From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751521Ab2GZFT5 (ORCPT ); Thu, 26 Jul 2012 01:19:57 -0400 Received: from e7.ny.us.ibm.com ([32.97.182.137]:44044 "EHLO e7.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751119Ab2GZFTz (ORCPT ); Thu, 26 Jul 2012 01:19:55 -0400 Date: Thu, 26 Jul 2012 10:48:39 +0530 From: Srikar Dronamraju To: Oleg Nesterov Cc: Ingo Molnar , Peter Zijlstra , Ananth N Mavinakayanahalli , Anton Arapov , Hugh Dickins , linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/4] uprobes: __replace_page() needs munlock_vma_page() Message-ID: <20120726051839.GE3810@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <20120712170934.GA25455@redhat.com> <20120712171025.GA25510@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20120712171025.GA25510@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12072605-5806-0000-0000-000017AC8ECF Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Oleg Nesterov [2012-07-12 19:10:25]: > Like do_wp_page(), __replace_page() should do munlock_vma_page() > for the case when the old page still has other !VM_LOCKED mappings. > Unfortunately this needs mm/internal.h. > > Also, move put_page() outside of ptl lock. This doesn't really > matter but looks a bit better. > > Signed-off-by: Oleg Nesterov One thing I wanted to check is, should we mlock the new page, i.e the replacing page. It may not a good idea to mlock the new page because then we can end up adding too many pages to the unevictable list. Acked-by: Srikar Dronamraju > --- > kernel/events/uprobes.c | 8 ++++++-- > 1 files changed, 6 insertions(+), 2 deletions(-) > > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c > index fc1df43..aeea41b 100644 > --- a/kernel/events/uprobes.c > +++ b/kernel/events/uprobes.c > @@ -32,6 +32,7 @@ > #include /* try_to_free_swap */ > #include /* user_enable_single_step */ > #include /* notifier mechanism */ > +#include "../../mm/internal.h" /* munlock_vma_page */ > > #include > > @@ -141,7 +142,7 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr, > pte_t *ptep; > int err; > > - /* freeze PageSwapCache() for try_to_free_swap() below */ > + /* For try_to_free_swap() and munlock_vma_page() below */ > lock_page(page); > > err = -EAGAIN; > @@ -164,9 +165,12 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr, > page_remove_rmap(page); > if (!page_mapped(page)) > try_to_free_swap(page); > - put_page(page); > pte_unmap_unlock(ptep, ptl); > > + if (vma->vm_flags & VM_LOCKED) > + munlock_vma_page(page); > + put_page(page); > + > err = 0; > unlock: > unlock_page(page); > -- > 1.5.5.1 >