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| author | Paul E. McKenney <paul.mckenney@linaro.org> | 2012-02-16 21:59:33 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2012-02-21 09:42:30 -0800 |
| commit | 696a02cc16b182dd78b1f395ae336f449cc90f11 (patch) | |
| tree | 5411af06d52a3f567e6b3fe592128d3fc0306be1 /kernel/rcutree_plugin.h | |
| parent | c3ce910b1456a45fa88959af3735bd6b285e54af (diff) | |
| download | linux-696a02cc16b182dd78b1f395ae336f449cc90f11.tar.gz linux-696a02cc16b182dd78b1f395ae336f449cc90f11.tar.bz2 linux-696a02cc16b182dd78b1f395ae336f449cc90f11.zip | |
rcu: Hold off RCU_FAST_NO_HZ after timer posted
This commit handles workloads that transition quickly between idle and
non-idle, and where the CPU's callbacks cannot be invoked, but where
RCU does not have anything immediate for the CPU to do. Without this
patch, the RCU_FAST_NO_HZ code can be invoked repeatedly on each entry
to idle. The commit sets the per-CPU rcu_dyntick_holdoff variable to
hold off further attempts for a tick.
Reported-by: "Abou Gazala, Neven M" <neven.m.abou.gazala@intel.com>
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_plugin.h')
| -rw-r--r-- | kernel/rcutree_plugin.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 392a65136a72..c023464816be 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -2138,7 +2138,7 @@ static void rcu_prepare_for_idle(int cpu) /* Can we go dyntick-idle despite still having callbacks? */ trace_rcu_prep_idle("Dyntick with callbacks"); per_cpu(rcu_dyntick_drain, cpu) = 0; - per_cpu(rcu_dyntick_holdoff, cpu) = jiffies - 1; + per_cpu(rcu_dyntick_holdoff, cpu) = jiffies; if (rcu_cpu_has_nonlazy_callbacks(cpu)) hrtimer_start(&per_cpu(rcu_idle_gp_timer, cpu), rcu_idle_gp_wait, HRTIMER_MODE_REL); |