Re: [PATCH 36 of 66] memcg compound

[Mel Gorman <mel@csn.ul.ie>]

On Wed, Nov 03, 2010 at 04:28:11PM +0100, Andrea Arcangeli wrote:
> From: Andrea Arcangeli <aarcange@redhat.com>
> 
> Teach memcg to charge/uncharge compound pages.
> 
> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
> Acked-by: Rik van Riel <riel@redhat.com>
> ---
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1019,6 +1019,10 @@ mem_cgroup_get_reclaim_stat_from_page(st
>  {
>  	struct page_cgroup *pc;
>  	struct mem_cgroup_per_zone *mz;
> +	int page_size = PAGE_SIZE;
> +
> +	if (PageTransHuge(page))
> +		page_size <<= compound_order(page);
>  
>  	if (mem_cgroup_disabled())
>  		return NULL;
> @@ -1879,12 +1883,14 @@ static int __mem_cgroup_do_charge(struct
>   * oom-killer can be invoked.
>   */
>  static int __mem_cgroup_try_charge(struct mm_struct *mm,
> -		gfp_t gfp_mask, struct mem_cgroup **memcg, bool oom)
> +				   gfp_t gfp_mask,
> +				   struct mem_cgroup **memcg, bool oom,
> +				   int page_size)

Any concerns about page_size overflowing int? ppc64 has 16G pages for example
although it will never be in this path. hmm, I see that charge size is already
int so maybe this is more of a memcg issue than it is THP but hugetlbfs
treats page sizes as unsigned long. For example see vma_kernel_pagesize()


>  {
>  	int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
>  	struct mem_cgroup *mem = NULL;
>  	int ret;
> -	int csize = CHARGE_SIZE;
> +	int csize = max(CHARGE_SIZE, (unsigned long) page_size);
>  
>  	/*
>  	 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
> @@ -1909,7 +1915,7 @@ again:
>  		VM_BUG_ON(css_is_removed(&mem->css));
>  		if (mem_cgroup_is_root(mem))
>  			goto done;
> -		if (consume_stock(mem))
> +		if (page_size == PAGE_SIZE && consume_stock(mem))
>  			goto done;
>  		css_get(&mem->css);
>  	} else {
> @@ -1933,7 +1939,7 @@ again:
>  			rcu_read_unlock();
>  			goto done;
>  		}
> -		if (consume_stock(mem)) {
> +		if (page_size == PAGE_SIZE && consume_stock(mem)) {
>  			/*
>  			 * It seems dagerous to access memcg without css_get().
>  			 * But considering how consume_stok works, it's not
> @@ -1974,7 +1980,7 @@ again:
>  		case CHARGE_OK:
>  			break;
>  		case CHARGE_RETRY: /* not in OOM situation but retry */
> -			csize = PAGE_SIZE;
> +			csize = page_size;
>  			css_put(&mem->css);
>  			mem = NULL;
>  			goto again;
> @@ -1995,8 +2001,8 @@ again:
>  		}
>  	} while (ret != CHARGE_OK);
>  
> -	if (csize > PAGE_SIZE)
> -		refill_stock(mem, csize - PAGE_SIZE);
> +	if (csize > page_size)
> +		refill_stock(mem, csize - page_size);
>  	css_put(&mem->css);
>  done:
>  	*memcg = mem;
> @@ -2024,9 +2030,10 @@ static void __mem_cgroup_cancel_charge(s
>  	}
>  }
>  
> -static void mem_cgroup_cancel_charge(struct mem_cgroup *mem)
> +static void mem_cgroup_cancel_charge(struct mem_cgroup *mem,
> +				     int page_size)
>  {
> -	__mem_cgroup_cancel_charge(mem, 1);
> +	__mem_cgroup_cancel_charge(mem, page_size >> PAGE_SHIFT);
>  }
>  
>  /*
> @@ -2082,8 +2089,9 @@ struct mem_cgroup *try_get_mem_cgroup_fr
>   */
>  
>  static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
> -				     struct page_cgroup *pc,
> -				     enum charge_type ctype)
> +				       struct page_cgroup *pc,
> +				       enum charge_type ctype,
> +				       int page_size)
>  {
>  	/* try_charge() can return NULL to *memcg, taking care of it. */
>  	if (!mem)
> @@ -2092,7 +2100,7 @@ static void __mem_cgroup_commit_charge(s
>  	lock_page_cgroup(pc);
>  	if (unlikely(PageCgroupUsed(pc))) {
>  		unlock_page_cgroup(pc);
> -		mem_cgroup_cancel_charge(mem);
> +		mem_cgroup_cancel_charge(mem, page_size);
>  		return;
>  	}
>  
> @@ -2166,7 +2174,7 @@ static void __mem_cgroup_move_account(st
>  	mem_cgroup_charge_statistics(from, pc, false);
>  	if (uncharge)
>  		/* This is not "cancel", but cancel_charge does all we need. */
> -		mem_cgroup_cancel_charge(from);
> +		mem_cgroup_cancel_charge(from, PAGE_SIZE);
>  
>  	/* caller should have done css_get */
>  	pc->mem_cgroup = to;
> @@ -2227,13 +2235,14 @@ static int mem_cgroup_move_parent(struct
>  		goto put;
>  
>  	parent = mem_cgroup_from_cont(pcg);
> -	ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false);
> +	ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false,
> +				      PAGE_SIZE);
>  	if (ret || !parent)
>  		goto put_back;
>  
>  	ret = mem_cgroup_move_account(pc, child, parent, true);
>  	if (ret)
> -		mem_cgroup_cancel_charge(parent);
> +		mem_cgroup_cancel_charge(parent, PAGE_SIZE);
>  put_back:
>  	putback_lru_page(page);
>  put:
> @@ -2254,6 +2263,10 @@ static int mem_cgroup_charge_common(stru
>  	struct mem_cgroup *mem = NULL;
>  	struct page_cgroup *pc;
>  	int ret;
> +	int page_size = PAGE_SIZE;
> +
> +	if (PageTransHuge(page))
> +		page_size <<= compound_order(page);
>  
>  	pc = lookup_page_cgroup(page);
>  	/* can happen at boot */
> @@ -2261,11 +2274,11 @@ static int mem_cgroup_charge_common(stru
>  		return 0;
>  	prefetchw(pc);
>  
> -	ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);
> +	ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true, page_size);
>  	if (ret || !mem)
>  		return ret;
>  
> -	__mem_cgroup_commit_charge(mem, pc, ctype);
> +	__mem_cgroup_commit_charge(mem, pc, ctype, page_size);
>  	return 0;
>  }
>  
> @@ -2274,8 +2287,6 @@ int mem_cgroup_newpage_charge(struct pag
>  {
>  	if (mem_cgroup_disabled())
>  		return 0;
> -	if (PageCompound(page))
> -		return 0;
>  	/*
>  	 * If already mapped, we don't have to account.
>  	 * If page cache, page->mapping has address_space.
> @@ -2381,13 +2392,13 @@ int mem_cgroup_try_charge_swapin(struct 
>  	if (!mem)
>  		goto charge_cur_mm;
>  	*ptr = mem;
> -	ret = __mem_cgroup_try_charge(NULL, mask, ptr, true);
> +	ret = __mem_cgroup_try_charge(NULL, mask, ptr, true, PAGE_SIZE);
>  	css_put(&mem->css);
>  	return ret;
>  charge_cur_mm:
>  	if (unlikely(!mm))
>  		mm = &init_mm;
> -	return __mem_cgroup_try_charge(mm, mask, ptr, true);
> +	return __mem_cgroup_try_charge(mm, mask, ptr, true, PAGE_SIZE);
>  }
>  
>  static void
> @@ -2403,7 +2414,7 @@ __mem_cgroup_commit_charge_swapin(struct
>  	cgroup_exclude_rmdir(&ptr->css);
>  	pc = lookup_page_cgroup(page);
>  	mem_cgroup_lru_del_before_commit_swapcache(page);
> -	__mem_cgroup_commit_charge(ptr, pc, ctype);
> +	__mem_cgroup_commit_charge(ptr, pc, ctype, PAGE_SIZE);
>  	mem_cgroup_lru_add_after_commit_swapcache(page);
>  	/*
>  	 * Now swap is on-memory. This means this page may be
> @@ -2452,11 +2463,12 @@ void mem_cgroup_cancel_charge_swapin(str
>  		return;
>  	if (!mem)
>  		return;
> -	mem_cgroup_cancel_charge(mem);
> +	mem_cgroup_cancel_charge(mem, PAGE_SIZE);
>  }
>  
>  static void
> -__do_uncharge(struct mem_cgroup *mem, const enum charge_type ctype)
> +__do_uncharge(struct mem_cgroup *mem, const enum charge_type ctype,
> +	      int page_size)
>  {
>  	struct memcg_batch_info *batch = NULL;
>  	bool uncharge_memsw = true;
> @@ -2491,14 +2503,14 @@ __do_uncharge(struct mem_cgroup *mem, co
>  	if (batch->memcg != mem)
>  		goto direct_uncharge;
>  	/* remember freed charge and uncharge it later */
> -	batch->bytes += PAGE_SIZE;
> +	batch->bytes += page_size;
>  	if (uncharge_memsw)
> -		batch->memsw_bytes += PAGE_SIZE;
> +		batch->memsw_bytes += page_size;
>  	return;
>  direct_uncharge:
> -	res_counter_uncharge(&mem->res, PAGE_SIZE);
> +	res_counter_uncharge(&mem->res, page_size);
>  	if (uncharge_memsw)
> -		res_counter_uncharge(&mem->memsw, PAGE_SIZE);
> +		res_counter_uncharge(&mem->memsw, page_size);
>  	if (unlikely(batch->memcg != mem))
>  		memcg_oom_recover(mem);
>  	return;
> @@ -2512,6 +2524,7 @@ __mem_cgroup_uncharge_common(struct page
>  {
>  	struct page_cgroup *pc;
>  	struct mem_cgroup *mem = NULL;
> +	int page_size = PAGE_SIZE;
>  
>  	if (mem_cgroup_disabled())
>  		return NULL;
> @@ -2519,6 +2532,9 @@ __mem_cgroup_uncharge_common(struct page
>  	if (PageSwapCache(page))
>  		return NULL;
>  
> +	if (PageTransHuge(page))
> +		page_size <<= compound_order(page);
> +
>  	/*
>  	 * Check if our page_cgroup is valid
>  	 */
> @@ -2572,7 +2588,7 @@ __mem_cgroup_uncharge_common(struct page
>  		mem_cgroup_get(mem);
>  	}
>  	if (!mem_cgroup_is_root(mem))
> -		__do_uncharge(mem, ctype);
> +		__do_uncharge(mem, ctype, page_size);
>  
>  	return mem;
>  
> @@ -2767,6 +2783,7 @@ int mem_cgroup_prepare_migration(struct 
>  	enum charge_type ctype;
>  	int ret = 0;
>  
> +	VM_BUG_ON(PageTransHuge(page));
>  	if (mem_cgroup_disabled())
>  		return 0;
>  
> @@ -2816,7 +2833,7 @@ int mem_cgroup_prepare_migration(struct 
>  		return 0;
>  
>  	*ptr = mem;
> -	ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, ptr, false);
> +	ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, ptr, false, PAGE_SIZE);
>  	css_put(&mem->css);/* drop extra refcnt */
>  	if (ret || *ptr == NULL) {
>  		if (PageAnon(page)) {
> @@ -2843,7 +2860,7 @@ int mem_cgroup_prepare_migration(struct 
>  		ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
>  	else
>  		ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
> -	__mem_cgroup_commit_charge(mem, pc, ctype);
> +	__mem_cgroup_commit_charge(mem, pc, ctype, PAGE_SIZE);
>  	return ret;
>  }
>  
> @@ -4452,7 +4469,8 @@ one_by_one:
>  			batch_count = PRECHARGE_COUNT_AT_ONCE;
>  			cond_resched();
>  		}
> -		ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false);
> +		ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false,
> +					      PAGE_SIZE);
>  		if (ret || !mem)
>  			/* mem_cgroup_clear_mc() will do uncharge later */
>  			return -ENOMEM;
> @@ -4614,6 +4632,7 @@ static int mem_cgroup_count_precharge_pt
>  	pte_t *pte;
>  	spinlock_t *ptl;
>  
> +	VM_BUG_ON(pmd_trans_huge(*pmd));
>  	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
>  	for (; addr != end; pte++, addr += PAGE_SIZE)
>  		if (is_target_pte_for_mc(vma, addr, *pte, NULL))
> @@ -4765,6 +4784,7 @@ static int mem_cgroup_move_charge_pte_ra
>  	spinlock_t *ptl;
>  
>  retry:
> +	VM_BUG_ON(pmd_trans_huge(*pmd));
>  	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
>  	for (; addr != end; addr += PAGE_SIZE) {
>  		pte_t ptent = *(pte++);
> 

-- 
Mel Gorman
Part-time Phd Student                          Linux Technology Center
University of Limerick                         IBM Dublin Software Lab

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