From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f170.google.com (mail-wi0-f170.google.com [209.85.212.170]) by kanga.kvack.org (Postfix) with ESMTP id 3A5A36B0038 for ; Fri, 23 Oct 2015 07:31:06 -0400 (EDT) Received: by wikq8 with SMTP id q8so72503488wik.1 for ; Fri, 23 Oct 2015 04:31:05 -0700 (PDT) Received: from mail-wi0-f179.google.com (mail-wi0-f179.google.com. [209.85.212.179]) by mx.google.com with ESMTPS id 14si391422wmg.115.2015.10.23.04.31.04 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 23 Oct 2015 04:31:04 -0700 (PDT) Received: by wicll6 with SMTP id ll6so27099157wic.0 for ; Fri, 23 Oct 2015 04:31:04 -0700 (PDT) Date: Fri, 23 Oct 2015 13:31:03 +0200 From: Michal Hocko Subject: Re: [PATCH 1/8] mm: page_counter: let page_counter_try_charge() return bool Message-ID: <20151023113103.GJ2410@dhcp22.suse.cz> References: <1445487696-21545-1-git-send-email-hannes@cmpxchg.org> <1445487696-21545-2-git-send-email-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1445487696-21545-2-git-send-email-hannes@cmpxchg.org> Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: "David S. Miller" , Andrew Morton , Vladimir Davydov , Tejun Heo , netdev@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org On Thu 22-10-15 00:21:29, Johannes Weiner wrote: > 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 > --- > 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 17fa4f8..7e62920 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 6a44263..d8fb10d 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 c71fe40..a8ccdbc 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2018,8 +2018,8 @@ 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); > @@ -2383,14 +2383,13 @@ 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 11b4bed..7c6a63d 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; > } > > /** > -- > 2.6.1 -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org