memcgroup: move memory controller allocations to their own slabs (b6ac57d5) · Commits · 戴 / test

Move the memory controller data structure page_cgroup to its own slab cache. 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. NOTE: Hugh Dickins brought up the issue of whether we want to mark page_cgroup as __GFP_MOVABLE or __GFP_RECLAIMABLE. I don't think there is an easy answer at the moment. page_cgroup's are associated with user pages, they can be reclaimed once the user page has been reclaimed, so it might make sense to mark them as __GFP_RECLAIMABLE. For now, I am leaving the marking to default values that the slab allocator uses. Signed-off-by:

Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Hugh Dickins <hugh@veritas.com> Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com> Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Cc: Paul Menage <menage@google.com> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/memcontrol.c

+10 −6

Original line number	Diff line number	Diff line
		@@ -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 +36,7 @@

		struct cgroup_subsys mem_cgroup_subsys;
		static const int MEM_CGROUP_RECLAIM_RETRIES = 5;
		static struct kmem_cache *page_cgroup_cache;

		/*
		* Statistics for memory cgroup.
		@@ -547,7 +549,7 @@ 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;

		@@ -609,7 +611,7 @@ 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);
		@@ -624,7 +626,7 @@ done:
		return 0;
		out:
		css_put(&mem->css);
		kfree(pc);
		kmem_cache_free(page_cgroup_cache, pc);
		err:
		return -ENOMEM;
		}
		@@ -682,7 +684,7 @@ void mem_cgroup_uncharge_page(struct page *page)
		res_counter_uncharge(&mem->res, PAGE_SIZE);
		css_put(&mem->css);

		kfree(pc);
		kmem_cache_free(page_cgroup_cache, pc);
		return;
		}

		@@ -989,10 +991,12 @@ mem_cgroup_create(struct cgroup_subsys ss, struct cgroup cont)
		struct mem_cgroup *mem;
		int node;

		if (unlikely((cont->parent) == NULL))
		if (unlikely((cont->parent) == NULL)) {
		mem = &init_mem_cgroup;
		else
		page_cgroup_cache = KMEM_CACHE(page_cgroup, SLAB_PANIC);
		} else {
		mem = kzalloc(sizeof(struct mem_cgroup), GFP_KERNEL);
		}

		if (mem == NULL)
		return ERR_PTR(-ENOMEM);

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