From 694fbc0fe78518d06efa63910bf4ecee660e7852 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Tue, 24 Sep 2013 15:27:37 -0700 Subject: [PATCH] revert "memcg: enhance memcg iterator to support predicates" Revert commit de57780dc659 ("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 Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 49 ++++---------------------- mm/memcontrol.c | 70 ++++++++------------------------------ mm/vmscan.c | 16 ++++++--- 3 files changed, 32 insertions(+), 103 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 60e95872da2..ef2b9bd7faf 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -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) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 916892c2b8e..65e7bec4b0f 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -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; @@ -896,31 +887,11 @@ skip_node: if (next_css) { struct mem_cgroup *mem = mem_cgroup_from_css(next_css); - switch (mem_cgroup_filter(mem, root, cond)) { - case SKIP: + if (css_tryget(&mem->css)) + return mem; + else { 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; } } @@ -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; + return root; } 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); diff --git a/mm/vmscan.c b/mm/vmscan.c index cdd300b8148..17a7134de4d 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -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, -- 2.43.2