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From: David Rientjes <rientjes@google.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Christoph Lameter <cl@linux-foundation.org>,
	Nick Piggin <npiggin@suse.de>, Paul Menage <menage@google.com>,
	Derek Fults <dfults@sgi.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [patch 1/7] cpusets: add dirty map to struct address_space
Date: Tue, 28 Oct 2008 19:24:33 -0700 (PDT)	[thread overview]
Message-ID: <alpine.DEB.1.10.0810281922320.32430@chino.kir.corp.google.com> (raw)
In-Reply-To: <alpine.DEB.1.10.0810281722290.23743@chino.kir.corp.google.com>

On Tue, 28 Oct 2008, David Rientjes wrote:

> diff --git a/kernel/cpuset.c b/kernel/cpuset.c
> --- a/kernel/cpuset.c
> +++ b/kernel/cpuset.c
> @@ -2413,10 +2413,7 @@ EXPORT_SYMBOL_GPL(cpuset_mem_spread_node);
>  #if MAX_NUMNODES > BITS_PER_LONG
>  /*
>   * Special functions for NUMA systems with a large number of nodes.  The
> - * nodemask is pointed to from the address_space structure.  The attachment of
> - * the dirty_nodes nodemask is protected by the tree_lock.  The nodemask is
> - * freed only when the inode is cleared (and therefore unused, thus no locking
> - * is necessary).
> + * nodemask is pointed to from the address_space structure.
>   */
>  void cpuset_update_dirty_nodes(struct address_space *mapping,
>  			       struct page *page)
> @@ -2424,14 +2421,18 @@ void cpuset_update_dirty_nodes(struct address_space *mapping,
>  	nodemask_t *nodes = mapping->dirty_nodes;
>  	int node = page_to_nid(page);
>  
> +	spin_lock_irq(&mapping->dirty_nodes_lock);
>  	if (!nodes) {
>  		nodes = kmalloc(sizeof(nodemask_t), GFP_ATOMIC);
> -		if (!nodes)
> +		if (!nodes) {
> +			spin_unlock_irq(&mapping->dirty_nodes_lock);
>  			return;
> +		}
>  
>  		*nodes = NODE_MASK_NONE;
>  		mapping->dirty_nodes = nodes;
>  	}
> +	spin_unlock_irq(&mapping->dirty_nodes_lock);
>  	node_set(node, *nodes);
>  }
>  

Would need to be

	spin_lock_irq(&mapping->dirty_nodes_lock);
	nodes = mapping->dirty_nodes;
	if (!nodes) {
		nodes = kmalloc(sizeof(nodemask_t), GFP_ATOMIC);
		if (!nodes) {
			spin_unlock_irq(&mapping->dirty_nodes_lock);
			return;
		}
		...
	}
	spin_unlock_irq(&mapping->dirty_nodes_lock);

but this shouldn't add much locking overhead without mapping->tree_lock.

  reply	other threads:[~2008-10-29  2:25 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-28 16:08 David Rientjes
2008-10-28 16:08 ` [patch 2/7] pdflush: allow the passing of a nodemask parameter David Rientjes
2008-10-28 16:08 ` [patch 3/7] mm: make page writeback obey cpuset constraints David Rientjes
2008-10-28 17:31   ` Peter Zijlstra
2008-10-28 19:16     ` David Rientjes
2008-10-28 17:32   ` Peter Zijlstra
2008-10-28 19:18     ` David Rientjes
2008-10-30  8:42       ` Peter Zijlstra
2008-10-30  9:10         ` David Rientjes
2008-10-30  9:34           ` Peter Zijlstra
2008-10-28 16:08 ` [patch 4/7] mm: cpuset aware reclaim writeout David Rientjes
2008-10-28 16:08 ` [patch 5/7] mm: throttle writeout with cpuset awareness David Rientjes
2008-10-28 16:08 ` [patch 6/7] cpusets: per cpuset dirty ratios David Rientjes
2008-10-30  6:59   ` Paul Menage
2008-10-30  8:48     ` David Rientjes
2008-10-30 15:28     ` Christoph Lameter
2008-10-30  8:44   ` Peter Zijlstra
2008-10-30  9:03     ` David Rientjes
2008-10-30  9:34       ` Peter Zijlstra
2008-10-30 10:02         ` David Rientjes
2008-10-28 16:08 ` [patch 7/7] cpusets: update documentation for writeback throttling David Rientjes
2008-10-30 16:06   ` Christoph Lameter
2008-10-28 17:37 ` [patch 1/7] cpusets: add dirty map to struct address_space Peter Zijlstra
2008-10-28 20:48   ` David Rientjes
2008-10-29  1:13     ` David Rientjes
2008-10-29  2:24       ` David Rientjes [this message]
2008-10-30  8:38       ` Peter Zijlstra
2008-10-28 17:46 ` Peter Zijlstra
2008-10-28 19:19   ` David Rientjes
2008-10-30 19:23 [patch 0/7] cpuset writeback throttling David Rientjes
2008-10-30 19:23 ` [patch 1/7] cpusets: add dirty map to struct address_space David Rientjes
2008-11-04 21:09   ` Andrew Morton
2008-11-04 21:20     ` Christoph Lameter
2008-11-04 21:42       ` Andrew Morton

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