/* * 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 #include #include #include #include #include #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; shmid = shmget(2, LENGTH, SHM_HUGETLB | IPC_CREAT | SHM_R | SHM_W); if (shmid < 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); exit(3); } dprintf("Done.\n"); if (shmdt((const void *)shmaddr) != 0) { perror("Detach failure"); shmctl(shmid, IPC_RMID, NULL); exit(4); } shmctl(shmid, IPC_RMID, NULL); return 0; } t' value='search'/>
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authorSedat Dilek <sedat.dilek@gmail.com>2016-12-26 11:05:11 +0100
committerThomas Gleixner <tglx@linutronix.de>2016-12-27 11:42:12 +0100
commit7e164ce4e8ecd7e9a58a83750bd3ee03125df154 (patch)
tree72014145699b741f20d3533c9b352e6db263c5a2 /sound/drivers
parent0dad3a3014a0b9e72521ff44f17e0054f43dcdea (diff)
perf/x86/amd/ibs: Fix typo after cleanup state names in cpu/hotplug
Fix a small typo after cleanup state names in cpu/hotplug. The new convention is 'subsys/xxx/yyy:state' where "state" here is called "starting" not "STARTING". Fixes: 73c1b41e63f0 ("cpu/hotplug: Cleanup state names") Signed-off-by: Sedat Dilek <sedat.dilek@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@suse.de> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Link: http://lkml.kernel.org/r/20161226100511.8662-1-sedat.dilek@gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'sound/drivers')