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Groups > linux.kernel > #1632562
| From | Michal Hocko <mhocko@kernel.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v2 2/2] mm: skip HWPoisoned pages when onlining pages |
| Date | 2017-04-28 09:00 +0200 |
| Message-ID | <tB82K-3Nr-5@gated-at.bofh.it> (permalink) |
| References | (1 earlier) <tA9Dz-5OC-5@gated-at.bofh.it> <tAkIG-4uM-9@gated-at.bofh.it> <tAlOp-57P-1@gated-at.bofh.it> <tB7Jn-3F8-7@gated-at.bofh.it> <tB82K-3Nr-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Fri 28-04-17 08:50:50, Michal Hocko wrote:
> [Drop Wen Congyang because his address bounces - we will have to find
> out ourselves...]
Ble, for real this time. Sorry about spamming
> On Fri 28-04-17 08:30:48, Michal Hocko wrote:
> > On Wed 26-04-17 03:13:04, Naoya Horiguchi wrote:
> > > On Wed, Apr 26, 2017 at 12:10:15PM +1000, Balbir Singh wrote:
> > > > On Tue, 2017-04-25 at 16:27 +0200, Laurent Dufour wrote:
> > > > > The commit b023f46813cd ("memory-hotplug: skip HWPoisoned page when
> > > > > offlining pages") skip the HWPoisoned pages when offlining pages, but
> > > > > this should be skipped when onlining the pages too.
> > > > >
> > > > > Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
> > > > > ---
> > > > > mm/memory_hotplug.c | 4 ++++
> > > > > 1 file changed, 4 insertions(+)
> > > > >
> > > > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> > > > > index 6fa7208bcd56..741ddb50e7d2 100644
> > > > > --- a/mm/memory_hotplug.c
> > > > > +++ b/mm/memory_hotplug.c
> > > > > @@ -942,6 +942,10 @@ static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
> > > > > if (PageReserved(pfn_to_page(start_pfn)))
> > > > > for (i = 0; i < nr_pages; i++) {
> > > > > page = pfn_to_page(start_pfn + i);
> > > > > + if (PageHWPoison(page)) {
> > > > > + ClearPageReserved(page);
> > > >
> > > > Why do we clear page reserved? Also if the page is marked PageHWPoison, it
> > > > was never offlined to begin with? Or do you expect this to be set on newly
> > > > hotplugged memory? Also don't we need to skip the entire pageblock?
> > >
> > > If I read correctly, to "skip HWPoiosned page" in commit b023f46813cd means
> > > that we skip the page status check for hwpoisoned pages *not* to prevent
> > > memory offlining for memblocks with hwpoisoned pages. That means that
> > > hwpoisoned pages can be offlined.
> >
> > Is this patch actually correct? I am trying to wrap my head around it
> > but it smells like it tries to avoid the problem rather than fix it
> > properly. I might be wrong here of course but to me it sounds like
> > poisoned page should simply be offlined and keep its poison state all
> > the time. If the memory is hot-removed and added again we have lost the
> > struct page along with the state which is the expected behavior. If it
> > is still broken we will re-poison it.
> >
> > Anyway a patch to skip over poisoned pages during online makes perfect
> > sense to me. The PageReserved fiddling around much less so.
> >
> > Or am I missing something. Let's CC Wen Congyang for the clarification
> > here.
>
> --
> Michal Hocko
> SUSE Labs
--
Michal Hocko
SUSE Labs
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[PATCH v2 0/2] BUG raised when onlining HWPoisoned page Laurent Dufour <ldufour@linux.vnet.ibm.com> - 2017-04-25 16:30 +0200
[PATCH v2 2/2] mm: skip HWPoisoned pages when onlining pages Laurent Dufour <ldufour@linux.vnet.ibm.com> - 2017-04-25 16:30 +0200
Re: [PATCH v2 2/2] mm: skip HWPoisoned pages when onlining pages Balbir Singh <bsingharora@gmail.com> - 2017-04-26 04:20 +0200
Re: [PATCH v2 2/2] mm: skip HWPoisoned pages when onlining pages Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> - 2017-04-26 05:30 +0200
Re: [PATCH v2 2/2] mm: skip HWPoisoned pages when onlining pages Balbir Singh <bsingharora@gmail.com> - 2017-04-28 05:00 +0200
Re: [PATCH v2 2/2] mm: skip HWPoisoned pages when onlining pages Michal Hocko <mhocko@kernel.org> - 2017-04-28 08:40 +0200
Re: [PATCH v2 2/2] mm: skip HWPoisoned pages when onlining pages Michal Hocko <mhocko@kernel.org> - 2017-04-28 09:00 +0200
Re: [PATCH v2 2/2] mm: skip HWPoisoned pages when onlining pages Michal Hocko <mhocko@kernel.org> - 2017-05-10 09:50 +0200
Re: [PATCH v2 2/2] mm: skip HWPoisoned pages when onlining pages Michal Hocko <mhocko@kernel.org> - 2017-04-28 09:00 +0200
[PATCH v2 1/2] mm: Uncharge poisoned pages Laurent Dufour <ldufour@linux.vnet.ibm.com> - 2017-04-25 16:30 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> - 2017-04-26 02:00 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Balbir Singh <bsingharora@gmail.com> - 2017-04-26 04:00 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> - 2017-04-26 05:20 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Balbir Singh <bsingharora@gmail.com> - 2017-04-26 05:50 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> - 2017-04-26 06:50 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Balbir Singh <bsingharora@gmail.com> - 2017-04-26 11:10 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Laurent Dufour <ldufour@linux.vnet.ibm.com> - 2017-04-28 11:40 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Michal Hocko <mhocko@kernel.org> - 2017-04-27 16:40 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Andi Kleen <andi@firstfloor.org> - 2017-04-27 23:00 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Michal Hocko <mhocko@kernel.org> - 2017-04-28 08:10 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Michal Hocko <mhocko@kernel.org> - 2017-04-28 09:40 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Laurent Dufour <ldufour@linux.vnet.ibm.com> - 2017-04-28 11:20 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Michal Hocko <mhocko@kernel.org> - 2017-04-28 15:50 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Laurent Dufour <ldufour@linux.vnet.ibm.com> - 2017-05-02 17:00 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Michal Hocko <mhocko@kernel.org> - 2017-05-02 21:00 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Laurent Dufour <ldufour@linux.vnet.ibm.com> - 2017-05-03 13:40 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Balbir Singh <bsingharora@gmail.com> - 2017-05-04 03:30 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Laurent Dufour <ldufour@linux.vnet.ibm.com> - 2017-05-08 12:50 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Balbir Singh <bsingharora@gmail.com> - 2017-05-09 03:50 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> - 2017-05-08 05:10 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Michal Hocko <mhocko@kernel.org> - 2017-05-09 11:20 +0200
Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> - 2017-05-10 01:10 +0200
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