Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932359Ab2KMRQP (ORCPT ); Tue, 13 Nov 2012 12:16:15 -0500 Received: from mail-ee0-f46.google.com ([74.125.83.46]:37723 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932319Ab2KMRPu (ORCPT ); Tue, 13 Nov 2012 12:15:50 -0500 From: Ingo Molnar To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Paul Turner , Lee Schermerhorn , Christoph Lameter , Rik van Riel , Mel Gorman , Andrew Morton , Andrea Arcangeli , Linus Torvalds , Peter Zijlstra , Thomas Gleixner Subject: [PATCH 31/31] mm: Allow the migration of shared pages Date: Tue, 13 Nov 2012 18:13:54 +0100 Message-Id: <1352826834-11774-32-git-send-email-mingo@kernel.org> X-Mailer: git-send-email 1.7.11.7 In-Reply-To: <1352826834-11774-1-git-send-email-mingo@kernel.org> References: <1352826834-11774-1-git-send-email-mingo@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1434 Lines: 43 There's no good reason to disallow the migration of pages shared by multiple processes - the migration code itself is already properly walking the rmap chain. So allow it. We've tested this with various workloads and no ill effect appears to have come from this. Cc: Peter Zijlstra Cc: Linus Torvalds Cc: Andrew Morton Cc: Andrea Arcangeli Cc: Rik van Riel Cc: Mel Gorman Signed-off-by: Ingo Molnar --- mm/migrate.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 72d1056..b89062d 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1427,12 +1427,6 @@ int migrate_misplaced_page(struct page *page, int node) gfp_t gfp = GFP_HIGHUSER_MOVABLE; /* - * Don't migrate pages that are mapped in multiple processes. - */ - if (page_mapcount(page) != 1) - goto out; - - /* * Never wait for allocations just to migrate on fault, but don't dip * into reserves. And, only accept pages from the specified node. No * sense migrating to a different "misplaced" page! -- 1.7.11.7 -- 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/