From: Christoph Hellwig <hch@infradead.org>
To: David Howells <dhowells@redhat.com>
Cc: 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>,
David Hildenbrand <david@redhat.com>,
Jason Gunthorpe <jgg@nvidia.com>,
Logan Gunthorpe <logang@deltatee.com>,
Hillf Danton <hdanton@sina.com>,
Christian Brauner <brauner@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.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 02:51:59 -0700 [thread overview]
Message-ID: <ZG8vvzbUdFmsLv5Z@infradead.org> (raw)
In-Reply-To: <3215177.1684918030@warthog.procyon.org.uk>
On Wed, May 24, 2023 at 09:47:10AM +0100, David Howells wrote:
> True - but I was thinking of just treating the zero_page specially and never
> hold a pin or a ref on it. It can be checked by address, e.g.:
>
> static inline void bio_release_page(struct bio *bio, struct page *page)
> {
> if (page == ZERO_PAGE(0))
> return;
> if (bio_flagged(bio, BIO_PAGE_PINNED))
> unpin_user_page(page);
> else if (bio_flagged(bio, BIO_PAGE_REFFED))
> put_page(page);
> }
That does sound good as well to me.
> I was looking at this:
>
> static inline void dio_bio_submit(struct dio *dio, struct dio_submit *sdio)
> {
> ...
> if (dio->is_async && dio_op == REQ_OP_READ && dio->should_dirty)
> bio_set_pages_dirty(bio);
> ...
> }
>
> but looking again, the lock is taken briefly and the dirty bit is set - which
> is reasonable. However, should we be doing it before starting the I/O?
It is done before starting the I/O - the submit_bio is just below this.
next prev parent reply other threads:[~2023-05-25 9:52 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 [this message]
2023-05-25 16:31 ` Linus Torvalds
2023-05-25 16:45 ` David Hildenbrand
2023-05-25 17:04 ` Linus Torvalds
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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