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author | Tejun Heo <tj@kernel.org> | 2012-08-03 19:30:47 +0200 |
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committer | Tejun Heo <tj@kernel.org> | 2012-08-03 19:30:47 +0200 |
commit | 8376fe22c7e79c7e90857d39f82aeae6cad6c4b8 (patch) | |
tree | 3a77fda11324a25abfe1ffe3ea0eba28a4fac03f /kernel/workqueue.c | |
parent | workqueue: mark a work item being canceled as such (diff) | |
download | linux-8376fe22c7e79c7e90857d39f82aeae6cad6c4b8.tar.xz linux-8376fe22c7e79c7e90857d39f82aeae6cad6c4b8.zip |
workqueue: implement mod_delayed_work[_on]()
Workqueue was lacking a mechanism to modify the timeout of an already
pending delayed_work. delayed_work users have been working around
this using several methods - using an explicit timer + work item,
messing directly with delayed_work->timer, and canceling before
re-queueing, all of which are error-prone and/or ugly.
This patch implements mod_delayed_work[_on]() which behaves similarly
to mod_timer() - if the delayed_work is idle, it's queued with the
given delay; otherwise, its timeout is modified to the new value.
Zero @delay guarantees immediate execution.
v2: Updated to reflect try_to_grab_pending() changes. Now safe to be
called from bh context.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Diffstat (limited to 'kernel/workqueue.c')
-rw-r--r-- | kernel/workqueue.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index b4a4e05c89e1..41ae2c0979fe 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1414,6 +1414,59 @@ bool queue_delayed_work(struct workqueue_struct *wq, EXPORT_SYMBOL_GPL(queue_delayed_work); /** + * mod_delayed_work_on - modify delay of or queue a delayed work on specific CPU + * @cpu: CPU number to execute work on + * @wq: workqueue to use + * @dwork: work to queue + * @delay: number of jiffies to wait before queueing + * + * If @dwork is idle, equivalent to queue_delayed_work_on(); otherwise, + * modify @dwork's timer so that it expires after @delay. If @delay is + * zero, @work is guaranteed to be scheduled immediately regardless of its + * current state. + * + * Returns %false if @dwork was idle and queued, %true if @dwork was + * pending and its timer was modified. + * + * This function is safe to call from any context other than IRQ handler. + * See try_to_grab_pending() for details. + */ +bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq, + struct delayed_work *dwork, unsigned long delay) +{ + unsigned long flags; + int ret; + + do { + ret = try_to_grab_pending(&dwork->work, true, &flags); + } while (unlikely(ret == -EAGAIN)); + + if (likely(ret >= 0)) { + __queue_delayed_work(cpu, wq, dwork, delay); + local_irq_restore(flags); + } + + /* -ENOENT from try_to_grab_pending() becomes %true */ + return ret; +} +EXPORT_SYMBOL_GPL(mod_delayed_work_on); + +/** + * mod_delayed_work - modify delay of or queue a delayed work + * @wq: workqueue to use + * @dwork: work to queue + * @delay: number of jiffies to wait before queueing + * + * mod_delayed_work_on() on local CPU. + */ +bool mod_delayed_work(struct workqueue_struct *wq, struct delayed_work *dwork, + unsigned long delay) +{ + return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); +} +EXPORT_SYMBOL_GPL(mod_delayed_work); + +/** * worker_enter_idle - enter idle state * @worker: worker which is entering idle state * |