diff options
| author | Ingo Molnar <mingo@kernel.org> | 2012-09-27 08:09:38 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-09-27 08:09:38 +0200 |
| commit | fa34da708cbe1e2d9a2ee7fc68ea8fccbf095d12 (patch) | |
| tree | b20795decb064af75aae8f9f6af77806b1a4769a /kernel/rcutree_plugin.h | |
| parent | a9b86fab4b0a36fc4cd2712a07259c2c0e769742 (diff) | |
| parent | cb349ca95407cbc11424d5e9fc7c8e700709041b (diff) | |
Merge branch 'rcu/idle' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull the RCU adaptive-idle feature from Paul E. McKenney:
"This series adds RCU APIs that allow non-idle tasks to
enter RCU idle mode and provides x86 code to make use of them, allowing
RCU to treat user-mode execution as an extended quiescent state when the
new RCU_USER_QS kernel configuration parameter is specified. Work is
in progress to port this to a few other architectures, but is not part
of this series."
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/rcutree_plugin.h')
| -rw-r--r-- | kernel/rcutree_plugin.h | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 9c71c1b18e0..f9211548818 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -1757,6 +1757,26 @@ static void rcu_prepare_for_idle(int cpu) if (!tne) return; + /* Adaptive-tick mode, where usermode execution is idle to RCU. */ + if (!is_idle_task(current)) { + rdtp->dyntick_holdoff = jiffies - 1; + if (rcu_cpu_has_nonlazy_callbacks(cpu)) { + trace_rcu_prep_idle("User dyntick with callbacks"); + rdtp->idle_gp_timer_expires = + round_up(jiffies + RCU_IDLE_GP_DELAY, + RCU_IDLE_GP_DELAY); + } else if (rcu_cpu_has_callbacks(cpu)) { + rdtp->idle_gp_timer_expires = + round_jiffies(jiffies + RCU_IDLE_LAZY_GP_DELAY); + trace_rcu_prep_idle("User dyntick with lazy callbacks"); + } else { + return; + } + tp = &rdtp->idle_gp_timer; + mod_timer_pinned(tp, rdtp->idle_gp_timer_expires); + return; + } + /* * If this is an idle re-entry, for example, due to use of * RCU_NONIDLE() or the new idle-loop tracing API within the idle |