Re: [PATCH 36 of 66] memcg compound

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

On Thu, 18 Nov 2010 15:26:28 +0000
Mel Gorman <mel@csn.ul.ie> wrote:

> 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()
> 

If there are requirements of big page > 4GB, unsigned long should be used.


> 
> >  {
> >  	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);
> >  

unsigned long here.


> >  	/*
> >  	 * 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;

Hmm, isn't it simpler to avoid batched-uncharge when page_size > 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++);
> > 
> 

Thanks,
-Kame

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