From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yw0-f200.google.com (mail-yw0-f200.google.com [209.85.161.200]) by kanga.kvack.org (Postfix) with ESMTP id C16686B007E for ; Fri, 17 Jun 2016 16:55:32 -0400 (EDT) Received: by mail-yw0-f200.google.com with SMTP id d137so57355927ywe.1 for ; Fri, 17 Jun 2016 13:55:32 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id o2si29758613qkc.210.2016.06.17.13.55.31 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 17 Jun 2016 13:55:31 -0700 (PDT) Date: Fri, 17 Jun 2016 15:55:26 -0500 From: Josh Poimboeuf Subject: Re: [PATCH v2 05/13] mm: Move memcg stack accounting to account_kernel_stack Message-ID: <20160617205526.5cjfm56prpstvowc@treble> References: <8a17889a9d47b7b4deb41f2fcccada8bf54d4b6f.1466192946.git.luto@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <8a17889a9d47b7b4deb41f2fcccada8bf54d4b6f.1466192946.git.luto@kernel.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andy Lutomirski Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Borislav Petkov , Nadav Amit , Kees Cook , Brian Gerst , "kernel-hardening@lists.openwall.com" , Linus Torvalds , Jann Horn , Heiko Carstens , Vladimir Davydov , Johannes Weiner , Michal Hocko , linux-mm@kvack.org On Fri, Jun 17, 2016 at 01:00:41PM -0700, Andy Lutomirski wrote: > We should account for stacks regardless of stack size. Move it into > account_kernel_stack. > > Fixes: 12580e4b54ba8 ("mm: memcontrol: report kernel stack usage in cgroup2 memory.stat") > Cc: Vladimir Davydov > Cc: Johannes Weiner > Cc: Michal Hocko > Cc: linux-mm@kvack.org > Signed-off-by: Andy Lutomirski > --- > kernel/fork.c | 15 ++++++--------- > 1 file changed, 6 insertions(+), 9 deletions(-) > > diff --git a/kernel/fork.c b/kernel/fork.c > index be7f006af727..cd2abe6e4e41 100644 > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -165,20 +165,12 @@ static struct thread_info *alloc_thread_info_node(struct task_struct *tsk, > struct page *page = alloc_kmem_pages_node(node, THREADINFO_GFP, > THREAD_SIZE_ORDER); > > - if (page) > - memcg_kmem_update_page_stat(page, MEMCG_KERNEL_STACK, > - 1 << THREAD_SIZE_ORDER); > - > return page ? page_address(page) : NULL; > } > > static inline void free_thread_info(struct thread_info *ti) > { > - struct page *page = virt_to_page(ti); > - > - memcg_kmem_update_page_stat(page, MEMCG_KERNEL_STACK, > - -(1 << THREAD_SIZE_ORDER)); > - __free_kmem_pages(page, THREAD_SIZE_ORDER); > + free_kmem_pages((unsigned long)ti, THREAD_SIZE_ORDER); > } > # else > static struct kmem_cache *thread_info_cache; > @@ -227,6 +219,11 @@ static void account_kernel_stack(struct thread_info *ti, int account) > > mod_zone_page_state(zone, NR_KERNEL_STACK_KB, > THREAD_SIZE / 1024 * account); > + > + /* All stack pages belong to the same memcg. */ > + memcg_kmem_update_page_stat( > + virt_to_page(ti), MEMCG_KERNEL_STACK, > + account * (THREAD_SIZE / PAGE_SIZE)); > } Won't this be broken in the case where THREAD_SIZE < PAGE_SIZE? -- Josh -- 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