From: John Hubbard <jhubbard@nvidia.com>
To: "Matthew Wilcox (Oracle)" <willy@infradead.org>, linux-mm@kvack.org
Cc: Christoph Hellwig <hch@infradead.org>,
William Kucharski <william.kucharski@oracle.com>,
linux-kernel@vger.kernel.org, Jason Gunthorpe <jgg@ziepe.ca>
Subject: Re: [PATCH v2 07/28] gup: Remove an assumption of a contiguous memmap
Date: Mon, 10 Jan 2022 19:27:47 -0800 [thread overview]
Message-ID: <cd1ea34d-340c-86c2-16d8-94e689e3edb5@nvidia.com> (raw)
In-Reply-To: <20220110042406.499429-8-willy@infradead.org>
On 1/9/22 20:23, Matthew Wilcox (Oracle) wrote:
> This assumption needs the inverse of nth_page(), which I've temporarily
> named page_nth() until someone comes up with a better name.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
> include/linux/mm.h | 2 ++
> mm/gup.c | 4 ++--
> 2 files changed, 4 insertions(+), 2 deletions(-)
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Maybe a better name for page_nth() will come to mind by the time I
reach the end of this series, we'll see. :)
thanks,
--
John Hubbard
NVIDIA
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index d8b7d7ed14dd..f2f3400665a4 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -216,8 +216,10 @@ int overcommit_policy_handler(struct ctl_table *, int, void *, size_t *,
>
> #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
> #define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
> +#define page_nth(head, tail) (page_to_pfn(tail) - page_to_pfn(head))
> #else
> #define nth_page(page,n) ((page) + (n))
> +#define page_nth(head, tail) ((tail) - (head))
> #endif
>
> /* to align the pointer to the (next) page boundary */
> diff --git a/mm/gup.c b/mm/gup.c
> index 9c0a702a4e03..afb638a30e44 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -238,8 +238,8 @@ static inline struct page *compound_range_next(unsigned long i,
> next = nth_page(start, i);
> page = compound_head(next);
> if (PageHead(page))
> - nr = min_t(unsigned int,
> - page + compound_nr(page) - next, npages - i);
> + nr = min_t(unsigned int, npages - i,
> + compound_nr(page) - page_nth(page, next));
>
> *ntails = nr;
> return page;
next prev parent reply other threads:[~2022-01-11 3:27 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-10 4:23 [PATCH v2 00/28] Convert GUP to folios Matthew Wilcox (Oracle)
2022-01-10 4:23 ` [PATCH v2 01/28] gup: Remove for_each_compound_range() Matthew Wilcox (Oracle)
2022-01-10 8:22 ` Christoph Hellwig
2022-01-11 1:07 ` John Hubbard
2022-01-10 4:23 ` [PATCH v2 02/28] gup: Remove for_each_compound_head() Matthew Wilcox (Oracle)
2022-01-10 8:23 ` Christoph Hellwig
2022-01-11 1:11 ` John Hubbard
2022-01-10 4:23 ` [PATCH v2 03/28] gup: Change the calling convention for compound_range_next() Matthew Wilcox (Oracle)
2022-01-10 8:25 ` Christoph Hellwig
2022-01-11 1:14 ` John Hubbard
2022-01-10 4:23 ` [PATCH v2 04/28] gup: Optimise compound_range_next() Matthew Wilcox (Oracle)
2022-01-10 8:26 ` Christoph Hellwig
2022-01-11 1:16 ` John Hubbard
2022-01-10 4:23 ` [PATCH v2 05/28] gup: Change the calling convention for compound_next() Matthew Wilcox (Oracle)
2022-01-10 8:27 ` Christoph Hellwig
2022-01-10 13:28 ` Matthew Wilcox
2022-01-11 1:18 ` John Hubbard
2022-01-10 4:23 ` [PATCH v2 06/28] gup: Fix some contiguous memmap assumptions Matthew Wilcox (Oracle)
2022-01-10 8:29 ` Christoph Hellwig
2022-01-10 13:37 ` Matthew Wilcox
2022-01-10 19:05 ` [External] : " Mike Kravetz
2022-01-11 1:47 ` John Hubbard
2022-01-10 4:23 ` [PATCH v2 07/28] gup: Remove an assumption of a contiguous memmap Matthew Wilcox (Oracle)
2022-01-10 8:30 ` Christoph Hellwig
2022-01-11 3:27 ` John Hubbard [this message]
2022-01-10 4:23 ` [PATCH v2 08/28] gup: Handle page split race more efficiently Matthew Wilcox (Oracle)
2022-01-10 8:31 ` Christoph Hellwig
2022-01-11 3:30 ` John Hubbard
2022-01-10 4:23 ` [PATCH v2 09/28] gup: Turn hpage_pincount_add() into page_pincount_add() Matthew Wilcox (Oracle)
2022-01-10 8:31 ` Christoph Hellwig
2022-01-11 3:35 ` John Hubbard
2022-01-11 4:32 ` John Hubbard
2022-01-11 13:46 ` Matthew Wilcox
2022-01-10 4:23 ` [PATCH v2 10/28] gup: Turn hpage_pincount_sub() into page_pincount_sub() Matthew Wilcox (Oracle)
2022-01-10 8:32 ` Christoph Hellwig
2022-01-11 6:40 ` John Hubbard
2022-01-10 4:23 ` [PATCH v2 11/28] mm: Make compound_pincount always available Matthew Wilcox (Oracle)
2022-01-11 4:06 ` John Hubbard
2022-01-11 4:38 ` Matthew Wilcox
2022-01-11 5:10 ` John Hubbard
2022-01-20 9:15 ` Christoph Hellwig
2022-01-10 4:23 ` [PATCH v2 12/28] mm: Add folio_put_refs() Matthew Wilcox (Oracle)
2022-01-10 8:32 ` Christoph Hellwig
2022-01-11 4:14 ` John Hubbard
2022-01-10 4:23 ` [PATCH v2 13/28] mm: Add folio_pincount_ptr() Matthew Wilcox (Oracle)
2022-01-10 8:33 ` Christoph Hellwig
2022-01-11 4:22 ` John Hubbard
2022-01-10 4:23 ` [PATCH v2 14/28] mm: Convert page_maybe_dma_pinned() to use a folio Matthew Wilcox (Oracle)
2022-01-10 8:33 ` Christoph Hellwig
2022-01-11 4:27 ` John Hubbard
2022-01-10 4:23 ` [PATCH v2 15/28] gup: Add try_get_folio() and try_grab_folio() Matthew Wilcox (Oracle)
2022-01-10 8:34 ` Christoph Hellwig
2022-01-11 5:00 ` John Hubbard
2022-01-10 4:23 ` [PATCH v2 16/28] mm: Remove page_cache_add_speculative() and page_cache_get_speculative() Matthew Wilcox (Oracle)
2022-01-10 8:35 ` Christoph Hellwig
2022-01-11 5:14 ` John Hubbard
2022-01-10 4:23 ` [PATCH v2 17/28] gup: Add gup_put_folio() Matthew Wilcox (Oracle)
2022-01-10 8:35 ` Christoph Hellwig
2022-01-11 6:44 ` John Hubbard
2022-01-10 4:23 ` [PATCH v2 18/28] hugetlb: Use try_grab_folio() instead of try_grab_compound_head() Matthew Wilcox (Oracle)
2022-01-10 8:36 ` Christoph Hellwig
2022-01-11 6:47 ` John Hubbard
2022-01-10 4:23 ` [PATCH v2 19/28] gup: Convert try_grab_page() to call try_grab_folio() Matthew Wilcox (Oracle)
2022-01-10 8:36 ` Christoph Hellwig
2022-01-11 7:01 ` John Hubbard
2022-01-10 4:23 ` [PATCH v2 20/28] gup: Convert gup_pte_range() to use a folio Matthew Wilcox (Oracle)
2022-01-10 8:37 ` Christoph Hellwig
2022-01-11 7:06 ` John Hubbard
2022-01-10 4:23 ` [PATCH v2 21/28] gup: Convert gup_hugepte() " Matthew Wilcox (Oracle)
2022-01-10 8:37 ` Christoph Hellwig
2022-01-11 7:33 ` John Hubbard
2022-01-10 4:24 ` [PATCH v2 22/28] gup: Convert gup_huge_pmd() " Matthew Wilcox (Oracle)
2022-01-10 8:37 ` Christoph Hellwig
2022-01-11 7:36 ` John Hubbard
2022-01-10 4:24 ` [PATCH v2 23/28] gup: Convert gup_huge_pud() " Matthew Wilcox (Oracle)
2022-01-10 8:38 ` Christoph Hellwig
2022-01-11 7:38 ` John Hubbard
2022-01-10 4:24 ` [PATCH v2 24/28] gup: Convert gup_huge_pgd() " Matthew Wilcox (Oracle)
2022-01-10 8:38 ` Christoph Hellwig
2022-01-11 7:38 ` John Hubbard
2022-01-10 4:24 ` [PATCH v2 25/28] gup: Convert compound_next() to gup_folio_next() Matthew Wilcox (Oracle)
2022-01-10 8:39 ` Christoph Hellwig
2022-01-11 7:41 ` John Hubbard
2022-01-10 4:24 ` [PATCH v2 26/28] gup: Convert compound_range_next() to gup_folio_range_next() Matthew Wilcox (Oracle)
2022-01-10 8:41 ` Christoph Hellwig
2022-01-10 13:41 ` Matthew Wilcox
2022-01-11 7:44 ` John Hubbard
2022-01-10 4:24 ` [PATCH v2 27/28] mm: Add isolate_lru_folio() Matthew Wilcox (Oracle)
2022-01-10 8:42 ` Christoph Hellwig
2022-01-11 7:49 ` John Hubbard
2022-01-10 4:24 ` [PATCH v2 28/28] gup: Convert check_and_migrate_movable_pages() to use a folio Matthew Wilcox (Oracle)
2022-01-10 8:42 ` Christoph Hellwig
2022-01-11 7:52 ` John Hubbard
2022-01-10 15:31 ` [PATCH v2 00/28] Convert GUP to folios Jason Gunthorpe
2022-01-10 16:09 ` Matthew Wilcox
2022-01-10 17:26 ` William Kucharski
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