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Commit efdc9490 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Linus Torvalds
Browse files

mm: fix memcg stack accounting for sub-page stacks 

We should account for stacks regardless of stack size, and we need to
account in sub-page units if THREAD_SIZE < PAGE_SIZE.  Change the units
to kilobytes and Move it into account_kernel_stack().

Fixes: 12580e4b ("mm: memcontrol: report kernel stack usage in cgroup2 memory.stat")
Link: http://lkml.kernel.org/r/9b5314e3ee5eda61b0317ec1563768602c1ef438.1468523549.git.luto@kernel.org


Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Reviewed-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: default avatarVladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d30dd8be

include/linux/memcontrol.h

+1 −1
Original line number Diff line number Diff line
@@ -52,7 +52,7 @@ enum mem_cgroup_stat_index { 
	MEM_CGROUP_STAT_SWAP,		/* # of pages, swapped out */

	MEM_CGROUP_STAT_NSTATS,

	/* default hierarchy stats */

	MEMCG_KERNEL_STACK = MEM_CGROUP_STAT_NSTATS,

	MEMCG_KERNEL_STACK_KB = MEM_CGROUP_STAT_NSTATS,

	MEMCG_SLAB_RECLAIMABLE,

	MEMCG_SLAB_UNRECLAIMABLE,

	MEMCG_SOCK,

kernel/fork.c

+8 −11
Original line number Diff line number Diff line
@@ -165,20 +165,12 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, 
	struct page *page = alloc_pages_node(node, THREADINFO_GFP,

					     THREAD_SIZE_ORDER);



	if (page)

		memcg_kmem_update_page_stat(page, MEMCG_KERNEL_STACK,

					    1 << THREAD_SIZE_ORDER);



	return page ? page_address(page) : NULL;

}



static inline void free_thread_stack(unsigned long *stack)

{

	struct page *page = virt_to_page(stack);



	memcg_kmem_update_page_stat(page, MEMCG_KERNEL_STACK,

				    -(1 << THREAD_SIZE_ORDER));

	__free_pages(page, THREAD_SIZE_ORDER);

	__free_pages(virt_to_page(stack), THREAD_SIZE_ORDER);

}

# else

static struct kmem_cache *thread_stack_cache;
@@ -223,10 +215,15 @@ static struct kmem_cache *mm_cachep; 


static void account_kernel_stack(unsigned long *stack, int account)

{

	struct zone *zone = page_zone(virt_to_page(stack));

	/* All stack pages are in the same zone and belong to the same memcg. */

	struct page *first_page = virt_to_page(stack);



	mod_zone_page_state(zone, NR_KERNEL_STACK_KB,

	mod_zone_page_state(page_zone(first_page), NR_KERNEL_STACK_KB,

			    THREAD_SIZE / 1024 * account);



	memcg_kmem_update_page_stat(

		first_page, MEMCG_KERNEL_STACK_KB,

		account * (THREAD_SIZE / 1024));

}



void free_task(struct task_struct *tsk)

mm/memcontrol.c

+1 −1
Original line number Diff line number Diff line
@@ -5171,7 +5171,7 @@ static int memory_stat_show(struct seq_file *m, void *v) 
	seq_printf(m, "file %llu\n",

		   (u64)stat[MEM_CGROUP_STAT_CACHE] * PAGE_SIZE);

	seq_printf(m, "kernel_stack %llu\n",

		   (u64)stat[MEMCG_KERNEL_STACK] * PAGE_SIZE);

		   (u64)stat[MEMCG_KERNEL_STACK_KB] * 1024);

	seq_printf(m, "slab %llu\n",

		   (u64)(stat[MEMCG_SLAB_RECLAIMABLE] +

			 stat[MEMCG_SLAB_UNRECLAIMABLE]) * PAGE_SIZE);