1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <sys/mman.h> 4 #include <unistd.h> 5 #include <fcntl.h> 6 7 /* This program allocates memory with multiple calls to remap. This 8 * can be used to verify if the remap api is working correctly. */ 9 10 #define PAGE_SHIFT 12 11 12 #define ROUND_PAGES(memsize) ((memsize >> (PAGE_SHIFT)) << PAGE_SHIFT) 13 14 int main(int argc, char *argv[]) { 15 unsigned int memsize; 16 char *mem; 17 int i, numpages, fd; 18 19 if (argc != 2) { 20 printf("Usage: %s <memory_size>\n", argv[0]); 21 exit(EXIT_FAILURE); 22 } 23 24 memsize = strtoul(argv[1], NULL, 10); 25 26 memsize = ROUND_PAGES(memsize); 27 28 /* We should be limited to < 4G so any size other than 0 is ok */ 29 if (memsize == 0) { 30 printf("Invalid memsize\n"); 31 exit(EXIT_FAILURE); 32 } 33 34 numpages = memsize >> PAGE_SHIFT; 35 36 mem = mmap(0, memsize, PROT_READ | PROT_WRITE, 37 MAP_PRIVATE | MAP_ANONYMOUS, 38 -1, 0); 39 40 if (mem == (void*) -1) { 41 perror("Failed to allocate anon private memory using mmap\n"); 42 exit(EXIT_FAILURE); 43 } 44 45 for (i = 2; i <= 16; i <<= 1) { 46 mem = mremap(mem , memsize * (i >> 1), 47 memsize * i, 48 1 /* MREMAP_MAYMOVE */); 49 50 if (mem == MAP_FAILED) { 51 perror("Failed to remap expand anon private memory\n"); 52 exit(EXIT_FAILURE); 53 } 54 55 printf("Successfully remapped %d bytes @%p\n", 56 memsize * i, mem); 57 } 58 59 if (munmap(mem, memsize * 16)) { 60 perror("Could not unmap and free memory\n"); 61 exit(EXIT_FAILURE); 62 } 63 64 mem = mmap(0, memsize, PROT_READ | PROT_WRITE, 65 MAP_PRIVATE | MAP_ANONYMOUS, 66 -1, 0); 67 68 if (mem == (void*) -1) { 69 perror("Failed to allocate anon private memory using mmap\n"); 70 exit(EXIT_FAILURE); 71 } 72 73 exit(EXIT_SUCCESS); 74 } 75
