[PATCH 0/4] memcg: unified easy patch series for mmotm-Nov30

[PATCH 0/4] memcg: unified easy patch series for mmotm-Nov30

[KAMEZAWA Hiroyuki]

This patch series are fixed and clean-up agasist
 "mm-of-the-moment snapshot 2008-11-30-22-35"

Picked up useful ones from recent linux-mm.
patches are numbered but I think each can be applied one by one independently.

[1/4] clean up move_tasks of memcg.
	(From Nikanth Karthikesan <knikanth@suse.de>)
	Obvious change.

[2/4] fixes mem+swap controller's limit check
	(From Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>)
	Maybe Ack from Balbir is appropriate.

[3/4] clean up gfp_mask passed to memcg.
	From me. I want a review by Hugh Dickins and Nick Piggin. please.

[4/4] fix the name of scan_global_lru().
	From me. Obvious change.

I'll queue Kosaki's memcg LRU fixes and cgroup-ID based on this.

Thanks,
-Kame

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[PATCH 1/4] memcg: remove unused logic in mem_cgroup_move_task()

[KAMEZAWA Hiroyuki]

Remove unnecessary codes (...fragments of not-implemented functionalilty...)

Changelog:
 - removed all unused fragments.
 - added comment.


Reported-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

Index: mmotm-2.6.28-Nov30/mm/memcontrol.c
===================================================================
--- mmotm-2.6.28-Nov30.orig/mm/memcontrol.c
+++ mmotm-2.6.28-Nov30/mm/memcontrol.c
@@ -2008,25 +2008,10 @@ static void mem_cgroup_move_task(struct 
 				struct cgroup *old_cont,
 				struct task_struct *p)
 {
-	struct mm_struct *mm;
-	struct mem_cgroup *mem, *old_mem;
-
-	mm = get_task_mm(p);
-	if (mm == NULL)
-		return;
-
-	mem = mem_cgroup_from_cont(cont);
-	old_mem = mem_cgroup_from_cont(old_cont);
-
 	/*
-	 * Only thread group leaders are allowed to migrate, the mm_struct is
-	 * in effect owned by the leader
+	 * FIXME: It's better to move charges of this process from old
+	 * memcg to new memcg. But it's just on TODO-List now.
 	 */
-	if (!thread_group_leader(p))
-		goto out;
-
-out:
-	mmput(mm);
 }
 
 struct cgroup_subsys mem_cgroup_subsys = {

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[PATCH 2/4] memcg: fix limit check for mem+swap controller

[KAMEZAWA Hiroyuki]

There are scatterd calls of res_counter_check_under_limit(), and most
of them don't take mem+swap accounting into account.

define mem_cgroup_check_under_limit() and avoid direct use of
res_counter_check_limit().

Changelog:
	- replaces all res_counter_check_under_limit().

Reported-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

 mm/memcontrol.c |   26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

Index: mmotm-2.6.28-Nov30/mm/memcontrol.c
===================================================================
--- mmotm-2.6.28-Nov30.orig/mm/memcontrol.c
+++ mmotm-2.6.28-Nov30/mm/memcontrol.c
@@ -571,6 +571,18 @@ done:
 	return ret;
 }
 
+static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem)
+{
+	if (do_swap_account) {
+		if (res_counter_check_under_limit(&mem->res) &&
+			res_counter_check_under_limit(&mem->memsw))
+			return true;
+	} else
+		if (res_counter_check_under_limit(&mem->res))
+			return true;
+	return false;
+}
+
 /*
  * Dance down the hierarchy if needed to reclaim memory. We remember the
  * last child we reclaimed from, so that we don't end up penalizing
@@ -592,7 +604,7 @@ static int mem_cgroup_hierarchical_recla
 	 * have left.
 	 */
 	ret = try_to_free_mem_cgroup_pages(root_mem, gfp_mask, noswap);
-	if (res_counter_check_under_limit(&root_mem->res))
+	if (mem_cgroup_check_under_limit(root_mem))
 		return 0;
 
 	next_mem = mem_cgroup_get_first_node(root_mem);
@@ -606,7 +618,7 @@ static int mem_cgroup_hierarchical_recla
 			continue;
 		}
 		ret = try_to_free_mem_cgroup_pages(next_mem, gfp_mask, noswap);
-		if (res_counter_check_under_limit(&root_mem->res))
+		if (mem_cgroup_check_under_limit(root_mem))
 			return 0;
 		cgroup_lock();
 		next_mem = mem_cgroup_get_next_node(next_mem, root_mem);
@@ -709,12 +721,8 @@ static int __mem_cgroup_try_charge(struc
 		 * current usage of the cgroup before giving up
 		 *
 		 */
-		if (do_swap_account) {
-			if (res_counter_check_under_limit(&mem_over_limit->res) &&
-			    res_counter_check_under_limit(&mem_over_limit->memsw))
-				continue;
-		} else if (res_counter_check_under_limit(&mem_over_limit->res))
-				continue;
+		if (mem_cgroup_check_under_limit(mem_over_limit))
+			continue;
 
 		if (!nr_retries--) {
 			if (oom) {
@@ -1334,7 +1342,7 @@ int mem_cgroup_shrink_usage(struct mm_st
 
 	do {
 		progress = try_to_free_mem_cgroup_pages(mem, gfp_mask, true);
-		progress += res_counter_check_under_limit(&mem->res);
+		progress += mem_cgroup_check_under_limit(mem);
 	} while (!progress && --retry);
 
 	css_put(&mem->css);

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[PATCH 3/4] memcg: explaing memcg's gfp_mask behavior in explicit way.

[KAMEZAWA Hiroyuki]

mem_cgroup_xxx_charge(...gfpmask) function take gfpmask as its argument.
But this gfp_t is only used for check GFP_RECALIM_MASK. In other words,
memcg has no interst where the memory should be reclaimed from.
It just see usage of pages.

Using bare gfp_t is misleading and this is a patch for explaining
expected behavior in explicit way. (better name/code is welcome.)

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

 include/linux/gfp.h |   19 +++++++++++++++++++
 mm/filemap.c        |    2 +-
 mm/memory.c         |   12 +++++++-----
 mm/shmem.c          |    8 ++++----
 mm/swapfile.c       |    2 +-
 mm/vmscan.c         |    3 +--
 6 files changed, 33 insertions(+), 13 deletions(-)

Index: mmotm-2.6.28-Nov30/include/linux/gfp.h
===================================================================
--- mmotm-2.6.28-Nov30.orig/include/linux/gfp.h
+++ mmotm-2.6.28-Nov30/include/linux/gfp.h
@@ -245,4 +245,23 @@ void drain_zone_pages(struct zone *zone,
 void drain_all_pages(void);
 void drain_local_pages(void *dummy);
 
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+static inline gfp_t gfp_memcg_mask(gfp_t gfp)
+{
+	gfp_t mask;
+	/*
+	 * Memory Resource Controller memory reclaim is called to reduce usage
+	 * of memory, not to get free memory from specified area.
+	 * Remove zone constraints.
+	 */
+	mask = gfp & GFP_RECLAIM_MASK;
+	return mask | (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
+}
+#else
+static inline gfp_t gfp_memcg_mask(gfp_t gfp)
+{
+	return gfp;
+}
+#endif
+
 #endif /* __LINUX_GFP_H */
Index: mmotm-2.6.28-Nov30/mm/filemap.c
===================================================================
--- mmotm-2.6.28-Nov30.orig/mm/filemap.c
+++ mmotm-2.6.28-Nov30/mm/filemap.c
@@ -461,7 +461,7 @@ int add_to_page_cache_locked(struct page
 	VM_BUG_ON(!PageLocked(page));
 
 	error = mem_cgroup_cache_charge(page, current->mm,
-					gfp_mask & ~__GFP_HIGHMEM);
+					gfp_memcg_mask(gfp_mask));
 	if (error)
 		goto out;
 
Index: mmotm-2.6.28-Nov30/mm/vmscan.c
===================================================================
--- mmotm-2.6.28-Nov30.orig/mm/vmscan.c
+++ mmotm-2.6.28-Nov30/mm/vmscan.c
@@ -1733,8 +1733,7 @@ unsigned long try_to_free_mem_cgroup_pag
 	if (noswap)
 		sc.may_swap = 0;
 
-	sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
-			(GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
+	sc.gfp_mask = gfp_memcg_mask(gfp_mask);
 	zonelist = NODE_DATA(numa_node_id())->node_zonelists;
 	return do_try_to_free_pages(zonelist, &sc);
 }
Index: mmotm-2.6.28-Nov30/mm/memory.c
===================================================================
--- mmotm-2.6.28-Nov30.orig/mm/memory.c
+++ mmotm-2.6.28-Nov30/mm/memory.c
@@ -1913,7 +1913,8 @@ gotten:
 	cow_user_page(new_page, old_page, address, vma);
 	__SetPageUptodate(new_page);
 
-	if (mem_cgroup_newpage_charge(new_page, mm, GFP_HIGHUSER_MOVABLE))
+	if (mem_cgroup_newpage_charge(new_page, mm,
+			gfp_memcg_mask(GFP_HIGHUSER_MOVABLE)))
 		goto oom_free_new;
 
 	/*
@@ -2345,7 +2346,7 @@ static int do_swap_page(struct mm_struct
 	delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
 
 	if (mem_cgroup_try_charge_swapin(mm, page,
-				GFP_HIGHUSER_MOVABLE, &ptr) == -ENOMEM) {
+		gfp_memcg_mask(GFP_HIGHUSER_MOVABLE), &ptr) == -ENOMEM) {
 		ret = VM_FAULT_OOM;
 		unlock_page(page);
 		goto out;
@@ -2437,7 +2438,8 @@ static int do_anonymous_page(struct mm_s
 		goto oom;
 	__SetPageUptodate(page);
 
-	if (mem_cgroup_newpage_charge(page, mm, GFP_HIGHUSER_MOVABLE))
+	if (mem_cgroup_newpage_charge(page, mm,
+				gfp_memcg_mask(GFP_HIGHUSER_MOVABLE)))
 		goto oom_free_page;
 
 	entry = mk_pte(page, vma->vm_page_prot);
@@ -2528,8 +2530,8 @@ static int __do_fault(struct mm_struct *
 				ret = VM_FAULT_OOM;
 				goto out;
 			}
-			if (mem_cgroup_newpage_charge(page,
-						mm, GFP_HIGHUSER_MOVABLE)) {
+			if (mem_cgroup_newpage_charge(page, mm,
+					gfp_memcg_mask(GFP_HIGHUSER_MOVABLE))) {
 				ret = VM_FAULT_OOM;
 				page_cache_release(page);
 				goto out;
Index: mmotm-2.6.28-Nov30/mm/swapfile.c
===================================================================
--- mmotm-2.6.28-Nov30.orig/mm/swapfile.c
+++ mmotm-2.6.28-Nov30/mm/swapfile.c
@@ -698,7 +698,7 @@ static int unuse_pte(struct vm_area_stru
 	int ret = 1;
 
 	if (mem_cgroup_try_charge_swapin(vma->vm_mm, page,
-					GFP_HIGHUSER_MOVABLE, &ptr))
+				gfp_memcg_mask(GFP_HIGHUSER_MOVABLE), &ptr))
 		ret = -ENOMEM;
 
 	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
Index: mmotm-2.6.28-Nov30/mm/shmem.c
===================================================================
--- mmotm-2.6.28-Nov30.orig/mm/shmem.c
+++ mmotm-2.6.28-Nov30/mm/shmem.c
@@ -924,8 +924,8 @@ found:
 	 * Charge page using GFP_HIGHUSER_MOVABLE while we can wait.
 	 * charged back to the user(not to caller) when swap account is used.
 	 */
-	error = mem_cgroup_cache_charge_swapin(page,
-			current->mm, GFP_HIGHUSER_MOVABLE, true);
+	error = mem_cgroup_cache_charge_swapin(page, current->mm,
+			gfp_memcg_mask(GFP_HIGHUSER_MOVABLE), true);
 	if (error)
 		goto out;
 	error = radix_tree_preload(GFP_KERNEL);
@@ -1267,7 +1267,7 @@ repeat:
 			 * charge against this swap cache here.
 			 */
 			if (mem_cgroup_cache_charge_swapin(swappage,
-						current->mm, gfp, false)) {
+				current->mm, gfp_memcg_mask(gfp), false)) {
 				page_cache_release(swappage);
 				error = -ENOMEM;
 				goto failed;
@@ -1385,7 +1385,7 @@ repeat:
 
 			/* Precharge page while we can wait, compensate after */
 			error = mem_cgroup_cache_charge(filepage, current->mm,
-					GFP_HIGHUSER_MOVABLE);
+					gfp_memcg_mask(GFP_HIGHUSER_MOVABLE));
 			if (error) {
 				page_cache_release(filepage);
 				shmem_unacct_blocks(info->flags, 1);

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Re: [PATCH 3/4] memcg: explaing memcg's gfp_mask behavior in explicit way.

[Hugh Dickins]

On Mon, 1 Dec 2008, KAMEZAWA Hiroyuki wrote:
> mem_cgroup_xxx_charge(...gfpmask) function take gfpmask as its argument.
> But this gfp_t is only used for check GFP_RECALIM_MASK. In other words,
> memcg has no interst where the memory should be reclaimed from.
> It just see usage of pages.
> 
> Using bare gfp_t is misleading and this is a patch for explaining
> expected behavior in explicit way. (better name/code is welcome.)
> 
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

Sorry, but I hate it.  You're spreading mem_cgroup ugliness throughout.

This is a good demonstation of why I wanted to go the opposite way to
Nick, why I wanted to push the masking as low as possible; I accept
Nick's point, but please, not at the expense of being this ugly.

It's a pity about loop over tmpfs, IIRC without that case you could
just remove the gfp_mask argument from every one of them - that is a
change I would appreciate!  Or am I forgetting some other cases?

I think you should remove the arg from every one you can, and change
those shmem_getpage() ones to say "gfp & GFP_RECLAIM_MASK" (just as
we'll be changing the radix_tree_preload later).

Hmm, shmem_getpage()'s mem_cgroup_cache_charge(,, gfp & ~__GFP_HIGHMEM)
has morphed into mem_cgroup_cache_charge(,, GFP_HIGHUSER_MOVABLE) in
mmotm (well, mmo2daysago, I've not looked today).  How come?

It used to be the case that the mem_cgroup calls made their own
memory allocations, and that could become the case again in future:
the gfp mask was passed down for those allocations, and it was almost
everywhere GFP_KERNEL.

mem_cgroup charging may need to reclaim some memory from the memcg:
it happens that the category of memory it goes for is HIGHUSER_MOVABLE;
and it happens that the gfp mask for any incidental allocations it might
want to make, also provides the GFP_RECLAIM_MASK flags for that reclaim.
But please keep that within mem_cgroup_cache_charge_common or whatever.

Hugh

> 
>  include/linux/gfp.h |   19 +++++++++++++++++++
>  mm/filemap.c        |    2 +-
>  mm/memory.c         |   12 +++++++-----
>  mm/shmem.c          |    8 ++++----
>  mm/swapfile.c       |    2 +-
>  mm/vmscan.c         |    3 +--
>  6 files changed, 33 insertions(+), 13 deletions(-)
> 
> Index: mmotm-2.6.28-Nov30/include/linux/gfp.h
> ===================================================================
> --- mmotm-2.6.28-Nov30.orig/include/linux/gfp.h
> +++ mmotm-2.6.28-Nov30/include/linux/gfp.h
> @@ -245,4 +245,23 @@ void drain_zone_pages(struct zone *zone,
>  void drain_all_pages(void);
>  void drain_local_pages(void *dummy);
>  
> +#ifdef CONFIG_CGROUP_MEM_RES_CTLR
> +static inline gfp_t gfp_memcg_mask(gfp_t gfp)
> +{
> +	gfp_t mask;
> +	/*
> +	 * Memory Resource Controller memory reclaim is called to reduce usage
> +	 * of memory, not to get free memory from specified area.
> +	 * Remove zone constraints.
> +	 */
> +	mask = gfp & GFP_RECLAIM_MASK;
> +	return mask | (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
> +}
> +#else
> +static inline gfp_t gfp_memcg_mask(gfp_t gfp)
> +{
> +	return gfp;
> +}
> +#endif
> +
>  #endif /* __LINUX_GFP_H */
> Index: mmotm-2.6.28-Nov30/mm/filemap.c
> ===================================================================
> --- mmotm-2.6.28-Nov30.orig/mm/filemap.c
> +++ mmotm-2.6.28-Nov30/mm/filemap.c
> @@ -461,7 +461,7 @@ int add_to_page_cache_locked(struct page
>  	VM_BUG_ON(!PageLocked(page));
>  
>  	error = mem_cgroup_cache_charge(page, current->mm,
> -					gfp_mask & ~__GFP_HIGHMEM);
> +					gfp_memcg_mask(gfp_mask));
>  	if (error)
>  		goto out;
>  
> Index: mmotm-2.6.28-Nov30/mm/vmscan.c
> ===================================================================
> --- mmotm-2.6.28-Nov30.orig/mm/vmscan.c
> +++ mmotm-2.6.28-Nov30/mm/vmscan.c
> @@ -1733,8 +1733,7 @@ unsigned long try_to_free_mem_cgroup_pag
>  	if (noswap)
>  		sc.may_swap = 0;
>  
> -	sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
> -			(GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
> +	sc.gfp_mask = gfp_memcg_mask(gfp_mask);
>  	zonelist = NODE_DATA(numa_node_id())->node_zonelists;
>  	return do_try_to_free_pages(zonelist, &sc);
>  }
> Index: mmotm-2.6.28-Nov30/mm/memory.c
> ===================================================================
> --- mmotm-2.6.28-Nov30.orig/mm/memory.c
> +++ mmotm-2.6.28-Nov30/mm/memory.c
> @@ -1913,7 +1913,8 @@ gotten:
>  	cow_user_page(new_page, old_page, address, vma);
>  	__SetPageUptodate(new_page);
>  
> -	if (mem_cgroup_newpage_charge(new_page, mm, GFP_HIGHUSER_MOVABLE))
> +	if (mem_cgroup_newpage_charge(new_page, mm,
> +			gfp_memcg_mask(GFP_HIGHUSER_MOVABLE)))
>  		goto oom_free_new;
>  
>  	/*
> @@ -2345,7 +2346,7 @@ static int do_swap_page(struct mm_struct
>  	delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
>  
>  	if (mem_cgroup_try_charge_swapin(mm, page,
> -				GFP_HIGHUSER_MOVABLE, &ptr) == -ENOMEM) {
> +		gfp_memcg_mask(GFP_HIGHUSER_MOVABLE), &ptr) == -ENOMEM) {
>  		ret = VM_FAULT_OOM;
>  		unlock_page(page);
>  		goto out;
> @@ -2437,7 +2438,8 @@ static int do_anonymous_page(struct mm_s
>  		goto oom;
>  	__SetPageUptodate(page);
>  
> -	if (mem_cgroup_newpage_charge(page, mm, GFP_HIGHUSER_MOVABLE))
> +	if (mem_cgroup_newpage_charge(page, mm,
> +				gfp_memcg_mask(GFP_HIGHUSER_MOVABLE)))
>  		goto oom_free_page;
>  
>  	entry = mk_pte(page, vma->vm_page_prot);
> @@ -2528,8 +2530,8 @@ static int __do_fault(struct mm_struct *
>  				ret = VM_FAULT_OOM;
>  				goto out;
>  			}
> -			if (mem_cgroup_newpage_charge(page,
> -						mm, GFP_HIGHUSER_MOVABLE)) {
> +			if (mem_cgroup_newpage_charge(page, mm,
> +					gfp_memcg_mask(GFP_HIGHUSER_MOVABLE))) {
>  				ret = VM_FAULT_OOM;
>  				page_cache_release(page);
>  				goto out;
> Index: mmotm-2.6.28-Nov30/mm/swapfile.c
> ===================================================================
> --- mmotm-2.6.28-Nov30.orig/mm/swapfile.c
> +++ mmotm-2.6.28-Nov30/mm/swapfile.c
> @@ -698,7 +698,7 @@ static int unuse_pte(struct vm_area_stru
>  	int ret = 1;
>  
>  	if (mem_cgroup_try_charge_swapin(vma->vm_mm, page,
> -					GFP_HIGHUSER_MOVABLE, &ptr))
> +				gfp_memcg_mask(GFP_HIGHUSER_MOVABLE), &ptr))
>  		ret = -ENOMEM;
>  
>  	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
> Index: mmotm-2.6.28-Nov30/mm/shmem.c
> ===================================================================
> --- mmotm-2.6.28-Nov30.orig/mm/shmem.c
> +++ mmotm-2.6.28-Nov30/mm/shmem.c
> @@ -924,8 +924,8 @@ found:
>  	 * Charge page using GFP_HIGHUSER_MOVABLE while we can wait.
>  	 * charged back to the user(not to caller) when swap account is used.
>  	 */
> -	error = mem_cgroup_cache_charge_swapin(page,
> -			current->mm, GFP_HIGHUSER_MOVABLE, true);
> +	error = mem_cgroup_cache_charge_swapin(page, current->mm,
> +			gfp_memcg_mask(GFP_HIGHUSER_MOVABLE), true);
>  	if (error)
>  		goto out;
>  	error = radix_tree_preload(GFP_KERNEL);
> @@ -1267,7 +1267,7 @@ repeat:
>  			 * charge against this swap cache here.
>  			 */
>  			if (mem_cgroup_cache_charge_swapin(swappage,
> -						current->mm, gfp, false)) {
> +				current->mm, gfp_memcg_mask(gfp), false)) {
>  				page_cache_release(swappage);
>  				error = -ENOMEM;
>  				goto failed;
> @@ -1385,7 +1385,7 @@ repeat:
>  
>  			/* Precharge page while we can wait, compensate after */
>  			error = mem_cgroup_cache_charge(filepage, current->mm,
> -					GFP_HIGHUSER_MOVABLE);
> +					gfp_memcg_mask(GFP_HIGHUSER_MOVABLE));
>  			if (error) {
>  				page_cache_release(filepage);
>  				shmem_unacct_blocks(info->flags, 1);
> 

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Re: [PATCH 3/4] memcg: explaing memcg's gfp_mask behavior in explicit way.

[KAMEZAWA Hiroyuki]

On Tue, 2 Dec 2008 00:32:29 +0000 (GMT)
Hugh Dickins <hugh@veritas.com> wrote:

> On Mon, 1 Dec 2008, KAMEZAWA Hiroyuki wrote:
> > mem_cgroup_xxx_charge(...gfpmask) function take gfpmask as its argument.
> > But this gfp_t is only used for check GFP_RECALIM_MASK. In other words,
> > memcg has no interst where the memory should be reclaimed from.
> > It just see usage of pages.
> > 
> > Using bare gfp_t is misleading and this is a patch for explaining
> > expected behavior in explicit way. (better name/code is welcome.)
> > 
> > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> 
> Sorry, but I hate it.  You're spreading mem_cgroup ugliness throughout.
> 
> This is a good demonstation of why I wanted to go the opposite way to
> Nick, why I wanted to push the masking as low as possible; I accept
> Nick's point, but please, not at the expense of being this ugly.
> 
Okay ;)


> It's a pity about loop over tmpfs, IIRC without that case you could
> just remove the gfp_mask argument from every one of them - that is a
> change I would appreciate!  Or am I forgetting some other cases?
> 

Ah, I considered that. putting gfp_mask here is for rememebering
"this will do page reclaim".

> I think you should remove the arg from every one you can, and change
> those shmem_getpage() ones to say "gfp & GFP_RECLAIM_MASK" (just as
> we'll be changing the radix_tree_preload later).
> 
I'll look into again 

> Hmm, shmem_getpage()'s mem_cgroup_cache_charge(,, gfp & ~__GFP_HIGHMEM)
> has morphed into mem_cgroup_cache_charge(,, GFP_HIGHUSER_MOVABLE) in
> mmotm (well, mmo2daysago, I've not looked today).  How come?
> 
Maybe my patches/memcg-fix-gfp_mask-of-callers-of-charge.patch.
Hmm, I'll write replacement patch for this and remove gfp_t.

> It used to be the case that the mem_cgroup calls made their own
> memory allocations, and that could become the case again in future:
> the gfp mask was passed down for those allocations, and it was almost
> everywhere GFP_KERNEL.
> 
> mem_cgroup charging may need to reclaim some memory from the memcg:
> it happens that the category of memory it goes for is HIGHUSER_MOVABLE;
> and it happens that the gfp mask for any incidental allocations it might
> want to make, also provides the GFP_RECLAIM_MASK flags for that reclaim.
> But please keep that within mem_cgroup_cache_charge_common or whatever.
> 

Okay. I'll write replacment for memcg-fix-gfp_mask-of-callers-of-charge.patch.

-Kame

> Hugh
> 
> > 
> >  include/linux/gfp.h |   19 +++++++++++++++++++
> >  mm/filemap.c        |    2 +-
> >  mm/memory.c         |   12 +++++++-----
> >  mm/shmem.c          |    8 ++++----
> >  mm/swapfile.c       |    2 +-
> >  mm/vmscan.c         |    3 +--
> >  6 files changed, 33 insertions(+), 13 deletions(-)
> > 
> > Index: mmotm-2.6.28-Nov30/include/linux/gfp.h
> > ===================================================================
> > --- mmotm-2.6.28-Nov30.orig/include/linux/gfp.h
> > +++ mmotm-2.6.28-Nov30/include/linux/gfp.h
> > @@ -245,4 +245,23 @@ void drain_zone_pages(struct zone *zone,
> >  void drain_all_pages(void);
> >  void drain_local_pages(void *dummy);
> >  
> > +#ifdef CONFIG_CGROUP_MEM_RES_CTLR
> > +static inline gfp_t gfp_memcg_mask(gfp_t gfp)
> > +{
> > +	gfp_t mask;
> > +	/*
> > +	 * Memory Resource Controller memory reclaim is called to reduce usage
> > +	 * of memory, not to get free memory from specified area.
> > +	 * Remove zone constraints.
> > +	 */
> > +	mask = gfp & GFP_RECLAIM_MASK;
> > +	return mask | (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
> > +}
> > +#else
> > +static inline gfp_t gfp_memcg_mask(gfp_t gfp)
> > +{
> > +	return gfp;
> > +}
> > +#endif
> > +
> >  #endif /* __LINUX_GFP_H */
> > Index: mmotm-2.6.28-Nov30/mm/filemap.c
> > ===================================================================
> > --- mmotm-2.6.28-Nov30.orig/mm/filemap.c
> > +++ mmotm-2.6.28-Nov30/mm/filemap.c
> > @@ -461,7 +461,7 @@ int add_to_page_cache_locked(struct page
> >  	VM_BUG_ON(!PageLocked(page));
> >  
> >  	error = mem_cgroup_cache_charge(page, current->mm,
> > -					gfp_mask & ~__GFP_HIGHMEM);
> > +					gfp_memcg_mask(gfp_mask));
> >  	if (error)
> >  		goto out;
> >  
> > Index: mmotm-2.6.28-Nov30/mm/vmscan.c
> > ===================================================================
> > --- mmotm-2.6.28-Nov30.orig/mm/vmscan.c
> > +++ mmotm-2.6.28-Nov30/mm/vmscan.c
> > @@ -1733,8 +1733,7 @@ unsigned long try_to_free_mem_cgroup_pag
> >  	if (noswap)
> >  		sc.may_swap = 0;
> >  
> > -	sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
> > -			(GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
> > +	sc.gfp_mask = gfp_memcg_mask(gfp_mask);
> >  	zonelist = NODE_DATA(numa_node_id())->node_zonelists;
> >  	return do_try_to_free_pages(zonelist, &sc);
> >  }
> > Index: mmotm-2.6.28-Nov30/mm/memory.c
> > ===================================================================
> > --- mmotm-2.6.28-Nov30.orig/mm/memory.c
> > +++ mmotm-2.6.28-Nov30/mm/memory.c
> > @@ -1913,7 +1913,8 @@ gotten:
> >  	cow_user_page(new_page, old_page, address, vma);
> >  	__SetPageUptodate(new_page);
> >  
> > -	if (mem_cgroup_newpage_charge(new_page, mm, GFP_HIGHUSER_MOVABLE))
> > +	if (mem_cgroup_newpage_charge(new_page, mm,
> > +			gfp_memcg_mask(GFP_HIGHUSER_MOVABLE)))
> >  		goto oom_free_new;
> >  
> >  	/*
> > @@ -2345,7 +2346,7 @@ static int do_swap_page(struct mm_struct
> >  	delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
> >  
> >  	if (mem_cgroup_try_charge_swapin(mm, page,
> > -				GFP_HIGHUSER_MOVABLE, &ptr) == -ENOMEM) {
> > +		gfp_memcg_mask(GFP_HIGHUSER_MOVABLE), &ptr) == -ENOMEM) {
> >  		ret = VM_FAULT_OOM;
> >  		unlock_page(page);
> >  		goto out;
> > @@ -2437,7 +2438,8 @@ static int do_anonymous_page(struct mm_s
> >  		goto oom;
> >  	__SetPageUptodate(page);
> >  
> > -	if (mem_cgroup_newpage_charge(page, mm, GFP_HIGHUSER_MOVABLE))
> > +	if (mem_cgroup_newpage_charge(page, mm,
> > +				gfp_memcg_mask(GFP_HIGHUSER_MOVABLE)))
> >  		goto oom_free_page;
> >  
> >  	entry = mk_pte(page, vma->vm_page_prot);
> > @@ -2528,8 +2530,8 @@ static int __do_fault(struct mm_struct *
> >  				ret = VM_FAULT_OOM;
> >  				goto out;
> >  			}
> > -			if (mem_cgroup_newpage_charge(page,
> > -						mm, GFP_HIGHUSER_MOVABLE)) {
> > +			if (mem_cgroup_newpage_charge(page, mm,
> > +					gfp_memcg_mask(GFP_HIGHUSER_MOVABLE))) {
> >  				ret = VM_FAULT_OOM;
> >  				page_cache_release(page);
> >  				goto out;
> > Index: mmotm-2.6.28-Nov30/mm/swapfile.c
> > ===================================================================
> > --- mmotm-2.6.28-Nov30.orig/mm/swapfile.c
> > +++ mmotm-2.6.28-Nov30/mm/swapfile.c
> > @@ -698,7 +698,7 @@ static int unuse_pte(struct vm_area_stru
> >  	int ret = 1;
> >  
> >  	if (mem_cgroup_try_charge_swapin(vma->vm_mm, page,
> > -					GFP_HIGHUSER_MOVABLE, &ptr))
> > +				gfp_memcg_mask(GFP_HIGHUSER_MOVABLE), &ptr))
> >  		ret = -ENOMEM;
> >  
> >  	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
> > Index: mmotm-2.6.28-Nov30/mm/shmem.c
> > ===================================================================
> > --- mmotm-2.6.28-Nov30.orig/mm/shmem.c
> > +++ mmotm-2.6.28-Nov30/mm/shmem.c
> > @@ -924,8 +924,8 @@ found:
> >  	 * Charge page using GFP_HIGHUSER_MOVABLE while we can wait.
> >  	 * charged back to the user(not to caller) when swap account is used.
> >  	 */
> > -	error = mem_cgroup_cache_charge_swapin(page,
> > -			current->mm, GFP_HIGHUSER_MOVABLE, true);
> > +	error = mem_cgroup_cache_charge_swapin(page, current->mm,
> > +			gfp_memcg_mask(GFP_HIGHUSER_MOVABLE), true);
> >  	if (error)
> >  		goto out;
> >  	error = radix_tree_preload(GFP_KERNEL);
> > @@ -1267,7 +1267,7 @@ repeat:
> >  			 * charge against this swap cache here.
> >  			 */
> >  			if (mem_cgroup_cache_charge_swapin(swappage,
> > -						current->mm, gfp, false)) {
> > +				current->mm, gfp_memcg_mask(gfp), false)) {
> >  				page_cache_release(swappage);
> >  				error = -ENOMEM;
> >  				goto failed;
> > @@ -1385,7 +1385,7 @@ repeat:
> >  
> >  			/* Precharge page while we can wait, compensate after */
> >  			error = mem_cgroup_cache_charge(filepage, current->mm,
> > -					GFP_HIGHUSER_MOVABLE);
> > +					gfp_memcg_mask(GFP_HIGHUSER_MOVABLE));
> >  			if (error) {
> >  				page_cache_release(filepage);
> >  				shmem_unacct_blocks(info->flags, 1);
> > 
> 

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[PATCH 4/4] memcg: rename scan_global_lru macro

[KAMEZAWA Hiroyuki]

Rename scan_grobal_lru() to scanning_global_lru().

scan_global_lru() sounds like that it does "scan" global lru.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

 mm/vmscan.c |   34 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 17 deletions(-)

Index: mmotm-2.6.28-Nov30/mm/vmscan.c
===================================================================
--- mmotm-2.6.28-Nov30.orig/mm/vmscan.c
+++ mmotm-2.6.28-Nov30/mm/vmscan.c
@@ -126,9 +126,9 @@ static LIST_HEAD(shrinker_list);
 static DECLARE_RWSEM(shrinker_rwsem);
 
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
-#define scan_global_lru(sc)	(!(sc)->mem_cgroup)
+#define scanning_global_lru(sc)	(!(sc)->mem_cgroup)
 #else
-#define scan_global_lru(sc)	(1)
+#define scanning_global_lru(sc)	(1)
 #endif
 
 /*
@@ -1124,7 +1124,7 @@ static unsigned long shrink_inactive_lis
 		__mod_zone_page_state(zone, NR_INACTIVE_ANON,
 						-count[LRU_INACTIVE_ANON]);
 
-		if (scan_global_lru(sc)) {
+		if (scanning_global_lru(sc)) {
 			zone->pages_scanned += nr_scan;
 			zone->recent_scanned[0] += count[LRU_INACTIVE_ANON];
 			zone->recent_scanned[0] += count[LRU_ACTIVE_ANON];
@@ -1162,7 +1162,7 @@ static unsigned long shrink_inactive_lis
 		if (current_is_kswapd()) {
 			__count_zone_vm_events(PGSCAN_KSWAPD, zone, nr_scan);
 			__count_vm_events(KSWAPD_STEAL, nr_freed);
-		} else if (scan_global_lru(sc))
+		} else if (scanning_global_lru(sc))
 			__count_zone_vm_events(PGSCAN_DIRECT, zone, nr_scan);
 
 		__count_zone_vm_events(PGSTEAL, zone, nr_freed);
@@ -1188,7 +1188,7 @@ static unsigned long shrink_inactive_lis
 			SetPageLRU(page);
 			lru = page_lru(page);
 			add_page_to_lru_list(zone, page, lru);
-			if (PageActive(page) && scan_global_lru(sc)) {
+			if (PageActive(page) && scanning_global_lru(sc)) {
 				int file = !!page_is_file_cache(page);
 				zone->recent_rotated[file]++;
 			}
@@ -1265,7 +1265,7 @@ static void shrink_active_list(unsigned 
 	 * zone->pages_scanned is used for detect zone's oom
 	 * mem_cgroup remembers nr_scan by itself.
 	 */
-	if (scan_global_lru(sc)) {
+	if (scanning_global_lru(sc)) {
 		zone->pages_scanned += pgscanned;
 		zone->recent_scanned[!!file] += pgmoved;
 	}
@@ -1301,7 +1301,7 @@ static void shrink_active_list(unsigned 
 	 * This helps balance scan pressure between file and anonymous
 	 * pages in get_scan_ratio.
 	 */
-	if (scan_global_lru(sc))
+	if (scanning_global_lru(sc))
 		zone->recent_rotated[!!file] += pgmoved;
 
 	/*
@@ -1361,7 +1361,7 @@ static unsigned long shrink_list(enum lr
 	}
 
 	if (lru == LRU_ACTIVE_ANON &&
-	    (!scan_global_lru(sc) || inactive_anon_is_low(zone))) {
+	    (!scanning_global_lru(sc) || inactive_anon_is_low(zone))) {
 		shrink_active_list(nr_to_scan, zone, sc, priority, file);
 		return 0;
 	}
@@ -1467,7 +1467,7 @@ static void shrink_zone(int priority, st
 	get_scan_ratio(zone, sc, percent);
 
 	for_each_evictable_lru(l) {
-		if (scan_global_lru(sc)) {
+		if (scanning_global_lru(sc)) {
 			int file = is_file_lru(l);
 			int scan;
 
@@ -1522,9 +1522,9 @@ static void shrink_zone(int priority, st
 	 * Even if we did not try to evict anon pages at all, we want to
 	 * rebalance the anon lru active/inactive ratio.
 	 */
-	if (!scan_global_lru(sc) || inactive_anon_is_low(zone))
+	if (!scanning_global_lru(sc) || inactive_anon_is_low(zone))
 		shrink_active_list(SWAP_CLUSTER_MAX, zone, sc, priority, 0);
-	else if (!scan_global_lru(sc))
+	else if (!scanning_global_lru(sc))
 		shrink_active_list(SWAP_CLUSTER_MAX, zone, sc, priority, 0);
 
 	throttle_vm_writeout(sc->gfp_mask);
@@ -1559,7 +1559,7 @@ static void shrink_zones(int priority, s
 		 * Take care memory controller reclaiming has small influence
 		 * to global LRU.
 		 */
-		if (scan_global_lru(sc)) {
+		if (scanning_global_lru(sc)) {
 			if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
 				continue;
 			note_zone_scanning_priority(zone, priority);
@@ -1612,12 +1612,12 @@ static unsigned long do_try_to_free_page
 
 	delayacct_freepages_start();
 
-	if (scan_global_lru(sc))
+	if (scanning_global_lru(sc))
 		count_vm_event(ALLOCSTALL);
 	/*
 	 * mem_cgroup will not do shrink_slab.
 	 */
-	if (scan_global_lru(sc)) {
+	if (scanning_global_lru(sc)) {
 		for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
 
 			if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
@@ -1636,7 +1636,7 @@ static unsigned long do_try_to_free_page
 		 * Don't shrink slabs when reclaiming memory from
 		 * over limit cgroups
 		 */
-		if (scan_global_lru(sc)) {
+		if (scanning_global_lru(sc)) {
 			shrink_slab(sc->nr_scanned, sc->gfp_mask, lru_pages, NULL);
 			if (reclaim_state) {
 				sc->nr_reclaimed += reclaim_state->reclaimed_slab;
@@ -1667,7 +1667,7 @@ static unsigned long do_try_to_free_page
 			congestion_wait(WRITE, HZ/10);
 	}
 	/* top priority shrink_zones still had more to do? don't OOM, then */
-	if (!sc->all_unreclaimable && scan_global_lru(sc))
+	if (!sc->all_unreclaimable && scanning_global_lru(sc))
 		ret = sc->nr_reclaimed;
 out:
 	/*
@@ -1680,7 +1680,7 @@ out:
 	if (priority < 0)
 		priority = 0;
 
-	if (scan_global_lru(sc)) {
+	if (scanning_global_lru(sc)) {
 		for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
 
 			if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))

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