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| Started by | Mike Kravetz <mike.kravetz@oracle.com> |
|---|---|
| First post | 2017-07-18 00:40 +0200 |
| Last post | 2017-07-26 12:00 +0200 |
| Articles | 3 — 3 participants |
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[RFC PATCH 1/3] mm:hugetlb: Define system call hugetlb size encodings in single file Mike Kravetz <mike.kravetz@oracle.com> - 2017-07-18 00:40 +0200
Re: [RFC PATCH 1/3] mm:hugetlb: Define system call hugetlb size encodings in single file Matthew Wilcox <willy@infradead.org> - 2017-07-18 02:10 +0200
Re: [RFC PATCH 1/3] mm:hugetlb: Define system call hugetlb size encodings in single file Michal Hocko <mhocko@kernel.org> - 2017-07-26 12:00 +0200
| From | Mike Kravetz <mike.kravetz@oracle.com> |
|---|---|
| Date | 2017-07-18 00:40 +0200 |
| Subject | [RFC PATCH 1/3] mm:hugetlb: Define system call hugetlb size encodings in single file |
| Message-ID | <u4mQh-2yQ-5@gated-at.bofh.it> |
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. arch specific code can still override if desired. Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> --- include/uapi/asm-generic/hugetlb_encode.h | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 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..aa09fc0 --- /dev/null +++ b/include/uapi/asm-generic/hugetlb_encode.h @@ -0,0 +1,30 @@ +#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_512KB (19 << MAP_HUGE_SHIFT +#define HUGETLB_FLAG_ENCODE_1MB (20 << MAP_HUGE_SHIFT) +#define HUGETLB_FLAG_ENCODE_2MB (21 << MAP_HUGE_SHIFT) +#define HUGETLB_FLAG_ENCODE_8MB (23 << MAP_HUGE_SHIFT) +#define HUGETLB_FLAG_ENCODE_16MB (24 << MAP_HUGE_SHIFT) +#define HUGETLB_FLAG_ENCODE_1GB (30 << MAP_HUGE_SHIFT) +#define HUGETLB_FLAG_ENCODE__16GB (34 << MAP_HUGE_SHIFT) + +#endif /* _ASM_GENERIC_HUGETLB_ENCODE_H_ */ -- 2.7.5
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| From | Matthew Wilcox <willy@infradead.org> |
|---|---|
| Date | 2017-07-18 02:10 +0200 |
| Subject | Re: [RFC PATCH 1/3] mm:hugetlb: Define system call hugetlb size encodings in single file |
| Message-ID | <u4ofo-3xU-19@gated-at.bofh.it> |
| In reply to | #1689539 |
On Mon, Jul 17, 2017 at 03:27:59PM -0700, Mike Kravetz wrote: > +#define HUGETLB_FLAG_ENCODE_512KB (19 << MAP_HUGE_SHIFT > +#define HUGETLB_FLAG_ENCODE_1MB (20 << MAP_HUGE_SHIFT) > +#define HUGETLB_FLAG_ENCODE_2MB (21 << MAP_HUGE_SHIFT) > +#define HUGETLB_FLAG_ENCODE_8MB (23 << MAP_HUGE_SHIFT) > +#define HUGETLB_FLAG_ENCODE_16MB (24 << MAP_HUGE_SHIFT) > +#define HUGETLB_FLAG_ENCODE_1GB (30 << MAP_HUGE_SHIFT) > +#define HUGETLB_FLAG_ENCODE__16GB (34 << MAP_HUGE_SHIFT) The __ seems like a mistake?
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| From | Michal Hocko <mhocko@kernel.org> |
|---|---|
| Date | 2017-07-26 12:00 +0200 |
| Subject | Re: [RFC PATCH 1/3] mm:hugetlb: Define system call hugetlb size encodings in single file |
| Message-ID | <u7rgL-77f-29@gated-at.bofh.it> |
| In reply to | #1689539 |
On Mon 17-07-17 15:27:59, 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. arch specific code can > still override if desired. > > Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> with s@HUGETLB_FLAG_ENCODE__16GB@HUGETLB_FLAG_ENCODE_16GB@ Acked-by: Michal Hocko <mhocko@suse.com> > --- > include/uapi/asm-generic/hugetlb_encode.h | 30 ++++++++++++++++++++++++++++++ > 1 file changed, 30 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..aa09fc0 > --- /dev/null > +++ b/include/uapi/asm-generic/hugetlb_encode.h > @@ -0,0 +1,30 @@ > +#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_512KB (19 << MAP_HUGE_SHIFT > +#define HUGETLB_FLAG_ENCODE_1MB (20 << MAP_HUGE_SHIFT) > +#define HUGETLB_FLAG_ENCODE_2MB (21 << MAP_HUGE_SHIFT) > +#define HUGETLB_FLAG_ENCODE_8MB (23 << MAP_HUGE_SHIFT) > +#define HUGETLB_FLAG_ENCODE_16MB (24 << MAP_HUGE_SHIFT) > +#define HUGETLB_FLAG_ENCODE_1GB (30 << MAP_HUGE_SHIFT) > +#define HUGETLB_FLAG_ENCODE__16GB (34 << MAP_HUGE_SHIFT) > + > +#endif /* _ASM_GENERIC_HUGETLB_ENCODE_H_ */ > -- > 2.7.5 > -- Michal Hocko SUSE Labs
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