Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934086AbaKMTZg (ORCPT ); Thu, 13 Nov 2014 14:25:36 -0500 Received: from mail-yk0-f178.google.com ([209.85.160.178]:53181 "EHLO mail-yk0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934026AbaKMTZb (ORCPT ); Thu, 13 Nov 2014 14:25:31 -0500 From: Pranith Kumar To: Andrew Morton , Joonsoo Kim , Naoya Horiguchi , "Kirill A. Shutemov" , Peter Zijlstra , David Rientjes , Joerg Roedel , NeilBrown , Sasha Levin , Paul McQuade , linux-mm@kvack.org (open list:MEMORY MANAGEMENT), linux-kernel@vger.kernel.org (open list) Cc: paulmck@linux.vnet.ibm.com Subject: [PATCH 13/16] ksm: Replace smp_read_barrier_depends() with lockless_dereference() Date: Thu, 13 Nov 2014 14:24:19 -0500 Message-Id: <1415906662-4576-14-git-send-email-bobby.prani@gmail.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1415906662-4576-1-git-send-email-bobby.prani@gmail.com> References: <1415906662-4576-1-git-send-email-bobby.prani@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Recently lockless_dereference() was added which can be used in place of hard-coding smp_read_barrier_depends(). The following PATCH makes the change. Signed-off-by: Pranith Kumar --- mm/ksm.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/mm/ksm.c b/mm/ksm.c index d247efa..a67de79 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -542,15 +542,14 @@ static struct page *get_ksm_page(struct stable_node *stable_node, bool lock_it) expected_mapping = (void *)stable_node + (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM); again: - kpfn = ACCESS_ONCE(stable_node->kpfn); - page = pfn_to_page(kpfn); - /* * page is computed from kpfn, so on most architectures reading * page->mapping is naturally ordered after reading node->kpfn, * but on Alpha we need to be more careful. */ - smp_read_barrier_depends(); + kpfn = lockless_dereference(stable_node->kpfn); + page = pfn_to_page(kpfn); + if (ACCESS_ONCE(page->mapping) != expected_mapping) goto stale; -- 1.9.1 -- 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/