From: Anshuman Khandual <anshuman.khandual@arm.com>
To: Steven Price <steven.price@arm.com>, linux-mm@kvack.org
Cc: "Andy Lutomirski" <luto@kernel.org>,
"Ard Biesheuvel" <ard.biesheuvel@linaro.org>,
"Arnd Bergmann" <arnd@arndb.de>, "Borislav Petkov" <bp@alien8.de>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Ingo Molnar" <mingo@redhat.com>,
"James Morse" <james.morse@arm.com>,
"Jérôme Glisse" <jglisse@redhat.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Will Deacon" <will@kernel.org>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
"Mark Rutland" <Mark.Rutland@arm.com>,
"Liang, Kan" <kan.liang@linux.intel.com>,
"Andrew Morton" <akpm@linux-foundation.org>
Subject: Re: [PATCH v9 11/21] mm: pagewalk: Add p4d_entry() and pgd_entry()
Date: Sun, 28 Jul 2019 18:03:36 +0530 [thread overview]
Message-ID: <b61435a3-0da0-de57-0993-b1fffeca3ca9@arm.com> (raw)
In-Reply-To: <20190722154210.42799-12-steven.price@arm.com>
On 07/22/2019 09:12 PM, Steven Price wrote:
> pgd_entry() and pud_entry() were removed by commit 0b1fbfe50006c410
> ("mm/pagewalk: remove pgd_entry() and pud_entry()") because there were
> no users. We're about to add users so reintroduce them, along with
> p4d_entry() as we now have 5 levels of tables.
>
> Note that commit a00cc7d9dd93d66a ("mm, x86: add support for
> PUD-sized transparent hugepages") already re-added pud_entry() but with
> different semantics to the other callbacks. Since there have never
> been upstream users of this, revert the semantics back to match the
> other callbacks. This means pud_entry() is called for all entries, not
> just transparent huge pages.
>
> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
> include/linux/mm.h | 15 +++++++++------
> mm/pagewalk.c | 27 ++++++++++++++++-----------
> 2 files changed, 25 insertions(+), 17 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 0334ca97c584..b22799129128 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1432,15 +1432,14 @@ void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
>
> /**
> * mm_walk - callbacks for walk_page_range
> - * @pud_entry: if set, called for each non-empty PUD (2nd-level) entry
> - * this handler should only handle pud_trans_huge() puds.
> - * the pmd_entry or pte_entry callbacks will be used for
> - * regular PUDs.
> - * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry
> + * @pgd_entry: if set, called for each non-empty PGD (top-level) entry
> + * @p4d_entry: if set, called for each non-empty P4D entry
> + * @pud_entry: if set, called for each non-empty PUD entry
> + * @pmd_entry: if set, called for each non-empty PMD entry
> * this handler is required to be able to handle
> * pmd_trans_huge() pmds. They may simply choose to
> * split_huge_page() instead of handling it explicitly.
> - * @pte_entry: if set, called for each non-empty PTE (4th-level) entry
> + * @pte_entry: if set, called for each non-empty PTE (lowest-level) entry
> * @pte_hole: if set, called for each hole at all levels
> * @hugetlb_entry: if set, called for each hugetlb entry
> * @test_walk: caller specific callback function to determine whether
> @@ -1455,6 +1454,10 @@ void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
> * (see the comment on walk_page_range() for more details)
> */
> struct mm_walk {
> + int (*pgd_entry)(pgd_t *pgd, unsigned long addr,
> + unsigned long next, struct mm_walk *walk);
> + int (*p4d_entry)(p4d_t *p4d, unsigned long addr,
> + unsigned long next, struct mm_walk *walk);
> int (*pud_entry)(pud_t *pud, unsigned long addr,
> unsigned long next, struct mm_walk *walk);
> int (*pmd_entry)(pmd_t *pmd, unsigned long addr,
> diff --git a/mm/pagewalk.c b/mm/pagewalk.c
> index c3084ff2569d..98373a9f88b8 100644
> --- a/mm/pagewalk.c
> +++ b/mm/pagewalk.c
> @@ -90,15 +90,9 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
> }
>
> if (walk->pud_entry) {
> - spinlock_t *ptl = pud_trans_huge_lock(pud, walk->vma);
> -
> - if (ptl) {
> - err = walk->pud_entry(pud, addr, next, walk);
> - spin_unlock(ptl);
> - if (err)
> - break;
> - continue;
> - }
> + err = walk->pud_entry(pud, addr, next, walk);
> + if (err)
> + break;
But will not this still encounter possible THP entries when walking user
page tables (valid walk->vma) in which case still needs to get a lock.
OR will the callback take care of it ?
next prev parent reply other threads:[~2019-07-28 12:33 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-22 15:41 [PATCH v9 00/21] Generic page walk and ptdump Steven Price
2019-07-22 15:41 ` [PATCH v9 01/21] arc: mm: Add p?d_leaf() definitions Steven Price
2019-07-22 15:41 ` [PATCH v9 02/21] arm: " Steven Price
2019-07-22 15:41 ` [PATCH v9 03/21] arm64: " Steven Price
2019-07-22 15:41 ` [PATCH v9 04/21] mips: " Steven Price
2019-07-22 21:47 ` Paul Burton
2019-07-24 13:03 ` Steven Price
2019-07-22 15:41 ` [PATCH v9 05/21] powerpc: " Steven Price
2019-07-22 15:41 ` [PATCH v9 06/21] riscv: " Steven Price
2019-07-22 15:41 ` [PATCH v9 07/21] s390: " Steven Price
2019-07-22 15:41 ` [PATCH v9 08/21] sparc: " Steven Price
2019-07-22 15:41 ` [PATCH v9 09/21] x86: " Steven Price
2019-07-22 15:41 ` [PATCH v9 10/21] mm: Add generic p?d_leaf() macros Steven Price
2019-07-23 9:41 ` Mark Rutland
2019-07-24 13:48 ` Steven Price
2019-07-28 11:44 ` Anshuman Khandual
2019-07-29 11:38 ` Steven Price
2019-08-01 6:09 ` Anshuman Khandual
2019-08-01 12:22 ` Steven Price
2019-07-29 12:50 ` Mark Rutland
2019-08-01 6:13 ` Anshuman Khandual
2019-07-22 15:42 ` [PATCH v9 11/21] mm: pagewalk: Add p4d_entry() and pgd_entry() Steven Price
2019-07-23 10:14 ` Mark Rutland
2019-07-24 13:53 ` Steven Price
2019-07-24 14:09 ` Mark Rutland
2019-07-28 12:33 ` Anshuman Khandual [this message]
2019-07-29 12:17 ` Steven Price
2019-07-22 15:42 ` [PATCH v9 12/21] mm: pagewalk: Allow walking without vma Steven Price
2019-07-28 14:20 ` Anshuman Khandual
2019-07-29 12:29 ` Steven Price
2019-08-01 6:41 ` Anshuman Khandual
2019-07-22 15:42 ` [PATCH v9 13/21] mm: pagewalk: Add test_p?d callbacks Steven Price
2019-07-28 13:41 ` Anshuman Khandual
2019-07-29 12:34 ` Steven Price
2019-07-22 15:42 ` [PATCH v9 14/21] x86: mm: Don't display pages which aren't present in debugfs Steven Price
2019-07-22 15:42 ` [PATCH v9 15/21] x86: mm: Point to struct seq_file from struct pg_state Steven Price
2019-07-22 15:42 ` [PATCH v9 16/21] x86: mm+efi: Convert ptdump_walk_pgd_level() to take a mm_struct Steven Price
2019-07-22 15:42 ` [PATCH v9 17/21] x86: mm: Convert ptdump_walk_pgd_level_debugfs() to take an mm_struct Steven Price
2019-07-22 15:42 ` [PATCH v9 18/21] x86: mm: Convert ptdump_walk_pgd_level_core() " Steven Price
2019-07-22 15:42 ` [PATCH v9 19/21] mm: Add generic ptdump Steven Price
2019-07-23 9:57 ` Mark Rutland
2019-07-24 16:36 ` Steven Price
2019-07-29 2:59 ` Anshuman Khandual
2019-07-29 13:56 ` Steven Price
2019-07-22 15:42 ` [PATCH v9 20/21] x86: mm: Convert dump_pagetables to use walk_page_range Steven Price
2019-07-22 15:42 ` [PATCH v9 21/21] arm64: mm: Convert mm/dump.c to use walk_page_range() Steven Price
2019-07-23 6:39 ` [PATCH v9 00/21] Generic page walk and ptdump Anshuman Khandual
2019-07-24 13:35 ` Steven Price
2019-07-25 9:09 ` Anshuman Khandual
2019-07-25 9:30 ` Will Deacon
2019-07-26 6:03 ` Anshuman Khandual
2019-07-25 10:15 ` Steven Price
2019-07-23 10:16 ` Mark Rutland
2019-07-24 13:35 ` Steven Price
2019-07-24 13:57 ` Thomas Gleixner
2019-07-24 14:07 ` Mark Rutland
2019-07-24 14:18 ` Steven Price
2019-07-24 14:37 ` Thomas Gleixner
2019-07-28 11:20 ` Anshuman Khandual
2019-07-29 11:32 ` Steven Price
2019-07-31 9:27 ` Sven Schnelle
2019-07-31 11:18 ` Steven Price
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