/* * hugepage-mmap: * * Example of using huge page memory in a user application using the mmap * system call. Before running this application, make sure that the * administrator has mounted the hugetlbfs filesystem (on some directory * like /mnt) using the command mount -t hugetlbfs nodev /mnt. In this * example, the app is requesting memory of size 256MB that is backed by * 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. */ #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <sys/mman.h> #include <fcntl.h> #define FILE_NAME "huge/hugepagefile" #define LENGTH (256UL*1024*1024) #define PROTECTION (PROT_READ | PROT_WRITE) /* Only ia64 requires this */ #ifdef __ia64__ #define ADDR (void *)(0x8000000000000000UL) #define FLAGS (MAP_SHARED | MAP_FIXED) #else #define ADDR (void *)(0x0UL) #define FLAGS (MAP_SHARED) #endif static void check_bytes(char *addr) { printf("First hex is %x\n", *((unsigned int *)addr)); } static void write_bytes(char *addr) { unsigned long i; for (i = 0; i < LENGTH; i++) *(addr + i) = (char)i; } static int read_bytes(char *addr) { unsigned long i; check_bytes(addr); for (i = 0; i < LENGTH; i++) if (*(addr + i) != (char)i) { printf("Mismatch at %lu\n", i); return 1; } return 0; } int main(void) { void *addr; int fd, ret; fd = open(FILE_NAME, O_CREAT | O_RDWR, 0755); if (fd < 0) { perror("Open failed"); exit(1); } addr = mmap(ADDR, LENGTH, PROTECTION, FLAGS, fd, 0); if (addr == MAP_FAILED) { perror("mmap"); unlink(FILE_NAME); exit(1); } printf("Returned address is %p\n", addr); check_bytes(addr); write_bytes(addr); ret = read_bytes(addr); munmap(addr, LENGTH); close(fd); unlink(FILE_NAME); return ret; } git/diff/net/tipc/node.c?h=nds-private-remove&id=db8cb0095b0ec9700d6f369f594eb31ff683e322'>diff</a></td><td class='form'><form class='right' method='get' action='/cgit.cgi/linux/net-next.git/log/net/tipc/node.c'> <input type='hidden' name='h' value='nds-private-remove'/><input type='hidden' name='id' value='db8cb0095b0ec9700d6f369f594eb31ff683e322'/><select name='qt'> <option value='grep'>log msg</option> <option value='author'>author</option> <option value='committer'>committer</option> <option value='range'>range</option> </select> <input class='txt' type='search' size='10' name='q' value=''/> <input type='submit' value='search'/> </form> </td></tr></table> <div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/log/?h=nds-private-remove&id=db8cb0095b0ec9700d6f369f594eb31ff683e322'>root</a>/<a href='/cgit.cgi/linux/net-next.git/log/net?h=nds-private-remove&id=db8cb0095b0ec9700d6f369f594eb31ff683e322'>net</a>/<a href='/cgit.cgi/linux/net-next.git/log/net/tipc?h=nds-private-remove&id=db8cb0095b0ec9700d6f369f594eb31ff683e322'>tipc</a>/<a href='/cgit.cgi/linux/net-next.git/log/net/tipc/node.c?h=nds-private-remove&id=db8cb0095b0ec9700d6f369f594eb31ff683e322'>node.c</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/cgit.cgi/linux/net-next.git/log/net/tipc/node.c?h=nds-private-remove&id=db8cb0095b0ec9700d6f369f594eb31ff683e322&showmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>