diff options
| author | Ingo Molnar <mingo@kernel.org> | 2012-04-14 13:18:27 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-04-14 13:19:04 +0200 |
| commit | 6ac1ef482d7ae0c690f1640bf6eb818ff9a2d91e (patch) | |
| tree | 021cc9f6b477146fcebe6f3be4752abfa2ba18a9 /Documentation/vm/hugepage-shm.c | |
| parent | 682968e0c425c60f0dde37977e5beb2b12ddc4cc (diff) | |
| parent | a385ec4f11bdcf81af094c03e2444ee9b7fad2e5 (diff) | |
Merge branch 'perf/core' into perf/uprobes
Merge in latest upstream (and the latest perf development tree),
to prepare for tooling changes, and also to pick up v3.4 MM
changes that the uprobes code needs to take care of.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'Documentation/vm/hugepage-shm.c')
| -rw-r--r-- | Documentation/vm/hugepage-shm.c | 98 |
1 files changed, 0 insertions, 98 deletions
diff --git a/Documentation/vm/hugepage-shm.c b/Documentation/vm/hugepage-shm.c deleted file mode 100644 index 07956d8592c9..000000000000 --- a/Documentation/vm/hugepage-shm.c +++ /dev/null @@ -1,98 +0,0 @@ -/* - * hugepage-shm: - * - * Example of using huge page memory in a user application using Sys V shared - * memory system calls. In this example the app is requesting 256MB of - * memory that is backed by huge pages. The application uses the flag - * SHM_HUGETLB in the shmget system call to inform the kernel that it is - * requesting huge pages. - * - * For the ia64 architecture, the Linux kernel reserves Region number 4 for - * huge pages. That means that if one requires a fixed address, a huge page - * aligned address starting with 0x800000... will be required. If a fixed - * address is not required, the kernel will select an address in the proper - * range. - * Other architectures, such as ppc64, i386 or x86_64 are not so constrained. - * - * Note: The default shared memory limit is quite low on many kernels, - * you may need to increase it via: - * - * echo 268435456 > /proc/sys/kernel/shmmax - * - * This will increase the maximum size per shared memory segment to 256MB. - * The other limit that you will hit eventually is shmall which is the - * total amount of shared memory in pages. To set it to 16GB on a system - * with a 4kB pagesize do: - * - * echo 4194304 > /proc/sys/kernel/shmall - */ - -#include <stdlib.h> -#include <stdio.h> -#include <sys/types.h> -#include <sys/ipc.h> -#include <sys/shm.h> -#include <sys/mman.h> - -#ifndef SHM_HUGETLB -#define SHM_HUGETLB 04000 -#endif - -#define LENGTH (256UL*1024*1024) - -#define dprintf(x) printf(x) - -/* Only ia64 requires this */ -#ifdef __ia64__ -#define ADDR (void *)(0x8000000000000000UL) -#define SHMAT_FLAGS (SHM_RND) -#else -#define ADDR (void *)(0x0UL) -#define SHMAT_FLAGS (0) -#endif - -int main(void) -{ - int shmid; - unsigned long i; - char *shmaddr; - - if ((shmid = shmget(2, LENGTH, - SHM_HUGETLB | IPC_CREAT | SHM_R | SHM_W)) < 0) { - perror("shmget"); - exit(1); - } - printf("shmid: 0x%x\n", shmid); - - shmaddr = shmat(shmid, ADDR, SHMAT_FLAGS); - if (shmaddr == (char *)-1) { - perror("Shared memory attach failure"); - shmctl(shmid, IPC_RMID, NULL); - exit(2); - } - printf("shmaddr: %p\n", shmaddr); - - dprintf("Starting the writes:\n"); - for (i = 0; i < LENGTH; i++) { - shmaddr[i] = (char)(i); - if (!(i % (1024 * 1024))) - dprintf("."); - } - dprintf("\n"); - - dprintf("Starting the Check..."); - for (i = 0; i < LENGTH; i++) - if (shmaddr[i] != (char)i) - printf("\nIndex %lu mismatched\n", i); - dprintf("Done.\n"); - - if (shmdt((const void *)shmaddr) != 0) { - perror("Detach failure"); - shmctl(shmid, IPC_RMID, NULL); - exit(3); - } - - shmctl(shmid, IPC_RMID, NULL); - - return 0; -} |
