From: Mike Rapoport <rppt@linux.ibm.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: "Mike Rapoport" <rppt@kernel.org>,
"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>,
"David Hildenbrand" <david@redhat.com>,
"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>, "Qian Cai" <cai@lca.pw>,
"Sarvela, Tomi P" <tomi.p.sarvela@intel.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
stable@vger.kernel.org, x86@kernel.org
Subject: Re: [PATCH v7 1/1] mm/page_alloc.c: refactor initialization of struct page for holes in memory layout
Date: Fri, 26 Feb 2021 12:59:00 +0200 [thread overview]
Message-ID: <20210226105900.GK1854360@linux.ibm.com> (raw)
In-Reply-To: <a458a933-91c7-9fb5-d7f8-b9a7af93a11c@suse.cz>
On Thu, Feb 25, 2021 at 07:38:44PM +0100, Vlastimil Babka wrote:
> On 2/25/21 7:05 PM, Mike Rapoport wrote:
> >>
> >> What if two zones are adjacent? I.e. if the hole was at a boundary between two
> >> zones.
> >
> > What do you mean by "adjacent zones"? If there is a hole near the zone
> > boundary, zone span would be clamped to exclude the hole.
>
> Yeah, zone span should exclude those pages, but you still somehow handle them?
> That's how I read "pages that are not spanned by any node will get links to the
> adjacent zone/node."
> So is it always a unique zone/node can be determined?
>
> Let's say we have:
>
> <memory on node 0>
> ---- pageblock boundary ----
> <more memory on node 0>
> <a hole>
> <memory on node 1>
> ---- pageblock boundary ----
>
> Now I hope such configurations don't really exist :) But if we simulated them in
> QEMU, what would be the linkage in struct pages in that hole?
I don't think such configuration is possible in practice but it can be
forced with e.g memmap="2M hole at 4G - 1M".
The hole in your example the hole will get node1 for node and zone that
spans the beginning of node1 for zone.
--
Sincerely yours,
Mike.
next prev parent reply other threads:[~2021-02-26 10:59 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-24 15:39 [PATCH v7 0/1] mm: fix initialization of struct page for holes in memory layout Mike Rapoport
2021-02-24 15:39 ` [PATCH v7 1/1] mm/page_alloc.c: refactor " Mike Rapoport
2021-02-25 15:59 ` David Hildenbrand
2021-02-25 17:06 ` Mike Rapoport
2021-02-25 17:54 ` David Hildenbrand
2021-02-25 17:54 ` Linus Torvalds
2021-02-25 18:09 ` Mike Rapoport
2021-02-25 17:51 ` Vlastimil Babka
2021-02-25 18:05 ` Mike Rapoport
2021-02-25 18:38 ` Vlastimil Babka
2021-02-26 10:59 ` Mike Rapoport [this message]
2021-02-26 11:08 ` Vlastimil Babka
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