From: Mike Kravetz <mike.kravetz@oracle.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Doug Berger <opendmb@gmail.com>, Jonathan Corbet <corbet@lwn.net>,
Rob Herring <robh+dt@kernel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
Frank Rowand <frowand.list@gmail.com>,
Muchun Song <songmuchun@bytedance.com>,
Mike Rapoport <rppt@kernel.org>, Christoph Hellwig <hch@lst.de>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Robin Murphy <robin.murphy@arm.com>, Borislav Petkov <bp@suse.de>,
"Paul E. McKenney" <paulmck@kernel.org>,
Neeraj Upadhyay <quic_neeraju@quicinc.com>,
Randy Dunlap <rdunlap@infradead.org>,
Damien Le Moal <damien.lemoal@opensource.wdc.com>,
Florian Fainelli <f.fainelli@gmail.com>,
David Hildenbrand <david@redhat.com>, Zi Yan <ziy@nvidia.com>,
Oscar Salvador <osalvador@suse.de>,
Hari Bathini <hbathini@linux.ibm.com>,
Kees Cook <keescook@chromium.org>,
- <devicetree-spec@vger.kernel.org>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Mel Gorman <mgorman@suse.de>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org, linux-mm@kvack.org,
iommu@lists.linux.dev
Subject: Re: [PATCH 02/21] mm/hugetlb: correct max_huge_pages accounting on demote
Date: Wed, 14 Sep 2022 14:11:05 -0700 [thread overview]
Message-ID: <YyJDaVRrKy5jgewU@monkey> (raw)
In-Reply-To: <20220914135825.88814aa1699e93c8a782abc6@linux-foundation.org>
On 09/14/22 13:58, Andrew Morton wrote:
> On Wed, 14 Sep 2022 10:23:05 -0700 Mike Kravetz <mike.kravetz@oracle.com> wrote:
>
> > On 09/13/22 12:54, Doug Berger wrote:
> > > When demoting a hugepage to a smaller order, the number of pages
> > > added to the target hstate will be the size of the large page
> > > divided by the size of the smaller page.
> > >
> > > Fixes: 8531fc6f52f5 ("hugetlb: add hugetlb demote page support")
> > > Signed-off-by: Doug Berger <opendmb@gmail.com>
> > > ---
> > > mm/hugetlb.c | 3 ++-
> > > 1 file changed, 2 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> > > index e070b8593b37..79949893ac12 100644
> > > --- a/mm/hugetlb.c
> > > +++ b/mm/hugetlb.c
> > > @@ -3472,7 +3472,8 @@ static int demote_free_huge_page(struct hstate *h, struct page *page)
> > > * based on pool changes for the demoted page.
> > > */
> > > h->max_huge_pages--;
> > > - target_hstate->max_huge_pages += pages_per_huge_page(h);
> > > + target_hstate->max_huge_pages += pages_per_huge_page(h) /
> > > + pages_per_huge_page(target_hstate);
> > >
> > > return rc;
> > > }
> >
> > This has already been fixed here,
> >
> > https://lore.kernel.org/linux-mm/20220823030209.57434-2-linmiaohe@huawei.com/
>
> Neither version tells us the user-visible runtime effects of the change :(
Sorry, I should have pushed harder on this with Miaohe's patch.
There are no user-visible runtime effects. In fact, this change really causes
no functional change (unless I am mistaken and Miaohe did not correct me).
max_huge_pages is not used again until it is reset. See my explanation at:
https://lore.kernel.org/linux-mm/YvwfvxXewnZpHQcz@monkey/
--
Mike Kravetz
next prev parent reply other threads:[~2022-09-14 21:11 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-13 19:54 [PATCH 00/21] mm: introduce Designated Movable Blocks Doug Berger
2022-09-13 19:54 ` [PATCH 01/21] mm/page_isolation: protect cma from isolate_single_pageblock Doug Berger
2022-09-14 0:02 ` Zi Yan
2022-09-14 0:59 ` Doug Berger
2022-09-14 1:09 ` Zi Yan
2022-09-14 1:47 ` Doug Berger
2022-09-14 1:53 ` Zi Yan
2022-09-14 17:27 ` Doug Berger
2022-09-13 19:54 ` [PATCH 02/21] mm/hugetlb: correct max_huge_pages accounting on demote Doug Berger
2022-09-14 17:23 ` Mike Kravetz
2022-09-14 17:26 ` Florian Fainelli
2022-09-14 18:43 ` Mike Kravetz
2022-09-14 17:30 ` Doug Berger
2022-09-14 20:58 ` Andrew Morton
2022-09-14 21:11 ` Mike Kravetz [this message]
2022-09-13 19:54 ` [PATCH 03/21] mm/hugetlb: correct demote page offset logic Doug Berger
2022-09-13 23:34 ` Matthew Wilcox
2022-09-14 1:07 ` Doug Berger
2022-09-14 17:08 ` Mike Kravetz
2022-09-14 17:54 ` Doug Berger
2022-09-15 1:40 ` Muchun Song
2022-09-13 19:54 ` [PATCH 04/21] mm/hugetlb: refactor alloc_and_dissolve_huge_page Doug Berger
2022-09-13 19:54 ` [PATCH 05/21] mm/hugetlb: allow migrated hugepage to dissolve when freed Doug Berger
2022-09-13 19:54 ` [PATCH 06/21] mm/hugetlb: add hugepage isolation support Doug Berger
2022-09-13 19:54 ` [PATCH 07/21] lib/show_mem.c: display MovableOnly Doug Berger
2022-09-13 19:54 ` [PATCH 08/21] mm/vmstat: show start_pfn when zone spans pages Doug Berger
2022-09-13 19:54 ` [PATCH 09/21] mm/page_alloc: calculate node_spanned_pages from pfns Doug Berger
2022-09-13 19:54 ` [PATCH 10/21] mm/page_alloc.c: allow oversized movablecore Doug Berger
2022-09-13 19:54 ` [PATCH 11/21] mm/page_alloc: introduce init_reserved_pageblock() Doug Berger
2022-09-13 19:54 ` [PATCH 12/21] memblock: introduce MEMBLOCK_MOVABLE flag Doug Berger
2022-09-13 19:55 ` [PATCH 13/21] mm/dmb: Introduce Designated Movable Blocks Doug Berger
2022-09-13 19:55 ` [PATCH 14/21] mm/page_alloc: make alloc_contig_pages DMB aware Doug Berger
2022-09-13 19:55 ` [PATCH 15/21] mm/page_alloc: allow base for movablecore Doug Berger
2022-09-13 19:55 ` [PATCH 16/21] dt-bindings: reserved-memory: introduce designated-movable-block Doug Berger
2022-09-14 14:55 ` Rob Herring
2022-09-14 17:13 ` Doug Berger
2022-09-18 10:31 ` Krzysztof Kozlowski
2022-09-18 23:12 ` Doug Berger
2022-09-19 11:03 ` Krzysztof Kozlowski
2022-09-21 0:14 ` Doug Berger
2022-09-21 6:35 ` Krzysztof Kozlowski
2022-09-18 10:28 ` Krzysztof Kozlowski
2022-09-18 22:41 ` Doug Berger
2022-09-13 19:55 ` [PATCH 17/21] mm/dmb: introduce rmem designated-movable-block Doug Berger
2022-09-13 19:55 ` [PATCH 18/21] mm/cma: support CMA in Designated Movable Blocks Doug Berger
2022-09-13 19:55 ` [PATCH 19/21] dt-bindings: reserved-memory: shared-dma-pool: support DMB Doug Berger
2022-09-13 19:55 ` [PATCH 20/21] mm/cma: introduce rmem shared-dmb-pool Doug Berger
2022-09-13 19:55 ` [PATCH 21/21] mm/hugetlb: introduce hugetlb_dmb Doug Berger
2022-09-14 13:21 ` [PATCH 00/21] mm: introduce Designated Movable Blocks Rob Herring
2022-09-14 16:57 ` Doug Berger
2022-09-14 18:07 ` Rob Herring
2022-09-19 9:00 ` David Hildenbrand
2022-09-20 1:03 ` Doug Berger
2022-09-23 11:19 ` Mike Rapoport
2022-09-23 22:10 ` Doug Berger
2022-09-29 9:00 ` David Hildenbrand
2022-10-01 0:42 ` Doug Berger
2022-10-05 18:39 ` David Hildenbrand
2022-10-12 23:38 ` Doug Berger
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