Messages in this thread Patch in this message | | | Subject | Re: [BUGFIX][PATCH] memory hotplug: fix notiier chain return value (Was Re: 2.6.28-rc4 mem_cgroup_charge_common panic) | From | Badari Pulavarty <> | Date | Thu, 13 Nov 2008 09:11:09 -0800 |
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On Thu, 2008-11-13 at 20:27 +0900, KAMEZAWA Hiroyuki wrote: > Badari, I think you used SLUB. If so, page_cgroup's notifier callback was not > called and newly allocated page's page_cgroup wasn't allocated. > This is a fix. (notifier saw STOP_HERE flag added by slub's notifier.)
No. I wasn't using SLUB.
# egrep "SLUB|SLAB" .config CONFIG_SLAB=y # CONFIG_SLUB is not set CONFIG_SLABINFO=y # CONFIG_DEBUG_SLAB is not set
I can test the patch and let you know.
Thanks, Badari
> > I'm now testing modified kernel, which does alloc/free page_cgroup by notifier. > (Usually, all page_cgroups are from bootmem and not freed. > so, modified a bit for test) > > And I cannot reproduce panic. I think you do "real" memory hotplug other than > online/offline and saw panic caused by this. > > Is this slub's behavior intentional ? page_cgroup's notifier has lower priority > than slub, now. > > Thanks, > -Kame > == > notifier callback's notifier_from_errno() just works well in error > route. (It adds mask for "stop here") > > Hanlder should return NOTIFY_OK in explict way. > > Signed-off-by:KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > --- > mm/page_cgroup.c | 5 ++++- > mm/slub.c | 6 ++++-- > 2 files changed, 8 insertions(+), 3 deletions(-) > > Index: mmotm-2.6.28-Nov10/mm/slub.c > =================================================================== > --- mmotm-2.6.28-Nov10.orig/mm/slub.c > +++ mmotm-2.6.28-Nov10/mm/slub.c > @@ -3220,8 +3220,10 @@ static int slab_memory_callback(struct n > case MEM_CANCEL_OFFLINE: > break; > } > - > - ret = notifier_from_errno(ret); > + if (ret) > + ret = notifier_from_errno(ret); > + else > + ret = NOTIFY_OK; > return ret; > } > > Index: mmotm-2.6.28-Nov10/mm/page_cgroup.c > =================================================================== > --- mmotm-2.6.28-Nov10.orig/mm/page_cgroup.c > +++ mmotm-2.6.28-Nov10/mm/page_cgroup.c > @@ -216,7 +216,10 @@ static int page_cgroup_callback(struct n > break; > } > > - ret = notifier_from_errno(ret); > + if (ret) > + ret = notifier_from_errno(ret); > + else > + ret = NOTIFY_OK; > > return ret; > } > >
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