From: Oscar Salvador <osalvador@suse.de>
To: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Muchun Song <songmuchun@bytedance.com>,
David Hildenbrand <david@redhat.com>,
Matthew Wilcox <willy@infradead.org>,
Miaohe Lin <linmiaohe@huawei.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v3 3/5] hugetlb: only set HPageMigratable for migratable hstates
Date: Thu, 28 Jan 2021 06:52:21 +0100 [thread overview]
Message-ID: <20210128055221.GA3166@localhost.localdomain> (raw)
In-Reply-To: <2196d93e-f573-7163-183e-0ad2cec7555e@oracle.com>
On Wed, Jan 27, 2021 at 03:36:41PM -0800, Mike Kravetz wrote:
> Yes, this patch is somewhat optional. It should be a minor improvement
> in cases where we are dealing with hpages in a non-migratable hstate.
> Although, I do not believe this is the common case.
>
> The real reason for even looking into this was a comment by Oscar. With
> the name change to HPageMigratable, it implies that the page is migratable.
> However, this is not the case if the page's hstate does not support migration.
> So, if we check the hstate when setting the flag we can eliminate those
> cases where the page is certainly not migratable.
>
> I don't really love this patch. It has minimal functional value.
>
> Oscar, what do you think about dropping this?
Yeah, I remember this topic arose during a discussion of patch#2 in the
early versions, about whether the renaming to HPageMigratable made
sense.
Back then I thought that we could have this in one place at fault-path [1],
which should have made this prettier, but it is not the case.
True is that the optimization is little, so I am fine with dropping this
patch.
unmap_and_move_huge_page() fences off pages belonging to non-migratable
hstates.
[1] https://patchwork.kernel.org/project/linux-mm/patch/20210120013049.311822-3-mike.kravetz@oracle.com/#23914033
Thanks
--
Oscar Salvador
SUSE L3
next prev parent reply other threads:[~2021-01-28 5:52 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-22 19:52 [PATCH v3 0/5] create hugetlb flags to consolidate state Mike Kravetz
2021-01-22 19:52 ` [PATCH v3 1/5] hugetlb: use page.private for hugetlb specific page flags Mike Kravetz
2021-01-26 8:17 ` Oscar Salvador
2021-01-27 10:20 ` Michal Hocko
2021-01-27 23:01 ` Mike Kravetz
2021-01-27 10:26 ` Michal Hocko
2021-01-22 19:52 ` [PATCH v3 2/5] hugetlb: convert page_huge_active() HPageMigratable flag Mike Kravetz
2021-01-27 10:25 ` Michal Hocko
2021-01-27 23:27 ` Mike Kravetz
2021-01-22 19:52 ` [PATCH v3 3/5] hugetlb: only set HPageMigratable for migratable hstates Mike Kravetz
2021-01-26 8:20 ` Oscar Salvador
2021-01-27 10:35 ` Michal Hocko
2021-01-27 23:36 ` Mike Kravetz
2021-01-28 5:52 ` Oscar Salvador [this message]
2021-01-28 21:37 ` Andrew Morton
2021-01-28 22:00 ` Mike Kravetz
2021-01-28 22:15 ` Andrew Morton
2021-01-29 9:09 ` Michal Hocko
2021-01-29 18:46 ` Mike Kravetz
2021-02-01 11:49 ` Michal Hocko
2021-02-04 1:11 ` Mike Kravetz
2021-01-22 19:52 ` [PATCH v3 4/5] hugetlb: convert PageHugeTemporary() to HPageTemporary flag Mike Kravetz
2021-01-23 3:15 ` [External] " Muchun Song
2021-01-27 10:39 ` Michal Hocko
2021-01-22 19:52 ` [PATCH v3 5/5] hugetlb: convert PageHugeFreed to HPageFreed flag Mike Kravetz
2021-01-27 10:41 ` Michal Hocko
2021-01-27 23:37 ` Mike Kravetz
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