From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755209Ab2CVFkL (ORCPT ); Thu, 22 Mar 2012 01:40:11 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:40625 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754809Ab2CVFkH (ORCPT ); Thu, 22 Mar 2012 01:40:07 -0400 Date: Thu, 22 Mar 2012 14:39:59 +0900 From: Minchan Kim To: Konstantin Khlebnikov Cc: Minchan Kim , Andrew Morton , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Linus Torvalds , Hugh Dickins , KOSAKI Motohiro , Ben Herrenschmidt , "linux@arm.linux.org.uk" Subject: Re: [PATCH 00/16] mm: prepare for converting vm->vm_flags to 64-bit Message-ID: <20120322053958.GA5278@barrios> References: <20120321065140.13852.52315.stgit@zurg> <20120321100602.GA5522@barrios> <4F69D496.2040509@openvz.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4F69D496.2040509@openvz.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 21, 2012 at 05:16:06PM +0400, Konstantin Khlebnikov wrote: > Minchan Kim wrote: > >Hi Konstantin, > > > >It seems to be nice clean up to me and you are a volunteer we have been wanted > >for a long time. Thanks! > >I am one of people who really want to expand vm_flags to 64 bit but when KOSAKI > >tried it, Linus said his concerning, I guess you already saw that. > > > >He want to tidy vm_flags's usage up rather than expanding it. > >Without the discussion about that, just expanding vm_flags would make us use > >it up easily so that we might need more space. > > Strictly speaking, my pachset does not expands vm_flags, it just prepares to this. > Anyway vm_flags_t looks better than hard-coded "unsigned long" and messy type-casts around it. Indeed. > > > > >Readahead flags are good candidate to move into another space and arch-specific flags, I guess. > >Another candidate I think of is THP flag. It's just for only anonymous vma now > >(But I am not sure we have a plan to support it for file-backed pages in future) > >so we can move it to anon_vma or somewhere. > >I think other guys might find more somethings > > > >The point is that at least, we have to discuss about clean up current vm_flags's > >use cases before expanding it unconditionally. > > Seems like we can easily remove VM_EXECUTABLE > (count in mm->num_exe_file_vmas amount of vmas with vma->vm_file == mm->exe_file > instead of vmas with VM_EXECUTABLE bit) > > And probably VM_CAN_NONLINEAR... I think we can also unify VM_MAPPED_COPY(nommu) and VM_SAO(powerpc) with one VM_ARCH_1 Okay. After this series is merged, let's try to remove flags we can do. Then, other guys might suggest another ideas. Thanks.