From: Dave Hansen <dave.hansen@intel.com>
To: Yang Shi <shy828301@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux MM <linux-mm@kvack.org>,
Dan Williams <dan.j.williams@intel.com>,
Keith Busch <keith.busch@intel.com>
Subject: Re: [PATCH 3/4] mm/vmscan: Attempt to migrate page in lieu of discard
Date: Fri, 18 Oct 2019 11:15:07 -0700 [thread overview]
Message-ID: <6ab6ca82-71d4-bdea-ae95-e0bebb5e71df@intel.com> (raw)
In-Reply-To: <CAHbLzkp_2UD50Vt8f_atxKcz4x8J3GB3YzTqMOd6Src_y2Yg2g@mail.gmail.com>
On 10/17/19 10:30 AM, Yang Shi wrote:
>> + if (!PageHuge(page)) {
>> + int rc = migrate_demote_mapping(page);
>> +
>> + /*
>> + * -ENOMEM on a THP may indicate either migration is
>> + * unsupported or there was not enough contiguous
>> + * space. Split the THP into base pages and retry the
>> + * head immediately. The tail pages will be considered
>> + * individually within the current loop's page list.
>> + */
>> + if (rc == -ENOMEM && PageTransHuge(page) &&
>> + !split_huge_page_to_list(page, page_list))
>> + rc = migrate_demote_mapping(page);
> I recalled when Keith posted the patch at the first time, I raised
> question about why not just migrating THP in a whole? The
> migrate_pages() could handle this. If it fails, it just fallbacks to
> base page.
There's a pair of migrate_demote_mapping()s in there. I expected that
the first will migrate the whole THP and the second plus the split is
only used if fails the whole migration.
Am I reading it wrong?
next prev parent reply other threads:[~2019-10-18 18:15 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-16 22:11 [PATCH 0/4] [RFC] Migrate Pages in lieu of discard Dave Hansen
2019-10-16 22:11 ` Dave Hansen
2019-10-16 22:11 ` [PATCH 1/4] node: Define and export memory migration path Dave Hansen
2019-10-16 22:11 ` Dave Hansen
2019-10-17 11:12 ` Kirill A. Shutemov
2019-10-17 11:44 ` Kirill A. Shutemov
2019-10-16 22:11 ` [PATCH 2/4] mm/migrate: Defer allocating new page until needed Dave Hansen
2019-10-16 22:11 ` Dave Hansen
2019-10-17 11:27 ` Kirill A. Shutemov
2019-10-16 22:11 ` [PATCH 3/4] mm/vmscan: Attempt to migrate page in lieu of discard Dave Hansen
2019-10-16 22:11 ` Dave Hansen
2019-10-17 17:30 ` Yang Shi
2019-10-17 17:30 ` Yang Shi
2019-10-18 18:15 ` Dave Hansen [this message]
2019-10-18 21:02 ` Yang Shi
2019-10-18 21:02 ` Yang Shi
2019-10-16 22:11 ` [PATCH 4/4] mm/vmscan: Consider anonymous pages without swap Dave Hansen
2019-10-16 22:11 ` Dave Hansen
2019-10-17 3:45 ` [PATCH 0/4] [RFC] Migrate Pages in lieu of discard Shakeel Butt
2019-10-17 3:45 ` Shakeel Butt
2019-10-17 14:26 ` Dave Hansen
2019-10-17 16:58 ` Shakeel Butt
2019-10-17 16:58 ` Shakeel Butt
2019-10-17 20:51 ` Dave Hansen
2019-10-17 17:20 ` Yang Shi
2019-10-17 17:20 ` Yang Shi
2019-10-17 21:05 ` Dave Hansen
2019-10-17 22:58 ` Shakeel Butt
2019-10-17 22:58 ` Shakeel Butt
2019-10-18 21:44 ` Yang Shi
2019-10-18 21:44 ` Yang Shi
2019-10-17 16:01 ` Suleiman Souhlal
2019-10-17 16:01 ` Suleiman Souhlal
2019-10-17 16:32 ` Dave Hansen
2019-10-17 16:39 ` Shakeel Butt
2019-10-17 16:39 ` Shakeel Butt
2019-10-18 8:11 ` Suleiman Souhlal
2019-10-18 8:11 ` Suleiman Souhlal
2019-10-18 15:10 ` Dave Hansen
2019-10-18 15:39 ` Suleiman Souhlal
2019-10-18 15:39 ` Suleiman Souhlal
2019-10-18 7:44 ` Michal Hocko
2019-10-18 14:54 ` Dave Hansen
2019-10-18 21:39 ` Yang Shi
2019-10-18 21:39 ` Yang Shi
2019-10-18 21:55 ` Dan Williams
2019-10-18 21:55 ` Dan Williams
2019-10-22 13:49 ` Michal Hocko
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