From: David Hildenbrand <david@redhat.com>
To: Yang Shi <shy828301@gmail.com>
Cc: Muchun Song <songmuchun@bytedance.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
hillf.zj@alibaba-inc.com,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
ak@linux.intel.com, yongjun_wei@trendmicro.com.cn,
mhocko@suse.cz, Linux MM <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/6] mm: migrate: do not migrate HugeTLB page whose refcount is one
Date: Tue, 5 Jan 2021 19:05:12 +0100 [thread overview]
Message-ID: <e6eb5ffa-403a-7012-db7e-f2e5a015f6de@redhat.com> (raw)
In-Reply-To: <CAHbLzko4BH6GOJsz33NEbwLTxJQJxVHH3qLzHzoM1LycT=ccbg@mail.gmail.com>
On 05.01.21 19:04, Yang Shi wrote:
> On Tue, Jan 5, 2021 at 8:58 AM David Hildenbrand <david@redhat.com> wrote:
>>
>> On 04.01.21 07:58, Muchun Song wrote:
>>> If the refcount is one when it is migrated, it means that the page
>>> was freed from under us. So we are done and do not need to migrate.
>>>
>>> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
>>> ---
>>> mm/migrate.c | 6 ++++++
>>> 1 file changed, 6 insertions(+)
>>>
>>> diff --git a/mm/migrate.c b/mm/migrate.c
>>> index 4385f2fb5d18..a6631c4eb6a6 100644
>>> --- a/mm/migrate.c
>>> +++ b/mm/migrate.c
>>> @@ -1279,6 +1279,12 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
>>> return -ENOSYS;
>>> }
>>>
>>> + if (page_count(hpage) == 1) {
>>> + /* page was freed from under us. So we are done. */
>>> + putback_active_hugepage(hpage);
>>> + return MIGRATEPAGE_SUCCESS;
>>> + }
>>> +
>>> new_hpage = get_new_page(hpage, private);
>>> if (!new_hpage)
>>> return -ENOMEM;
>>>
>>
>> This series seems to fix quite some important cases (thanks). Do we want
>> to cc stable some/all?
>
> For this particular one, I don't think so IMHO. It is an optimization
> rather than a bug fix.
I'm rather referring to the actual fixes (I received no cover letter so
I picked the first patch in the series)
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2021-01-05 18:07 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
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 [this message]
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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