Re: Query regarding synchronize_sched_expedited and resched_cpu

On Thu, Sep 21, 2017 at 06:30:12PM +0200, Peter Zijlstra wrote: > On Thu, Sep 21, 2017 at 09:00:48AM -0700, Paul E. McKenney wrote: > > commit c21c9b78182e35eb0e72ef4e3bba3054f26eaaea [ . . . ] > Inconsistent spacing after your bullet 'o', first two points have a > space the last two a tab or

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Thu, Sep 21, 2017 at 06:30:12PM +0200, Peter Zijlstra wrote: > On Thu, Sep 21, 2017 at 09:00:48AM -0700, Paul E. McKenney wrote: > > commit c21c9b78182e35eb0e72ef4e3bba3054f26eaaea [ . . . ] > Inconsistent spacing after your bullet 'o', first two points have a > space the last two a tab or

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Thu, Sep 21, 2017 at 09:00:48AM -0700, Paul E. McKenney wrote: > commit c21c9b78182e35eb0e72ef4e3bba3054f26eaaea > Author: Paul E. McKenney > Date: Mon Sep 18 08:54:40 2017 -0700 > > sched: Make resched_cpu() unconditional > > The current

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Thu, Sep 21, 2017 at 09:00:48AM -0700, Paul E. McKenney wrote: > commit c21c9b78182e35eb0e72ef4e3bba3054f26eaaea > Author: Paul E. McKenney > Date: Mon Sep 18 08:54:40 2017 -0700 > > sched: Make resched_cpu() unconditional > > The current implementation of

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Thu, Sep 21, 2017 at 08:31:34AM -0700, Paul E. McKenney wrote: > > And given RCU is the only user of that thing, I suppose we can indeed > > change it to a full lock. > > Thank you! May I have your ack? Last version I saw still had a Changelog that looked like whitespace damage.

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Thu, Sep 21, 2017 at 08:31:34AM -0700, Paul E. McKenney wrote: > > And given RCU is the only user of that thing, I suppose we can indeed > > change it to a full lock. > > Thank you! May I have your ack? Last version I saw still had a Changelog that looked like whitespace damage.

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Thu, Sep 21, 2017 at 03:59:46PM +0200, Peter Zijlstra wrote: > On Tue, Sep 19, 2017 at 08:31:26AM -0700, Paul E. McKenney wrote: > > So I have this one queued. Objections? > > Changelog reads like its whitespace damaged. It does, now that you mention it. How about the updated version below?

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Thu, Sep 21, 2017 at 03:59:46PM +0200, Peter Zijlstra wrote: > On Tue, Sep 19, 2017 at 08:31:26AM -0700, Paul E. McKenney wrote: > > So I have this one queued. Objections? > > Changelog reads like its whitespace damaged. It does, now that you mention it. How about the updated version below?

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Thu, 21 Sep 2017 15:55:46 +0200 Peter Zijlstra wrote: > On Mon, Sep 18, 2017 at 11:11:05AM -0400, Steven Rostedt wrote: > > On Sun, 17 Sep 2017 11:37:06 +0530 > > Neeraj Upadhyay wrote: > > > > > Hi Paul, how about replacing

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Thu, 21 Sep 2017 15:55:46 +0200 Peter Zijlstra wrote: > On Mon, Sep 18, 2017 at 11:11:05AM -0400, Steven Rostedt wrote: > > On Sun, 17 Sep 2017 11:37:06 +0530 > > Neeraj Upadhyay wrote: > > > > > Hi Paul, how about replacing raw_spin_trylock_irqsave with > > > raw_spin_lock_irqsave in

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Thu, Sep 21, 2017 at 03:57:49PM +0200, Peter Zijlstra wrote: > On Mon, Sep 18, 2017 at 09:55:27AM -0700, Paul E. McKenney wrote: > > On Mon, Sep 18, 2017 at 12:29:31PM -0400, Steven Rostedt wrote: > > > On Mon, 18 Sep 2017 09:24:12 -0700 > > > "Paul E. McKenney"

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Thu, Sep 21, 2017 at 03:57:49PM +0200, Peter Zijlstra wrote: > On Mon, Sep 18, 2017 at 09:55:27AM -0700, Paul E. McKenney wrote: > > On Mon, Sep 18, 2017 at 12:29:31PM -0400, Steven Rostedt wrote: > > > On Mon, 18 Sep 2017 09:24:12 -0700 > > > "Paul E. McKenney" wrote: > > > > > > > > > > As

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Thu, Sep 21, 2017 at 03:55:46PM +0200, Peter Zijlstra wrote: > On Mon, Sep 18, 2017 at 11:11:05AM -0400, Steven Rostedt wrote: > > On Sun, 17 Sep 2017 11:37:06 +0530 > > Neeraj Upadhyay wrote: > > > > > Hi Paul, how about replacing raw_spin_trylock_irqsave with > > >

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Thu, Sep 21, 2017 at 03:55:46PM +0200, Peter Zijlstra wrote: > On Mon, Sep 18, 2017 at 11:11:05AM -0400, Steven Rostedt wrote: > > On Sun, 17 Sep 2017 11:37:06 +0530 > > Neeraj Upadhyay wrote: > > > > > Hi Paul, how about replacing raw_spin_trylock_irqsave with > > > raw_spin_lock_irqsave in

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, Sep 19, 2017 at 08:31:26AM -0700, Paul E. McKenney wrote: > So I have this one queued. Objections? Changelog reads like its whitespace damaged. > commit bc43e2e7e08134e6f403ac845edcf4f85668d803 > Author: Paul E. McKenney > Date: Mon Sep 18 08:54:40 2017

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, Sep 19, 2017 at 08:31:26AM -0700, Paul E. McKenney wrote: > So I have this one queued. Objections? Changelog reads like its whitespace damaged. > commit bc43e2e7e08134e6f403ac845edcf4f85668d803 > Author: Paul E. McKenney > Date: Mon Sep 18 08:54:40 2017 -0700 > > sched: Make

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 09:55:27AM -0700, Paul E. McKenney wrote: > On Mon, Sep 18, 2017 at 12:29:31PM -0400, Steven Rostedt wrote: > > On Mon, 18 Sep 2017 09:24:12 -0700 > > "Paul E. McKenney" wrote: > > > > > > > As soon as I work through the backlog of lockdep

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 09:55:27AM -0700, Paul E. McKenney wrote: > On Mon, Sep 18, 2017 at 12:29:31PM -0400, Steven Rostedt wrote: > > On Mon, 18 Sep 2017 09:24:12 -0700 > > "Paul E. McKenney" wrote: > > > > > > > As soon as I work through the backlog of lockdep complaints that > > > appeared

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 11:11:05AM -0400, Steven Rostedt wrote: > On Sun, 17 Sep 2017 11:37:06 +0530 > Neeraj Upadhyay wrote: > > > Hi Paul, how about replacing raw_spin_trylock_irqsave with > > raw_spin_lock_irqsave in resched_cpu()? Are there any paths > > in RCU code,

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 11:11:05AM -0400, Steven Rostedt wrote: > On Sun, 17 Sep 2017 11:37:06 +0530 > Neeraj Upadhyay wrote: > > > Hi Paul, how about replacing raw_spin_trylock_irqsave with > > raw_spin_lock_irqsave in resched_cpu()? Are there any paths > > in RCU code, which depend on trylock

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, Sep 19, 2017 at 11:58:59AM -0400, Steven Rostedt wrote: > On Tue, 19 Sep 2017 08:31:26 -0700 > "Paul E. McKenney" wrote: > > > commit bc43e2e7e08134e6f403ac845edcf4f85668d803 > > Author: Paul E. McKenney > > Date: Mon Sep 18

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, Sep 19, 2017 at 11:58:59AM -0400, Steven Rostedt wrote: > On Tue, 19 Sep 2017 08:31:26 -0700 > "Paul E. McKenney" wrote: > > > commit bc43e2e7e08134e6f403ac845edcf4f85668d803 > > Author: Paul E. McKenney > > Date: Mon Sep 18 08:54:40 2017 -0700 > > > > sched: Make resched_cpu()

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, 19 Sep 2017 08:31:26 -0700 "Paul E. McKenney" wrote: > commit bc43e2e7e08134e6f403ac845edcf4f85668d803 > Author: Paul E. McKenney > Date: Mon Sep 18 08:54:40 2017 -0700 > > sched: Make resched_cpu() unconditional > >

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, 19 Sep 2017 08:31:26 -0700 "Paul E. McKenney" wrote: > commit bc43e2e7e08134e6f403ac845edcf4f85668d803 > Author: Paul E. McKenney > Date: Mon Sep 18 08:54:40 2017 -0700 > > sched: Make resched_cpu() unconditional > > The current implementation of

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 09:24:12AM -0700, Paul E. McKenney wrote: > On Mon, Sep 18, 2017 at 12:12:13PM -0400, Steven Rostedt wrote: > > On Mon, 18 Sep 2017 09:01:25 -0700 > > "Paul E. McKenney" wrote: > > > > > > > sched: Make resched_cpu() unconditional > > >

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 09:24:12AM -0700, Paul E. McKenney wrote: > On Mon, Sep 18, 2017 at 12:12:13PM -0400, Steven Rostedt wrote: > > On Mon, 18 Sep 2017 09:01:25 -0700 > > "Paul E. McKenney" wrote: > > > > > > > sched: Make resched_cpu() unconditional > > > > > > The current

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, Sep 19, 2017 at 08:11:53AM +0200, Mike Galbraith wrote: > On Tue, 2017-09-19 at 13:37 +0800, Boqun Feng wrote: > > On Mon, Sep 18, 2017 at 09:04:56PM -0700, Paul E. McKenney wrote: > > > On Tue, Sep 19, 2017 at 11:48:22AM +0900, Byungchul Park wrote: > > > > On Mon, Sep 18, 2017 at

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, Sep 19, 2017 at 08:11:53AM +0200, Mike Galbraith wrote: > On Tue, 2017-09-19 at 13:37 +0800, Boqun Feng wrote: > > On Mon, Sep 18, 2017 at 09:04:56PM -0700, Paul E. McKenney wrote: > > > On Tue, Sep 19, 2017 at 11:48:22AM +0900, Byungchul Park wrote: > > > > On Mon, Sep 18, 2017 at

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, Sep 19, 2017 at 08:11:53AM +0200, Mike Galbraith wrote: > https://lkml.org/lkml/2017/9/5/184 Now, I checked the patches above. It looks to be a good approach to me. Thanks, Byungchul > Peter's patches worked for me, but per tglx, additional (non- > grasshopper level) hotplug-fu is

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, Sep 19, 2017 at 08:11:53AM +0200, Mike Galbraith wrote: > https://lkml.org/lkml/2017/9/5/184 Now, I checked the patches above. It looks to be a good approach to me. Thanks, Byungchul > Peter's patches worked for me, but per tglx, additional (non- > grasshopper level) hotplug-fu is

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, 2017-09-19 at 13:37 +0800, Boqun Feng wrote: > On Mon, Sep 18, 2017 at 09:04:56PM -0700, Paul E. McKenney wrote: > > On Tue, Sep 19, 2017 at 11:48:22AM +0900, Byungchul Park wrote: > > > On Mon, Sep 18, 2017 at 07:33:29PM -0700, Paul E. McKenney wrote: > > > > > > Hello Paul and Steven, >

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, 2017-09-19 at 13:37 +0800, Boqun Feng wrote: > On Mon, Sep 18, 2017 at 09:04:56PM -0700, Paul E. McKenney wrote: > > On Tue, Sep 19, 2017 at 11:48:22AM +0900, Byungchul Park wrote: > > > On Mon, Sep 18, 2017 at 07:33:29PM -0700, Paul E. McKenney wrote: > > > > > > Hello Paul and Steven, >

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 09:04:56PM -0700, Paul E. McKenney wrote: > On Tue, Sep 19, 2017 at 11:48:22AM +0900, Byungchul Park wrote: > > On Mon, Sep 18, 2017 at 07:33:29PM -0700, Paul E. McKenney wrote: > > > > > Hello Paul and Steven, > > > > > So I think this is another false positive, and the

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 09:04:56PM -0700, Paul E. McKenney wrote: > On Tue, Sep 19, 2017 at 11:48:22AM +0900, Byungchul Park wrote: > > On Mon, Sep 18, 2017 at 07:33:29PM -0700, Paul E. McKenney wrote: > > > > > Hello Paul and Steven, > > > > > So I think this is another false positive, and the

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, Sep 19, 2017 at 11:48:22AM +0900, Byungchul Park wrote: > On Mon, Sep 18, 2017 at 07:33:29PM -0700, Paul E. McKenney wrote: > > > > Hello Paul and Steven, > > > > > > > > This is saying: > > > > > > > > Thread A > > > > > > > > takedown_cpu() > > > >irq_lock_sparse() > > > >

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, Sep 19, 2017 at 11:48:22AM +0900, Byungchul Park wrote: > On Mon, Sep 18, 2017 at 07:33:29PM -0700, Paul E. McKenney wrote: > > > > Hello Paul and Steven, > > > > > > > > This is saying: > > > > > > > > Thread A > > > > > > > > takedown_cpu() > > > >irq_lock_sparse() > > > >

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 07:33:29PM -0700, Paul E. McKenney wrote: > > > Hello Paul and Steven, > > > > > > This is saying: > > > > > > Thread A > > > > > > takedown_cpu() > > >irq_lock_sparse() > > >wait_for_completion(>done) // Wait for completion of B > > >

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 07:33:29PM -0700, Paul E. McKenney wrote: > > > Hello Paul and Steven, > > > > > > This is saying: > > > > > > Thread A > > > > > > takedown_cpu() > > >irq_lock_sparse() > > >wait_for_completion(>done) // Wait for completion of B > > >

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, Sep 19, 2017 at 11:06:10AM +0900, Byungchul Park wrote: > On Tue, Sep 19, 2017 at 10:50:27AM +0900, Byungchul Park wrote: > > On Mon, Sep 18, 2017 at 04:53:11PM -0700, Paul E. McKenney wrote: > > > So, Byungchul, any enlightenment? Please see lockdep splat below. > > > > > >

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, Sep 19, 2017 at 11:06:10AM +0900, Byungchul Park wrote: > On Tue, Sep 19, 2017 at 10:50:27AM +0900, Byungchul Park wrote: > > On Mon, Sep 18, 2017 at 04:53:11PM -0700, Paul E. McKenney wrote: > > > So, Byungchul, any enlightenment? Please see lockdep splat below. > > > > > >

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 09:23:01PM -0400, Steven Rostedt wrote: > On Mon, 18 Sep 2017 16:53:11 -0700 > "Paul E. McKenney" wrote: > > > On Mon, Sep 18, 2017 at 09:55:27AM -0700, Paul E. McKenney wrote: > > > On Mon, Sep 18, 2017 at 12:29:31PM -0400, Steven Rostedt

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 09:23:01PM -0400, Steven Rostedt wrote: > On Mon, 18 Sep 2017 16:53:11 -0700 > "Paul E. McKenney" wrote: > > > On Mon, Sep 18, 2017 at 09:55:27AM -0700, Paul E. McKenney wrote: > > > On Mon, Sep 18, 2017 at 12:29:31PM -0400, Steven Rostedt wrote: > > > > On Mon, 18 Sep

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, Sep 19, 2017 at 10:50:27AM +0900, Byungchul Park wrote: > On Mon, Sep 18, 2017 at 04:53:11PM -0700, Paul E. McKenney wrote: > > So, Byungchul, any enlightenment? Please see lockdep splat below. > > > > Thanx, Paul > > > >

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Tue, Sep 19, 2017 at 10:50:27AM +0900, Byungchul Park wrote: > On Mon, Sep 18, 2017 at 04:53:11PM -0700, Paul E. McKenney wrote: > > So, Byungchul, any enlightenment? Please see lockdep splat below. > > > > Thanx, Paul > > > >

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 12:29:31PM -0400, Steven Rostedt wrote: > On Mon, 18 Sep 2017 09:24:12 -0700 > "Paul E. McKenney" wrote: > > > > As soon as I work through the backlog of lockdep complaints that > > appeared in the last merge window... :-( > > > >

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 12:29:31PM -0400, Steven Rostedt wrote: > On Mon, 18 Sep 2017 09:24:12 -0700 > "Paul E. McKenney" wrote: > > > > As soon as I work through the backlog of lockdep complaints that > > appeared in the last merge window... :-( > > > > sparse_irq_lock, I am looking at

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 04:53:11PM -0700, Paul E. McKenney wrote: > So, Byungchul, any enlightenment? Please see lockdep splat below. > > Thanx, Paul > > > > [

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 04:53:11PM -0700, Paul E. McKenney wrote: > So, Byungchul, any enlightenment? Please see lockdep splat below. > > Thanx, Paul > > > > [

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, 18 Sep 2017 16:53:11 -0700 "Paul E. McKenney" wrote: > On Mon, Sep 18, 2017 at 09:55:27AM -0700, Paul E. McKenney wrote: > > On Mon, Sep 18, 2017 at 12:29:31PM -0400, Steven Rostedt wrote: > > > On Mon, 18 Sep 2017 09:24:12 -0700 > > > "Paul E. McKenney"

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, 18 Sep 2017 16:53:11 -0700 "Paul E. McKenney" wrote: > On Mon, Sep 18, 2017 at 09:55:27AM -0700, Paul E. McKenney wrote: > > On Mon, Sep 18, 2017 at 12:29:31PM -0400, Steven Rostedt wrote: > > > On Mon, 18 Sep 2017 09:24:12 -0700 > > > "Paul E. McKenney" wrote: > > > > > > > > > >

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 09:55:27AM -0700, Paul E. McKenney wrote: > On Mon, Sep 18, 2017 at 12:29:31PM -0400, Steven Rostedt wrote: > > On Mon, 18 Sep 2017 09:24:12 -0700 > > "Paul E. McKenney" wrote: > > > > > > > As soon as I work through the backlog of lockdep

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 09:55:27AM -0700, Paul E. McKenney wrote: > On Mon, Sep 18, 2017 at 12:29:31PM -0400, Steven Rostedt wrote: > > On Mon, 18 Sep 2017 09:24:12 -0700 > > "Paul E. McKenney" wrote: > > > > > > > As soon as I work through the backlog of lockdep complaints that > > > appeared

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 12:29:31PM -0400, Steven Rostedt wrote: > On Mon, 18 Sep 2017 09:24:12 -0700 > "Paul E. McKenney" wrote: > > > > As soon as I work through the backlog of lockdep complaints that > > appeared in the last merge window... :-( > > > >

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 12:29:31PM -0400, Steven Rostedt wrote: > On Mon, 18 Sep 2017 09:24:12 -0700 > "Paul E. McKenney" wrote: > > > > As soon as I work through the backlog of lockdep complaints that > > appeared in the last merge window... :-( > > > > sparse_irq_lock, I am looking at

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, 18 Sep 2017 09:24:12 -0700 "Paul E. McKenney" wrote: > As soon as I work through the backlog of lockdep complaints that > appeared in the last merge window... :-( > > sparse_irq_lock, I am looking at you!!! ;-) I just hit one too, and decided to write a

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, 18 Sep 2017 09:24:12 -0700 "Paul E. McKenney" wrote: > As soon as I work through the backlog of lockdep complaints that > appeared in the last merge window... :-( > > sparse_irq_lock, I am looking at you!!! ;-) I just hit one too, and decided to write a patch to show a chain of 3

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 12:12:13PM -0400, Steven Rostedt wrote: > On Mon, 18 Sep 2017 09:01:25 -0700 > "Paul E. McKenney" wrote: > > > > sched: Make resched_cpu() unconditional > > > > The current implementation of synchronize_sched_expedited()

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 12:12:13PM -0400, Steven Rostedt wrote: > On Mon, 18 Sep 2017 09:01:25 -0700 > "Paul E. McKenney" wrote: > > > > sched: Make resched_cpu() unconditional > > > > The current implementation of synchronize_sched_expedited() incorrectly > > assumes that

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, 18 Sep 2017 09:01:25 -0700 "Paul E. McKenney" wrote: > sched: Make resched_cpu() unconditional > > The current implementation of synchronize_sched_expedited() incorrectly > assumes that resched_cpu() is unconditional, which it is not. This

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, 18 Sep 2017 09:01:25 -0700 "Paul E. McKenney" wrote: > sched: Make resched_cpu() unconditional > > The current implementation of synchronize_sched_expedited() incorrectly > assumes that resched_cpu() is unconditional, which it is not. This means > that

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 11:11:05AM -0400, Steven Rostedt wrote: > On Sun, 17 Sep 2017 11:37:06 +0530 > Neeraj Upadhyay wrote: > > > Hi Paul, how about replacing raw_spin_trylock_irqsave with > > raw_spin_lock_irqsave in resched_cpu()? Are there any paths > > in RCU code,

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Mon, Sep 18, 2017 at 11:11:05AM -0400, Steven Rostedt wrote: > On Sun, 17 Sep 2017 11:37:06 +0530 > Neeraj Upadhyay wrote: > > > Hi Paul, how about replacing raw_spin_trylock_irqsave with > > raw_spin_lock_irqsave in resched_cpu()? Are there any paths > > in RCU code, which depend on trylock

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Sun, 17 Sep 2017 11:37:06 +0530 Neeraj Upadhyay wrote: > Hi Paul, how about replacing raw_spin_trylock_irqsave with > raw_spin_lock_irqsave in resched_cpu()? Are there any paths > in RCU code, which depend on trylock check/spinlock recursion? It looks to me that

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Sun, 17 Sep 2017 11:37:06 +0530 Neeraj Upadhyay wrote: > Hi Paul, how about replacing raw_spin_trylock_irqsave with > raw_spin_lock_irqsave in resched_cpu()? Are there any paths > in RCU code, which depend on trylock check/spinlock recursion? It looks to me that resched_cpu() was added for

Re: Query regarding synchronize_sched_expedited and resched_cpu

On 09/17/2017 06:30 AM, Paul E. McKenney wrote: On Fri, Sep 15, 2017 at 04:44:38PM +0530, Neeraj Upadhyay wrote: Hi, We have one query regarding the behavior of RCU expedited grace period, for scenario where resched_cpu() in sync_sched_exp_handler() fails to acquire the rq lock and returns

Re: Query regarding synchronize_sched_expedited and resched_cpu

On 09/17/2017 06:30 AM, Paul E. McKenney wrote: On Fri, Sep 15, 2017 at 04:44:38PM +0530, Neeraj Upadhyay wrote: Hi, We have one query regarding the behavior of RCU expedited grace period, for scenario where resched_cpu() in sync_sched_exp_handler() fails to acquire the rq lock and returns

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Fri, Sep 15, 2017 at 04:44:38PM +0530, Neeraj Upadhyay wrote: > Hi, > > We have one query regarding the behavior of RCU expedited grace period, > for scenario where resched_cpu() in sync_sched_exp_handler() fails to > acquire the rq lock and returns w/o setting the need_resched. In this >

Re: Query regarding synchronize_sched_expedited and resched_cpu

On Fri, Sep 15, 2017 at 04:44:38PM +0530, Neeraj Upadhyay wrote: > Hi, > > We have one query regarding the behavior of RCU expedited grace period, > for scenario where resched_cpu() in sync_sched_exp_handler() fails to > acquire the rq lock and returns w/o setting the need_resched. In this >

Query regarding synchronize_sched_expedited and resched_cpu

Hi, We have one query regarding the behavior of RCU expedited grace period, for scenario where resched_cpu() in sync_sched_exp_handler() fails to acquire the rq lock and returns w/o setting the need_resched. In this case, how do we ensure that the CPU notify rcu about the end of sched grace

Query regarding synchronize_sched_expedited and resched_cpu

Hi, We have one query regarding the behavior of RCU expedited grace period, for scenario where resched_cpu() in sync_sched_exp_handler() fails to acquire the rq lock and returns w/o setting the need_resched. In this case, how do we ensure that the CPU notify rcu about the end of sched grace