[PATCH v1 3/6] workqueue: introduce schedule_on_each_cpu_cond
From: Gilad Ben-Yossef <gilad@benyossef.com>
Date: 2012-05-03 14:58:34
Also in:
lkml
Subsystem:
the rest, workqueue · Maintainers:
Linus Torvalds, Tejun Heo
Introduce the schedule_on_each_cpu_cond() function that schedules a work item on each online CPU for which the supplied condition function returns true. This function should be used instead of schedule_on_each_cpu() when only some of the CPUs have actual work to do and a predicate function can tell if a certain CPU does or does not have work to do, thus saving unneeded wakeups and schedules. Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com> CC: Thomas Gleixner <redacted> CC: Tejun Heo <tj@kernel.org> CC: John Stultz <redacted> CC: Andrew Morton <akpm@linux-foundation.org> CC: KOSAKI Motohiro <redacted> CC: Mel Gorman <redacted> CC: Mike Frysinger <redacted> CC: David Rientjes <rientjes@google.com> CC: Hugh Dickins <hughd@google.com> CC: Minchan Kim <redacted> CC: Konstantin Khlebnikov <redacted> CC: Christoph Lameter <redacted> CC: Chris Metcalf <redacted> CC: Hakan Akkan <redacted> CC: Max Krasnyansky <redacted> CC: Frederic Weisbecker <redacted> CC: linux-kernel@vger.kernel.org CC: linux-mm@kvack.org --- include/linux/workqueue.h | 2 ++ kernel/workqueue.c | 37 +++++++++++++++++++++++++++++++++++++ 2 files changed, 39 insertions(+), 0 deletions(-)
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 20da95a..d7bb104 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h@@ -385,6 +385,8 @@ extern int schedule_delayed_work_on(int cpu, struct delayed_work *work, extern int schedule_on_each_cpu(work_func_t func); extern int schedule_on_each_cpu_mask(work_func_t func, const struct cpumask *mask); +extern int schedule_on_each_cpu_cond(work_func_t func, + bool (*cond_func)(int cpu)); extern int keventd_up(void); int execute_in_process_context(work_func_t fn, struct execute_work *);
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 1c9782b..3322d30 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c@@ -2828,6 +2828,43 @@ int schedule_on_each_cpu_mask(work_func_t func, const struct cpumask *mask) } /** + * schedule_on_each_cpu_cond - execute a function synchronously on each + * online CPU for which the supplied condition function returns true + * @func: the function to run on the selected CPUs + * @cond_func: the function to call to select the CPUs + * + * schedule_on_each_cpu_cond() executes @func on each online CPU for + * @cond_func returns true using the system workqueue and blocks until + * all CPUs have completed. + * schedule_on_each_cpu_cond() is very slow. + * + * RETURNS: + * 0 on success, -errno on failure. + */ +int schedule_on_each_cpu_cond(work_func_t func, bool (*cond_func)(int cpu)) +{ + int cpu, ret; + cpumask_var_t mask; + + if (unlikely(!zalloc_cpumask_var(&mask, GFP_KERNEL))) + return -ENOMEM; + + get_online_cpus(); + + for_each_online_cpu(cpu) + if (cond_func(cpu)) + cpumask_set_cpu(cpu, mask); + + ret = schedule_on_each_cpu_mask(func, mask); + + put_online_cpus(); + + free_cpumask_var(mask); + + return ret; +} + +/** * schedule_on_each_cpu - execute a function synchronously on each online CPU * @func: the function to call *
--
1.7.0.4
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