Re: [PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

On 2018-06-27 08:36:57 [-0400], Steven Rostedt wrote: > On Wed, Apr 11, 2018 at 09:07:30PM +0200, Sebastian Andrzej Siewior wrote: > > > > This already happens: > > - vmstat_shepherd() does get_online_cpus() and within this block it does > > queue_delayed_work_on(). So this has to wait until

Re: [PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

On 2018-06-27 08:36:57 [-0400], Steven Rostedt wrote: > On Wed, Apr 11, 2018 at 09:07:30PM +0200, Sebastian Andrzej Siewior wrote: > > > > This already happens: > > - vmstat_shepherd() does get_online_cpus() and within this block it does > > queue_delayed_work_on(). So this has to wait until

Re: [PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

On Wed, Apr 11, 2018 at 09:07:30PM +0200, Sebastian Andrzej Siewior wrote: > > This already happens: > - vmstat_shepherd() does get_online_cpus() and within this block it does > queue_delayed_work_on(). So this has to wait until cpuhotplug > completed before it can schedule something and then

Re: [PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

On Wed, Apr 11, 2018 at 09:07:30PM +0200, Sebastian Andrzej Siewior wrote: > > This already happens: > - vmstat_shepherd() does get_online_cpus() and within this block it does > queue_delayed_work_on(). So this has to wait until cpuhotplug > completed before it can schedule something and then

Re: [PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

On Wed, 18 Apr 2018 17:44:36 +0200 Sebastian Andrzej Siewior wrote: > On 2018-04-11 21:07:29 [+0200], To Tejun Heo wrote: > > On 2018-04-11 16:42:21 [+0200], To Tejun Heo wrote: > > > > > So is this perhaps related to the cpu hotplug that [1] mentions? e.g. > > > > > is

Re: [PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

On Wed, 18 Apr 2018 17:44:36 +0200 Sebastian Andrzej Siewior wrote: > On 2018-04-11 21:07:29 [+0200], To Tejun Heo wrote: > > On 2018-04-11 16:42:21 [+0200], To Tejun Heo wrote: > > > > > So is this perhaps related to the cpu hotplug that [1] mentions? e.g. > > > > > is > > > > > the cpu being

Re: [PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

ping. any reason not to accept the revert? On 2018-04-11 21:07:29 [+0200], To Tejun Heo wrote: > On 2018-04-11 16:42:21 [+0200], To Tejun Heo wrote: > > > > So is this perhaps related to the cpu hotplug that [1] mentions? e.g. is > > > > the cpu being hotplugged cpu 1, the worker started too

Re: [PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

ping. any reason not to accept the revert? On 2018-04-11 21:07:29 [+0200], To Tejun Heo wrote: > On 2018-04-11 16:42:21 [+0200], To Tejun Heo wrote: > > > > So is this perhaps related to the cpu hotplug that [1] mentions? e.g. is > > > > the cpu being hotplugged cpu 1, the worker started too

Re: [PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

On 2018-04-11 16:42:21 [+0200], To Tejun Heo wrote: > > > So is this perhaps related to the cpu hotplug that [1] mentions? e.g. is > > > the cpu being hotplugged cpu 1, the worker started too early before > > > stuff can be scheduled on the CPU, so it has to run on different than > > > designated

Re: [PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

On 2018-04-11 16:42:21 [+0200], To Tejun Heo wrote: > > > So is this perhaps related to the cpu hotplug that [1] mentions? e.g. is > > > the cpu being hotplugged cpu 1, the worker started too early before > > > stuff can be scheduled on the CPU, so it has to run on different than > > > designated

Re: [PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

On 2018-04-11 07:09:13 [-0700], Tejun Heo wrote: > Hello, > > On Wed, Apr 11, 2018 at 03:56:43PM +0200, Vlastimil Babka wrote: > > > vmstat_update() is invoked by a kworker on a specific CPU. This worker > > > it bound to this CPU. The name of the worker was "kworker/1:1" so it > > > should have

Re: [PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

On 2018-04-11 07:09:13 [-0700], Tejun Heo wrote: > Hello, > > On Wed, Apr 11, 2018 at 03:56:43PM +0200, Vlastimil Babka wrote: > > > vmstat_update() is invoked by a kworker on a specific CPU. This worker > > > it bound to this CPU. The name of the worker was "kworker/1:1" so it > > > should have

Re: [PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

Hello, On Wed, Apr 11, 2018 at 03:56:43PM +0200, Vlastimil Babka wrote: > > vmstat_update() is invoked by a kworker on a specific CPU. This worker > > it bound to this CPU. The name of the worker was "kworker/1:1" so it > > should have been a worker which was bound to CPU1. A worker which can > >

Re: [PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

Hello, On Wed, Apr 11, 2018 at 03:56:43PM +0200, Vlastimil Babka wrote: > > vmstat_update() is invoked by a kworker on a specific CPU. This worker > > it bound to this CPU. The name of the worker was "kworker/1:1" so it > > should have been a worker which was bound to CPU1. A worker which can > >

Re: [PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

On 04/11/2018 11:57 AM, Sebastian Andrzej Siewior wrote: > This patch reverts commit c7f26ccfb2c3 ("mm/vmstat.c: fix > vmstat_update() preemption BUG"). > Steven saw a "using smp_processor_id() in preemptible" message and > added a preempt_disable() section around it to keep it quiet. This is >

Re: [PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

On 04/11/2018 11:57 AM, Sebastian Andrzej Siewior wrote: > This patch reverts commit c7f26ccfb2c3 ("mm/vmstat.c: fix > vmstat_update() preemption BUG"). > Steven saw a "using smp_processor_id() in preemptible" message and > added a preempt_disable() section around it to keep it quiet. This is >

[PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

This patch reverts commit c7f26ccfb2c3 ("mm/vmstat.c: fix vmstat_update() preemption BUG"). Steven saw a "using smp_processor_id() in preemptible" message and added a preempt_disable() section around it to keep it quiet. This is not the right thing to do it does not fix the real problem.

[PATCH] Revert mm/vmstat.c: fix vmstat_update() preemption BUG

This patch reverts commit c7f26ccfb2c3 ("mm/vmstat.c: fix vmstat_update() preemption BUG"). Steven saw a "using smp_processor_id() in preemptible" message and added a preempt_disable() section around it to keep it quiet. This is not the right thing to do it does not fix the real problem.