From: Zi Yan <ziy@nvidia.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Matthew Wilcox <willy@infradead.org>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@lst.de>,
Eric Biggers <ebiggers@kernel.org>
Subject: Re: [PATCH] mm: Move nth_page from folio_page into folio_next
Date: Thu, 13 Mar 2025 21:40:02 -0400 [thread overview]
Message-ID: <EBEF95E8-92ED-4381-A001-E7206FD0E1A7@nvidia.com> (raw)
In-Reply-To: <Z9OD5MsHZnzG4Smt@gondor.apana.org.au>
On 13 Mar 2025, at 21:18, Herbert Xu wrote:
> On Thu, Mar 13, 2025 at 12:25:50PM +0000, Matthew Wilcox wrote:
>>
>> That isn't true. HugeTLB can construct a folio which crosses a
>> contiguity boundary.
>
> Thanks. So thea means we do need to use nth_page when iterating
> through a folio or a scatterlist generated from a folio.
When you know the folio is hugetlb with gigantic order. Folios
come out of buddy allocator are all within contiguity boundaries.
To be precise, the boundary here means a section boundary.
In addition, nth_page() is a trivial addition for SPARSEMEM_VMEMMAP
or FLATMEM. For SPARSEMEM && !SPARSEMEM_VMEMMAP, it needs to use
pfn for the calculation.
Best Regards,
Yan, Zi
prev parent reply other threads:[~2025-03-14 1:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-13 4:40 Herbert Xu
2025-03-13 12:25 ` Matthew Wilcox
2025-03-14 1:18 ` Herbert Xu
2025-03-14 1:40 ` Zi Yan [this message]
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