Re: Review: Reduce in-core superblock lock contention near ENOSPC

[Lachlan McIlroy <lachlan@sgi.com>]

David Chinner wrote:
> On Tue, Dec 05, 2006 at 12:46:46PM +0100, Klaus Strebel wrote:
> 
>>Hi guys,
>>
>>just updated my CVS copy from oss.sgi.com ( the linux-2.6-xfs ) and 
>>tried to compile ... but your patch failes to compile if HAVE_PERCPU_SB 
>>is #ifndef'd :-(, the m_icsb_mutex is not in the struct see xfs_mount.h. 
>>Make oldconfig didn't show HAVE_PERCPU_SB as option for .config, looks 
>>like nobody tested on a single processor config ??
> 
> 
> Sorry - my bad. The code did not change for UP, so I didn't think to
> test it.  The patch below abstracts the icsb_mutex so that it
> doesn't get directly referenced by code outside the per-cpu counter
> code. Builds with and without HAVE_PERCPU_SB defined.
> 
> I'll run a test cycle on it and get it fixed up.
> 
> Cheers,
> 
> Dave.

@@ -1803,6 +1803,7 @@ xfs_icsb_destroy_counters(
  		unregister_hotcpu_notifier(&mp->m_icsb_notifier);
  		free_percpu(mp->m_sb_cnts);
  	}
+	mutex_destroy(&mp->m_icsb_mutex);
  }

Do you need to abstract the call to mutex_destroy too?

The rest of the change looks good.

Lachlan