From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id 87AF06810C3 for ; Fri, 25 Aug 2017 12:56:18 -0400 (EDT) Received: by mail-pg0-f71.google.com with SMTP id r133so2081578pgr.6 for ; Fri, 25 Aug 2017 09:56:18 -0700 (PDT) Received: from mga05.intel.com (mga05.intel.com. [192.55.52.43]) by mx.google.com with ESMTPS id c22si5605106plk.805.2017.08.25.09.56.17 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 25 Aug 2017 09:56:17 -0700 (PDT) Date: Fri, 25 Aug 2017 19:56:12 +0300 From: "Kirill A. Shutemov" Subject: Re: [PATCH v6 3/5] mm: introduce mmap3 for safely defining new mmap flags Message-ID: <20170825165612.xsv3akgjk6tajcpk@black.fi.intel.com> References: <150353211413.5039.5228914877418362329.stgit@dwillia2-desk3.amr.corp.intel.com> <150353213097.5039.6729469069608762658.stgit@dwillia2-desk3.amr.corp.intel.com> <20170824165546.GA3121@infradead.org> <20170825130011.GA30072@infradead.org> <20170825155803.4km7wttzadfqw2vb@node.shutemov.name> <20170825160236.GA2561@infradead.org> <20170825161607.6v6beg4zjktllt2z@node.shutemov.name> <4de21e8d-5e10-ec40-c731-0c079953cf48@gmx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4de21e8d-5e10-ec40-c731-0c079953cf48@gmx.de> Sender: owner-linux-mm@kvack.org List-ID: To: Helge Deller Cc: "Kirill A. Shutemov" , Christoph Hellwig , Dan Williams , Andrew Morton , Jan Kara , Arnd Bergmann , "linux-nvdimm@lists.01.org" , Linux API , "linux-kernel@vger.kernel.org" , linux-xfs@vger.kernel.org, Linux MM , Andy Lutomirski , linux-fsdevel , linux-parisc@vger.kernel.org On Fri, Aug 25, 2017 at 04:19:19PM +0000, Helge Deller wrote: > On 25.08.2017 18:16, Kirill A. Shutemov wrote: > > On Fri, Aug 25, 2017 at 09:02:36AM -0700, Christoph Hellwig wrote: > >> On Fri, Aug 25, 2017 at 06:58:03PM +0300, Kirill A. Shutemov wrote: > >>> Not all archs are ready for this: > >>> > >>> arch/parisc/include/uapi/asm/mman.h:#define MAP_TYPE 0x03 /* Mask for type of mapping */ > >>> arch/parisc/include/uapi/asm/mman.h:#define MAP_FIXED 0x04 /* Interpret addr exactly */ > >> > >> I'd be happy to say that we should not care about parisc for > >> persistent memory. We'll just have to find a way to exclude > >> parisc without making life too ugly. > > > > I don't think creapling mmap() interface for one arch is the right way to > > go. I think the interface should be universal. > > > > I may imagine MAP_DIRECT can be useful not only for persistent memory. > > For tmpfs instead of mlock()? > > On parisc we have > #define MAP_SHARED 0x01 /* Share changes */ > #define MAP_PRIVATE 0x02 /* Changes are private */ > #define MAP_TYPE 0x03 /* Mask for type of mapping */ > #define MAP_FIXED 0x04 /* Interpret addr exactly */ > #define MAP_ANONYMOUS 0x10 /* don't use a file */ > > So, if you need a MAP_DIRECT, wouldn't e.g. > #define MAP_DIRECT 0x08 > be possible (for parisc, and others 0x04). > And if MAP_TYPE needs to include this flag on parisc: > #define MAP_TYPE (0x03 | 0x08) /* Mask for type of mapping */ I guess it's better to re-define MAP_TYPE as 0x3 everywhere and make MAP_DIRECT a normal flag. It's not new type of mapping anyway. -- Kirill A. Shutemov -- 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