Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754062Ab3I0UrB (ORCPT ); Fri, 27 Sep 2013 16:47:01 -0400 Received: from e33.co.us.ibm.com ([32.97.110.151]:56620 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753120Ab3I0Uq5 (ORCPT ); Fri, 27 Sep 2013 16:46:57 -0400 Message-ID: <5245EEAD.7010901@linux.vnet.ibm.com> Date: Fri, 27 Sep 2013 13:46:37 -0700 From: Cody P Schafer User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.0 MIME-Version: 1.0 To: "Kirill A. Shutemov" , Alex Thorlton , Ingo Molnar , Andrew Morton , Naoya Horiguchi CC: "Eric W . Biederman" , "Paul E . McKenney" , Al Viro , Andi Kleen , Andrea Arcangeli , Dave Hansen , Dave Jones , David Howells , Frederic Weisbecker , Johannes Weiner , Kees Cook , Mel Gorman , Michael Kerrisk , Oleg Nesterov , Peter Zijlstra , Rik van Riel , Robin Holt , Sedat Dilek , Srikar Dronamraju , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCHv4 02/10] mm: convert mm->nr_ptes to atomic_t References: <1380287787-30252-1-git-send-email-kirill.shutemov@linux.intel.com> <1380287787-30252-3-git-send-email-kirill.shutemov@linux.intel.com> In-Reply-To: <1380287787-30252-3-git-send-email-kirill.shutemov@linux.intel.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13092720-0928-0000-0000-000001F1F4AC Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1490 Lines: 37 On 09/27/2013 06:16 AM, Kirill A. Shutemov wrote: > With split page table lock for PMD level we can't hold > mm->page_table_lock while updating nr_ptes. > > Let's convert it to atomic_t to avoid races. > > --- > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > index 84e0c56e1e..99f19e850d 100644 > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -339,6 +339,7 @@ struct mm_struct { > pgd_t * pgd; > atomic_t mm_users; /* How many users with user space? */ > atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */ > + atomic_t nr_ptes; /* Page table pages */ > int map_count; /* number of VMAs */ > > spinlock_t page_table_lock; /* Protects page tables and some counters */ > @@ -360,7 +361,6 @@ struct mm_struct { > unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE */ > unsigned long stack_vm; /* VM_GROWSUP/DOWN */ > unsigned long def_flags; > - unsigned long nr_ptes; /* Page table pages */ > unsigned long start_code, end_code, start_data, end_data; > unsigned long start_brk, brk, start_stack; > unsigned long arg_start, arg_end, env_start, env_end; Will 32bits always be enough here? Should atomic_long_t be used instead? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/