From: Matthew Wilcox <willy@infradead.org>
To: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Yu Zhao <yuzhao@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Nick Piggin <npiggin@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Joel Fernandes <joel@joelfernandes.org>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
Mark Rutland <mark.rutland@arm.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Chintan Pandya <cpandya@codeaurora.org>,
Jun Yao <yaojun8558363@gmail.com>,
Laura Abbott <labbott@redhat.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH v2 1/3] arm64: mm: use appropriate ctors for page tables
Date: Tue, 19 Feb 2019 17:34:07 -0800 [thread overview]
Message-ID: <20190220013407.GD12668@bombadil.infradead.org> (raw)
In-Reply-To: <8f9b0bfb-b787-fa3e-7322-73a56a618aa8@arm.com>
On Tue, Feb 19, 2019 at 11:47:12AM +0530, Anshuman Khandual wrote:
> + Matthew Wilcox
> On 02/19/2019 11:02 AM, Yu Zhao wrote:
> > On Tue, Feb 19, 2019 at 09:51:01AM +0530, Anshuman Khandual wrote:
> >>
> >>
> >> On 02/19/2019 04:43 AM, Yu Zhao wrote:
> >>> For pte page, use pgtable_page_ctor(); for pmd page, use
> >>> pgtable_pmd_page_ctor() if not folded; and for the rest (pud,
> >>> p4d and pgd), don't use any.
> >> pgtable_page_ctor()/dtor() is not optional for any level page table page
> >> as it determines the struct page state and zone statistics.
> >
> > This is not true. pgtable_page_ctor() is only meant for user pte
> > page. The name isn't perfect (we named it this way before we had
> > split pmd page table lock, and never bothered to change it).
> >
> > The commit cccd843f54be ("mm: mark pages in use for page tables")
Where did you get that commit ID from? In Linus' tree, it's
1d40a5ea01d53251c23c7be541d3f4a656cfc537
> > clearly states so:
> > Note that only pages currently accounted as NR_PAGETABLES are
> > tracked as PageTable; this does not include pgd/p4d/pud/pmd pages.
>
> I think the commit is the following one and it does say so. But what is
> the rationale of tagging only PTE page as PageTable and updating the zone
> stat but not doing so for higher level page table pages ? Are not they
> used as page table pages ? Should not they count towards NR_PAGETABLE ?
>
> 1d40a5ea01d53251c ("mm: mark pages in use for page tables")
I think they should all be accounted towards NR_PAGETABLE and marked
as being PageTable. Somebody needs to make the case for that and
send the patches. That patch even says that there should be follow-up
patches to do that. I've been a little busy and haven't got back to it.
I thought you said you were going to do it.
> pgtable_page_ctor/dtor() use across arch is not consistent and there is a need
> for generalization which has been already acknowledged earlier. But for now we
> can atleast fix this on arm64.
>
> https://lore.kernel.org/lkml/1547619692-7946-1-git-send-email-anshuman.khandual@arm.com/
... were you not listening when you were told that was completely
inadequate?
next prev parent reply other threads:[~2019-02-20 1:34 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-14 21:16 [PATCH] arm64: mm: enable per pmd page table lock Yu Zhao
2019-02-18 15:12 ` Will Deacon
2019-02-18 19:49 ` Yu Zhao
2019-02-18 20:48 ` Yu Zhao
2019-02-19 4:09 ` Anshuman Khandual
2019-02-18 23:13 ` [PATCH v2 1/3] arm64: mm: use appropriate ctors for page tables Yu Zhao
2019-02-18 23:13 ` [PATCH v2 2/3] arm64: mm: don't call page table ctors for init_mm Yu Zhao
2019-02-26 15:13 ` Mark Rutland
2019-03-09 3:52 ` Yu Zhao
2019-02-18 23:13 ` [PATCH v2 3/3] arm64: mm: enable per pmd page table lock Yu Zhao
2019-02-19 4:21 ` [PATCH v2 1/3] arm64: mm: use appropriate ctors for page tables Anshuman Khandual
2019-02-19 5:32 ` Yu Zhao
2019-02-19 6:17 ` Anshuman Khandual
2019-02-19 22:28 ` Yu Zhao
2019-02-20 10:27 ` Anshuman Khandual
2019-02-20 12:24 ` Matthew Wilcox
2019-02-20 20:22 ` Yu Zhao
2019-02-20 20:59 ` Matthew Wilcox
2019-02-20 1:34 ` Matthew Wilcox [this message]
2019-02-20 3:20 ` Anshuman Khandual
2019-02-20 21:03 ` Matthew Wilcox
2019-02-26 15:12 ` Mark Rutland
2019-03-09 4:01 ` Yu Zhao
2019-03-10 1:19 ` [PATCH v3 " Yu Zhao
2019-03-10 1:19 ` [PATCH v3 2/3] arm64: mm: don't call page table ctors for init_mm Yu Zhao
2019-03-10 1:19 ` [PATCH v3 3/3] arm64: mm: enable per pmd page table lock Yu Zhao
2019-03-11 8:28 ` Anshuman Khandual
2019-03-11 23:10 ` Yu Zhao
2019-03-11 12:12 ` Mark Rutland
2019-03-11 12:57 ` Anshuman Khandual
2019-03-11 23:11 ` Yu Zhao
2019-03-11 7:45 ` [PATCH v3 1/3] arm64: mm: use appropriate ctors for page tables Anshuman Khandual
2019-03-11 23:23 ` Yu Zhao
2019-03-12 0:57 ` [PATCH v4 1/4] " Yu Zhao
2019-03-12 0:57 ` [PATCH v4 2/4] arm64: mm: don't call page table ctors for init_mm Yu Zhao
2019-03-12 0:57 ` [PATCH v4 3/4] arm64: mm: call ctor for stage2 pmd page Yu Zhao
2019-03-12 2:19 ` [PATCH] KVM: ARM: Remove pgtable page standard functions from stage-2 page tables Anshuman Khandual
2019-03-12 2:40 ` Yu Zhao
2019-03-12 10:37 ` Suzuki K Poulose
2019-03-12 11:31 ` Anshuman Khandual
2019-03-12 11:43 ` Suzuki K Poulose
2019-03-12 13:25 ` [PATCH V2] " Anshuman Khandual
2019-04-01 16:16 ` Will Deacon
2019-04-01 18:34 ` Yu Zhao
2019-04-02 9:03 ` Will Deacon
2019-04-08 14:22 ` Will Deacon
2019-04-08 17:18 ` Yu Zhao
2019-04-08 9:09 ` Marc Zyngier
2019-03-12 0:57 ` [PATCH v4 4/4] arm64: mm: enable per pmd page table lock Yu Zhao
2019-02-19 3:08 ` [PATCH] " Anshuman Khandual
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