From: Linus Torvalds <torvalds@linux-foundation.org>
To: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>,
Christoph Hellwig <hch@infradead.org>,
Jens Axboe <axboe@kernel.dk>, Al Viro <viro@zeniv.linux.org.uk>,
Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
Jeff Layton <jlayton@kernel.org>,
Jason Gunthorpe <jgg@nvidia.com>,
Logan Gunthorpe <logang@deltatee.com>,
Hillf Danton <hdanton@sina.com>,
Christian Brauner <brauner@kernel.org>,
linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: Extending page pinning into fs/direct-io.c
Date: Thu, 25 May 2023 10:04:53 -0700 [thread overview]
Message-ID: <CAHk-=wgPWUCyhiM+=S3nmh4JK8qtBQteYvtiXpoYpDjfKHnEhQ@mail.gmail.com> (raw)
In-Reply-To: <e00ee9f5-0f02-6463-bc84-b94c17f488bc@redhat.com>
On Thu, May 25, 2023 at 9:45 AM David Hildenbrand <david@redhat.com> wrote:
>
> I think the correct way to test for a zero page is
> is_zero_pfn(page_to_pfn(page).
Yeah. Except it's really ugly and strange, and we should probably add
a helper for that pattern.
The reason it has that odd "look at pfn" is just because I think the
first users were in the page table code, which had the pfn already,
and the test is basically based on the zero_page_mask thing that the
affected architectures have.
So I suspect we should add that
is_zero_pfn(page_to_pfn(page))
as a helper inline function rather than write it out even more times
(that "is this 'struct page' a zero page" pattern already exists in
/proc and a few other places.
is_longterm_pinnable_page() already has it, so adding it as a helper
there in <linux/mm.h> is probably a good idea.
Linus
next prev parent reply other threads:[~2023-05-25 17:05 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-22 20:57 [PATCH v21 0/6] block: Use page pinning David Howells
2023-05-22 20:57 ` [PATCH v21 1/6] iomap: Don't get an reference on ZERO_PAGE for direct I/O block zeroing David Howells
2023-05-23 8:07 ` Jan Kara
2023-05-23 12:35 ` Christian Brauner
2023-05-22 20:57 ` [PATCH v21 2/6] block: Fix bio_flagged() so that gcc can better optimise it David Howells
2023-05-23 8:07 ` Jan Kara
2023-05-23 12:37 ` Christian Brauner
2023-05-22 20:57 ` [PATCH v21 3/6] block: Replace BIO_NO_PAGE_REF with BIO_PAGE_REFFED with inverted logic David Howells
2023-05-23 8:07 ` Jan Kara
2023-05-22 20:57 ` [PATCH v21 4/6] block: Add BIO_PAGE_PINNED and associated infrastructure David Howells
2023-05-23 8:08 ` Jan Kara
2023-05-22 20:57 ` [PATCH v21 5/6] block: Convert bio_iov_iter_get_pages to use iov_iter_extract_pages David Howells
2023-05-23 8:15 ` Jan Kara
2023-05-22 20:57 ` [PATCH v21 6/6] block: convert bio_map_user_iov " David Howells
2023-05-23 8:14 ` Jan Kara
2023-05-23 6:39 ` [PATCH v21 0/6] block: Use page pinning Christoph Hellwig
2023-05-23 20:16 ` Extending page pinning into fs/direct-io.c David Howells
2023-05-24 5:55 ` Christoph Hellwig
2023-05-24 7:06 ` David Hildenbrand
2023-05-24 8:47 ` David Howells
2023-05-25 9:51 ` Christoph Hellwig
2023-05-25 16:31 ` Linus Torvalds
2023-05-25 16:45 ` David Hildenbrand
2023-05-25 17:04 ` Linus Torvalds [this message]
2023-05-25 17:15 ` David Howells
2023-05-25 17:25 ` Linus Torvalds
2023-05-25 17:07 ` David Howells
2023-05-25 17:17 ` Linus Torvalds
2023-05-25 17:00 ` David Howells
2023-05-25 17:13 ` Linus Torvalds
2023-05-23 21:38 ` [PATCH v21 0/6] block: Use page pinning Jens Axboe
2023-05-24 5:52 ` Christoph Hellwig
2023-05-24 14:43 ` Jens Axboe
2023-05-24 7:35 ` David Howells
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