From: Kefeng Wang <wangkefeng.wang@huawei.com>
To: Mike Rapoport <rppt@kernel.org>, <linux-arm-kernel@lists.infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Ard Biesheuvel <ardb@kernel.org>,
"Catalin Marinas" <catalin.marinas@arm.com>,
David Hildenbrand <david@redhat.com>,
"Marc Zyngier" <maz@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mike Rapoport <rppt@linux.ibm.com>, Will Deacon <will@kernel.org>,
<kvmarm@lists.cs.columbia.edu>, <linux-kernel@vger.kernel.org>,
<linux-mm@kvack.org>
Subject: Re: [PATCH v2 0/4] arm64: drop pfn_valid_within() and simplify pfn_valid()
Date: Thu, 22 Apr 2021 15:00:20 +0800 [thread overview]
Message-ID: <9aa68d26-d736-3b75-4828-f148964eb7f0@huawei.com> (raw)
In-Reply-To: <20210421065108.1987-1-rppt@kernel.org>
On 2021/4/21 14:51, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
>
> Hi,
>
> These patches aim to remove CONFIG_HOLES_IN_ZONE and essentially hardwire
> pfn_valid_within() to 1.
>
> The idea is to mark NOMAP pages as reserved in the memory map and restore
> the intended semantics of pfn_valid() to designate availability of struct
> page for a pfn.
>
> With this the core mm will be able to cope with the fact that it cannot use
> NOMAP pages and the holes created by NOMAP ranges within MAX_ORDER blocks
> will be treated correctly even without the need for pfn_valid_within.
>
> The patches are only boot tested on qemu-system-aarch64 so I'd really
> appreciate memory stress tests on real hardware.
>
> If this actually works we'll be one step closer to drop custom pfn_valid()
> on arm64 altogether.
Hi Mike，I have a question, without HOLES_IN_ZONE, the pfn_valid_within()
in move_freepages_block()->move_freepages()
will be optimized, if there are holes in zone, the 'struce page'(memory
map) for pfn range of hole will be free by
free_memmap(), and then the page traverse in the zone(with holes) from
move_freepages() will meet the wrong page，
then it could panic at PageLRU(page) test, check link[1],
"The idea is to mark NOMAP pages as reserved in the memory map", I see
the patch2 check memblock_is_nomap() in memory region
of memblock, but it seems that memblock_mark_nomap() is not called(maybe
I missed), then memmap_init_reserved_pages() won't
work, so should the HOLES_IN_ZONE still be needed for generic mm code?
[1]
https://lore.kernel.org/linux-arm-kernel/541193a6-2bce-f042-5bb2-88913d5f1047@arm.com/
next prev parent reply other threads:[~2021-04-22 7:00 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-21 6:51 [PATCH v2 0/4] arm64: drop pfn_valid_within() and simplify pfn_valid() Mike Rapoport
2021-04-21 6:51 ` [PATCH v2 1/4] include/linux/mmzone.h: add documentation for pfn_valid() Mike Rapoport
2021-04-21 10:49 ` Anshuman Khandual
2021-04-21 6:51 ` [PATCH v2 2/4] memblock: update initialization of reserved pages Mike Rapoport
2021-04-21 7:49 ` David Hildenbrand
2021-04-21 10:51 ` Anshuman Khandual
2021-04-21 6:51 ` [PATCH v2 3/4] arm64: decouple check whether pfn is in linear map from pfn_valid() Mike Rapoport
2021-04-21 10:59 ` Anshuman Khandual
2021-04-21 12:19 ` Mike Rapoport
2021-04-21 13:13 ` Anshuman Khandual
2021-04-21 6:51 ` [PATCH v2 4/4] arm64: drop pfn_valid_within() and simplify pfn_valid() Mike Rapoport
2021-04-21 7:49 ` David Hildenbrand
2021-04-21 11:06 ` Anshuman Khandual
2021-04-21 12:24 ` Mike Rapoport
2021-04-21 13:15 ` Anshuman Khandual
2021-04-22 7:00 ` Kefeng Wang [this message]
2021-04-22 7:29 ` [PATCH v2 0/4] " Mike Rapoport
2021-04-22 15:28 ` Kefeng Wang
2021-04-23 8:11 ` Kefeng Wang
2021-04-25 7:19 ` arm32: panic in move_freepages (Was [PATCH v2 0/4] arm64: drop pfn_valid_within() and simplify pfn_valid()) Mike Rapoport
[not found] ` <52f7d03b-7219-46bc-c62d-b976bc31ebd5@huawei.com>
2021-04-26 5:20 ` Mike Rapoport
2021-04-26 15:26 ` Kefeng Wang
2021-04-27 6:23 ` Mike Rapoport
2021-04-27 11:08 ` Kefeng Wang
2021-04-28 5:59 ` Mike Rapoport
2021-04-29 0:48 ` Kefeng Wang
2021-04-29 6:57 ` Mike Rapoport
2021-04-29 10:22 ` Kefeng Wang
2021-04-30 9:51 ` Mike Rapoport
2021-04-30 11:24 ` Kefeng Wang
2021-05-03 6:26 ` Mike Rapoport
2021-05-03 8:07 ` David Hildenbrand
2021-05-03 8:44 ` Mike Rapoport
2021-05-06 12:47 ` Kefeng Wang
2021-05-07 7:17 ` Kefeng Wang
2021-05-07 10:30 ` Mike Rapoport
2021-05-07 12:34 ` Kefeng Wang
2021-05-09 5:59 ` Mike Rapoport
2021-05-10 3:10 ` Kefeng Wang
2021-05-11 8:48 ` Mike Rapoport
2021-05-12 3:08 ` Kefeng Wang
2021-05-12 8:26 ` Mike Rapoport
2021-05-13 3:44 ` Kefeng Wang
2021-05-13 10:55 ` Mike Rapoport
2021-05-14 2:18 ` Kefeng Wang
2021-05-12 3:50 ` Matthew Wilcox
2021-04-25 6:59 ` [PATCH v2 0/4] arm64: drop pfn_valid_within() and simplify pfn_valid() Mike Rapoport
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