Linux-MIPS Archive on
 help / color / Atom feed
From: Mike Kravetz <>
To: "Aneesh Kumar K.V" <>,
	Bibo Mao <>,
	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 09:46:06 -0700
Message-ID: <> (raw)
In-Reply-To: <>

On 6/25/20 5:01 AM, Aneesh Kumar K.V wrote:
> Mike Kravetz <> writes:
>> 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?
>> 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?
>> 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.
> Also we added update_mmu_cache_pmd to update a THP entry. That could be
> different from a hugetlb entry on some architectures. If we need to do
> hugetlb equivalent for update_mmu_cache, we should add a different
> function.

I do not know the mips architecture well enough or if the motivation for
this patch was based on THP or hugetlb pages.  However, it will change
the address passed to update_mmu_cache_pmd from huge page aligned to the
actual faulting address.  Will such a change in the passed address impact
the powerpc update_mmu_cache_pmd routine?

Mike Kravetz

  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
2020-06-25 12:01     ` Aneesh Kumar K.V
2020-06-25 16:46       ` Mike Kravetz [this message]
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \ \ \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-MIPS Archive on

Archives are clonable:
	git clone --mirror linux-mips/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-mips linux-mips/ \
	public-inbox-index linux-mips

Example config snippet for mirrors

Newsgroup available over NNTP:

AGPL code for this site: git clone