From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752499AbcDYXzA (ORCPT ); Mon, 25 Apr 2016 19:55:00 -0400 Received: from mail-pf0-f172.google.com ([209.85.192.172]:34639 "EHLO mail-pf0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752394AbcDYXy5 (ORCPT ); Mon, 25 Apr 2016 19:54:57 -0400 Date: Mon, 25 Apr 2016 16:54:55 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Andrew Morton cc: Michal Hocko , Nikolay Borisov , Johannes Weiner , "Kirill A. Shutemov" , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [patch v3] mm, hugetlb_cgroup: round limit_in_bytes down to hugepage size In-Reply-To: <20160425145223.22617d4c1f12b0f7f4702988@linux-foundation.org> Message-ID: References: <5704BA37.2080508@kyup.com> <5704BBBF.8040302@kyup.com> <20160407125145.GD32755@dhcp22.suse.cz> <20160415132451.GL32377@dhcp22.suse.cz> <20160425145223.22617d4c1f12b0f7f4702988@linux-foundation.org> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The page_counter rounds limits down to page size values. This makes sense, except in the case of hugetlb_cgroup where it's not possible to charge partial hugepages. If the hugetlb_cgroup margin is less than the hugepage size being charged, it will fail as expected. Round the hugetlb_cgroup limit down to hugepage size, since it is the effective limit of the cgroup. For consistency, round down PAGE_COUNTER_MAX as well when a hugetlb_cgroup is created: this prevents error reports when a user cannot restore the value to the kernel default. Signed-off-by: David Rientjes --- v3: update changelog per akpm no stable backport needed mm/hugetlb_cgroup.c | 35 ++++++++++++++++++++++++++--------- 1 file changed, 26 insertions(+), 9 deletions(-) diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c --- a/mm/hugetlb_cgroup.c +++ b/mm/hugetlb_cgroup.c @@ -67,26 +67,42 @@ static inline bool hugetlb_cgroup_have_usage(struct hugetlb_cgroup *h_cg) return false; } +static void hugetlb_cgroup_init(struct hugetlb_cgroup *h_cgroup, + struct hugetlb_cgroup *parent_h_cgroup) +{ + int idx; + + for (idx = 0; idx < HUGE_MAX_HSTATE; idx++) { + struct page_counter *counter = &h_cgroup->hugepage[idx]; + struct page_counter *parent = NULL; + unsigned long limit; + int ret; + + if (parent_h_cgroup) + parent = &parent_h_cgroup->hugepage[idx]; + page_counter_init(counter, parent); + + limit = round_down(PAGE_COUNTER_MAX, + 1 << huge_page_order(&hstates[idx])); + ret = page_counter_limit(counter, limit); + VM_BUG_ON(ret); + } +} + static struct cgroup_subsys_state * hugetlb_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) { struct hugetlb_cgroup *parent_h_cgroup = hugetlb_cgroup_from_css(parent_css); struct hugetlb_cgroup *h_cgroup; - int idx; h_cgroup = kzalloc(sizeof(*h_cgroup), GFP_KERNEL); if (!h_cgroup) return ERR_PTR(-ENOMEM); - if (parent_h_cgroup) { - for (idx = 0; idx < HUGE_MAX_HSTATE; idx++) - page_counter_init(&h_cgroup->hugepage[idx], - &parent_h_cgroup->hugepage[idx]); - } else { + if (!parent_h_cgroup) root_h_cgroup = h_cgroup; - for (idx = 0; idx < HUGE_MAX_HSTATE; idx++) - page_counter_init(&h_cgroup->hugepage[idx], NULL); - } + + hugetlb_cgroup_init(h_cgroup, parent_h_cgroup); return &h_cgroup->css; } @@ -285,6 +301,7 @@ static ssize_t hugetlb_cgroup_write(struct kernfs_open_file *of, return ret; idx = MEMFILE_IDX(of_cft(of)->private); + nr_pages = round_down(nr_pages, 1 << huge_page_order(&hstates[idx])); switch (MEMFILE_ATTR(of_cft(of)->private)) { case RES_LIMIT: