Re: [PATCH 09/11] memcg: propagate kmem limiting information to children
From: Andrew Morton <akpm@linux-foundation.org>
Date: 2012-06-25 23:22:03
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On Tue, 26 Jun 2012 02:36:27 +0400 Glauber Costa [off-list ref] wrote:
On 06/25/2012 10:29 PM, Tejun Heo wrote:quoted
Feeling like a nit pervert but.. On Mon, Jun 25, 2012 at 06:15:26PM +0400, Glauber Costa wrote:quoted
@@ -287,7 +287,11 @@ struct mem_cgroup { * Should the accounting and control be hierarchical, per subtree? */ bool use_hierarchy; - bool kmem_accounted; + /* + * bit0: accounted by this cgroup + * bit1: accounted by a parent. + */ + volatile unsigned long kmem_accounted;Is the volatile declaration really necessary? Why is it necessary? Why no comment explaining it?Seems to be required by set_bit and friends. gcc will complain if it is not volatile (take a look at the bit function headers)
That would be a broken gcc. We run test_bit()/set_bit() and friends against plain old `unsigned long' in thousands of places. There's nothing special about this one! -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>