From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Wei Yang <richardw.yang@linux.intel.com>
Cc: akpm@linux-foundation.org, kirill.shutemov@linux.intel.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] mm/page_vma_mapped: page table boundary is already guaranteed
Date: Thu, 28 Nov 2019 11:31:43 +0300 [thread overview]
Message-ID: <20191128083143.kwih655snxqa2qnm@box.shutemov.name> (raw)
In-Reply-To: <20191128010321.21730-2-richardw.yang@linux.intel.com>
On Thu, Nov 28, 2019 at 09:03:21AM +0800, Wei Yang wrote:
> The check here is to guarantee pvmw->address iteration is limited in one
> page table boundary. To be specific, here the address range should be in
> one PMD_SIZE.
>
> If my understanding is correct, this check is already done in the above
> check:
>
> address >= __vma_address(page, vma) + PMD_SIZE
>
> The boundary check here seems not necessary.
>
> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
NAK.
THP can be mapped with PTE not aligned to PMD_SIZE. Consider mremap().
> Test:
> more than 48 hours kernel build test shows this code is not touched.
Not an argument. I doubt mremap(2) is ever called in kernel build
workload.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2019-11-28 8:31 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-28 1:03 [PATCH 1/2] mm/page_vma_mapped: use PMD_SIZE instead of calculating it Wei Yang
2019-11-28 1:03 ` [PATCH 2/2] mm/page_vma_mapped: page table boundary is already guaranteed Wei Yang
2019-11-28 8:31 ` Kirill A. Shutemov [this message]
2019-11-28 21:09 ` Wei Yang
2019-11-28 22:39 ` Matthew Wilcox
2019-11-29 8:30 ` Wei Yang
2019-11-29 11:18 ` Matthew Wilcox
2019-12-02 6:53 ` Wei Yang
2019-11-28 8:32 ` [PATCH 1/2] mm/page_vma_mapped: use PMD_SIZE instead of calculating it Kirill A. Shutemov
2019-11-28 21:22 ` Wei Yang
2019-12-02 8:03 ` Kirill A. Shutemov
2019-12-02 8:54 ` Wei Yang
2019-12-02 22:21 ` Wei Yang
2019-12-03 9:47 ` Kirill A. Shutemov
2019-12-03 15:14 ` Wei Yang
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