From: Mike Kravetz <mike.kravetz@oracle.com>
To: Muchun Song <songmuchun@bytedance.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Andi Kleen <ak@linux.intel.com>,
mhocko@suse.cz, Linux Memory Management List <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [External] Re: [PATCH 4/6] mm: hugetlb: add return -EAGAIN for dissolve_free_huge_page
Date: Tue, 5 Jan 2021 16:07:48 -0800 [thread overview]
Message-ID: <7b30ad06-aced-817c-181c-a2099ba08918@oracle.com> (raw)
In-Reply-To: <CAMZfGtVU5WfEWbin5hxAkkWLVJw15n2crtPMkmHDRxkBo4_TOQ@mail.gmail.com>
On 1/4/21 7:46 PM, Muchun Song wrote:
> On Tue, Jan 5, 2021 at 11:14 AM Muchun Song <songmuchun@bytedance.com> wrote:
>>
>> On Tue, Jan 5, 2021 at 9:33 AM Mike Kravetz <mike.kravetz@oracle.com> wrote:
>>>
>>> On 1/3/21 10:58 PM, Muchun Song wrote:
>>>> When dissolve_free_huge_page() races with __free_huge_page(), we can
>>>> do a retry. Because the race window is small.
>>>
>>> In general, I agree that the race window is small. However, worst case
>>> would be if the freeing of the page is put on a work queue. Is it acceptable
>>> to keep retrying in that case? In addition, the 'Free some vmemmap' series
>>> may slow the free_huge_page path even more.
>>
>> I also consider the 'Free some vmemmap' series case. In my next
>> version series, I will flush the work before dissolve_free_huge_page
>> returns when encountering this race. So the retry is acceptable.
>> Right?
>
> Hi Mike,
>
> How about flushing the @free_hpage_work when
> encountering this race?
Flushing should be fine.
The more I think about it, the more I think spinning to retry is not
going to be an issue. Why? As you mentioned the race window is quite
small. It just makes me a bit nervous to retry in a tight loop.
--
Mike Kravetz
next prev parent reply other threads:[~2021-01-06 0:07 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-04 6:58 [PATCH 1/6] mm: migrate: do not migrate HugeTLB page whose refcount is one Muchun Song
2021-01-04 6:58 ` [PATCH 2/6] hugetlbfs: fix cannot migrate the fallocated HugeTLB page Muchun Song
2021-01-04 22:38 ` Mike Kravetz
2021-01-05 2:44 ` [External] " Muchun Song
2021-01-05 22:27 ` Mike Kravetz
2021-01-06 2:57 ` Muchun Song
2021-01-04 6:58 ` [PATCH 3/6] mm: hugetlb: fix a race between freeing and dissolving the page Muchun Song
2021-01-05 0:00 ` Mike Kravetz
2021-01-05 2:55 ` [External] " Muchun Song
2021-01-05 23:22 ` Mike Kravetz
2021-01-06 6:05 ` Muchun Song
2021-01-05 6:12 ` Muchun Song
2021-01-04 6:58 ` [PATCH 4/6] mm: hugetlb: add return -EAGAIN for dissolve_free_huge_page Muchun Song
2021-01-05 1:32 ` Mike Kravetz
2021-01-05 3:14 ` [External] " Muchun Song
2021-01-05 3:46 ` Muchun Song
2021-01-06 0:07 ` Mike Kravetz [this message]
2021-01-05 6:37 ` HORIGUCHI NAOYA(堀口 直也)
2021-01-05 7:10 ` [External] " Muchun Song
2021-01-05 7:30 ` HORIGUCHI NAOYA(堀口 直也)
2021-01-04 6:58 ` [PATCH 5/6] mm: hugetlb: fix a race between isolating and freeing page Muchun Song
2021-01-05 1:42 ` Mike Kravetz
2021-01-04 6:58 ` [PATCH 6/6] mm: hugetlb: remove VM_BUG_ON_PAGE from page_huge_active Muchun Song
2021-01-05 1:50 ` Mike Kravetz
2021-01-04 22:17 ` [PATCH 1/6] mm: migrate: do not migrate HugeTLB page whose refcount is one Mike Kravetz
2021-01-05 16:58 ` David Hildenbrand
2021-01-05 18:04 ` Yang Shi
2021-01-05 18:05 ` David Hildenbrand
2021-01-05 18:04 ` Yang Shi
2021-01-06 16:11 ` Michal Hocko
2021-01-06 16:12 ` Michal Hocko
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