From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751793AbcDOSlc (ORCPT ); Fri, 15 Apr 2016 14:41:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59536 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751016AbcDOSlb (ORCPT ); Fri, 15 Apr 2016 14:41:31 -0400 Date: Fri, 15 Apr 2016 14:41:29 -0400 (EDT) From: Mikulas Patocka X-X-Sender: mpatocka@file01.intranet.prod.int.rdu2.redhat.com To: Michal Hocko cc: linux-mm@kvack.org, Andrew Morton , LKML , Shaohua Li Subject: Re: [PATCH 17/19] dm: get rid of superfluous gfp flags In-Reply-To: <20160415130839.GJ32377@dhcp22.suse.cz> Message-ID: References: <1460372892-8157-1-git-send-email-mhocko@kernel.org> <1460372892-8157-18-git-send-email-mhocko@kernel.org> <20160415130839.GJ32377@dhcp22.suse.cz> User-Agent: Alpine 2.02 (LRH 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Fri, 15 Apr 2016 18:41:30 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 15 Apr 2016, Michal Hocko wrote: > On Fri 15-04-16 08:29:28, Mikulas Patocka wrote: > > > > > > On Mon, 11 Apr 2016, Michal Hocko wrote: > > > > > From: Michal Hocko > > > > > > copy_params seems to be little bit confused about which allocation flags > > > to use. It enforces GFP_NOIO even though it uses > > > memalloc_noio_{save,restore} which enforces GFP_NOIO at the page > > > > memalloc_noio_{save,restore} is used because __vmalloc is flawed and > > doesn't respect GFP_NOIO properly (it doesn't use gfp flags when > > allocating pagetables). > > Yes and there are no plans to change __vmalloc to properly propagate gfp > flags through the whole call chain and that is why we have > memalloc_noio thingy. If that ever changes later the GFP_NOIO can be > added in favor of memalloc_noio API. Both are clearly redundant. > -- > Michal Hocko > SUSE Labs You could move memalloc_noio_{save,restore} to __vmalloc. Something like if (!(gfp_mask & __GFP_IO)) noio_flag = memalloc_noio_save(); ... if (!(gfp_mask & __GFP_IO)) memalloc_noio_restore(noio_flag); That would be better than repeating this hack in every __vmalloc caller that need GFP_NOIO. Mikulas From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yw0-f198.google.com (mail-yw0-f198.google.com [209.85.161.198]) by kanga.kvack.org (Postfix) with ESMTP id 4629C6B0005 for ; Fri, 15 Apr 2016 14:41:32 -0400 (EDT) Received: by mail-yw0-f198.google.com with SMTP id d68so228787993ywe.1 for ; Fri, 15 Apr 2016 11:41:32 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id l74si34343934qhb.68.2016.04.15.11.41.31 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 15 Apr 2016 11:41:31 -0700 (PDT) Date: Fri, 15 Apr 2016 14:41:29 -0400 (EDT) From: Mikulas Patocka Subject: Re: [PATCH 17/19] dm: get rid of superfluous gfp flags In-Reply-To: <20160415130839.GJ32377@dhcp22.suse.cz> Message-ID: References: <1460372892-8157-1-git-send-email-mhocko@kernel.org> <1460372892-8157-18-git-send-email-mhocko@kernel.org> <20160415130839.GJ32377@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: linux-mm@kvack.org, Andrew Morton , LKML , Shaohua Li On Fri, 15 Apr 2016, Michal Hocko wrote: > On Fri 15-04-16 08:29:28, Mikulas Patocka wrote: > > > > > > On Mon, 11 Apr 2016, Michal Hocko wrote: > > > > > From: Michal Hocko > > > > > > copy_params seems to be little bit confused about which allocation flags > > > to use. It enforces GFP_NOIO even though it uses > > > memalloc_noio_{save,restore} which enforces GFP_NOIO at the page > > > > memalloc_noio_{save,restore} is used because __vmalloc is flawed and > > doesn't respect GFP_NOIO properly (it doesn't use gfp flags when > > allocating pagetables). > > Yes and there are no plans to change __vmalloc to properly propagate gfp > flags through the whole call chain and that is why we have > memalloc_noio thingy. If that ever changes later the GFP_NOIO can be > added in favor of memalloc_noio API. Both are clearly redundant. > -- > Michal Hocko > SUSE Labs You could move memalloc_noio_{save,restore} to __vmalloc. Something like if (!(gfp_mask & __GFP_IO)) noio_flag = memalloc_noio_save(); ... if (!(gfp_mask & __GFP_IO)) memalloc_noio_restore(noio_flag); That would be better than repeating this hack in every __vmalloc caller that need GFP_NOIO. Mikulas -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org