From: Ken Raeburn <raeburn@permabit.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: fio@vger.kernel.org
Subject: Re: fio --direct=1 and Linux page cache effects
Date: Mon, 10 Dec 2012 20:00:28 -0500 [thread overview]
Message-ID: <6evcc9bdxv.fsf@just-testing.permabit.com> (raw)
In-Reply-To: <50C1B02F.3000902@kernel.dk> (Jens Axboe's message of "Fri, 07 Dec 2012 10:00:31 +0100")
Jens Axboe <axboe@kernel.dk> writes:
> Another idea would be to ensure that we do the bdev cache invalidation
> at a safe point. But that is done at open time right now, which should
> invalidate any cache mappings for the device. If the file close triggers
> blkid and there are no further opens of the device, then those mappings
> would remain.
>
> Would the below work for you?
It looks like it's not enough; the BLKFLSBUF ioctl winds up happening
before blkid runs. I added some instrumentation to the patch and saw
that one thread took the "f->fd != -1" path and then, after
add_file_hash failed, came back to the "from_hash" path. But all of that
seems to finish before blkid gets going, so the pages it pulls in still
won't get invalidated.
Ken
next prev parent reply other threads:[~2012-12-11 1:00 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-05 0:23 fio --direct=1 and Linux page cache effects Ken Raeburn
2012-12-06 21:06 ` Jens Axboe
2012-12-07 9:00 ` Jens Axboe
2012-12-11 1:00 ` Ken Raeburn [this message]
2012-12-11 13:29 ` Jens Axboe
2012-12-11 20:10 ` Ken Raeburn
2012-12-12 7:24 ` Jens Axboe
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