Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1314894
| From | Shiraz Hashim <shiraz.linux.kernel@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! |
| Date | 2016-01-22 12:10 +0100 |
| Message-ID | <qTHLk-3dT-27@gated-at.bofh.it> (permalink) |
| References | (7 earlier) <qT8Xg-3WS-13@gated-at.bofh.it> <qTiMW-2Ez-5@gated-at.bofh.it> <qTpEK-7eF-5@gated-at.bofh.it> <qTqKv-7ZR-35@gated-at.bofh.it> <qTrnb-5X-9@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Thu, Jan 21, 2016 at 11:08 PM, Christoph Lameter <cl@linux.com> wrote:
> Subject: vmstat: Queue work before clearing cpu_stat_off
>
> There is a race between vmstat_shepherd and quiet_vmstat() because
> the responsibility for checking for counter updates changes depending
> on the state of teh bit in cpu_stat_off. So queue the work before
> changing state of the bit in vmstat_shepherd. That way quiet_vmstat
> is guaranteed to remove the work request when clearing the bit and the
> bug in vmstat_update wont trigger anymore.
>
> Signed-off-by: Christoph Lameter <cl@linux.com>
>
> Index: linux/mm/vmstat.c
> ===================================================================
> --- linux.orig/mm/vmstat.c
> +++ linux/mm/vmstat.c
> @@ -1480,12 +1480,14 @@ static void vmstat_shepherd(struct work_
> get_online_cpus();
> /* Check processors whose vmstat worker threads have been disabled */
> for_each_cpu(cpu, cpu_stat_off)
> - if (need_update(cpu) &&
> - cpumask_test_and_clear_cpu(cpu, cpu_stat_off))
> + if (need_update(cpu)) {
>
> queue_delayed_work_on(cpu, vmstat_wq,
> &per_cpu(vmstat_work, cpu), 0);
>
> + cpumask_clear_cpu(smp_processor_id(), cpu_stat_off);
> + }
> +
> put_online_cpus();
>
> schedule_delayed_work(&shepherd,
This can alternatively lead to following where vmstat may not be
scheduled for cpu when it is back from idle.
CPU0: CPU1:
vmstat_shepherd
<enter idle> queue_delayed_work_on(CPU0)
quiet_vmstat
cancel_delayed_work
cpumask_test_and_set_cpu (0->1)
cpumask_clear_cpu(CPU0) (1->0)
--
regards
Shiraz Hashim
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Michal Hocko <mhocko@kernel.org> - 2016-01-20 15:40 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Sasha Levin <sasha.levin@oracle.com> - 2016-01-20 16:00 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Michal Hocko <mhocko@kernel.org> - 2016-01-20 16:20 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Christoph Lameter <cl@linux.com> - 2016-01-20 16:30 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Sasha Levin <sasha.levin@oracle.com> - 2016-01-20 17:00 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Christoph Lameter <cl@linux.com> - 2016-01-20 17:00 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Michal Hocko <mhocko@kernel.org> - 2016-01-20 22:30 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Christoph Lameter <cl@linux.com> - 2016-01-20 23:00 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Michal Hocko <mhocko@kernel.org> - 2016-01-21 09:30 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Christoph Lameter <cl@linux.com> - 2016-01-21 16:50 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Michal Hocko <mhocko@kernel.org> - 2016-01-21 18:00 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Christoph Lameter <cl@linux.com> - 2016-01-21 18:40 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Shiraz Hashim <shiraz.linux.kernel@gmail.com> - 2016-01-22 12:10 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Michal Hocko <mhocko@kernel.org> - 2016-01-22 15:10 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Christoph Lameter <cl@linux.com> - 2016-01-22 17:10 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Michal Hocko <mhocko@kernel.org> - 2016-01-22 17:20 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Christoph Lameter <cl@linux.com> - 2016-01-22 17:50 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Michal Hocko <mhocko@kernel.org> - 2016-01-22 18:20 +0100
fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-01-23 17:30 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Christoph Lameter <cl@linux.com> - 2016-01-24 01:40 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-01-24 03:50 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Christoph Lameter <cl@linux.com> - 2016-01-24 04:50 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-01-24 06:40 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Michal Hocko <mhocko@kernel.org> - 2016-01-25 18:50 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Christoph Lameter <cl@linux.com> - 2016-01-25 19:10 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Michal Hocko <mhocko@kernel.org> - 2016-01-25 21:20 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Christoph Lameter <cl@linux.com> - 2016-01-26 17:30 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Christoph Lameter <cl@linux.com> - 2016-01-26 19:40 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-01-26 19:50 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Christoph Lameter <cl@linux.com> - 2016-01-26 20:30 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-01-27 04:20 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-01-27 05:20 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Christoph Lameter <cl@linux.com> - 2016-01-27 17:30 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-01-26 19:40 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-01-26 03:20 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-01-26 03:30 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Christoph Lameter <cl@linux.com> - 2016-01-26 17:30 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-01-26 18:40 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Christoph Lameter <cl@linux.com> - 2016-01-26 19:20 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Christoph Lameter <cl@linux.com> - 2016-01-26 17:30 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-01-26 18:10 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Christoph Lameter <cl@linux.com> - 2016-01-26 19:30 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-01-26 20:10 +0100
Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Christoph Lameter <cl@linux.com> - 2016-01-26 20:30 +0100
[PATCH] mm, vmstat: make quiet_vmstat lighter (was: Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable) again and shut down on idle) Michal Hocko <mhocko@kernel.org> - 2016-01-27 17:50 +0100
Re: [PATCH] mm, vmstat: make quiet_vmstat lighter (was: Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable) again and shut down on idle) Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-01-27 18:10 +0100
Re: [PATCH] mm, vmstat: make quiet_vmstat lighter (was: Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable) again and shut down on idle) Christoph Lameter <cl@linux.com> - 2016-01-27 19:30 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Linus Torvalds <torvalds@linux-foundation.org> - 2016-01-24 18:00 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Christoph Lameter <cl@linux.com> - 2016-01-20 16:20 +0100
Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! Michal Hocko <mhocko@kernel.org> - 2016-01-20 16:30 +0100
csiph-web