From: Christoph Hellwig <hch@infradead.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Peng Zhang <zhangpeng362@huawei.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
sidhartha.kumar@oracle.com, akpm@linux-foundation.org,
wangkefeng.wang@huawei.com, sunnanyong@huawei.com,
Kent Overstreet <kent.overstreet@gmail.com>
Subject: Re: [PATCH 2/6] mm/page_io: use a folio in sio_read_complete()
Date: Wed, 19 Jul 2023 22:22:33 -0700 [thread overview]
Message-ID: <ZLjEmULp8gQ4TkGf@infradead.org> (raw)
In-Reply-To: <ZLVEyG7SZMzgY7ov@casper.infradead.org>
On Mon, Jul 17, 2023 at 02:40:24PM +0100, Matthew Wilcox wrote:
> > for (p = 0; p < sio->pages; p++) {
> > - struct page *page = sio->bvec[p].bv_page;
> > + struct folio *folio = page_folio(sio->bvec[p].bv_page);
> >
> > - SetPageUptodate(page);
> > - unlock_page(page);
> > + folio_mark_uptodate(folio);
> > + folio_unlock(folio);
> > }
>
> I'm kind of shocked this works today. Usually bvecs coalesce adjacent
> pages into a single entry, so you need to use a real iterator like
> bio_for_each_folio_all() to extract individual pages from a bvec.
> Maybe the sio bvec is constructed inefficiently.
sio_read_complete is a kiocb.ki_complete handler. There is no
coalesce going on for ITER_BVEC iov_iters, which share nothing
but the underlying data structure with the block I/O path.
next prev parent reply other threads:[~2023-07-20 5:22 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-17 13:25 [PATCH 0/6] Convert several functions in page_io.c to use a folio Peng Zhang
2023-07-17 13:25 ` [PATCH 1/6] mm/page_io: use a folio in __end_swap_bio_read() Peng Zhang
2023-07-17 13:34 ` Matthew Wilcox
2023-07-18 12:56 ` zhangpeng (AS)
2023-07-18 16:16 ` Matthew Wilcox
2023-07-19 7:46 ` zhangpeng (AS)
2023-07-20 5:21 ` Christoph Hellwig
2023-07-17 13:25 ` [PATCH 2/6] mm/page_io: use a folio in sio_read_complete() Peng Zhang
2023-07-17 13:40 ` Matthew Wilcox
2023-07-18 12:58 ` zhangpeng (AS)
2023-07-18 16:21 ` Matthew Wilcox
2023-07-19 7:47 ` zhangpeng (AS)
2023-07-20 5:22 ` Christoph Hellwig [this message]
2023-07-17 13:25 ` [PATCH 3/6] mm/page_io: use a folio in swap_writepage_bdev_sync() Peng Zhang
2023-07-17 14:00 ` Matthew Wilcox
2023-07-17 13:26 ` [PATCH 4/6] mm/page_io: use a folio in swap_writepage_bdev_async() Peng Zhang
2023-07-17 14:01 ` Matthew Wilcox
2023-07-17 13:26 ` [PATCH 5/6] mm/page_io: convert count_swpout_vm_event() to take in a folio Peng Zhang
2023-07-17 13:48 ` Matthew Wilcox
2023-07-18 12:56 ` zhangpeng (AS)
2023-07-17 13:26 ` [PATCH 6/6] mm/page_io: convert bio_associate_blkg_from_page() " Peng Zhang
2023-07-17 13:46 ` Matthew Wilcox
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