Re: [PATCH 31 of 41] memcg compound

[Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>]

On Fri, 26 Mar 2010 18:00:35 +0100, Andrea Arcangeli <aarcange@redhat.com> 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/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
> --- a/Documentation/cgroups/memory.txt
> +++ b/Documentation/cgroups/memory.txt
> @@ -4,6 +4,10 @@ NOTE: The Memory Resource Controller has
>  to as the memory controller in this document. Do not confuse memory controller
>  used here with the memory controller that is used in hardware.
>  
> +NOTE: When in this documentation we refer to PAGE_SIZE, we actually
> +mean the real page size of the page being accounted which is bigger than
> +PAGE_SIZE for compound pages.
> +
>  Salient features
>  
>  a. Enable control of Anonymous, Page Cache (mapped and unmapped) and
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c

I'm afraid, I get confused by these changes to __mem_cgroup_try_charge().

You want to charge by @page_size, right ?
Then, I think you should initialize "csize" first as:

	csize = max(CHARGE_SIZE, page_size);

> @@ -1577,7 +1577,9 @@ static int __cpuinit memcg_stock_cpu_cal
>   * 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)
>  {
>  	struct mem_cgroup *mem, *mem_over_limit;
>  	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
> @@ -1617,8 +1619,9 @@ static int __mem_cgroup_try_charge(struc
>  		int ret = 0;
>  		unsigned long flags = 0;
>  
> -		if (consume_stock(mem))
> -			goto done;
> +		if (page_size == PAGE_SIZE)
> +			if (consume_stock(mem))
> +				goto done;
>  
>  		ret = res_counter_charge(&mem->res, csize, &fail_res);
>  		if (likely(!ret)) {
> @@ -1638,8 +1641,8 @@ static int __mem_cgroup_try_charge(struc
>  									res);
>  
>  		/* reduce request size and retry */
> -		if (csize > PAGE_SIZE) {
> -			csize = PAGE_SIZE;
> +		if (csize > page_size) {
> +			csize = page_size;
>  			continue;
>  		}
>  		if (!(gfp_mask & __GFP_WAIT))
> @@ -1715,8 +1718,8 @@ static int __mem_cgroup_try_charge(struc
>  			goto bypass;
>  		}
>  	}
> -	if (csize > PAGE_SIZE)
> -		refill_stock(mem, csize - PAGE_SIZE);
> +	if (csize > page_size)
> +		refill_stock(mem, csize - page_size);
>  done:
>  	return 0;
>  nomem:
And __mem_cgroup_cancel_charge() puts the css by its @count, so you need additional
css_get() in __mem_cgroup_try_charge() in case of "page_size != PAGE_SIZE".

So,  I think __mem_cgroup_try_charge() needs the change like:


@@ -1582,12 +1582,13 @@ static int __cpuinit memcg_stock_cpu_callback(struct notifier_block *nb,
  * 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)
 {
 	struct mem_cgroup *mem, *mem_over_limit;
 	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
 	struct res_counter *fail_res;
-	int csize = CHARGE_SIZE;
+	int csize = max(CHARGE_SIZE, page_size);
 
 	/*
 	 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
@@ -1622,8 +1623,9 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
 		int ret = 0;
 		unsigned long flags = 0;
 
-		if (consume_stock(mem))
-			goto done;
+		if (page_size == PAGE_SIZE)
+			if (consume_stock(mem))
+				goto done;
 
 		ret = res_counter_charge(&mem->res, csize, &fail_res);
 		if (likely(!ret)) {
@@ -1643,8 +1645,8 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
 									res);
 
 		/* reduce request size and retry */
-		if (csize > PAGE_SIZE) {
-			csize = PAGE_SIZE;
+		if (csize > page_size) {
+			csize = page_size;
 			continue;
 		}
 		if (!(gfp_mask & __GFP_WAIT))
@@ -1720,8 +1722,10 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
 			goto bypass;
 		}
 	}
-	if (csize > PAGE_SIZE)
-		refill_stock(mem, csize - PAGE_SIZE);
+	if (csize > page_size)
+		refill_stock(mem, csize - page_size);
+	if (page_size != PAGE_SIZE)
+		__css_get(&mem->css, page_size >> PAGE_SHIFT - 1);
 done:
 	return 0;
 nomem:


Thanks,
Daisuke Nishimura.

> @@ -1746,9 +1749,10 @@ static void __mem_cgroup_cancel_charge(s
>  	/* we don't need css_put for root */
>  }
>  
> -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);
>  }
>  
>  /*
> @@ -1804,8 +1808,9 @@ 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)
> @@ -1814,7 +1819,7 @@ 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;
>  	}
>  
> @@ -1891,7 +1896,7 @@ 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;
> @@ -1952,13 +1957,14 @@ 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:
> @@ -1980,6 +1986,10 @@ static int mem_cgroup_charge_common(stru
>  	struct mem_cgroup *mem;
>  	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 */
> @@ -1988,11 +1998,11 @@ static int mem_cgroup_charge_common(stru
>  	prefetchw(pc);
>  
>  	mem = memcg;
> -	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;
>  }
>  
> @@ -2001,8 +2011,6 @@ 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.
> @@ -2015,7 +2023,7 @@ int mem_cgroup_newpage_charge(struct pag
>  	if (unlikely(!mm))
>  		mm = &init_mm;
>  	return mem_cgroup_charge_common(page, mm, gfp_mask,
> -				MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
> +					MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
>  }
>  
>  static void
> @@ -2108,14 +2116,14 @@ 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);
>  	/* drop extra refcnt from tryget */
>  	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
> @@ -2131,7 +2139,7 @@ __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
> @@ -2180,11 +2188,12 @@ 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;
> @@ -2219,14 +2228,14 @@ __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;
> @@ -2241,6 +2250,10 @@ __mem_cgroup_uncharge_common(struct page
>  	struct page_cgroup *pc;
>  	struct mem_cgroup *mem = NULL;
>  	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;
> @@ -2280,7 +2293,7 @@ __mem_cgroup_uncharge_common(struct page
>  	}
>  
>  	if (!mem_cgroup_is_root(mem))
> -		__do_uncharge(mem, ctype);
> +		__do_uncharge(mem, ctype, page_size);
>  	if (ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
>  		mem_cgroup_swap_statistics(mem, true);
>  	mem_cgroup_charge_statistics(mem, pc, false);
> @@ -2506,7 +2519,8 @@ int mem_cgroup_prepare_migration(struct 
>  	unlock_page_cgroup(pc);
>  
>  	if (mem) {
> -		ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false);
> +		ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false,
> +					      PAGE_SIZE);
>  		css_put(&mem->css);
>  	}
>  	*ptr = mem;
> @@ -2549,7 +2563,7 @@ void mem_cgroup_end_migration(struct mem
>  	 * __mem_cgroup_commit_charge() check PCG_USED bit of page_cgroup.
>  	 * So, double-counting is effectively avoided.
>  	 */
> -	__mem_cgroup_commit_charge(mem, pc, ctype);
> +	__mem_cgroup_commit_charge(mem, pc, ctype, PAGE_SIZE);
>  
>  	/*
>  	 * Both of oldpage and newpage are still under lock_page().
> @@ -4144,7 +4158,8 @@ 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;
> @@ -4259,6 +4274,7 @@ 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))
> @@ -4407,6 +4423,7 @@ 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++);
> 
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