Date: Wed, 30 Jun 2010 22:06:31 +1000
From: Nick Piggin <npiggin@suse.de>
To: Dave Chinner <david@fromorbit.com>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
       John Stultz <johnstul@us.ibm.com>, Frank Mayhar <fmayhar@google.com>
Subject: Re: [patch 37/52] fs: icache lazy lru
Message-ID: <20100630120631.GC21358@laptop>
References: <20100624030212.676457061@suse.de>
 <20100624030731.563540438@suse.de>
 <20100630083814.GG24712@dastard>
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On Wed, Jun 30, 2010 at 06:38:14PM +1000, Dave Chinner wrote:
> On Thu, Jun 24, 2010 at 01:02:49PM +1000, npiggin@suse.de wrote:
> > Impelemnt lazy inode lru similarly to dcache. This will reduce lock
> > acquisition and will help to improve lock ordering subsequently.
> 
> I'm not sure we want the I_REFERENCED reclaim free pass for a clean
> inode that has been put on the LRU directly. I can see exactly how
> it is benficial to delay reclaim of dirty inodes (XFS uses that
> trick), but in terms of aging the cache we've already done this
> free pass trick at the dentry level. Hence I think the frequent
> separate access patterns tend to be filtered out at the dcache level
> and hence we don't need to handle that in the inode cache.
> 
> Perhaps we only need the I_REFERENCED flag to give dirty inodes a
> chance to be flushed by other means before forcing reclaim to do
> inode writeback?

It doesn't force flush, but it force invalidates pagecache.

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