Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756690AbZJHJlZ (ORCPT ); Thu, 8 Oct 2009 05:41:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754441AbZJHJlZ (ORCPT ); Thu, 8 Oct 2009 05:41:25 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45968 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754351AbZJHJlY (ORCPT ); Thu, 8 Oct 2009 05:41:24 -0400 Date: Thu, 8 Oct 2009 11:40:55 +0200 From: Gleb Natapov To: Johannes Weiner Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org Subject: Re: [PATCH v2][RFC] add MAP_UNLOCKED mmap flag Message-ID: <20091008094055.GE16702@redhat.com> References: <20091006170218.GM9832@redhat.com> <20091006183436.GA23110@cmpxchg.org> <20091006185344.GA19692@redhat.com> <20091008093752.GA30858@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091008093752.GA30858@cmpxchg.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1999 Lines: 44 On Thu, Oct 08, 2009 at 11:37:52AM +0200, Johannes Weiner wrote: > On Tue, Oct 06, 2009 at 08:53:44PM +0200, Gleb Natapov wrote: > > On Tue, Oct 06, 2009 at 08:34:36PM +0200, Johannes Weiner wrote: > > > On Tue, Oct 06, 2009 at 07:02:18PM +0200, Gleb Natapov wrote: > > > > diff --git a/include/asm-generic/mman.h b/include/asm-generic/mman.h > > > > index 32c8bd6..59e0f29 100644 > > > > --- a/include/asm-generic/mman.h > > > > +++ b/include/asm-generic/mman.h > > > > @@ -12,6 +12,7 @@ > > > > #define MAP_NONBLOCK 0x10000 /* do not block on IO */ > > > > #define MAP_STACK 0x20000 /* give out an address that is best suited for process/thread stacks */ > > > > #define MAP_HUGETLB 0x40000 /* create a huge page mapping */ > > > > +#define MAP_UNLOCKED 0x80000 /* force page unlocking */ > > > > > > > > #define MCL_CURRENT 1 /* lock all current mappings */ > > > > #define MCL_FUTURE 2 /* lock all future mappings */ > > > > diff --git a/mm/mmap.c b/mm/mmap.c > > > > index 73f5e4b..7c2abdb 100644 > > > > --- a/mm/mmap.c > > > > +++ b/mm/mmap.c > > > > @@ -985,6 +985,9 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, > > > > if (!can_do_mlock()) > > > > return -EPERM; > > > > > > > > + if (flags & MAP_UNLOKED) > > > > + vm_flags &= ~VM_LOCKED; > > > > > Should we do something special about (MAP_UNLOCKED | MAP_LOCKED)? > > > > It is simpler to just ignore it. What do you think? > > I think we should filter it out. It's unlocking even when MAP_LOCKED > is set and doing mlock-specific checks also no mlock will happen. > What do you mean by "filter it out"? Return error. mlock-specific checks don't make much sense indeed since locking will not happen. -- Gleb. -- 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/