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 13/21] mm: pagewalk: Add test_p?d callbacks
Date: Sun, 28 Jul 2019 19:11:00 +0530 [thread overview]
Message-ID: <b74e545f-cbe0-9dd0-004c-5919e5cabb6f@arm.com> (raw)
In-Reply-To: <20190722154210.42799-14-steven.price@arm.com>
On 07/22/2019 09:12 PM, Steven Price wrote:
> It is useful to be able to skip parts of the page table tree even when
> walking without VMAs. Add test_p?d callbacks similar to test_walk but
> which are called just before a table at that level is walked. If the
> callback returns non-zero then the entire table is skipped.
>
> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
> include/linux/mm.h | 11 +++++++++++
> mm/pagewalk.c | 24 ++++++++++++++++++++++++
> 2 files changed, 35 insertions(+)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index b22799129128..325a1ca6f820 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1447,6 +1447,11 @@ void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
> * value means "do page table walk over the current vma,"
> * and a negative one means "abort current page table walk
> * right now." 1 means "skip the current vma."
> + * @test_pmd: similar to test_walk(), but called for every pmd.
> + * @test_pud: similar to test_walk(), but called for every pud.
> + * @test_p4d: similar to test_walk(), but called for every p4d.
> + * Returning 0 means walk this part of the page tables,
> + * returning 1 means to skip this range.
> * @mm: mm_struct representing the target process of page table walk
> * @vma: vma currently walked (NULL if walking outside vmas)
> * @private: private data for callbacks' usage
> @@ -1471,6 +1476,12 @@ struct mm_walk {
> struct mm_walk *walk);
> int (*test_walk)(unsigned long addr, unsigned long next,
> struct mm_walk *walk);
> + int (*test_pmd)(unsigned long addr, unsigned long next,
> + pmd_t *pmd_start, struct mm_walk *walk);
> + int (*test_pud)(unsigned long addr, unsigned long next,
> + pud_t *pud_start, struct mm_walk *walk);
> + int (*test_p4d)(unsigned long addr, unsigned long next,
> + p4d_t *p4d_start, struct mm_walk *walk);
> struct mm_struct *mm;
> struct vm_area_struct *vma;
> void *private;
> diff --git a/mm/pagewalk.c b/mm/pagewalk.c
> index 1cbef99e9258..6bea79b95be3 100644
> --- a/mm/pagewalk.c
> +++ b/mm/pagewalk.c
> @@ -32,6 +32,14 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
> unsigned long next;
> int err = 0;
>
> + if (walk->test_pmd) {
> + err = walk->test_pmd(addr, end, pmd_offset(pud, 0UL), walk);
> + if (err < 0)
> + return err;
> + if (err > 0)
> + return 0;
> + }
Though this attempts to match semantics with test_walk() and be comprehensive
just wondering what are the real world situations when page walking need to be
aborted based on error condition at a given page table level.
next prev parent reply other threads:[~2019-07-28 13:40 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
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 [this message]
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
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:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=b74e545f-cbe0-9dd0-004c-5919e5cabb6f@arm.com \
--to=anshuman.khandual@arm.com \
--cc=Mark.Rutland@arm.com \
--cc=akpm@linux-foundation.org \
--cc=ard.biesheuvel@linaro.org \
--cc=arnd@arndb.de \
--cc=bp@alien8.de \
--cc=catalin.marinas@arm.com \
--cc=dave.hansen@linux.intel.com \
--cc=hpa@zytor.com \
--cc=james.morse@arm.com \
--cc=jglisse@redhat.com \
--cc=kan.liang@linux.intel.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=steven.price@arm.com \
--cc=tglx@linutronix.de \
--cc=will@kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).