From: Ben Myers <bpm@sgi.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 06/11] xfs: replace i_flock with a sleeping bitlock
Date: Fri, 13 Jan 2012 15:49:41 -0600 [thread overview]
Message-ID: <20120113214941.GA16386@sgi.com> (raw)
In-Reply-To: <20111218200131.745039484@bombadil.infradead.org>
On Sun, Dec 18, 2011 at 03:00:09PM -0500, Christoph Hellwig wrote:
> Index: xfs/fs/xfs/xfs_inode.c
> ===================================================================
> --- xfs.orig/fs/xfs/xfs_inode.c 2011-12-18 08:05:01.469974560 -0800
> +++ xfs/fs/xfs/xfs_inode.c 2011-12-18 08:06:23.266640737 -0800
...
> -/*
> * In-core inode flags.
> */
> -#define XFS_IRECLAIM 0x0001 /* started reclaiming this inode */
> -#define XFS_ISTALE 0x0002 /* inode has been staled */
> -#define XFS_IRECLAIMABLE 0x0004 /* inode can be reclaimed */
> -#define XFS_INEW 0x0008 /* inode has just been allocated */
> -#define XFS_IFILESTREAM 0x0010 /* inode is in a filestream directory */
> -#define XFS_ITRUNCATED 0x0020 /* truncated down so flush-on-close */
> -#define XFS_IDIRTY_RELEASE 0x0040 /* dirty release already seen */
> +#define XFS_IRECLAIM (1 << 0) /* started reclaiming this inode */
> +#define XFS_ISTALE (1 << 1) /* inode has been staled */
> +#define XFS_IRECLAIMABLE (1 << 2) /* inode can be reclaimed */
> +#define XFS_INEW (1 << 3) /* inode has just been allocated */
> +#define XFS_IFILESTREAM (1 << 4) /* inode is in a filestream dir. */
> +#define XFS_ITRUNCATED (1 << 5) /* truncated down so flush-on-close */
> +#define XFS_IDIRTY_RELEASE (1 << 6) /* dirty release already seen */
> +#define __XFS_IFLOCK_BIT 7 /* inode is being flushed right now */
> +#define XFS_IFLOCK (1 << __XFS_IFLOCK_BIT)
Nice.
> +static inline void xfs_iflock(struct xfs_inode *ip)
> +{
> + if (!xfs_iflock_nowait(ip))
> + __xfs_iflock(ip);
> +}
Going after the iflock nowait first seems a little silly, but I'm
guessing that you're trying to avoid touching the zone wait_table in
bit_waitqueue if you can avoid it, along with the rest of the overhead
related to seeting up the wait queue in __xfs_iflock.
> +
> +static inline void xfs_ifunlock(struct xfs_inode *ip)
> +{
> + xfs_iflags_clear(ip, XFS_IFLOCK);
> + wake_up_bit(&ip->i_flags, __XFS_IFLOCK_BIT);
> +}
I was going to suggest this:
spin_lock(&ip->i_flags_lock);
ip->i_flags &= ~XFS_IFLOCK;
wake_up_bit(...
spin_unlock(&ip->i_flags_lock);
After some study I believe what you have is ok:
Say this is process A. If process B got the lock after A cleared IFLOCK
and before A wake_up_bit wakes process C. C will just go back to sleep
in __xfs_iflock until B calls xfs_ifunlock to wake C again.
Looks good.
Reviewed-by: Ben Myers <bpm@sgi.com>
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next prev parent reply other threads:[~2012-01-13 21:49 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-18 20:00 [PATCH 00/11] inode shrink and misc updates V2 Christoph Hellwig
2011-12-18 20:00 ` [PATCH 01/11] xfs: remove xfs_itruncate_data Christoph Hellwig
2012-01-03 21:53 ` Ben Myers
2012-01-04 9:27 ` Christoph Hellwig
2011-12-18 20:00 ` [PATCH 02/11] xfs: cleanup xfs_iomap_eof_align_last_fsb Christoph Hellwig
2012-01-04 20:32 ` Ben Myers
2011-12-18 20:00 ` [PATCH 03/11] xfs: remove the unused dm_attrs structure Christoph Hellwig
2012-01-04 21:13 ` Ben Myers
2011-12-18 20:00 ` [PATCH 04/11] xfs: remove the if_ext_max field in struct xfs_ifork Christoph Hellwig
2012-01-06 16:58 ` Ben Myers
2012-01-16 22:45 ` Ben Myers
2012-01-17 15:16 ` Ben Myers
2012-01-17 17:04 ` Mark Tinguely
2011-12-18 20:00 ` [PATCH 05/11] xfs: make i_flags an unsigned long Christoph Hellwig
2011-12-18 20:00 ` [PATCH 06/11] xfs: replace i_flock with a sleeping bitlock Christoph Hellwig
2012-01-13 21:49 ` Ben Myers [this message]
2011-12-18 20:00 ` [PATCH 07/11] xfs: replace i_pin_wait with a bit waitqueue Christoph Hellwig
2012-01-13 22:42 ` Ben Myers
2011-12-18 20:00 ` [PATCH 08/11] xfs: remove the i_size field in struct xfs_inode Christoph Hellwig
2012-01-16 18:32 ` Ben Myers
2012-01-16 19:45 ` Ben Myers
2011-12-18 20:00 ` [PATCH 09/11] xfs: remove the i_new_size " Christoph Hellwig
2011-12-18 22:13 ` Dave Chinner
2012-01-16 22:41 ` Ben Myers
2012-01-17 20:14 ` Ben Myers
2011-12-18 20:00 ` [PATCH 10/11] xfs: always return with the iolock held from xfs_file_aio_write_checks Christoph Hellwig
2012-01-17 20:18 ` Ben Myers
2012-01-20 12:51 ` Jeff Liu
2011-12-18 20:00 ` [PATCH 11/11] xfs: cleanup xfs_file_aio_write Christoph Hellwig
2012-01-17 20:42 ` Ben Myers
-- strict thread matches above, loose matches on Subject: below --
2011-12-08 15:57 [PATCH 00/11] inode shrink and misc updates Christoph Hellwig
2011-12-08 15:58 ` [PATCH 06/11] xfs: replace i_flock with a sleeping bitlock Christoph Hellwig
2011-12-13 22:19 ` Dave Chinner
2011-12-18 18:11 ` Christoph Hellwig
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