From: Mike Rapoport <rppt@kernel.org>
To: David Hildenbrand <david@redhat.com>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
"Andrea Arcangeli" <aarcange@redhat.com>,
"Baoquan He" <bhe@redhat.com>, "Borislav Petkov" <bp@alien8.de>,
"Chris Wilson" <chris@chris-wilson.co.uk>,
"H. Peter Anvin" <hpa@zytor.com>,
"Ingo Molnar" <mingo@redhat.com>,
"Linus Torvalds" <torvalds@linux-foundation.org>,
"Łukasz Majczak" <lma@semihalf.com>,
"Mel Gorman" <mgorman@suse.de>,
"Michal Hocko" <mhocko@kernel.org>,
"Mike Rapoport" <rppt@linux.ibm.com>, "Qian Cai" <cai@lca.pw>,
"Sarvela, Tomi P" <tomi.p.sarvela@intel.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Vlastimil Babka" <vbabka@suse.cz>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
stable@vger.kernel.org, x86@kernel.org
Subject: Re: [PATCH v5 1/1] mm: refactor initialization of struct page for holes in memory layout
Date: Sun, 14 Feb 2021 19:29:06 +0200 [thread overview]
Message-ID: <20210214172906.GN242749@kernel.org> (raw)
In-Reply-To: <a6cf3a26-a174-abab-a5a0-6cf89ebe4af7@redhat.com>
On Fri, Feb 12, 2021 at 10:56:19AM +0100, David Hildenbrand wrote:
> On 12.02.21 10:55, David Hildenbrand wrote:
> > On 08.02.21 12:08, Mike Rapoport wrote:
> > > +#ifdef CONFIG_SPARSEMEM
> > > + /*
> > > + * Sections in the memory map may not match actual populated
> > > + * memory, extend the node span to cover the entire section.
> > > + */
> > > + *start_pfn = round_down(*start_pfn, PAGES_PER_SECTION);
> > > + *end_pfn = round_up(*end_pfn, PAGES_PER_SECTION);
> >
> > Does that mean that we might create overlapping zones when one node
>
> s/overlapping zones/overlapping nodes/
>
> > starts in the middle of a section and the other one ends in the middle
> > of a section?
>
> > Could it be a problem? (e.g., would we have to look at neighboring nodes
> > when making the decision to extend, and how far to extend?)
Having a node end/start in a middle of a section would be a problem, but in
this case I don't see a way to detect how a node should be extended :(
We can return to a v4 [1] without x86 modifications.
With that we'll have struct pages corresponding to a hole in a middle of a
zone with correct zone link and a good guess for the node.
As for the pfn 0 on x86, it'll remain outside any node and zone, but since
it was the case since, like forever, I think we can live with it.
[1] https://lore.kernel.org/lkml/20210130221035.4169-1-rppt@kernel.org
--
Sincerely yours,
Mike.
next prev parent reply other threads:[~2021-02-14 17:29 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-08 11:08 [PATCH v5 1/1] mm: refactor initialization of struct page for holes in memory layout Mike Rapoport
2021-02-08 21:11 ` Andrew Morton
2021-02-08 21:25 ` Mike Rapoport
2021-02-12 9:55 ` David Hildenbrand
2021-02-12 9:56 ` David Hildenbrand
2021-02-12 10:11 ` Michal Hocko
2021-02-12 10:16 ` David Hildenbrand
2021-02-12 10:37 ` Michal Hocko
2021-02-14 17:29 ` Mike Rapoport [this message]
2021-02-15 8:45 ` David Hildenbrand
2021-02-16 11:13 ` Mike Rapoport
2021-02-12 10:33 ` Michal Hocko
2021-02-12 10:42 ` David Hildenbrand
2021-02-12 13:18 ` Michal Hocko
2021-02-14 18:00 ` Mike Rapoport
2021-02-15 9:00 ` Michal Hocko
2021-02-15 9:05 ` David Hildenbrand
2021-02-15 21:24 ` Mike Rapoport
2021-02-16 8:33 ` Michal Hocko
2021-02-16 11:01 ` Mike Rapoport
2021-02-16 11:39 ` Michal Hocko
2021-02-16 12:34 ` Vlastimil Babka
2021-02-16 12:59 ` Vlastimil Babka
2021-02-16 13:11 ` Michal Hocko
2021-02-16 16:39 ` Vlastimil Babka
2021-02-16 17:49 ` Mike Rapoport
2021-02-17 12:27 ` Vlastimil Babka
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