From: Yu Zhao <yuzhao@google.com>
To: Mark Rutland <mark.rutland@arm.com>
Cc: 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>,
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: Fri, 8 Mar 2019 21:01:53 -0700 [thread overview]
Message-ID: <20190309040153.GB214016@google.com> (raw)
In-Reply-To: <20190226151230.GA20230@lakrids.cambridge.arm.com>
On Tue, Feb 26, 2019 at 03:12:31PM +0000, Mark Rutland wrote:
> Hi,
>
> On Mon, Feb 18, 2019 at 04:13:17PM -0700, 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.
> >
> > Signed-off-by: Yu Zhao <yuzhao@google.com>
> > ---
> > arch/arm64/mm/mmu.c | 33 +++++++++++++++++++++------------
> > 1 file changed, 21 insertions(+), 12 deletions(-)
>
> [...]
>
> > -static phys_addr_t pgd_pgtable_alloc(void)
> > +static phys_addr_t pgd_pgtable_alloc(int shift)
> > {
> > void *ptr = (void *)__get_free_page(PGALLOC_GFP);
> > - if (!ptr || !pgtable_page_ctor(virt_to_page(ptr)))
> > - BUG();
> > + BUG_ON(!ptr);
> > +
> > + /*
> > + * Initialize page table locks in case later we need to
> > + * call core mm functions like apply_to_page_range() on
> > + * this pre-allocated page table.
> > + */
> > + if (shift == PAGE_SHIFT)
> > + BUG_ON(!pgtable_page_ctor(virt_to_page(ptr)));
> > + else if (shift == PMD_SHIFT && PMD_SHIFT != PUD_SHIFT)
> > + BUG_ON(!pgtable_pmd_page_ctor(virt_to_page(ptr)));
>
> IIUC, this is for nopmd kernels, where we only have real PGD and PTE
> levels of table. From my PoV, that would be clearer if we did:
>
> else if (shift == PMD_SHIFT && !is_defined(__PAGETABLE_PMD_FOLDED))
>
> ... though IMO it would be a bit nicer if the generic
> pgtable_pmd_page_ctor() were nop'd out for __PAGETABLE_PMD_FOLDED
> builds, so that callers don't have to be aware of folding.
Agreed. Will make pgtable_pmd_page_ctor() nop when pmd is folded.
> I couldn't think of a nicer way of distinguishing levels of table, and
> having separate function pointers for each level seems over-the-top, so
> otehr than that this looks good to me.
>
> Assuming you're happy with the above change:
>
> Acked-by: Mark Rutland <mark.rutland@arm.com>
>
> Thanks,
> Mark.
next prev parent reply other threads:[~2019-03-09 4:02 UTC|newest]
Thread overview: 38+ 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
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 [this message]
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 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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