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From: maobibo <>
To: Mike Kravetz <>,
	Andrew Morton <>,
	Thomas Bogendoerfer <>,
	Paul Burton <>,
	Anshuman Khandual <>,
	Mike Rapoport <>,
	Daniel Silsby <>
Subject: Re: [PATCH 2/3] mm/huge_memory.c: update tlb entry if pmd is changed
Date: Thu, 25 Jun 2020 17:57:02 +0800
Message-ID: <> (raw)
In-Reply-To: <>

On 06/25/2020 08:30 AM, Mike Kravetz wrote:
> On 6/24/20 2:26 AM, Bibo Mao wrote:
>> When set_pmd_at is called in function do_huge_pmd_anonymous_page,
>> new tlb entry can be added by software on MIPS platform.
>> Here add update_mmu_cache_pmd when pmd entry is set, and
>> update_mmu_cache_pmd is defined as empty excepts arc/mips platform.
>> This patch has no negative effect on other platforms except arc/mips
>> system.
> I am confused by this comment.  It appears that update_mmu_cache_pmd
> is defined as non-empty on arc, mips, powerpc and sparc architectures.
> Am I missing something?
ohh, sparc is missing here, it not defined as empty. On powerpc it is defined
as empty.

> If those architectures do provide update_mmu_cache_pmd, then the previous
> patch and this one now call update_mmu_cache_pmd with the actual faulting
> address instead of the huge page aligned address.  This was intentional
> for mips.  However, are there any potential issues on the other architectures?
It is not special for mips, only that fault address is useful on mips system.
In function huge_pmd_set_accessed/do_huge_pmd_wp_page, update_mmu_cache_pmd is
called with vmf->address, rather than start address of pmd page.


> I am no expert in any of those architectures.  arc looks like it could be
> problematic as update_mmu_cache_pmd calls update_mmu_cache and then
> operates on (address & PAGE_MASK).  That could now be different.

  reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-24  9:26 [PATCH 1/3] mm: set page fault address for update_mmu_cache_pmd Bibo Mao
2020-06-24  9:26 ` [PATCH 2/3] mm/huge_memory.c: update tlb entry if pmd is changed Bibo Mao
2020-06-25  0:30   ` Mike Kravetz
2020-06-25  9:57     ` maobibo [this message]
2020-06-25 12:01     ` Aneesh Kumar K.V
2020-06-25 16:46       ` Mike Kravetz
2020-06-26  8:13         ` Aneesh Kumar K.V
2020-08-07  4:35           ` Andrew Morton
2020-06-24  9:26 ` [PATCH 3/3] MIPS: Do not call flush_tlb_all when setting pmd entry Bibo Mao
2020-06-24 19:49 ` [PATCH 1/3] mm: set page fault address for update_mmu_cache_pmd Andrew Morton
2020-06-30 10:09 ` Kirill A. Shutemov
2020-06-30 10:42   ` maobibo
2020-07-01  2:54     ` maobibo

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