Re: [RFC PATCH] page_cgroup: Reduce allocation overhead for page_cgroup array for CONFIG_SPARSEMEM
From: Michal Hocko <hidden>
Date: 2011-02-24 09:35:22
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On Thu 24-02-11 08:52:27, KAMEZAWA Hiroyuki wrote:
On Wed, 23 Feb 2011 10:19:22 -0800 Dave Hansen [off-list ref] wrote:quoted
On Wed, 2011-02-23 at 16:10 +0100, Michal Hocko wrote:quoted
We can reduce this internal fragmentation by splitting the single page_cgroup array into more arrays where each one is well kmalloc aligned. This patch implements this idea.How about using alloc_pages_exact()? These things aren't allocated often enough to really get most of the benefits of being in a slab. That'll at least get you down to a maximum of about PAGE_SIZE wasted.yes, alloc_pages_exact() is much better. packing page_cgroups for multiple sections causes breakage in memory hotplug logic.
I am not sure I understand this. What do you mean by packing page_cgroups for multiple sections? The patch I have posted doesn't do any packing. Or do you mean that using a double array can break hotplog? Not that this would change anything, alloc_pages_exact is really a better solution, I am just curious ;) -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>