915c1b9ab505b9efad9 (patch)
tree1339bc7b3bef920b4641a5af2f182e9dfa2a6632 /arch/um/drivers/mconsole_kern.c
parent66f75a5d028beaf67c931435fdc3e7823125730c (diff)
downloadvexpress-lsk-616c310e83b872024271c915c1b9ab505b9efad9.tar.gz
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 'arch/um/drivers/mconsole_kern.c')
-rw-r--r--arch/um/drivers/mconsole_kern.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
index 43b39d61b53..88e466b159d 100644
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -705,6 +705,7 @@ static void stack_proc(void *arg)
struct task_struct *from = current, *to = arg;
to->thread.saved_task = from;
+ rcu_switch_from(from);
switch_to(from, to, from);
}