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From: Michal Hocko <mhocko@suse.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Pavel Tatashin <pasha.tatashin@soleen.com>,
	Oscar Salvador <osalvador@suse.de>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: Re: [PATCH 9/9] mm, page_alloc: optionally disable pcplists during page isolation
Date: Mon, 5 Oct 2020 18:56:51 +0200	[thread overview]
Message-ID: <20201005165651.GG4555@dhcp22.suse.cz> (raw)
In-Reply-To: <5ea97462-7924-e106-c486-2a0164ea27fb@suse.cz>

On Mon 05-10-20 16:22:46, Vlastimil Babka wrote:
> On 10/5/20 4:05 PM, Michal Hocko wrote:
> > On Fri 25-09-20 13:10:05, Vlastimil Babka wrote:
> >> On 9/25/20 12:54 PM, David Hildenbrand wrote:
> >>
> >> Hmm that temporary write lock would still block new callers until previous
> >> finish with the downgraded-to-read lock.
> >>
> >> But I guess something like this would work:
> >>
> >> retry:
> >>   if (atomic_read(...) == 0) {
> >>     // zone_update... + drain
> >>     atomic_inc(...);
> >>   else if (atomic_inc_return == 1)
> >>     // atomic_cmpxchg from 0 to 1; if that fails, goto retry
> >>
> >> Tricky, but races could only read to unnecessary duplicated updates + flushing
> >> but nothing worse?
> >>
> >> Or add another spinlock to cover this part instead of the temp write lock...
> > 
> > Do you plan to post a new version or should I review this one?
> 
> I will, hopefully this week, but you could comment on other details and
> overall approach meanwhile? I don't think it will change significantly.

OK. I will have a look tomorrow.

-- 
Michal Hocko
SUSE Labs


  reply	other threads:[~2020-10-05 16:56 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-22 14:37 [PATCH 0/9] disable pcplists during memory offline Vlastimil Babka
2020-09-22 14:37 ` [PATCH 1/9] mm, page_alloc: clean up pageset high and batch update Vlastimil Babka
2020-09-25 10:18   ` David Hildenbrand
2020-10-05 12:03   ` Michal Hocko
2020-09-22 14:37 ` [PATCH 2/9] mm, page_alloc: calculate pageset high and batch once per zone Vlastimil Babka
2020-10-05 12:52   ` Michal Hocko
2020-10-06 22:04     ` Vlastimil Babka
2020-09-22 14:37 ` [PATCH 3/9] mm, page_alloc: remove setup_pageset() Vlastimil Babka
2020-09-25 10:19   ` David Hildenbrand
2020-10-05 12:59   ` Michal Hocko
2020-10-06 22:11     ` Vlastimil Babka
2020-09-22 14:37 ` [PATCH 4/9] mm, page_alloc: simplify pageset_update() Vlastimil Babka
2020-09-25 10:23   ` David Hildenbrand
2020-10-05 13:20   ` Michal Hocko
2020-09-22 14:37 ` [PATCH 5/9] mm, page_alloc: make per_cpu_pageset accessible only after init Vlastimil Babka
2020-09-25 10:25   ` David Hildenbrand
2020-10-05 13:24   ` Michal Hocko
2020-10-06 22:28     ` Vlastimil Babka
2020-09-22 14:37 ` [PATCH 6/9] mm, page_alloc: cache pageset high and batch in struct zone Vlastimil Babka
2020-09-25 10:34   ` David Hildenbrand
2020-10-06 22:31     ` Vlastimil Babka
2020-10-05 13:28   ` Michal Hocko
2020-10-06 22:34     ` Vlastimil Babka
2020-09-22 14:37 ` [PATCH 7/9] mm, page_alloc: move draining pcplists to page isolation users Vlastimil Babka
2020-09-25 10:39   ` David Hildenbrand
2020-10-05 13:57   ` Michal Hocko
2020-09-22 14:37 ` [PATCH 8/9] mm, page_alloc: drain all pcplists during memory offline Vlastimil Babka
2020-09-25 10:46   ` David Hildenbrand
2020-10-05 14:03     ` Michal Hocko
2020-09-22 14:37 ` [PATCH 9/9] mm, page_alloc: optionally disable pcplists during page isolation Vlastimil Babka
2020-09-25 10:53   ` David Hildenbrand
2020-09-25 10:54     ` David Hildenbrand
2020-09-25 11:10       ` Vlastimil Babka
2020-10-01  8:47         ` David Hildenbrand
2020-10-05 14:05         ` Michal Hocko
2020-10-05 14:22           ` Vlastimil Babka
2020-10-05 16:56             ` Michal Hocko [this message]
2020-10-06  8:34   ` Michal Hocko
2020-10-06  8:40     ` David Hildenbrand
2020-10-06 10:05       ` Michal Hocko
2020-09-22 17:15 ` [PATCH 0/9] disable pcplists during memory offline David Hildenbrand

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