On Fri 04-09-20 10:25:02, Pavel Tatashin wrote:
> > Another alternative would be to enable/disable static branch only from
> > users who really care but this is quite tricky because how do you tell
> > you need or not? It seems that alloc_contig_range would be just fine
> > with a weaker semantic
> Another alternative would be to enable/disable static branch only from
> users who really care but this is quite tricky because how do you tell
> you need or not? It seems that alloc_contig_range would be just fine
> with a weaker semantic because it would "only" to a spurious failure.
> Memory
On Thu 03-09-20 20:31:04, David Hildenbrand wrote:
> On 03.09.20 20:23, Pavel Tatashin wrote:
> > On Thu, Sep 3, 2020 at 2:20 PM David Hildenbrand wrote:
> >>
> >> On 03.09.20 08:38, Michal Hocko wrote:
[...]
> >>> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> >>> index
On 9/3/20 8:23 PM, Pavel Tatashin wrote:
>>
>> As expressed in reply to v2, I dislike this hack. There is strong
>> synchronization, just PCP is special. Allocating from MIGRATE_ISOLATE is
>> just plain ugly.
>>
>> Can't we temporarily disable PCP (while some pageblock in the zone is
>> isolated,
On 03.09.20 20:23, Pavel Tatashin wrote:
> On Thu, Sep 3, 2020 at 2:20 PM David Hildenbrand wrote:
>>
>> On 03.09.20 08:38, Michal Hocko wrote:
>>> On Wed 02-09-20 19:51:45, Vlastimil Babka wrote:
On 9/2/20 5:13 PM, Michal Hocko wrote:
> On Wed 02-09-20 16:55:05, Vlastimil Babka wrote:
On Thu, Sep 3, 2020 at 2:20 PM David Hildenbrand wrote:
>
> On 03.09.20 08:38, Michal Hocko wrote:
> > On Wed 02-09-20 19:51:45, Vlastimil Babka wrote:
> >> On 9/2/20 5:13 PM, Michal Hocko wrote:
> >>> On Wed 02-09-20 16:55:05, Vlastimil Babka wrote:
> On 9/2/20 4:26 PM, Pavel Tatashin
On 03.09.20 08:38, Michal Hocko wrote:
> On Wed 02-09-20 19:51:45, Vlastimil Babka wrote:
>> On 9/2/20 5:13 PM, Michal Hocko wrote:
>>> On Wed 02-09-20 16:55:05, Vlastimil Babka wrote:
On 9/2/20 4:26 PM, Pavel Tatashin wrote:
> On Wed, Sep 2, 2020 at 10:08 AM Michal Hocko wrote:
>>
Thanks Michal, I will add your comments.
Pasha
On Thu, Sep 3, 2020 at 3:07 AM Michal Hocko wrote:
>
> On Tue 01-09-20 08:46:15, Pavel Tatashin wrote:
> [...]
> > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> > index e9d5ab5d3ca0..d6d54922bfce 100644
> > --- a/mm/memory_hotplug.c
> >
On 9/1/20 2:46 PM, Pavel Tatashin wrote:
> There is a race during page offline that can lead to infinite loop:
> a page never ends up on a buddy list and __offline_pages() keeps
> retrying infinitely or until a termination signal is received.
>
> Thread#1 - a new process:
>
> load_elf_binary
>
On Tue 01-09-20 08:46:15, Pavel Tatashin wrote:
[...]
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index e9d5ab5d3ca0..d6d54922bfce 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1575,6 +1575,15 @@ static int __ref __offline_pages(unsigned long
> start_pfn,
>
On Wed 02-09-20 19:51:45, Vlastimil Babka wrote:
> On 9/2/20 5:13 PM, Michal Hocko wrote:
> > On Wed 02-09-20 16:55:05, Vlastimil Babka wrote:
> >> On 9/2/20 4:26 PM, Pavel Tatashin wrote:
> >> > On Wed, Sep 2, 2020 at 10:08 AM Michal Hocko wrote:
> >> >>
> >> >> >
> >> >> > Thread#1 - continue
>
On 9/2/20 5:13 PM, Michal Hocko wrote:
> On Wed 02-09-20 16:55:05, Vlastimil Babka wrote:
>> On 9/2/20 4:26 PM, Pavel Tatashin wrote:
>> > On Wed, Sep 2, 2020 at 10:08 AM Michal Hocko wrote:
>> >>
>> >> >
>> >> > Thread#1 - continue
>> >> > free_unref_page_commit
>> >> >
> > >> But this means that the page is not isolated and so it could be reused
> > >> for something else. No?
> > >
> > > The page is in a movable zone, has zero references, and the section is
> > > isolated (i.e. set_pageblock_migratetype(page, MIGRATE_ISOLATE);) is
> > > set. The page should be
On Wed 02-09-20 16:55:05, Vlastimil Babka wrote:
> On 9/2/20 4:26 PM, Pavel Tatashin wrote:
> > On Wed, Sep 2, 2020 at 10:08 AM Michal Hocko wrote:
> >>
> >> >
> >> > Thread#1 - continue
> >> > free_unref_page_commit
> >> >migratetype = get_pcppage_migratetype(page);
> >> >
On 9/2/20 4:26 PM, Pavel Tatashin wrote:
> On Wed, Sep 2, 2020 at 10:08 AM Michal Hocko wrote:
>>
>> >
>> > Thread#1 - continue
>> > free_unref_page_commit
>> >migratetype = get_pcppage_migratetype(page);
>> > // get old migration type
>> >
On 9/2/20 4:31 PM, Pavel Tatashin wrote:
>> > > The fix is to try to drain per-cpu lists again after
>> > > check_pages_isolated_cb() fails.
>>
>> Still trying to wrap my head around this but I think this is not a
>> proper fix. It should be the page isolation to make sure no races are
>> possible
> > > The fix is to try to drain per-cpu lists again after
> > > check_pages_isolated_cb() fails.
>
> Still trying to wrap my head around this but I think this is not a
> proper fix. It should be the page isolation to make sure no races are
> possible with the page freeing path.
>
As Bharata B
On Wed, Sep 2, 2020 at 10:08 AM Michal Hocko wrote:
>
> On Tue 01-09-20 08:46:15, Pavel Tatashin wrote:
> > There is a race during page offline that can lead to infinite loop:
> > a page never ends up on a buddy list and __offline_pages() keeps
> > retrying infinitely or until a termination
On Wed 02-09-20 16:01:17, Michal Hocko wrote:
> [Cc Mel and Vlastimil - I am still rummaging]
>
> On Tue 01-09-20 08:46:15, Pavel Tatashin wrote:
> > There is a race during page offline that can lead to infinite loop:
> > a page never ends up on a buddy list and __offline_pages() keeps
> >
On Tue 01-09-20 08:46:15, Pavel Tatashin wrote:
> There is a race during page offline that can lead to infinite loop:
> a page never ends up on a buddy list and __offline_pages() keeps
> retrying infinitely or until a termination signal is received.
>
> Thread#1 - a new process:
>
>
[Cc Mel and Vlastimil - I am still rummaging]
On Tue 01-09-20 08:46:15, Pavel Tatashin wrote:
> There is a race during page offline that can lead to infinite loop:
> a page never ends up on a buddy list and __offline_pages() keeps
> retrying infinitely or until a termination signal is received.
>
On Tue, 1 Sep 2020, Pavel Tatashin wrote:
> There is a race during page offline that can lead to infinite loop:
> a page never ends up on a buddy list and __offline_pages() keeps
> retrying infinitely or until a termination signal is received.
>
> Thread#1 - a new process:
>
> load_elf_binary
>
Hi
[This is an automated email]
This commit has been processed because it contains a -stable tag.
The stable tag indicates that it's relevant for the following trees: all
The bot has tested the following trees: v5.8.5, v5.4.61, v4.19.142, v4.14.195,
v4.9.234, v4.4.234.
v5.8.5: Build OK!
There is a race during page offline that can lead to infinite loop:
a page never ends up on a buddy list and __offline_pages() keeps
retrying infinitely or until a termination signal is received.
Thread#1 - a new process:
load_elf_binary
begin_new_exec
exec_mmap
mmput
exit_mmap
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