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Commit 694fbc0f authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds
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revert "memcg: enhance memcg iterator to support predicates" 



Revert commit de57780d ("memcg: enhance memcg iterator to support
predicates")

I merged this prematurely - Michal and Johannes still disagree about the
overall design direction and the future remains unclear.

Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 30361e51

include/linux/memcontrol.h

+6 −43
Original line number Diff line number Diff line
@@ -53,23 +53,6 @@ struct mem_cgroup_reclaim_cookie { 
	unsigned int generation;

};



enum mem_cgroup_filter_t {

	VISIT,		/* visit current node */

	SKIP,		/* skip the current node and continue traversal */

	SKIP_TREE,	/* skip the whole subtree and continue traversal */

};



/*

 * mem_cgroup_filter_t predicate might instruct mem_cgroup_iter_cond how to

 * iterate through the hierarchy tree. Each tree element is checked by the

 * predicate before it is returned by the iterator. If a filter returns

 * SKIP or SKIP_TREE then the iterator code continues traversal (with the

 * next node down the hierarchy or the next node that doesn't belong under the

 * memcg's subtree).

 */

typedef enum mem_cgroup_filter_t

(*mem_cgroup_iter_filter)(struct mem_cgroup *memcg, struct mem_cgroup *root);



#ifdef CONFIG_MEMCG

/*

 * All "charge" functions with gfp_mask should use GFP_KERNEL or
@@ -137,18 +120,9 @@ mem_cgroup_prepare_migration(struct page *page, struct page *newpage, 
extern void mem_cgroup_end_migration(struct mem_cgroup *memcg,

	struct page *oldpage, struct page *newpage, bool migration_ok);



struct mem_cgroup *mem_cgroup_iter_cond(struct mem_cgroup *root,

				   struct mem_cgroup *prev,

				   struct mem_cgroup_reclaim_cookie *reclaim,

				   mem_cgroup_iter_filter cond);



static inline struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,

				   struct mem_cgroup *prev,

				   struct mem_cgroup_reclaim_cookie *reclaim)

{

	return mem_cgroup_iter_cond(root, prev, reclaim, NULL);

}



struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *,

				   struct mem_cgroup *,

				   struct mem_cgroup_reclaim_cookie *);

void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *);



/*
@@ -260,8 +234,7 @@ static inline void mem_cgroup_dec_page_stat(struct page *page, 
	mem_cgroup_update_page_stat(page, idx, -1);

}



enum mem_cgroup_filter_t

mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,

bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,

		struct mem_cgroup *root);



void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx);
@@ -376,15 +349,6 @@ static inline void mem_cgroup_end_migration(struct mem_cgroup *memcg, 
		struct page *oldpage, struct page *newpage, bool migration_ok)

{

}

static inline struct mem_cgroup *

mem_cgroup_iter_cond(struct mem_cgroup *root,

		struct mem_cgroup *prev,

		struct mem_cgroup_reclaim_cookie *reclaim,

		mem_cgroup_iter_filter cond)

{

	/* first call must return non-NULL, second return NULL */

	return (struct mem_cgroup *)(unsigned long)!prev;

}



static inline struct mem_cgroup *

mem_cgroup_iter(struct mem_cgroup *root,
@@ -471,11 +435,10 @@ static inline void mem_cgroup_dec_page_stat(struct page *page, 
}



static inline

enum mem_cgroup_filter_t

mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,

bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,

		struct mem_cgroup *root)

{

	return VISIT;

	return false;

}



static inline void mem_cgroup_split_huge_fixup(struct page *head)

mm/memcontrol.c

+15 −55
Original line number Diff line number Diff line
@@ -862,15 +862,6 @@ struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) 
	return memcg;

}



static enum mem_cgroup_filter_t

mem_cgroup_filter(struct mem_cgroup *memcg, struct mem_cgroup *root,

		mem_cgroup_iter_filter cond)

{

	if (!cond)

		return VISIT;

	return cond(memcg, root);

}



/*

 * Returns a next (in a pre-order walk) alive memcg (with elevated css

 * ref. count) or NULL if the whole root's subtree has been visited.
@@ -878,7 +869,7 @@ mem_cgroup_filter(struct mem_cgroup *memcg, struct mem_cgroup *root, 
 * helper function to be used by mem_cgroup_iter

 */

static struct mem_cgroup *__mem_cgroup_iter_next(struct mem_cgroup *root,

		struct mem_cgroup *last_visited, mem_cgroup_iter_filter cond)

		struct mem_cgroup *last_visited)

{

	struct cgroup_subsys_state *prev_css, *next_css;
@@ -896,32 +887,12 @@ skip_node: 
	if (next_css) {

		struct mem_cgroup *mem = mem_cgroup_from_css(next_css);



		switch (mem_cgroup_filter(mem, root, cond)) {

		case SKIP:

			prev_css = next_css;

			goto skip_node;

		case SKIP_TREE:

			if (mem == root)

				return NULL;

			/*

			 * css_rightmost_descendant is not an optimal way to

			 * skip through a subtree (especially for imbalanced

			 * trees leaning to right) but that's what we have right

			 * now. More effective solution would be traversing

			 * right-up for first non-NULL without calling

			 * css_next_descendant_pre afterwards.

			 */

			prev_css = css_rightmost_descendant(next_css);

			goto skip_node;

		case VISIT:

		if (css_tryget(&mem->css))

			return mem;

		else {

			prev_css = next_css;

			goto skip_node;

		}

			break;

		}

	}



	return NULL;
@@ -984,7 +955,6 @@ static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter *iter, 
 * @root: hierarchy root

 * @prev: previously returned memcg, NULL on first invocation

 * @reclaim: cookie for shared reclaim walks, NULL for full walks

 * @cond: filter for visited nodes, NULL for no filter

 *

 * Returns references to children of the hierarchy below @root, or

 * @root itself, or %NULL after a full round-trip.
@@ -997,18 +967,15 @@ static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter *iter, 
 * divide up the memcgs in the hierarchy among all concurrent

 * reclaimers operating on the same zone and priority.

 */

struct mem_cgroup *mem_cgroup_iter_cond(struct mem_cgroup *root,

struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,

				   struct mem_cgroup *prev,

				   struct mem_cgroup_reclaim_cookie *reclaim,

				   mem_cgroup_iter_filter cond)

				   struct mem_cgroup_reclaim_cookie *reclaim)

{

	struct mem_cgroup *memcg = NULL;

	struct mem_cgroup *last_visited = NULL;



	if (mem_cgroup_disabled()) {

		/* first call must return non-NULL, second return NULL */

		return (struct mem_cgroup *)(unsigned long)!prev;

	}

	if (mem_cgroup_disabled())

		return NULL;



	if (!root)

		root = root_mem_cgroup;
@@ -1019,9 +986,7 @@ struct mem_cgroup *mem_cgroup_iter_cond(struct mem_cgroup *root, 
	if (!root->use_hierarchy && root != root_mem_cgroup) {

		if (prev)

			goto out_css_put;

		if (mem_cgroup_filter(root, root, cond) == VISIT)

		return root;

		return NULL;

	}



	rcu_read_lock();
@@ -1044,7 +1009,7 @@ struct mem_cgroup *mem_cgroup_iter_cond(struct mem_cgroup *root, 
			last_visited = mem_cgroup_iter_load(iter, root, &seq);

		}



		memcg = __mem_cgroup_iter_next(root, last_visited, cond);

		memcg = __mem_cgroup_iter_next(root, last_visited);



		if (reclaim) {

			mem_cgroup_iter_update(iter, last_visited, memcg, seq);
@@ -1055,11 +1020,7 @@ struct mem_cgroup *mem_cgroup_iter_cond(struct mem_cgroup *root, 
				reclaim->generation = iter->generation;

		}



		/*

		 * We have finished the whole tree walk or no group has been

		 * visited because filter told us to skip the root node.

		 */

		if (!memcg && (prev || (cond && !last_visited)))

		if (prev && !memcg)

			goto out_unlock;

	}

out_unlock:
@@ -1804,14 +1765,13 @@ int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) 
 *	a) it is over its soft limit

 *	b) any parent up the hierarchy is over its soft limit

 */

enum mem_cgroup_filter_t

mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,

bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,

		struct mem_cgroup *root)

{

	struct mem_cgroup *parent = memcg;



	if (res_counter_soft_limit_excess(&memcg->res))

		return VISIT;

		return true;



	/*

	 * If any parent up to the root in the hierarchy is over its soft limit
@@ -1819,12 +1779,12 @@ mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg, 
	 */

	while ((parent = parent_mem_cgroup(parent))) {

		if (res_counter_soft_limit_excess(&parent->res))

			return VISIT;

			return true;

		if (parent == root)

			break;

	}



	return SKIP;

	return false;

}



static DEFINE_SPINLOCK(memcg_oom_lock);

mm/vmscan.c

+11 −5
Original line number Diff line number Diff line
@@ -2185,16 +2185,21 @@ __shrink_zone(struct zone *zone, struct scan_control *sc, bool soft_reclaim) 
			.zone = zone,

			.priority = sc->priority,

		};

		struct mem_cgroup *memcg = NULL;

		mem_cgroup_iter_filter filter = (soft_reclaim) ?

			mem_cgroup_soft_reclaim_eligible : NULL;

		struct mem_cgroup *memcg;



		nr_reclaimed = sc->nr_reclaimed;

		nr_scanned = sc->nr_scanned;



		while ((memcg = mem_cgroup_iter_cond(root, memcg, &reclaim, filter))) {

		memcg = mem_cgroup_iter(root, NULL, &reclaim);

		do {

			struct lruvec *lruvec;



			if (soft_reclaim &&

			    !mem_cgroup_soft_reclaim_eligible(memcg, root)) {

				memcg = mem_cgroup_iter(root, memcg, &reclaim);

				continue;

			}



			lruvec = mem_cgroup_zone_lruvec(zone, memcg);



			shrink_lruvec(lruvec, sc);
@@ -2214,7 +2219,8 @@ __shrink_zone(struct zone *zone, struct scan_control *sc, bool soft_reclaim) 
				mem_cgroup_iter_break(root, memcg);

				break;

			}

		}

			memcg = mem_cgroup_iter(root, memcg, &reclaim);

		} while (memcg);



		vmpressure(sc->gfp_mask, sc->target_mem_cgroup,

			   sc->nr_scanned - nr_scanned,