Re: [PATCH 3/3] mm:shm: Use new hugetlb size encoding definitions
On Mon 31-07-17 11:56:26, Mike Kravetz wrote:
> Use the common definitions from hugetlb_encode.h header file for
> encoding hugetlb size definitions in shmget system call flags.
>
> In addition, move these definitions from the internal (kernel) to
> user (uapi) header file.
>
> Suggested-by: Matthew Wilcox
> Signed-off-by: Mike Kravetz
Acked-by: Michal Hocko
> ---
> include/linux/shm.h | 17 -
> include/uapi/linux/shm.h | 31 +--
> 2 files changed, 29 insertions(+), 19 deletions(-)
>
> diff --git a/include/linux/shm.h b/include/linux/shm.h
> index 04e8818..d56285a 100644
> --- a/include/linux/shm.h
> +++ b/include/linux/shm.h
> @@ -27,23 +27,6 @@ struct shmid_kernel /* private to the kernel */
> /* shm_mode upper byte flags */
> #define SHM_DEST01000 /* segment will be destroyed on last
> detach */
> #define SHM_LOCKED 02000 /* segment will not be swapped */
> -#define SHM_HUGETLB 04000 /* segment will use huge TLB pages */
> -#define SHM_NORESERVE 01 /* don't check for reservations */
> -
> -/* Bits [26:31] are reserved */
> -
> -/*
> - * When SHM_HUGETLB is set bits [26:31] encode the log2 of the huge page
> size.
> - * This gives us 6 bits, which is enough until someone invents 128 bit
> address
> - * spaces.
> - *
> - * Assume these are all power of twos.
> - * When 0 use the default page size.
> - */
> -#define SHM_HUGE_SHIFT 26
> -#define SHM_HUGE_MASK 0x3f
> -#define SHM_HUGE_2MB(21 << SHM_HUGE_SHIFT)
> -#define SHM_HUGE_1GB(30 << SHM_HUGE_SHIFT)
>
> #ifdef CONFIG_SYSVIPC
> struct sysv_shm {
> diff --git a/include/uapi/linux/shm.h b/include/uapi/linux/shm.h
> index 1fbf24e..cf23c87 100644
> --- a/include/uapi/linux/shm.h
> +++ b/include/uapi/linux/shm.h
> @@ -3,6 +3,7 @@
>
> #include
> #include
> +#include
> #ifndef __KERNEL__
> #include
> #endif
> @@ -40,11 +41,37 @@ struct shmid_ds {
> /* Include the definition of shmid64_ds and shminfo64 */
> #include
>
> -/* permission flag for shmget */
> +/*
> + * shmget() shmflg values.
> + */
> +/* The bottom nine bits are the same as open(2) mode flags */
> #define SHM_R0400/* or S_IRUGO from */
> #define SHM_W0200/* or S_IWUGO from */
> +/* Bits 9 & 10 are IPC_CREAT and IPC_EXCL */
> +#define SHM_HUGETLB 04000 /* segment will use huge TLB pages */
> +#define SHM_NORESERVE01 /* don't check for reservations */
> +
> +/*
> + * Huge page size encoding when SHM_HUGETLB is specified, and a huge page
> + * size other than the default is desired. See hugetlb_encode.h
> + */
> +#define SHM_HUGE_SHIFT HUGETLB_FLAG_ENCODE_SHIFT
> +#define SHM_HUGE_MASKHUGETLB_FLAG_ENCODE_MASK
> +
> +#define SHM_HUGE_64KBHUGETLB_FLAG_ENCODE_64KB
> +#define SHM_HUGE_512KB HUGETLB_FLAG_ENCODE_512KB
> +#define SHM_HUGE_1MB HUGETLB_FLAG_ENCODE_1MB
> +#define SHM_HUGE_2MB HUGETLB_FLAG_ENCODE_2MB
> +#define SHM_HUGE_8MB HUGETLB_FLAG_ENCODE_8MB
> +#define SHM_HUGE_16MBHUGETLB_FLAG_ENCODE_16MB
> +#define SHM_HUGE_256MB HUGETLB_FLAG_ENCODE_256MB
> +#define SHM_HUGE_1GB HUGETLB_FLAG_ENCODE_1GB
> +#define SHM_HUGE_2GB HUGETLB_FLAG_ENCODE_2GB
> +#define SHM_HUGE_16GBHUGETLB_FLAG_ENCODE_16GB
>
> -/* mode for attach */
> +/*
> + * shmat() shmflg values
> + */
> #define SHM_RDONLY 01 /* read-only access */
> #define SHM_RND 02 /* round attach address to SHMLBA
> boundary */
> #define SHM_REMAP 04 /* take-over region on attach */
> --
> 2.7.5
--
Michal Hocko
SUSE Labs
[PATCH 3/3] mm:shm: Use new hugetlb size encoding definitions
Use the common definitions from hugetlb_encode.h header file for
encoding hugetlb size definitions in shmget system call flags.
In addition, move these definitions from the internal (kernel) to
user (uapi) header file.
Suggested-by: Matthew Wilcox
Signed-off-by: Mike Kravetz
---
include/linux/shm.h | 17 -
include/uapi/linux/shm.h | 31 +--
2 files changed, 29 insertions(+), 19 deletions(-)
diff --git a/include/linux/shm.h b/include/linux/shm.h
index 04e8818..d56285a 100644
--- a/include/linux/shm.h
+++ b/include/linux/shm.h
@@ -27,23 +27,6 @@ struct shmid_kernel /* private to the kernel */
/* shm_mode upper byte flags */
#defineSHM_DEST01000 /* segment will be destroyed on last
detach */
#define SHM_LOCKED 02000 /* segment will not be swapped */
-#define SHM_HUGETLB 04000 /* segment will use huge TLB pages */
-#define SHM_NORESERVE 01 /* don't check for reservations */
-
-/* Bits [26:31] are reserved */
-
-/*
- * When SHM_HUGETLB is set bits [26:31] encode the log2 of the huge page size.
- * This gives us 6 bits, which is enough until someone invents 128 bit address
- * spaces.
- *
- * Assume these are all power of twos.
- * When 0 use the default page size.
- */
-#define SHM_HUGE_SHIFT 26
-#define SHM_HUGE_MASK 0x3f
-#define SHM_HUGE_2MB(21 << SHM_HUGE_SHIFT)
-#define SHM_HUGE_1GB(30 << SHM_HUGE_SHIFT)
#ifdef CONFIG_SYSVIPC
struct sysv_shm {
diff --git a/include/uapi/linux/shm.h b/include/uapi/linux/shm.h
index 1fbf24e..cf23c87 100644
--- a/include/uapi/linux/shm.h
+++ b/include/uapi/linux/shm.h
@@ -3,6 +3,7 @@
#include
#include
+#include
#ifndef __KERNEL__
#include
#endif
@@ -40,11 +41,37 @@ struct shmid_ds {
/* Include the definition of shmid64_ds and shminfo64 */
#include
-/* permission flag for shmget */
+/*
+ * shmget() shmflg values.
+ */
+/* The bottom nine bits are the same as open(2) mode flags */
#define SHM_R 0400/* or S_IRUGO from */
#define SHM_W 0200/* or S_IWUGO from */
+/* Bits 9 & 10 are IPC_CREAT and IPC_EXCL */
+#define SHM_HUGETLB04000 /* segment will use huge TLB pages */
+#define SHM_NORESERVE 01 /* don't check for reservations */
+
+/*
+ * Huge page size encoding when SHM_HUGETLB is specified, and a huge page
+ * size other than the default is desired. See hugetlb_encode.h
+ */
+#define SHM_HUGE_SHIFT HUGETLB_FLAG_ENCODE_SHIFT
+#define SHM_HUGE_MASK HUGETLB_FLAG_ENCODE_MASK
+
+#define SHM_HUGE_64KB HUGETLB_FLAG_ENCODE_64KB
+#define SHM_HUGE_512KB HUGETLB_FLAG_ENCODE_512KB
+#define SHM_HUGE_1MB HUGETLB_FLAG_ENCODE_1MB
+#define SHM_HUGE_2MB HUGETLB_FLAG_ENCODE_2MB
+#define SHM_HUGE_8MB HUGETLB_FLAG_ENCODE_8MB
+#define SHM_HUGE_16MB HUGETLB_FLAG_ENCODE_16MB
+#define SHM_HUGE_256MB HUGETLB_FLAG_ENCODE_256MB
+#define SHM_HUGE_1GB HUGETLB_FLAG_ENCODE_1GB
+#define SHM_HUGE_2GB HUGETLB_FLAG_ENCODE_2GB
+#define SHM_HUGE_16GB HUGETLB_FLAG_ENCODE_16GB
-/* mode for attach */
+/*
+ * shmat() shmflg values
+ */
#defineSHM_RDONLY 01 /* read-only access */
#defineSHM_RND 02 /* round attach address to SHMLBA
boundary */
#defineSHM_REMAP 04 /* take-over region on attach */
--
2.7.5
