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Groups > linux.kernel > #1314373
| From | Christoph Lameter <cl@linux.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: mm, vmstat: kernel BUG at mm/vmstat.c:1408! |
| Date | 2016-01-21 18:40 +0100 |
| Message-ID | <qTrnb-5X-9@gated-at.bofh.it> (permalink) |
| References | (6 earlier) <qT8ue-3LS-11@gated-at.bofh.it> <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> |
| Organization | linux.* mail to news gateway |
On Thu, 21 Jan 2016, Michal Hocko wrote:
> It goes like this:
> CPU0: CPU1
> vmstat_update
> cpumask_test_and_set_cpu (0->1)
> [...]
> vmstat_shepherd
> <enter idle> cpumask_test_and_clear_cpu(CPU0) (1->0)
> quiet_vmstat
> cpumask_test_and_set_cpu (0->1)
> queue_delayed_work_on(CPU0)
> refresh_cpu_vm_stats()
> [...]
> vmstat_update
> nothing_to_do
> cpumask_test_and_set_cpu (1->1)
> VM_BUG_ON
>
> Or am I missing something?
Ok then the following should fix it:
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,
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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
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