From: maobibo <maobibo@loongson.cn>
To: Mike Kravetz <mike.kravetz@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Paul Burton <paulburton@kernel.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Mike Rapoport <rppt@linux.ibm.com>,
Daniel Silsby <dansilsby@gmail.com>
Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
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 [thread overview]
Message-ID: <b6f29ae6-8246-9110-1d93-3a68d55e19d0@loongson.cn> (raw)
In-Reply-To: <07f78e99-6e59-0bce-8ac0-50d7c7600461@oracle.com>
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.
regards
bibo,mao
> 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.
next prev parent reply other threads:[~2020-06-25 9:57 UTC|newest]
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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