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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	linux-block <linux-block@vger.kernel.org>,
	Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH 3/3] io_uring: add io_uring_event cache hit information
Date: Fri, 15 Mar 2019 18:34:35 -0700	[thread overview]
Message-ID: <CAHk-=wg3iyLvh4L2us0WZc18UPKwFtZYA2L5h3OnP01a+T+59w@mail.gmail.com> (raw)
In-Reply-To: <aa0e7a3a-d7dc-2b6e-5a2c-adf99aab27a6@kernel.dk>

On Fri, Mar 15, 2019 at 9:27 AM Jens Axboe <axboe@kernel.dk> wrote:
>
> Linus, curious on your opinion on this one. I had this as part of the
> original series, but removed it from the pull request due to the
> mincore etc discussions.

I'd rather not have new ways to leak cache information, and in fact
already the IOCB_NOWAIT is a bit questionable for that. But afaik, the
non-O_DIRECT paths don't even support it to begin with for some
filesystems.

Wasn't the whole point of this io_ring that we'd move *away* from
direct block access and O_DIRECT?

I'm seeing a lot of stuff that looks like just "more of the same old
O_DIRECT garbage" that seems to be all about thinking that IO doesn't
cache.

Haven't we gotten over that already? It was one of the arguments you
used for io_ring to begin with.

                      Linus

  reply	other threads:[~2019-03-16  1:38 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-15 14:59 [PATCHSET 0/3] io_uring improvements Jens Axboe
2019-03-15 14:59 ` [PATCH 1/3] iov_iter: add ITER_BVEC_FLAG_NO_REF flag Jens Axboe
2019-03-15 14:59 ` [PATCH 2/3] block: add BIO_NO_PAGE_REF flag Jens Axboe
2019-03-15 14:59 ` [PATCH 3/3] io_uring: add io_uring_event cache hit information Jens Axboe
2019-03-15 16:27   ` Jens Axboe
2019-03-16  1:34     ` Linus Torvalds [this message]
2019-03-16 16:27       ` Jens Axboe

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