From: Alex Elder <aelder@sgi.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 3/4] xfs: replace i_pin_wait with a bit waitqueue
Date: Wed, 26 Oct 2011 16:07:33 -0500 [thread overview]
Message-ID: <1319663253.5239.75.camel@doink> (raw)
In-Reply-To: <20111019182421.048260722@bombadil.infradead.org>
On Wed, 2011-10-19 at 14:23 -0400, Christoph Hellwig wrote:
> Replace i_pin_wait, which is only used during synchronous inode flushing
> with a bit waitqueue. This trades off a much smaller inode against
> slightly slower wakeup performance, and saves 12 (32-bit) or 20 (64-bit)
> bytes in the XFS inode.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
One minor suggestion, plus some discussion from
inside my head below.
Reviewed-by: Alex Elder <aelder@sgi.com>
. . .
> @@ -2163,14 +2163,29 @@ xfs_iunpin_nowait(
>
> }
>
> +static void
> +__xfs_iunpin_wait(
> + struct xfs_inode *ip)
> +{
> + wait_queue_head_t *wq = bit_waitqueue(&ip->i_flags, __XFS_IPINNED_BIT);
> + DEFINE_WAIT_BIT(q, &ip->i_flags, __XFS_IPINNED_BIT);
In your last patch, you used "wait" as the name
rather than "q". Minor consistency nit...
> + xfs_iunpin(ip);
> +
This initially struck me as unsafe or something,
assuming the inode was pinned. But I was thinking
of it more like an unlock request, which it is not.
It's more like unplugging something so the inode
will eventually get unpinned. (Just thinking aloud
here, nevermind me...)
> + do {
> + prepare_to_wait(wq, &q.wait, TASK_UNINTERRUPTIBLE);
> + if (xfs_ipincount(ip))
> + io_schedule();
> + } while (xfs_ipincount(ip));
> + finish_wait(wq, &q.wait);
> +}
> +
. . .
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next prev parent reply other threads:[~2011-10-26 21:07 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-19 18:23 [PATCH 0/4] inode diet, part1 V2 Christoph Hellwig
2011-10-19 18:23 ` [PATCH 1/4] xfs: make i_flags and unsigned long Christoph Hellwig
2011-10-26 21:07 ` Alex Elder
2011-10-19 18:23 ` [PATCH 2/4] xfs: replace i_flock with a sleeping bitlock Christoph Hellwig
2011-10-26 21:07 ` Alex Elder
2011-10-19 18:23 ` [PATCH 3/4] xfs: replace i_pin_wait with a bit waitqueue Christoph Hellwig
2011-10-26 21:07 ` Alex Elder [this message]
2011-10-27 16:42 ` Christoph Hellwig
2011-10-19 18:23 ` [PATCH 4/4] xfs: remove the unused dm_attrs structure Christoph Hellwig
2011-10-26 21:07 ` Alex Elder
-- strict thread matches above, loose matches on Subject: below --
2011-10-18 20:13 [PATCH 0/4] inode diet, part1 Christoph Hellwig
2011-10-18 20:13 ` [PATCH 3/4] xfs: replace i_pin_wait with a bit waitqueue Christoph Hellwig
2011-10-19 0:50 ` Dave Chinner
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