linux-kernel - Re: [PATCH] Move memory controller allocations to their own slabs

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Message-Id: <20080311134556.297e8c10.kamezawa.hiroyu@jp.fujitsu.com>
Date:	Tue, 11 Mar 2008 13:45:56 +0900
From:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To:	Balbir Singh <balbir@...ux.vnet.ibm.com>
Cc:	Paul Menage <menage@...gle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Pavel Emelianov <xemul@...nvz.org>,
	Hugh Dickins <hugh@...itas.com>,
	Sudhir Kumar <skumar@...ux.vnet.ibm.com>,
	YAMAMOTO Takashi <yamamoto@...inux.co.jp>, lizf@...fujitsu.com,
	linux-kernel@...r.kernel.org, taka@...inux.co.jp,
	linux-mm@...ck.org, David Rientjes <rientjes@...gle.com>
Subject: Re: [PATCH] Move memory controller allocations to their own slabs

On Tue, 11 Mar 2008 10:01:49 +0530
Balbir Singh <balbir@...ux.vnet.ibm.com> wrote:

> 
> Move the memory controller data structures page_cgroup and
> mem_cgroup_per_zone to their own slab caches. It saves space on the system,
> allocations are not necessarily pushed to order of 2 and should provide
> performance benefits. Users who disable the memory controller can also double
> check that the memory controller is not allocating page_cgroup's.
> 
> Signed-off-by: Balbir Singh <balbir@...ux.vnet.ibm.com>
> ---
I think using its own kmem_cache for mem_cgroup_per_zone is a bit overkill.

Thanks,
-Kame



> 
>  linux/memcontrol.h |    0 
>  mm/memcontrol.c    |   21 ++++++++++++++-------
>  2 files changed, 14 insertions(+), 7 deletions(-)
> 
> diff -puN mm/memcontrol.c~memory-controller-move-to-own-slab mm/memcontrol.c
> --- linux-2.6.25-rc4/mm/memcontrol.c~memory-controller-move-to-own-slab	2008-03-10 23:22:34.000000000 +0530
> +++ linux-2.6.25-rc4-balbir/mm/memcontrol.c	2008-03-10 23:34:42.000000000 +0530
> @@ -26,6 +26,7 @@
>  #include <linux/backing-dev.h>
>  #include <linux/bit_spinlock.h>
>  #include <linux/rcupdate.h>
> +#include <linux/slab.h>
>  #include <linux/swap.h>
>  #include <linux/spinlock.h>
>  #include <linux/fs.h>
> @@ -35,6 +36,8 @@
>  
>  struct cgroup_subsys mem_cgroup_subsys;
>  static const int MEM_CGROUP_RECLAIM_RETRIES = 5;
> +static struct kmem_cache *page_cgroup_cache;
> +static struct kmem_cache *mem_cgroup_per_zone_cache;
>  
>  /*
>   * Statistics for memory cgroup.
> @@ -560,7 +563,7 @@ retry:
>  	}
>  	unlock_page_cgroup(page);
>  
> -	pc = kzalloc(sizeof(struct page_cgroup), gfp_mask);
> +	pc = kmem_cache_zalloc(page_cgroup_cache, gfp_mask);
>  	if (pc == NULL)
>  		goto err;
>  
> @@ -622,7 +625,7 @@ retry:
>  		 */
>  		res_counter_uncharge(&mem->res, PAGE_SIZE);
>  		css_put(&mem->css);
> -		kfree(pc);
> +		kmem_cache_free(page_cgroup_cache, pc);
>  		goto retry;
>  	}
>  	page_assign_page_cgroup(page, pc);
> @@ -637,7 +640,7 @@ done:
>  	return 0;
>  out:
>  	css_put(&mem->css);
> -	kfree(pc);
> +	kmem_cache_free(page_cgroup_cache, pc);
>  err:
>  	return -ENOMEM;
>  }
> @@ -695,7 +698,7 @@ void mem_cgroup_uncharge_page(struct pag
>  		res_counter_uncharge(&mem->res, PAGE_SIZE);
>  		css_put(&mem->css);
>  
> -		kfree(pc);
> +		kmem_cache_free(page_cgroup_cache, pc);
>  		return;
>  	}
>  
> @@ -988,9 +991,10 @@ static int alloc_mem_cgroup_per_zone_inf
>  	 *       function.
>  	 */
>  	if (node_state(node, N_HIGH_MEMORY))
> -		pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, node);
> +		pn = kmem_cache_alloc_node(mem_cgroup_per_zone_cache,
> +						GFP_KERNEL, node);
>  	else
> -		pn = kmalloc(sizeof(*pn), GFP_KERNEL);
> +		pn = kmem_cache_alloc(mem_cgroup_per_zone_cache, GFP_KERNEL);
>  	if (!pn)
>  		return 1;
>  
> @@ -1008,7 +1012,7 @@ static int alloc_mem_cgroup_per_zone_inf
>  
>  static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
>  {
> -	kfree(mem->info.nodeinfo[node]);
> +	kmem_cache_free(mem_cgroup_per_zone_cache, mem->info.nodeinfo[node]);
>  }
>  
>  static struct cgroup_subsys_state *
> @@ -1020,6 +1024,9 @@ mem_cgroup_create(struct cgroup_subsys *
>  	if (unlikely((cont->parent) == NULL)) {
>  		mem = &init_mem_cgroup;
>  		init_mm.mem_cgroup = mem;
> +		page_cgroup_cache = KMEM_CACHE(page_cgroup, SLAB_PANIC);
> +		mem_cgroup_per_zone_cache = KMEM_CACHE(mem_cgroup_per_zone,
> +							SLAB_PANIC);
>  	} else
>  		mem = kzalloc(sizeof(struct mem_cgroup), GFP_KERNEL);
>  
> diff -puN include/linux/memcontrol.h~memory-controller-move-to-own-slab include/linux/memcontrol.h
> _
> 
> -- 
> 	Warm Regards,
> 	Balbir Singh
> 	Linux Technology Center
> 	IBM, ISTL
> 
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@...ck.org.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@...ck.org"> email@...ck.org </a>
> 

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