Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753628AbaB0QqO (ORCPT ); Thu, 27 Feb 2014 11:46:14 -0500 Received: from mx1.redhat.com ([209.132.183.28]:8510 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753107AbaB0QqN (ORCPT ); Thu, 27 Feb 2014 11:46:13 -0500 Date: Thu, 27 Feb 2014 17:45:24 +0100 From: Oleg Nesterov To: Gerald Schaefer Cc: Alex Thorlton , Peter Zijlstra , Christian Borntraeger , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk, schwidefsky@de.ibm.com, rientjes@google.com, riel@redhat.com, pbonzini@redhat.com, mingo@kernel.org, mgorman@suse.de, kirill.shutemov@linux.intel.com, heiko.carstens@de.ibm.com, hannes@cmpxchg.org, ebiederm@xmission.com, aarcange@redhat.com Subject: Re: + mm-revert-thp-make-madv_hugepage-check-for-mm-def_flags.patch added to -mm tree Message-ID: <20140227164524.GB909@redhat.com> References: <530d2ce9.eikv0ULecNwxF4I5%akpm@linux-foundation.org> <530D9F50.1080400@de.ibm.com> <20140226145025.GA12571@redhat.com> <530E0306.7020601@de.ibm.com> <20140226153144.GA15527@redhat.com> <20140226165759.GB22802@laptop.programming.kicks-ass.net> <20140226172253.GQ3041@sgi.com> <20140226180603.GA25644@redhat.com> <20140226200535.5fdf4c25@thinkpad> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140226200535.5fdf4c25@thinkpad> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/26, Gerald Schaefer wrote: > > On Wed, 26 Feb 2014 19:06:03 +0100 > Oleg Nesterov wrote: > > > It would be nice to also change thp_split_mm() to not not play with > > mm->def_flags, but I am not sure if we can do this. > > Hmm, I'm also wondering about this. Basically, we only need VM_NOHUGEPAGE > in vma->vm_flags, which is done for all existing vmas in thp_split_mm(). > But if there should be new vmas created afterwards, it would still be > necessary to also have VM_NOHUGEPAGE in mm->def_flags, because the > vm_flags for new vmas will be set via OR of mm->def_flags, e.g. in > do_brk() and do_mmap_pgoff(). Yes, exactly, this was my concern. And while I know nothing about s390, it seems to me that huge pages should be forbidden for any vma if ->has_pgste was set. > Anyway, this would then have to be a separate patch, to keep the > "revertability" of this hack. Agreed. Thanks! Oleg. -- 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/