From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932195AbXGZXxR (ORCPT ); Thu, 26 Jul 2007 19:53:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752240AbXGZXxI (ORCPT ); Thu, 26 Jul 2007 19:53:08 -0400 Received: from smtp-out.google.com ([216.239.33.17]:42292 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755485AbXGZXxH (ORCPT ); Thu, 26 Jul 2007 19:53:07 -0400 From: Suleiman Souhlal To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, Suleiman Souhlal , Suleiman Souhlal Subject: [PATCH] Don't needlessly dirty mlocked pages when initially faulting them in. Date: Thu, 26 Jul 2007 16:52:44 -0700 Message-Id: <11854939641916-git-send-email-ssouhlal@FreeBSD.org> X-Mailer: git-send-email 1.4.2 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org make_pages_present() is dirtying mlocked pages if the VMA is writable, even though it shouldn't, by telling get_user_pages() to simulate a write fault. A simple way to test this is to mlock a multi-GB file, and then sync. The sync will take a long time. As far as I can see, it should be safe to just not simulate a write fault. Signed-off-by: Suleiman Souhlal --- mm/memory.c | 5 ++--- 1 files changed, 2 insertions(+), 3 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index f64cbf9..f43c9e8 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2664,18 +2664,17 @@ #endif /* __PAGETABLE_PMD_FOLDED */ int make_pages_present(unsigned long addr, unsigned long end) { - int ret, len, write; + int ret, len; struct vm_area_struct * vma; vma = find_vma(current->mm, addr); if (!vma) return -1; - write = (vma->vm_flags & VM_WRITE) != 0; BUG_ON(addr >= end); BUG_ON(end > vma->vm_end); len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE; ret = get_user_pages(current, current->mm, addr, - len, write, 0, NULL, NULL); + len, 0, 0, NULL, NULL); if (ret < 0) return ret; return ret == len ? 0 : -1; -- 1.4.2