Re: [PATCH] kthread: Fix the race condition when kthread is parked

2014-11-03 Thread Thomas Gleixner
On Sun, 2 Nov 2014, Daniel J Blueman wrote: > I just got a window to test this, and it reliably addresses the boot-time core > onlining race that we've seen occasionally on a 2000-core customer system. > Splendid work, Thomas. > > Tested-by: Daniel J Blueman Well, you forgot to read my follow up

Re: [PATCH] kthread: Fix the race condition when kthread is parked

2014-11-02 Thread Daniel J Blueman
On Thursday, June 26, 2014 8:50:01 AM UTC+8, Thomas Gleixner wrote: > On Wed, 25 Jun 2014, Subbaraman Narayanamurthy wrote: > > While stressing the CPU hotplug path, sometimes we hit a problem > > as shown below. > > > > [57056.416774] [ cut here ] > > [57056.489232] ksofti

Re: [PATCH] kthread: Fix the race condition when kthread is parked

2014-06-26 Thread Thomas Gleixner
On Thu, 26 Jun 2014, Subbaraman Narayanamurthy wrote: > On 06/25/14 17:43, Thomas Gleixner wrote: > > The kthread park/unpark logic has the following issue: > > > > Task CPU 0CPU 1 > > > > T1 unplug cpu1 > > kthread_park(T2) > > set_bit(KTHREA

Re: [PATCH] kthread: Fix the race condition when kthread is parked

2014-06-26 Thread Subbaraman Narayanamurthy
On 06/25/14 17:43, Thomas Gleixner wrote: The kthread park/unpark logic has the following issue: Task CPU 0CPU 1 T1 unplug cpu1 kthread_park(T2) set_bit(KTHREAD_SHOULD_PARK); wait_for_completion() T2

Re: [PATCH] kthread: Fix the race condition when kthread is parked

2014-06-25 Thread Steven Rostedt
On Wed, Jun 25, 2014 at 10:00:22PM -0400, Steven Rostedt wrote: > On Thu, Jun 26, 2014 at 02:43:56AM +0200, Thomas Gleixner wrote: > > > > Subject: kthread: Plug park/ unplug race > > From: Thomas Gleixner > > Date: Thu, 26 Jun 2014 01:24:36 +0200 > > > > The kthread park/unpark logic has the fo

Re: [PATCH] kthread: Fix the race condition when kthread is parked

2014-06-25 Thread Steven Rostedt
On Thu, Jun 26, 2014 at 02:43:56AM +0200, Thomas Gleixner wrote: > > Subject: kthread: Plug park/ unplug race > From: Thomas Gleixner > Date: Thu, 26 Jun 2014 01:24:36 +0200 > > The kthread park/unpark logic has the following issue: > > Task CPU 0 CPU 1 > > T1 un

Re: [PATCH] kthread: Fix the race condition when kthread is parked

2014-06-25 Thread Thomas Gleixner
On Wed, 25 Jun 2014, Subbaraman Narayanamurthy wrote: > While stressing the CPU hotplug path, sometimes we hit a problem > as shown below. > > [57056.416774] [ cut here ] > [57056.489232] ksoftirqd/1 (14): undefined instruction: pc=c01931e8 > [57056.489245] Code: e594a000

[PATCH] kthread: Fix the race condition when kthread is parked

2014-06-25 Thread Subbaraman Narayanamurthy
While stressing the CPU hotplug path, sometimes we hit a problem as shown below. [57056.416774] [ cut here ] [57056.489232] ksoftirqd/1 (14): undefined instruction: pc=c01931e8 [57056.489245] Code: e594a000 eb085236 e15a 0a00 (e7f001f2) [57056.489259] [