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From: Dave Chinner <david@fromorbit.com>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 08/21] fs: rework icount to be a locked variable
Date: Fri, 22 Oct 2010 09:32:34 +1100	[thread overview]
Message-ID: <20101021223234.GT32255@dastard> (raw)
In-Reply-To: <20101021194044.GC19804@ZenIV.linux.org.uk>

On Thu, Oct 21, 2010 at 08:40:45PM +0100, Al Viro wrote:
> On Thu, Oct 21, 2010 at 11:49:33AM +1100, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> > 
> > The inode reference count is currently an atomic variable so that it
> > can be sampled/modified outside the inode_lock. However, the
> > inode_lock is still needed to synchronise the final reference count
> > and checks against the inode state.
> > 
> > To avoid needing the protection of the inode lock, protect the inode
> > reference count with the per-inode i_lock and convert it to a normal
> > variable. To avoid existing out-of-tree code accidentally compiling
> > against the new method, rename the i_count field to i_ref. This is
> > relatively straight forward as there are limited external references
> > to the i_count field remaining.
> 
> BTW, the same thing as with Nick's set - separate patch for "clone the
> reference to inode we are already holding" helper, in front of queue.

Isn't that already done by the patch 6 "fs: Clean up inode reference
counting"? That patch does the converting of stand-alone
atomic_inc(&inode->i-count) into iref(inode), not this one.
Maybe I've misunderstood what you are wanting to be changed with
this patch - can you clarify, Al?

Cheers,

Dave.

-- 
Dave Chinner
david@fromorbit.com

  reply	other threads:[~2010-10-21 22:32 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-21  0:49 Inode Lock Scalability V6 Dave Chinner
2010-10-21  0:49 ` [PATCH 01/21] fs: switch bdev inode bdi's correctly Dave Chinner
2010-10-21  0:49 ` [PATCH 02/21] kernel: add bl_list Dave Chinner
2010-10-21  0:49 ` [PATCH 03/21] fs: Convert nr_inodes and nr_unused to per-cpu counters Dave Chinner
2010-10-21  0:49 ` [PATCH 04/21] fs: Implement lazy LRU updates for inodes Dave Chinner
2010-10-21  2:14   ` Christian Stroetmann
2010-10-21 10:07   ` Nick Piggin
2010-10-21 12:22     ` Christoph Hellwig
2010-10-23  9:32   ` Al Viro
2010-10-21  0:49 ` [PATCH 05/21] fs: inode split IO and LRU lists Dave Chinner
2010-10-21  0:49 ` [PATCH 06/21] fs: Clean up inode reference counting Dave Chinner
2010-10-21  1:41   ` Christoph Hellwig
2010-10-21  0:49 ` [PATCH 07/21] exofs: use iput() for inode reference count decrements Dave Chinner
2010-10-21  0:49 ` [PATCH 08/21] fs: rework icount to be a locked variable Dave Chinner
2010-10-21 19:40   ` Al Viro
2010-10-21 22:32     ` Dave Chinner [this message]
2010-10-21  0:49 ` [PATCH 09/21] fs: Factor inode hash operations into functions Dave Chinner
2010-10-21  0:49 ` [PATCH 10/21] fs: Stop abusing find_inode_fast in iunique Dave Chinner
2010-10-21  0:49 ` [PATCH 11/21] fs: move i_ref increments into find_inode/find_inode_fast Dave Chinner
2010-10-21  0:49 ` [PATCH 12/21] fs: remove inode_add_to_list/__inode_add_to_list Dave Chinner
2010-10-21  0:49 ` [PATCH 13/21] fs: Introduce per-bucket inode hash locks Dave Chinner
2010-10-21  0:49 ` [PATCH 14/21] fs: add a per-superblock lock for the inode list Dave Chinner
2010-10-21  0:49 ` [PATCH 15/21] fs: split locking of inode writeback and LRU lists Dave Chinner
2010-10-21  0:49 ` [PATCH 16/21] fs: Protect inode->i_state with the inode->i_lock Dave Chinner
2010-10-22  1:56   ` Al Viro
2010-10-22  2:26     ` Nick Piggin
2010-10-22  3:14     ` Dave Chinner
2010-10-22 10:37       ` Al Viro
2010-10-22 11:40         ` Christoph Hellwig
2010-10-23 21:40           ` Al Viro
2010-10-23 21:37         ` Al Viro
2010-10-24 14:13           ` Christoph Hellwig
2010-10-24 16:21             ` Christoph Hellwig
2010-10-24 19:17               ` Al Viro
2010-10-24 20:04                 ` Christoph Hellwig
2010-10-24 20:36                   ` Al Viro
2010-10-24  2:18       ` Nick Piggin
2010-10-21  0:49 ` [PATCH 17/21] fs: protect wake_up_inode with inode->i_lock Dave Chinner
2010-10-21  2:17   ` Christoph Hellwig
2010-10-21 13:16     ` Nick Piggin
2010-10-21  0:49 ` [PATCH 18/21] fs: introduce a per-cpu last_ino allocator Dave Chinner
2010-10-21  0:49 ` [PATCH 19/21] fs: icache remove inode_lock Dave Chinner
2010-10-21  2:14   ` Christian Stroetmann
2010-10-21  0:49 ` [PATCH 20/21] fs: Reduce inode I_FREEING and factor inode disposal Dave Chinner
2010-10-21  0:49 ` [PATCH 21/21] fs: do not assign default i_ino in new_inode Dave Chinner
2010-10-21  5:04 ` Inode Lock Scalability V7 (was V6) Dave Chinner
2010-10-21 13:20   ` Nick Piggin
2010-10-21 23:52     ` Dave Chinner
2010-10-22  0:45       ` Nick Piggin
2010-10-22  2:20         ` Al Viro
2010-10-22  2:34           ` Nick Piggin
2010-10-22  2:41             ` Nick Piggin
2010-10-22  2:48               ` Nick Piggin
2010-10-22  3:12                 ` Al Viro
2010-10-22  4:48                   ` Nick Piggin
2010-10-22  3:07             ` Al Viro
2010-10-22  4:46               ` Nick Piggin
2010-10-22  5:01                 ` Nick Piggin

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