From 145949a1387ba7a4fd0df15181e09345ec7b0492 Mon Sep 17 00:00:00 2001 From: Raghavendra K T Date: Thu, 5 Nov 2015 18:46:26 -0800 Subject: mm/list_lru.c: replace nr_node_ids for loop with for_each_node() The functions used in the patch are in slowpath, which gets called whenever alloc_super is called during mounts. Though this should not make difference for the architectures with sequential numa node ids, for the powerpc which can potentially have sparse node ids (for e.g., 4 node system having numa ids, 0,1,16,17 is common), this patch saves some unnecessary allocations for non existing numa nodes. Even without that saving, perhaps patch makes code more readable. [vdavydov@parallels.com: take memcg_aware check outside for_each loop] Signed-off-by: Raghavendra K T Reviewed-by: Vladimir Davydov Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: Anton Blanchard Cc: Nishanth Aravamudan Cc: Greg Kurz Cc: Grant Likely Cc: Nikunj A Dadhania Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/list_lru.c | 34 +++++++++++++++++++++++----------- 1 file changed, 23 insertions(+), 11 deletions(-) (limited to 'mm/list_lru.c') diff --git a/mm/list_lru.c b/mm/list_lru.c index e1da19fac1b3..28237476b055 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -42,6 +42,10 @@ static void list_lru_unregister(struct list_lru *lru) #ifdef CONFIG_MEMCG_KMEM static inline bool list_lru_memcg_aware(struct list_lru *lru) { + /* + * This needs node 0 to be always present, even + * in the systems supporting sparse numa ids. + */ return !!lru->node[0].memcg_lrus; } @@ -377,16 +381,20 @@ static int memcg_init_list_lru(struct list_lru *lru, bool memcg_aware) { int i; - for (i = 0; i < nr_node_ids; i++) { - if (!memcg_aware) - lru->node[i].memcg_lrus = NULL; - else if (memcg_init_list_lru_node(&lru->node[i])) + if (!memcg_aware) + return 0; + + for_each_node(i) { + if (memcg_init_list_lru_node(&lru->node[i])) goto fail; } return 0; fail: - for (i = i - 1; i >= 0; i--) + for (i = i - 1; i >= 0; i--) { + if (!lru->node[i].memcg_lrus) + continue; memcg_destroy_list_lru_node(&lru->node[i]); + } return -ENOMEM; } @@ -397,7 +405,7 @@ static void memcg_destroy_list_lru(struct list_lru *lru) if (!list_lru_memcg_aware(lru)) return; - for (i = 0; i < nr_node_ids; i++) + for_each_node(i) memcg_destroy_list_lru_node(&lru->node[i]); } @@ -409,16 +417,20 @@ static int memcg_update_list_lru(struct list_lru *lru, if (!list_lru_memcg_aware(lru)) return 0; - for (i = 0; i < nr_node_ids; i++) { + for_each_node(i) { if (memcg_update_list_lru_node(&lru->node[i], old_size, new_size)) goto fail; } return 0; fail: - for (i = i - 1; i >= 0; i--) + for (i = i - 1; i >= 0; i--) { + if (!lru->node[i].memcg_lrus) + continue; + memcg_cancel_update_list_lru_node(&lru->node[i], old_size, new_size); + } return -ENOMEM; } @@ -430,7 +442,7 @@ static void memcg_cancel_update_list_lru(struct list_lru *lru, if (!list_lru_memcg_aware(lru)) return; - for (i = 0; i < nr_node_ids; i++) + for_each_node(i) memcg_cancel_update_list_lru_node(&lru->node[i], old_size, new_size); } @@ -485,7 +497,7 @@ static void memcg_drain_list_lru(struct list_lru *lru, if (!list_lru_memcg_aware(lru)) return; - for (i = 0; i < nr_node_ids; i++) + for_each_node(i) memcg_drain_list_lru_node(&lru->node[i], src_idx, dst_idx); } @@ -522,7 +534,7 @@ int __list_lru_init(struct list_lru *lru, bool memcg_aware, if (!lru->node) goto out; - for (i = 0; i < nr_node_ids; i++) { + for_each_node(i) { spin_lock_init(&lru->node[i].lock); if (key) lockdep_set_class(&lru->node[i].lock, key); -- cgit v1.2.3-55-g7522