diff options
author | Mike Kravetz <mike.kravetz@oracle.com> | 2017-09-06 16:23:25 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-06 17:27:28 -0700 |
commit | e652f694598273c5d749687032d1534a30e6a3a5 (patch) | |
tree | 223fd6d2b041e1723bc124f52b38f3cf56151945 /include | |
parent | a446d6f9ce545248c62ab9694d05ac6f68563706 (diff) |
mm: hugetlb: define system call hugetlb size encodings in single file
Patch series "Consolidate system call hugetlb page size encodings".
These patches are the result of discussions in
https://lkml.org/lkml/2017/3/8/548. The following changes are made in the
patch set:
1) Put all the log2 encoded huge page size definitions in a common
header file. The idea is have a set of definitions that can be use as
the basis for system call specific definitions such as MAP_HUGE_* and
SHM_HUGE_*.
2) Remove MAP_HUGE_* definitions in arch specific files. All these
definitions are the same. Consolidate all definitions in the primary
user header file (uapi/linux/mman.h).
3) Remove SHM_HUGE_* definitions intended for user space from kernel
header file, and add to user (uapi/linux/shm.h) header file. Add
definitions for all known huge page size encodings as in mmap.
This patch (of 3):
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.
Link: http://lkml.kernel.org/r/1501527386-10736-2-git-send-email-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r-- | include/uapi/asm-generic/hugetlb_encode.h | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/include/uapi/asm-generic/hugetlb_encode.h b/include/uapi/asm-generic/hugetlb_encode.h new file mode 100644 index 000000000000..e4732d3c2998 --- /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_ */ |