From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id 939FF2808A3 for ; Wed, 10 May 2017 11:24:04 -0400 (EDT) Received: by mail-wr0-f198.google.com with SMTP id y106so9975675wrb.14 for ; Wed, 10 May 2017 08:24:04 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id m15si3854711wrm.44.2017.05.10.08.24.03 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 10 May 2017 08:24:03 -0700 (PDT) Subject: Re: Question on ___GFP_NOLOCKDEP - Was: Re: [PATCH 1/1] Remove hardcoding of ___GFP_xxx bitmasks References: <20170426133549.22603-1-igor.stoppa@huawei.com> <20170426133549.22603-2-igor.stoppa@huawei.com> <20170426144750.GH12504@dhcp22.suse.cz> <9929419e-c22e-2a9f-a8a6-ad98d5a9da06@huawei.com> <20170427133523.GG4706@dhcp22.suse.cz> From: Vlastimil Babka Message-ID: <0da15f82-bc01-64e8-94a6-d9a5745d3eb1@suse.cz> Date: Wed, 10 May 2017 17:24:01 +0200 MIME-Version: 1.0 In-Reply-To: <20170427133523.GG4706@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko , Igor Stoppa , Andrew Morton Cc: namhyung@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On 04/27/2017 03:35 PM, Michal Hocko wrote: > On Thu 27-04-17 15:16:47, Igor Stoppa wrote: >> On 26/04/17 18:29, Igor Stoppa wrote: >> >>> On 26/04/17 17:47, Michal Hocko wrote: >> >> [...] >> >>>> Also the current mm tree has ___GFP_NOLOCKDEP which is not addressed >>>> here so I suspect you have based your change on the Linus tree. >> >>> I used your tree from kernel.org >> >> I found it, I was using master, instead of auto-latest (is it correct?) > > yes > >> But now I see something that I do not understand (apologies if I'm >> asking something obvious). >> >> First there is: >> >> [...] >> #define ___GFP_WRITE 0x800000u >> #define ___GFP_KSWAPD_RECLAIM 0x1000000u >> #ifdef CONFIG_LOCKDEP >> #define ___GFP_NOLOCKDEP 0x4000000u >> #else >> #define ___GFP_NOLOCKDEP 0 >> #endif >> >> Then: >> >> /* Room for N __GFP_FOO bits */ >> #define __GFP_BITS_SHIFT (25 + IS_ENABLED(CONFIG_LOCKDEP)) >> >> >> >> Shouldn't it be either: >> ___GFP_NOLOCKDEP 0x2000000u > > Yes it should. At the time when this patch was written this value was > used. Later I've removed __GFP_OTHER by 41b6167e8f74 ("mm: get rid of > __GFP_OTHER_NODE") and forgot to refresh this one. Thanks for noticing > this. > > Andrew, could you fold the following in please? > --- > From 8dc9c917af215f659bb990fa48ae7b4753027c19 Mon Sep 17 00:00:00 2001 > From: Michal Hocko > Date: Thu, 27 Apr 2017 15:28:10 +0200 > Subject: [PATCH] lockdep-allow-to-disable-reclaim-lockup-detection-fix > > Igor Stoppa has noticed that __GFP_NOLOCKDEP can use a lower bit. At the > time lockdep-allow-to-disable-reclaim-lockup-detection was written we > still had __GFP_OTHER_NODE but I have removed it in 41b6167e8f74 ("mm: > get rid of __GFP_OTHER_NODE") and forgot to lower the bit value. > > Signed-off-by: Michal Hocko Ping, I have noticed (at least in the mmotm-2017-05-08-16-30 git tag) there's still 0x4000000u ? > --- > include/linux/gfp.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/gfp.h b/include/linux/gfp.h > index 2b1a44f5bdb6..a89d37e8b387 100644 > --- a/include/linux/gfp.h > +++ b/include/linux/gfp.h > @@ -41,7 +41,7 @@ struct vm_area_struct; > #define ___GFP_WRITE 0x800000u > #define ___GFP_KSWAPD_RECLAIM 0x1000000u > #ifdef CONFIG_LOCKDEP > -#define ___GFP_NOLOCKDEP 0x4000000u > +#define ___GFP_NOLOCKDEP 0x2000000u > #else > #define ___GFP_NOLOCKDEP 0 > #endif > -- 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