Re: [PATCH 05/12] workqueue: don't wake up other workers in rescuer
On 09/27/2012 02:34 AM, Tejun Heo wrote: > (cc'ing Ray Jui) > > On Thu, Sep 27, 2012 at 01:20:36AM +0800, Lai Jiangshan wrote: >> rescuer is NOT_RUNNING, so there is no sense when it wakes up other workers, >> if there are available normal workers, they are already woken up when needed. >> >> Signed-off-by: Lai Jiangshan >> --- >> kernel/workqueue.c |8 >> 1 files changed, 0 insertions(+), 8 deletions(-) >> >> diff --git a/kernel/workqueue.c b/kernel/workqueue.c >> index c718b94..6c339bf 100644 >> --- a/kernel/workqueue.c >> +++ b/kernel/workqueue.c >> @@ -2438,14 +2438,6 @@ repeat: >> >> process_scheduled_works(rescuer); >> >> -/* >> - * Leave this gcwq. If keep_working() is %true, notify a >> - * regular worker; otherwise, we end up with 0 concurrency >> - * and stalling the execution. >> - */ >> -if (keep_working(pool)) >> -wake_up_worker(pool); >> - > > This was added by 7576958a9d5a4a6 ("workqueue: wake up a worker when a > rescuer is leaving a gcwq") to fix a bug reported by Ray Jui. > > http://thread.gmane.org/gmane.linux.kernel/1098131 > > I'm fairly sure it was a valid bug report. I don't think the > depletion comes from concurrency management. It's just the lack of > chaining which could lead to stall. What am I missing here? > "http://thread.gmane.org/gmane.linux.kernel/1098131"; does not find out the root cause. I find out the root cause with hard searching from the code, I will describe it later. Thanks, Lai -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 05/12] workqueue: don't wake up other workers in rescuer
(cc'ing Ray Jui) On Thu, Sep 27, 2012 at 01:20:36AM +0800, Lai Jiangshan wrote: > rescuer is NOT_RUNNING, so there is no sense when it wakes up other workers, > if there are available normal workers, they are already woken up when needed. > > Signed-off-by: Lai Jiangshan > --- > kernel/workqueue.c |8 > 1 files changed, 0 insertions(+), 8 deletions(-) > > diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index c718b94..6c339bf 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -2438,14 +2438,6 @@ repeat: > > process_scheduled_works(rescuer); > > - /* > - * Leave this gcwq. If keep_working() is %true, notify a > - * regular worker; otherwise, we end up with 0 concurrency > - * and stalling the execution. > - */ > - if (keep_working(pool)) > - wake_up_worker(pool); > - This was added by 7576958a9d5a4a6 ("workqueue: wake up a worker when a rescuer is leaving a gcwq") to fix a bug reported by Ray Jui. http://thread.gmane.org/gmane.linux.kernel/1098131 I'm fairly sure it was a valid bug report. I don't think the depletion comes from concurrency management. It's just the lack of chaining which could lead to stall. What am I missing here? Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 05/12] workqueue: don't wake up other workers in rescuer
rescuer is NOT_RUNNING, so there is no sense when it wakes up other workers, if there are available normal workers, they are already woken up when needed. Signed-off-by: Lai Jiangshan --- kernel/workqueue.c |8 1 files changed, 0 insertions(+), 8 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index c718b94..6c339bf 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2438,14 +2438,6 @@ repeat: process_scheduled_works(rescuer); - /* -* Leave this gcwq. If keep_working() is %true, notify a -* regular worker; otherwise, we end up with 0 concurrency -* and stalling the execution. -*/ - if (keep_working(pool)) - wake_up_worker(pool); - spin_unlock_irq(&gcwq->lock); } -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/