From: Zi Yan <ziy@nvidia.com>
To: Ryan Roberts <ryan.roberts@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
SeongJae Park <sj@kernel.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
damon@lists.linux.dev
Subject: Re: [RESEND PATCH v1 2/5] mm: damon must atomically clear young on ptes and pmds
Date: Thu, 11 May 2023 11:01:12 -0400 [thread overview]
Message-ID: <9F292AC7-6632-437B-9F9F-DB3CC10240E7@nvidia.com> (raw)
In-Reply-To: <20230511132113.80196-3-ryan.roberts@arm.com>
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On 11 May 2023, at 9:21, Ryan Roberts wrote:
> It is racy to non-atomically read a pte, then clear the young bit, then
> write it back as this could discard dirty information. Further, it is
> bad practice to directly set a pte entry within a table. Instead
> clearing young must go through the arch-provided helper,
> ptep_test_and_clear_young() to ensure it is modified atomically and to
> give the arch code visibility and allow it to validate (and potentially
> modify) the operation.
>
> Fixes: 46c3a0accdc4 ("mm/damon/vaddr: separate commonly usable functions")
> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
> ---
> mm/damon/ops-common.c | 16 ++++++----------
> mm/damon/ops-common.h | 4 ++--
> mm/damon/paddr.c | 4 ++--
> mm/damon/vaddr.c | 4 ++--
> 4 files changed, 12 insertions(+), 16 deletions(-)
>
LGTM. Reviewed-by: Zi Yan <ziy@nvidia.com>
--
Best Regards,
Yan, Zi
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next prev parent reply other threads:[~2023-05-11 15:01 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-11 13:21 [RESEND PATCH v1 0/5] Encapsulate PTE contents from non-arch code Ryan Roberts
2023-05-11 13:21 ` [RESEND PATCH v1 1/5] mm: vmalloc must set pte via arch code Ryan Roberts
2023-05-11 15:00 ` Zi Yan
2023-05-12 11:01 ` Ryan Roberts
2023-05-13 13:14 ` Lorenzo Stoakes
2023-05-15 8:29 ` Ryan Roberts
2023-05-15 11:25 ` Lorenzo Stoakes
2023-05-15 12:14 ` Ryan Roberts
2023-05-17 6:20 ` Christoph Hellwig
2023-05-17 6:23 ` Lorenzo Stoakes
2023-05-17 6:18 ` Christoph Hellwig
2023-05-11 13:21 ` [RESEND PATCH v1 2/5] mm: damon must atomically clear young on ptes and pmds Ryan Roberts
2023-05-11 15:01 ` Zi Yan [this message]
2023-05-11 13:21 ` [RESEND PATCH v1 3/5] mm: Fix failure to unmap pte on highmem systems Ryan Roberts
2023-05-11 15:01 ` Zi Yan
2023-05-11 13:21 ` [RESEND PATCH v1 4/5] mm: Add new ptep_deref() helper to fully encapsulate pte_t Ryan Roberts
2023-05-11 13:21 ` [RESEND PATCH v1 5/5] mm: ptep_deref() conversion Ryan Roberts
2023-05-11 17:37 ` kernel test robot
2023-05-12 10:50 ` Ryan Roberts
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