From: Christoph Hellwig <hch@infradead.org>
To: Rik van Riel <riel@surriel.com>
Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com,
Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@kernel.org>,
Jason Gunthorpe <jgg@ziepe.ca>,
John Hubbard <jhubbard@nvidia.com>, Peter Xu <peterx@redhat.com>,
linux-mm@kvack.org
Subject: Re: [RFC PATCH v3 0/8] batch lookups in follow_page_mask()
Date: Tue, 25 Aug 2026 00:52:32 -0700 [thread overview]
Message-ID: <ao1JwEAeNcP9OyKR@infradead.org> (raw)
In-Reply-To: <20260811025157.1632867-1-riel@surriel.com>
On Mon, Aug 10, 2026 at 10:51:49PM -0400, Rik van Riel wrote:
> follow_page_mask() walks the page tables one page at a time, even when the
> caller asked for a whole run of contiguous pages. Every page of a large folio
> re-enters the pmd/pud/pte walk and re-takes the page table lock.
>
> This series changes follow_page_mask() to return a page count and a fill an
> array of pages, instead of a single struct page, so a walker can hand back
> more than one page per call.
And what many including the most performance critical callers want
instead is really a single bio_vec. Maybe we can go the extra step for
that, as it would reduce the number of calls into gup significantly.
next prev parent reply other threads:[~2026-08-25 7:52 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-11 2:51 [RFC PATCH v3 0/8] batch lookups in follow_page_mask() Rik van Riel
2026-08-11 2:51 ` [RFC PATCH v3 1/8] mm/gup: break out gup_fill_pages() helper Rik van Riel
2026-08-11 2:51 ` [RFC PATCH v3 2/8] mm/gup: convert follow_page_mask() to return a long Rik van Riel
2026-08-11 2:51 ` [RFC PATCH v3 3/8] mm/gup: split follow_page_pte_commit() out of follow_page_pte() Rik van Riel
2026-08-12 11:50 ` David Hildenbrand (Arm)
2026-08-12 13:02 ` Rik van Riel
2026-08-12 13:23 ` David Hildenbrand (Arm)
2026-08-12 16:19 ` Rik van Riel
2026-08-21 17:38 ` Rik van Riel
2026-08-21 22:04 ` John Hubbard
2026-08-22 13:20 ` Rik van Riel
2026-08-22 21:31 ` John Hubbard
2026-08-24 13:20 ` Rik van Riel
2026-08-11 2:51 ` [RFC PATCH v3 4/8] mm/gup: break out follow_one_pte() helper Rik van Riel
2026-08-11 2:51 ` [RFC PATCH v3 5/8] mm/gup: fill the pages array outside the pud/pmd lock Rik van Riel
2026-08-11 2:51 ` [RFC PATCH v3 6/8] mm/gup: return a huge page's full count from follow_page_mask() Rik van Riel
2026-08-11 2:51 ` [RFC PATCH v3 7/8] mm/gup: walk multiple PTEs per follow_page_pte() call Rik van Riel
2026-08-11 2:51 ` [RFC PATCH v3 8/8] mm/gup: batch contiguous same-folio PTEs into one refcount grab Rik van Riel
2026-08-12 11:41 ` [RFC PATCH v3 0/8] batch lookups in follow_page_mask() David Hildenbrand (Arm)
2026-08-25 7:52 ` Christoph Hellwig [this message]
2026-08-25 13:37 ` Rik van Riel
2026-08-26 4:39 ` Christoph Hellwig
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