Re: [PATCH v3 05/13] mm: Fix memcg stack accounting for sub-page stacks

Michal Hocko
2016-06-22T07:38:03Z

On Mon 20-06-16 16:43:35, Andy Lutomirski wrote:
> 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: 12580e4b54ba8 ("mm: memcontrol: report kernel stack usage in cgroup2 memory.stat")
> Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: linux-mm@kvack.org
> Signed-off-by: Andy Lutomirski <luto@kernel.org>

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
> include/linux/memcontrol.h | 2 +-
> kernel/fork.c | 15 ++++++---------
> mm/memcontrol.c | 2 +-
> 3 files changed, 8 insertions(+), 11 deletions(-)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index a805474df4ab..3b653b86bb8f 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -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,
> diff --git a/kernel/fork.c b/kernel/fork.c
> index be7f006af727..ff3c41c2ba96 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -165,20 +165,12 @@ static struct thread_info *alloc_thread_info_node(struct task_struct *tsk,
> struct page *page = alloc_kmem_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_info(struct thread_info *ti)
> {
> - struct page *page = virt_to_page(ti);
> -
> - memcg_kmem_update_page_stat(page, MEMCG_KERNEL_STACK,
> - -(1 << THREAD_SIZE_ORDER));
> - __free_kmem_pages(page, THREAD_SIZE_ORDER);
> + free_kmem_pages((unsigned long)ti, THREAD_SIZE_ORDER);
> }
> # else
> static struct kmem_cache *thread_info_cache;
> @@ -227,6 +219,11 @@ static void account_kernel_stack(struct thread_info *ti, int account)
>
> mod_zone_page_state(zone, NR_KERNEL_STACK_KB,
> THREAD_SIZE / 1024 * account);
> +
> + /* All stack pages belong to the same memcg. */
> + memcg_kmem_update_page_stat(
> + virt_to_page(ti), MEMCG_KERNEL_STACK_KB,
> + account * (THREAD_SIZE / 1024));
> }
>
> void free_task(struct task_struct *tsk)
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 75e74408cc8f..8e13a2419dad 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -5133,7 +5133,7 @@ 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);
> --
> 2.5.5

--
Michal Hocko
SUSE Labs

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