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Commit 6a1a0d3b authored by Glauber Costa's avatar Glauber Costa Committed by Linus Torvalds
Browse files

mm: allocate kernel pages to the right memcg 



When a process tries to allocate a page with the __GFP_KMEMCG flag, the
page allocator will call the corresponding memcg functions to validate
the allocation.  Tasks in the root memcg can always proceed.

To avoid adding markers to the page - and a kmem flag that would
necessarily follow, as much as doing page_cgroup lookups for no reason,
whoever is marking its allocations with __GFP_KMEMCG flag is responsible
for telling the page allocator that this is such an allocation at
free_pages() time.  This is done by the invocation of
__free_accounted_pages() and free_accounted_pages().

Signed-off-by: default avatarGlauber Costa <glommer@parallels.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
Acked-by: default avatarMel Gorman <mgorman@suse.de>
Acked-by: default avatarKamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: default avatarDavid Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7ae1e1d0

include/linux/gfp.h

+3 −0
Original line number Diff line number Diff line
@@ -367,6 +367,9 @@ extern void free_pages(unsigned long addr, unsigned int order); 
extern void free_hot_cold_page(struct page *page, int cold);

extern void free_hot_cold_page_list(struct list_head *list, int cold);



extern void __free_memcg_kmem_pages(struct page *page, unsigned int order);

extern void free_memcg_kmem_pages(unsigned long addr, unsigned int order);



#define __free_page(page) __free_pages((page), 0)

#define free_page(addr) free_pages((addr), 0)

mm/page_alloc.c

+35 −0
Original line number Diff line number Diff line
@@ -2612,6 +2612,7 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, 
	int migratetype = allocflags_to_migratetype(gfp_mask);

	unsigned int cpuset_mems_cookie;

	int alloc_flags = ALLOC_WMARK_LOW|ALLOC_CPUSET;

	struct mem_cgroup *memcg = NULL;



	gfp_mask &= gfp_allowed_mask;
@@ -2630,6 +2631,13 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, 
	if (unlikely(!zonelist->_zonerefs->zone))

		return NULL;



	/*

	 * Will only have any effect when __GFP_KMEMCG is set.  This is

	 * verified in the (always inline) callee

	 */

	if (!memcg_kmem_newpage_charge(gfp_mask, &memcg, order))

		return NULL;



retry_cpuset:

	cpuset_mems_cookie = get_mems_allowed();
@@ -2665,6 +2673,8 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, 
	if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))

		goto retry_cpuset;



	memcg_kmem_commit_charge(page, memcg, order);



	return page;

}

EXPORT_SYMBOL(__alloc_pages_nodemask);
@@ -2717,6 +2727,31 @@ void free_pages(unsigned long addr, unsigned int order) 


EXPORT_SYMBOL(free_pages);



/*

 * __free_memcg_kmem_pages and free_memcg_kmem_pages will free

 * pages allocated with __GFP_KMEMCG.

 *

 * Those pages are accounted to a particular memcg, embedded in the

 * corresponding page_cgroup. To avoid adding a hit in the allocator to search

 * for that information only to find out that it is NULL for users who have no

 * interest in that whatsoever, we provide these functions.

 *

 * The caller knows better which flags it relies on.

 */

void __free_memcg_kmem_pages(struct page *page, unsigned int order)

{

	memcg_kmem_uncharge_pages(page, order);

	__free_pages(page, order);

}



void free_memcg_kmem_pages(unsigned long addr, unsigned int order)

{

	if (addr != 0) {

		VM_BUG_ON(!virt_addr_valid((void *)addr));

		__free_memcg_kmem_pages(virt_to_page((void *)addr), order);

	}

}



static void *make_alloc_exact(unsigned long addr, unsigned order, size_t size)

{

	if (addr) {