From: Yang Shi <shy828301@gmail.com>
To: Zi Yan <ziy@nvidia.com>
Cc: Eric Ren <renzhengeek@gmail.com>,
David Hildenbrand <david@redhat.com>,
Linux MM <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Christoph Hellwig <hch@lst.de>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Robin Murphy <robin.murphy@arm.com>,
linuxppc-dev@lists.ozlabs.org,
virtualization@lists.linux-foundation.org,
iommu@lists.linux-foundation.org,
Vlastimil Babka <vbabka@suse.cz>,
Mel Gorman <mgorman@techsingularity.net>
Subject: Re: [RFC PATCH v2 3/7] mm: migrate: allocate the right size of non hugetlb or THP compound pages.
Date: Fri, 10 Dec 2021 09:59:46 -0800 [thread overview]
Message-ID: <CAHbLzkr627vwDovZ23Ofje1vfu+m6BbYWs=tvptNpQwf1ramyQ@mail.gmail.com> (raw)
In-Reply-To: <971750C3-DAEC-4EE8-B838-2DD3CBC29781@nvidia.com>
On Fri, Dec 10, 2021 at 8:08 AM Zi Yan <ziy@nvidia.com> wrote:
>
> On 10 Dec 2021, at 2:53, Eric Ren wrote:
>
> > Hi,
> >
> > On 2021/12/10 07:04, Zi Yan wrote:
> >> From: Zi Yan <ziy@nvidia.com>
> >>
> >> alloc_migration_target() is used by alloc_contig_range() and non-LRU
> >> movable compound pages can be migrated. Current code does not allocate the
> >> right page size for such pages. Check THP precisely using
> >> is_transparent_huge() and add allocation support for non-LRU compound
> >> pages.
> > Could you elaborate on why the current code doesn't get the right size? how this patch fixes it.
>
> The current code only check PageHuge() and PageTransHuge(). Non-LRU compound
> pages will be regarded as PageTransHuge() and an order-9 page is always allocated
> regardless of the actual page order. This patch makes the exact check for
> THPs using is_transparent_huge() instead of PageTransHuge() and checks PageCompound()
> after PageHuge() and is_transparent_huge() for non-LRU compound pages.
>
> >
> > The description sounds like it's an existing bug, if so, the patch subject should be changed to
> > "Fixes ..."?
>
> I have not seen any related bug report.
>
> >
> >>
> >> Signed-off-by: Zi Yan <ziy@nvidia.com>
> >> ---
> >> mm/migrate.c | 8 ++++++--
> >> 1 file changed, 6 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/mm/migrate.c b/mm/migrate.c
> >> index d487a399253b..2ce3c771b1de 100644
> >> --- a/mm/migrate.c
> >> +++ b/mm/migrate.c
> >> @@ -1563,7 +1563,7 @@ struct page *alloc_migration_target(struct page *page, unsigned long private)
> >> return alloc_huge_page_nodemask(h, nid, mtc->nmask, gfp_mask);
> >> }
> >> - if (PageTransHuge(page)) {
> >> + if (is_transparent_hugepage(page)) {
> >> /*
> >> * clear __GFP_RECLAIM to make the migration callback
> >> * consistent with regular THP allocations.
> >> @@ -1572,13 +1572,17 @@ struct page *alloc_migration_target(struct page *page, unsigned long private)
> > if (PageTransHuge(page)) { // just give more code context
> > ...
> >> gfp_mask |= GFP_TRANSHUGE;
> >> order = HPAGE_PMD_ORDER;
> > order assigned here
> >> }
> >> + if (PageCompound(page)) {
> >> + gfp_mask |= __GFP_COMP;
> >> + order = compound_order(page);
> > re-assinged again as THP is a compound page?
>
> Ah, you are right. Will use else if instead. Thanks.
You don't have to use else if, you could just do:
if (PageCompound(page)) {
gfp_mask |= __GFP_COMP;
order = compound_order(page);
}
if (is_transparent_hugepage(page)) {
/* Manipulate THP specific gfp mask */
....
}
>
> > Thanks,
> > Eric
> >> + }
> >> zidx = zone_idx(page_zone(page));
> >> if (is_highmem_idx(zidx) || zidx == ZONE_MOVABLE)
> >> gfp_mask |= __GFP_HIGHMEM;
> >> new_page = __alloc_pages(gfp_mask, order, nid, mtc->nmask);
> >> - if (new_page && PageTransHuge(new_page))
> >> + if (new_page && is_transparent_hugepage(page))
> >> prep_transhuge_page(new_page);
> >> return new_page;
>
>
> --
> Best Regards,
> Yan, Zi
next prev parent reply other threads:[~2021-12-10 18:00 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-09 23:04 [RFC PATCH v2 0/7] Use pageblock_order for cma and alloc_contig_range alignment Zi Yan
2021-12-09 23:04 ` [RFC PATCH v2 1/7] mm: page_alloc: avoid merging non-fallbackable pageblocks with others Zi Yan
2021-12-10 7:43 ` Eric Ren
2021-12-10 15:39 ` Zi Yan
2021-12-09 23:04 ` [RFC PATCH v2 2/7] mm: compaction: handle non-lru compound pages properly in isolate_migratepages_block() Zi Yan
2021-12-09 23:04 ` [RFC PATCH v2 3/7] mm: migrate: allocate the right size of non hugetlb or THP compound pages Zi Yan
2021-12-10 7:53 ` Eric Ren
2021-12-10 15:48 ` Zi Yan
2021-12-10 17:59 ` Yang Shi [this message]
2021-12-09 23:04 ` [RFC PATCH v2 4/7] mm: make alloc_contig_range work at pageblock granularity Zi Yan
2021-12-10 8:12 ` Eric Ren
2021-12-09 23:04 ` [RFC PATCH v2 5/7] mm: cma: use pageblock_order as the single alignment Zi Yan
2021-12-09 23:04 ` [RFC PATCH v2 6/7] drivers: virtio_mem: use pageblock size as the minimum virtio_mem size Zi Yan
2021-12-09 23:04 ` [RFC PATCH v2 7/7] arch: powerpc: adjust fadump alignment to be pageblock aligned Zi Yan
2021-12-10 7:30 ` [RFC PATCH v2 0/7] Use pageblock_order for cma and alloc_contig_range alignment Eric Ren
2021-12-10 15:30 ` Zi Yan
2021-12-10 18:36 ` David Hildenbrand
2021-12-10 20:17 ` Zi Yan
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='CAHbLzkr627vwDovZ23Ofje1vfu+m6BbYWs=tvptNpQwf1ramyQ@mail.gmail.com' \
--to=shy828301@gmail.com \
--cc=david@redhat.com \
--cc=hch@lst.de \
--cc=iommu@lists.linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=m.szyprowski@samsung.com \
--cc=mgorman@techsingularity.net \
--cc=mpe@ellerman.id.au \
--cc=renzhengeek@gmail.com \
--cc=robin.murphy@arm.com \
--cc=vbabka@suse.cz \
--cc=virtualization@lists.linux-foundation.org \
--cc=ziy@nvidia.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).