From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753626AbdBJQvg (ORCPT ); Fri, 10 Feb 2017 11:51:36 -0500 Received: from mx2.suse.de ([195.135.220.15]:41686 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753605AbdBJQvd (ORCPT ); Fri, 10 Feb 2017 11:51:33 -0500 Date: Fri, 10 Feb 2017 08:51:11 -0800 From: Davidlohr Bueso To: Michal Hocko Cc: akpm@linux-foundation.org, manfred@colorfullife.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Davidlohr Bueso Subject: Re: [PATCH 4/4] mm,hugetlb: compute page_size_log properly Message-ID: <20170210165111.GB2392@linux-80c1.suse> Mail-Followup-To: Michal Hocko , akpm@linux-foundation.org, manfred@colorfullife.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Davidlohr Bueso References: <1486673582-6979-1-git-send-email-dave@stgolabs.net> <1486673582-6979-5-git-send-email-dave@stgolabs.net> <20170210102044.GA10054@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20170210102044.GA10054@dhcp22.suse.cz> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 10 Feb 2017, Michal Hocko wrote: >On Thu 09-02-17 12:53:02, Davidlohr Bueso wrote: >> The SHM_HUGE_* stuff was introduced in: >> >> 42d7395feb5 (mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB) >> >> It unnecessarily adds another layer, specific to sysv shm, without >> anything special about it: the macros are identical to the MAP_HUGE_* >> stuff, which in turn does correctly describe the hugepage subsystem. >> >> One example of the problems with extra layers what this patch fixes: >> mmap_pgoff() should never be using SHM_HUGE_* logic. It is obviously >> harmless but it would still be grand to get rid of it -- although >> now in the manpages I don't see that happening. > >Can we just drop SHM_HUGE_MASK altogether? It is not exported in uapi >headers AFAICS. Yeah that was my original idea, however I noticed that shmget.2 mentions kernel internals as part of SHM_HUGE_{2MB,1GB}, ie: SHM_HUGE_SHIFT. So dropping _MASK doesn't make sense if we are going to keep _SHIFT. Thanks, Davidlohr