diff options
| author | Paul E. McKenney <paul.mckenney@linaro.org> | 2011-08-04 06:59:03 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2011-09-28 21:38:37 -0700 |
| commit | 5c51dd7349d4bb26f845f17f85daa168f5fa03f2 (patch) | |
| tree | a846bf11cb973e8d0bb28d9c07653663759fb6c8 /kernel/rcutree.c | |
| parent | 4627e240dfee4a0a46a58010b1b721b4ded1918f (diff) | |
| download | lwn-5c51dd7349d4bb26f845f17f85daa168f5fa03f2.tar.gz lwn-5c51dd7349d4bb26f845f17f85daa168f5fa03f2.zip | |
rcu: Prevent early boot set_need_resched() from __rcu_pending()
There isn't a whole lot of point in poking the scheduler before there
are other tasks to switch to. This commit therefore adds a check
for rcu_scheduler_fully_active in __rcu_pending() to suppress any
pre-scheduler calls to set_need_resched(). The downside of this approach
is additional runtime overhead in a reasonably hot code path.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcutree.c')
| -rw-r--r-- | kernel/rcutree.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c index a07bf553e02a..0051dbf6958e 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1707,7 +1707,8 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp) check_cpu_stall(rsp, rdp); /* Is the RCU core waiting for a quiescent state from this CPU? */ - if (rdp->qs_pending && !rdp->passed_quiesce) { + if (rcu_scheduler_fully_active && + rdp->qs_pending && !rdp->passed_quiesce) { /* * If force_quiescent_state() coming soon and this CPU |