From: Baolin Wang <baolin.wang@linux.alibaba.com>
To: David Hildenbrand <david@redhat.com>,
Mike Kravetz <mike.kravetz@oracle.com>
Cc: akpm@linux-foundation.org, songmuchun@bytedance.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/5] mm/hugetlb: fix races when looking up a CONT-PTE size hugetlb page
Date: Thu, 25 Aug 2022 15:58:45 +0800 [thread overview]
Message-ID: <3c381602-26ea-883c-859a-4007cb7cb289@linux.alibaba.com> (raw)
In-Reply-To: <50703dda-bbee-7484-97ff-87d6ea75bf80@redhat.com>
On 8/25/2022 3:10 PM, David Hildenbrand wrote:
>
>>> + /*
>>> + * try_grab_page() should always succeed here, because we hold
>>> + * the ptl lock and have verified pte_present().
>>> + */
>>> + if (WARN_ON_ONCE(!try_grab_page(page, flags))) {
>>> + page = NULL;
>>> + goto out;
>>> + }
>>> + } else {
>>
>> Should add FOLL_MIGRATION validation before waiting a migration entry.
>
> We really only need FOLL_MIGRATION for KSM. As hugetlb pages cannot be
> KSM pages, we don't need this.
>
> Actually, I do have patches in the works that rip out FOLL_MIGRATION
> completely by adjusting KSM code.
>
> So let's try to not add dead code (although it would make sense for
> feature completeness as is -- but then, FOLL_MIGRATION really needs to go).
Make sense. Thanks for your explanation.
next prev parent reply other threads:[~2022-08-25 7:58 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-23 7:50 [PATCH v2 0/5] Fix some issues when looking up hugetlb page Baolin Wang
2022-08-23 7:50 ` [PATCH v2 1/5] mm/hugetlb: fix races when looking up a CONT-PTE size " Baolin Wang
2022-08-23 8:29 ` David Hildenbrand
2022-08-23 10:02 ` Baolin Wang
2022-08-23 10:23 ` David Hildenbrand
2022-08-23 23:55 ` Mike Kravetz
2022-08-24 2:06 ` Baolin Wang
2022-08-24 7:31 ` David Hildenbrand
2022-08-24 9:41 ` Baolin Wang
2022-08-24 11:55 ` David Hildenbrand
2022-08-24 14:30 ` Baolin Wang
2022-08-24 14:33 ` David Hildenbrand
2022-08-24 15:06 ` Baolin Wang
2022-08-24 15:13 ` David Hildenbrand
2022-08-24 15:23 ` Baolin Wang
2022-08-24 23:34 ` Mike Kravetz
2022-08-25 1:43 ` Baolin Wang
2022-08-25 7:10 ` David Hildenbrand
2022-08-25 7:58 ` Baolin Wang [this message]
2022-08-25 18:30 ` Mike Kravetz
2022-08-25 7:25 ` David Hildenbrand
2022-08-25 10:54 ` Baolin Wang
2022-08-25 21:13 ` Mike Kravetz
2022-08-26 22:40 ` Mike Kravetz
2022-08-27 13:59 ` Aneesh Kumar K.V
2022-08-29 18:30 ` Mike Kravetz
2022-08-23 7:50 ` [PATCH v2 2/5] mm/hugetlb: use PTE page lock to protect CONT-PTE entries Baolin Wang
2022-08-23 7:50 ` [PATCH v2 3/5] mm/hugetlb: fix races when looking up a CONT-PMD size hugetlb page Baolin Wang
2022-08-23 7:50 ` [PATCH v2 4/5] mm/hugetlb: use PMD page lock to protect CONT-PTE entries Baolin Wang
2022-08-23 8:14 ` David Hildenbrand
2022-08-23 10:12 ` Baolin Wang
2022-08-23 7:50 ` [PATCH v2 5/5] mm/hugetlb: add FOLL_MIGRATION validation before waiting for a migration entry Baolin Wang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=3c381602-26ea-883c-859a-4007cb7cb289@linux.alibaba.com \
--to=baolin.wang@linux.alibaba.com \
--cc=akpm@linux-foundation.org \
--cc=david@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mike.kravetz@oracle.com \
--cc=songmuchun@bytedance.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).