From 6071ca5201066f4b2a61cfb693dd186d6bc6e9f3 Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Thu, 5 Nov 2015 18:50:26 -0800 Subject: [PATCH] mm: page_counter: let page_counter_try_charge() return bool page_counter_try_charge() currently returns 0 on success and -ENOMEM on failure, which is surprising behavior given the function name. Make it follow the expected pattern of try_stuff() functions that return a boolean true to indicate success, or false for failure. Signed-off-by: Johannes Weiner Acked-by: Michal Hocko Cc: Vladimir Davydov Signed-off-by: Linus Torvalds --- include/linux/page_counter.h | 6 +++--- mm/hugetlb_cgroup.c | 3 ++- mm/memcontrol.c | 11 +++++------ mm/page_counter.c | 14 +++++++------- 4 files changed, 17 insertions(+), 17 deletions(-) diff --git a/include/linux/page_counter.h b/include/linux/page_counter.h index 17fa4f8de3a6..7e62920a3a94 100644 --- a/include/linux/page_counter.h +++ b/include/linux/page_counter.h @@ -36,9 +36,9 @@ static inline unsigned long page_counter_read(struct page_counter *counter) void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages); void page_counter_charge(struct page_counter *counter, unsigned long nr_pages); -int page_counter_try_charge(struct page_counter *counter, - unsigned long nr_pages, - struct page_counter **fail); +bool page_counter_try_charge(struct page_counter *counter, + unsigned long nr_pages, + struct page_counter **fail); void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages); int page_counter_limit(struct page_counter *counter, unsigned long limit); int page_counter_memparse(const char *buf, const char *max, diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c index 6e0057439a46..33d59abe91f1 100644 --- a/mm/hugetlb_cgroup.c +++ b/mm/hugetlb_cgroup.c @@ -186,7 +186,8 @@ again: } rcu_read_unlock(); - ret = page_counter_try_charge(&h_cg->hugepage[idx], nr_pages, &counter); + if (!page_counter_try_charge(&h_cg->hugepage[idx], nr_pages, &counter)) + ret = -ENOMEM; css_put(&h_cg->css); done: *ptr = h_cg; diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 59b100fde35f..d47de73d7c36 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2016,8 +2016,8 @@ retry: return 0; if (!do_swap_account || - !page_counter_try_charge(&memcg->memsw, batch, &counter)) { - if (!page_counter_try_charge(&memcg->memory, batch, &counter)) + page_counter_try_charge(&memcg->memsw, batch, &counter)) { + if (page_counter_try_charge(&memcg->memory, batch, &counter)) goto done_restock; if (do_swap_account) page_counter_uncharge(&memcg->memsw, batch); @@ -2381,14 +2381,13 @@ int __memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order, { unsigned int nr_pages = 1 << order; struct page_counter *counter; - int ret = 0; + int ret; if (!memcg_kmem_is_active(memcg)) return 0; - ret = page_counter_try_charge(&memcg->kmem, nr_pages, &counter); - if (ret) - return ret; + if (!page_counter_try_charge(&memcg->kmem, nr_pages, &counter)) + return -ENOMEM; ret = try_charge(memcg, gfp, nr_pages); if (ret) { diff --git a/mm/page_counter.c b/mm/page_counter.c index 11b4beda14ba..7c6a63d2c27f 100644 --- a/mm/page_counter.c +++ b/mm/page_counter.c @@ -56,12 +56,12 @@ void page_counter_charge(struct page_counter *counter, unsigned long nr_pages) * @nr_pages: number of pages to charge * @fail: points first counter to hit its limit, if any * - * Returns 0 on success, or -ENOMEM and @fail if the counter or one of - * its ancestors has hit its configured limit. + * Returns %true on success, or %false and @fail if the counter or one + * of its ancestors has hit its configured limit. */ -int page_counter_try_charge(struct page_counter *counter, - unsigned long nr_pages, - struct page_counter **fail) +bool page_counter_try_charge(struct page_counter *counter, + unsigned long nr_pages, + struct page_counter **fail) { struct page_counter *c; @@ -99,13 +99,13 @@ int page_counter_try_charge(struct page_counter *counter, if (new > c->watermark) c->watermark = new; } - return 0; + return true; failed: for (c = counter; c != *fail; c = c->parent) page_counter_cancel(c, nr_pages); - return -ENOMEM; + return false; } /**