From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751680AbdHAI6F (ORCPT ); Tue, 1 Aug 2017 04:58:05 -0400 Received: from mx2.suse.de ([195.135.220.15]:51037 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751003AbdHAI6C (ORCPT ); Tue, 1 Aug 2017 04:58:02 -0400 Date: Tue, 1 Aug 2017 10:57:59 +0200 From: Michal Hocko To: Mike Kravetz Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Matthew Wilcox , akpm@linux-foundation.org, ak@linux.intel.com, mtk.manpages@gmail.com, Davidlohr Bueso , khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com, aarcange@redhat.com, Arnd Bergmann Subject: Re: [PATCH 1/3] mm:hugetlb: Define system call hugetlb size encodings in single file Message-ID: <20170801085759.GC15774@dhcp22.suse.cz> References: <1501527386-10736-1-git-send-email-mike.kravetz@oracle.com> <1501527386-10736-2-git-send-email-mike.kravetz@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1501527386-10736-2-git-send-email-mike.kravetz@oracle.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 31-07-17 11:56:24, Mike Kravetz wrote: > If hugetlb pages are requested in mmap or shmget system calls, a huge > page size other than default can be requested. This is accomplished by > encoding the log2 of the huge page size in the upper bits of the flag > argument. asm-generic and arch specific headers all define the same > values for these encodings. > > Put common definitions in a single header file. The primary uapi > header files for mmap and shm will use these definitions as a basis > for definitions specific to those system calls. > > Signed-off-by: Mike Kravetz Acked-by: Michal Hocko > --- > include/uapi/asm-generic/hugetlb_encode.h | 34 +++++++++++++++++++++++++++++++ > 1 file changed, 34 insertions(+) > create mode 100644 include/uapi/asm-generic/hugetlb_encode.h > > diff --git a/include/uapi/asm-generic/hugetlb_encode.h b/include/uapi/asm-generic/hugetlb_encode.h > new file mode 100644 > index 0000000..e4732d3 > --- /dev/null > +++ b/include/uapi/asm-generic/hugetlb_encode.h > @@ -0,0 +1,34 @@ > +#ifndef _ASM_GENERIC_HUGETLB_ENCODE_H_ > +#define _ASM_GENERIC_HUGETLB_ENCODE_H_ > + > +/* > + * Several system calls take a flag to request "hugetlb" huge pages. > + * Without further specification, these system calls will use the > + * system's default huge page size. If a system supports multiple > + * huge page sizes, the desired huge page size can be specified in > + * bits [26:31] of the flag arguments. The value in these 6 bits > + * will encode the log2 of the huge page size. > + * > + * The following definitions are associated with this huge page size > + * encoding in flag arguments. System call specific header files > + * that use this encoding should include this file. They can then > + * provide definitions based on these with their own specific prefix. > + * for example: > + * #define MAP_HUGE_SHIFT HUGETLB_FLAG_ENCODE_SHIFT > + */ > + > +#define HUGETLB_FLAG_ENCODE_SHIFT 26 > +#define HUGETLB_FLAG_ENCODE_MASK 0x3f > + > +#define HUGETLB_FLAG_ENCODE_64KB (16 << HUGETLB_FLAG_ENCODE_SHIFT) > +#define HUGETLB_FLAG_ENCODE_512KB (19 << HUGETLB_FLAG_ENCODE_SHIFT) > +#define HUGETLB_FLAG_ENCODE_1MB (20 << HUGETLB_FLAG_ENCODE_SHIFT) > +#define HUGETLB_FLAG_ENCODE_2MB (21 << HUGETLB_FLAG_ENCODE_SHIFT) > +#define HUGETLB_FLAG_ENCODE_8MB (23 << HUGETLB_FLAG_ENCODE_SHIFT) > +#define HUGETLB_FLAG_ENCODE_16MB (24 << HUGETLB_FLAG_ENCODE_SHIFT) > +#define HUGETLB_FLAG_ENCODE_256MB (28 << HUGETLB_FLAG_ENCODE_SHIFT) > +#define HUGETLB_FLAG_ENCODE_1GB (30 << HUGETLB_FLAG_ENCODE_SHIFT) > +#define HUGETLB_FLAG_ENCODE_2GB (31 << HUGETLB_FLAG_ENCODE_SHIFT) > +#define HUGETLB_FLAG_ENCODE_16GB (34 << HUGETLB_FLAG_ENCODE_SHIFT) > + > +#endif /* _ASM_GENERIC_HUGETLB_ENCODE_H_ */ > -- > 2.7.5 -- Michal Hocko SUSE Labs