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From: Pasha Tatashin <pasha.tatashin@oracle.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org,
	linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
	linux-s390@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	x86@kernel.org, kasan-dev@googlegroups.com,
	borntraeger@de.ibm.com, heiko.carstens@de.ibm.com,
	davem@davemloft.net, willy@infradead.org,
	ard.biesheuvel@linaro.org, will.deacon@arm.com,
	catalin.marinas@arm.com, sam@ravnborg.org
Subject: Re: [v6 01/15] x86/mm: reserve only exiting low pages
Date: Mon, 14 Aug 2017 09:30:35 -0400	[thread overview]
Message-ID: <8da779a0-ade4-e43e-3b14-2686e347f8ab@oracle.com> (raw)
In-Reply-To: <20170814114011.GG19063@dhcp22.suse.cz>

>> Correct, the pgflags asserts were triggered when we were setting reserved
>> flags to struct page for PFN 0 in which was never initialized through
>> __init_single_page(). The reason they were triggered is because we set all
>> uninitialized memory to ones in one of the debug patches.
> 
> And why don't we need the same treatment for other architectures?
> 

I have not seen similar issues on other architectures. At least this low 
memory reserve is x86 specific for BIOS purposes:

Documentation/admin-guide/kernel-parameters.txt
3624	reservelow=	[X86]
3625			Format: nn[K]
3626			Set the amount of memory to reserve for BIOS at
3627			the bottom of the address space.

If there are similar cases with other architectures, they will be caught 
by the last patch in this series, where all allocated memory is set to 
ones, and page flags asserts will be triggered. I have boot-tested on 
SPARC, ARM, and x86.

Pasha

  reply	other threads:[~2017-08-14 13:31 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-07 20:38 [v6 00/15] complete deferred page initialization Pavel Tatashin
2017-08-07 20:38 ` [v6 01/15] x86/mm: reserve only exiting low pages Pavel Tatashin
2017-08-11  8:07   ` Michal Hocko
2017-08-11 15:24     ` Pasha Tatashin
2017-08-14 11:40       ` Michal Hocko
2017-08-14 13:30         ` Pasha Tatashin [this message]
2017-08-14 13:55   ` Michal Hocko
2017-08-17 15:37     ` Pasha Tatashin
2017-08-07 20:38 ` [v6 02/15] x86/mm: setting fields in deferred pages Pavel Tatashin
2017-08-11  9:02   ` Michal Hocko
2017-08-11 15:39     ` Pasha Tatashin
2017-08-14 11:43       ` Michal Hocko
2017-08-14 13:32         ` Pasha Tatashin
2017-08-07 20:38 ` [v6 03/15] sparc64/mm: " Pavel Tatashin
2017-08-07 20:38 ` [v6 04/15] mm: discard memblock data later Pavel Tatashin
2017-08-11  9:32   ` Michal Hocko
2017-08-11  9:50     ` Mel Gorman
2017-08-11 15:49     ` Pasha Tatashin
2017-08-11 16:04       ` Michal Hocko
2017-08-11 16:22         ` Pasha Tatashin
2017-08-14 11:36           ` Michal Hocko
2017-08-14 13:35             ` Pasha Tatashin
2017-08-11 19:00     ` Pasha Tatashin
2017-08-14 11:34       ` Michal Hocko
2017-08-14 13:39         ` Pasha Tatashin
2017-08-14 13:42           ` Michal Hocko
2017-08-07 20:38 ` [v6 05/15] mm: don't accessed uninitialized struct pages Pavel Tatashin
2017-08-11  9:37   ` Michal Hocko
2017-08-11 15:55     ` Pasha Tatashin
2017-08-14 11:47       ` Michal Hocko
2017-08-14 13:51         ` Pasha Tatashin
2017-08-17 15:28           ` Pasha Tatashin
2017-08-17 15:43             ` Michal Hocko
2017-08-15  9:33   ` Michal Hocko
2017-08-07 20:38 ` [v6 06/15] sparc64: simplify vmemmap_populate Pavel Tatashin
2017-08-07 20:38 ` [v6 07/15] mm: defining memblock_virt_alloc_try_nid_raw Pavel Tatashin
2017-08-11 12:39   ` Michal Hocko
2017-08-11 15:58     ` Pasha Tatashin
2017-08-11 16:06       ` Michal Hocko
2017-08-11 16:24         ` Pasha Tatashin
2017-08-07 20:38 ` [v6 08/15] mm: zero struct pages during initialization Pavel Tatashin
2017-08-11 12:50   ` Michal Hocko
2017-08-11 16:03     ` Pasha Tatashin
2017-08-07 20:38 ` [v6 09/15] sparc64: optimized struct page zeroing Pavel Tatashin
2017-08-11 12:53   ` Michal Hocko
2017-08-11 16:04     ` Pasha Tatashin
2017-08-07 20:38 ` [v6 10/15] x86/kasan: explicitly zero kasan shadow memory Pavel Tatashin
2017-08-07 20:38 ` [v6 11/15] arm64/kasan: " Pavel Tatashin
2017-08-08  9:07   ` Will Deacon
2017-08-08 11:49     ` Pasha Tatashin
2017-08-08 12:30       ` Will Deacon
2017-08-08 12:49         ` Pasha Tatashin
2017-08-08 13:15       ` David Laight
2017-08-08 13:30         ` Pasha Tatashin
2017-08-07 20:38 ` [v6 12/15] mm: explicitly zero pagetable memory Pavel Tatashin
2017-08-07 20:38 ` [v6 13/15] mm: stop zeroing memory during allocation in vmemmap Pavel Tatashin
2017-08-11 13:04   ` Michal Hocko
2017-08-11 16:11     ` Pasha Tatashin
2017-08-07 20:38 ` [v6 14/15] mm: optimize early system hash allocations Pavel Tatashin
2017-08-11 13:05   ` Michal Hocko
2017-08-11 16:13     ` Pasha Tatashin
2017-08-07 20:38 ` [v6 15/15] mm: debug for raw alloctor Pavel Tatashin
2017-08-11 13:08   ` Michal Hocko
2017-08-11 16:18     ` Pasha Tatashin
2017-08-14 11:50       ` Michal Hocko
2017-08-14 14:01         ` Pasha Tatashin
2017-08-15  9:36           ` Michal Hocko
2017-08-11  7:58 ` [v6 00/15] complete deferred page initialization Michal Hocko
2017-08-11 15:13   ` Pasha Tatashin
2017-08-11 15:22     ` Michal Hocko

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