The patch titled
Subject: mm: hugetlb: define system call hugetlb size encodings in single file
has been added to the -mm tree. Its filename is
mm-hugetlb-define-system-call-hugetlb-size-encodings-in-single-file.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlb-define-system-call-hugetlb-size-encodings-in-single-file.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlb-define-system-call-hugetlb-size-encodings-in-single-file.patch
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------------------------------------------------------
From: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Michael Kerrisk <mtk.manpages@xxxxxxxxx>
Cc: Davidlohr Bueso <dbueso@xxxxxxx>
Cc: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/uapi/asm-generic/hugetlb_encode.h | 34 ++++++++++++++++++++
1 file changed, 34 insertions(+)
diff -puN /dev/null include/uapi/asm-generic/hugetlb_encode.h
--- /dev/null
+++ a/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_ */
_
Patches currently in -mm which might be from mike.kravetz@xxxxxxxxxx are
mm-mremap-fail-map-duplication-attempts-for-private-mappings.patch
mm-hugetlb-define-system-call-hugetlb-size-encodings-in-single-file.patch
mm-arch-consolidate-mmap-hugetlb-size-encodings.patch
mm-shm-use-new-hugetlb-size-encoding-definitions.patch
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