From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755806Ab3JGN4e (ORCPT ); Mon, 7 Oct 2013 09:56:34 -0400 Received: from mga14.intel.com ([143.182.124.37]:1182 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752764Ab3JGNyn (ORCPT ); Mon, 7 Oct 2013 09:54:43 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.90,1050,1371106800"; d="scan'208";a="370868822" From: "Kirill A. Shutemov" To: 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, "Kirill A. Shutemov" Subject: [PATCHv5 01/11] mm: avoid increase sizeof(struct page) due to split page table lock Date: Mon, 7 Oct 2013 16:54:03 +0300 Message-Id: <1381154053-4848-2-git-send-email-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 1.8.4.rc3 In-Reply-To: <1381154053-4848-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1381154053-4848-1-git-send-email-kirill.shutemov@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org CONFIG_GENERIC_LOCKBREAK increases sizeof(spinlock_t) to 8 bytes. It leads to increase sizeof(struct page) by 4 bytes on 32-bit system if split page table lock is in use, since page->ptl shares space in union with longs and pointers. Let's disable split page table lock on 32-bit systems with GENERIC_LOCKBREAK enabled. Signed-off-by: Kirill A. Shutemov --- mm/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/Kconfig b/mm/Kconfig index 026771a9b0..6f5be0dac9 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -212,6 +212,7 @@ config SPLIT_PTLOCK_CPUS default "999999" if ARM && !CPU_CACHE_VIPT default "999999" if PARISC && !PA20 default "999999" if DEBUG_SPINLOCK || DEBUG_LOCK_ALLOC + default "999999" if !64BIT && GENERIC_LOCKBREAK default "4" # -- 1.8.4.rc3