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From: Jens Axboe <axboe@kernel.dk>
To: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Cc: hch@infradead.org, akpm@linux-foundation.org
Subject: [PATCHSET v2 0/3] Improve IOCB_NOWAIT O_DIRECT reads
Date: Mon,  8 Feb 2021 19:30:05 -0700	[thread overview]
Message-ID: <20210209023008.76263-1-axboe@kernel.dk> (raw)

Hi,

For v1, see:

https://lore.kernel.org/linux-fsdevel/20210208221829.17247-1-axboe@kernel.dk/

tldr; don't -EAGAIN IOCB_NOWAIT dio reads just because we have page cache
entries for the given range. This causes unnecessary work from the callers
side, when the IO could have been issued totally fine without blocking on
writeback when there is none.

 fs/iomap/direct-io.c | 23 ++++++++++++++--------
 include/linux/fs.h   |  2 ++
 mm/filemap.c         | 47 ++++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 62 insertions(+), 10 deletions(-)

Since v1:

- Simplify the filemap_range_needs_writeback() loop (Willy)
- Drop the write side (Chinner)

-- 
Jens Axboe



             reply	other threads:[~2021-02-09  2:31 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-09  2:30 Jens Axboe [this message]
2021-02-09  2:30 ` [PATCH 1/3] mm: provide filemap_range_needs_writeback() helper Jens Axboe
2021-02-09  7:47   ` Christoph Hellwig
2021-02-09 14:30     ` Jens Axboe
2021-02-09  2:30 ` [PATCH 2/3] mm: use filemap_range_needs_writeback() for O_DIRECT reads Jens Axboe
2021-02-09  7:48   ` Christoph Hellwig
2021-02-09 14:27     ` Jens Axboe
2021-02-09  2:30 ` [PATCH 3/3] iomap: " Jens Axboe
2021-02-09  7:51   ` Christoph Hellwig
2021-02-09 14:29     ` Jens Axboe
2021-02-09 19:55 ` [PATCHSET v2 0/3] Improve IOCB_NOWAIT " Andrew Morton
2021-02-09 20:11   ` Jens Axboe
2021-02-10  8:07     ` Sedat Dilek
2021-02-10  8:07       ` Sedat Dilek
2021-02-10 14:47       ` Jens Axboe

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