35 lines
1.3 KiB
Diff
35 lines
1.3 KiB
Diff
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From 05b0c3b7b05471a6d53300cf6d7d88ee66eff7ed Mon Sep 17 00:00:00 2001
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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
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Date: Thu, 4 Aug 2011 11:10:24 -0400
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Subject: [PATCH] rcu: Prevent early boot set_need_resched() from
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__rcu_pending()
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There isn't a whole lot of point in poking the scheduler before there
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are other tasks to switch to. This commit therefore adds a check
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for rcu_scheduler_fully_active in __rcu_pending() to suppress any
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pre-scheduler calls to set_need_resched(). The downside of this approach
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is additional runtime overhead in a reasonably hot code path.
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Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
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Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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---
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kernel/rcutree.c | 2 +-
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1 files changed, 1 insertions(+), 1 deletions(-)
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diff --git a/kernel/rcutree.c b/kernel/rcutree.c
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index ba06207..9c8a3f9 100644
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--- a/kernel/rcutree.c
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+++ b/kernel/rcutree.c
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@@ -1671,7 +1671,7 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp)
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check_cpu_stall(rsp, rdp);
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/* Is the RCU core waiting for a quiescent state from this CPU? */
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- if (rdp->qs_pending && !rdp->passed_quiesc) {
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+ if (rcu_scheduler_fully_active && rdp->qs_pending && !rdp->passed_quiesc) {
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/*
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* If force_quiescent_state() coming soon and this CPU
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--
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1.7.6
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