diff options
Diffstat (limited to '')
-rw-r--r-- | tools/testing/selftests/vm/hugepage-mremap.c | 66 |
1 files changed, 49 insertions, 17 deletions
diff --git a/tools/testing/selftests/vm/hugepage-mremap.c b/tools/testing/selftests/vm/hugepage-mremap.c index 257df94697a5..e63a0214f639 100644 --- a/tools/testing/selftests/vm/hugepage-mremap.c +++ b/tools/testing/selftests/vm/hugepage-mremap.c @@ -3,8 +3,13 @@ * hugepage-mremap: * * Example of remapping huge page memory in a user application using the - * mremap system call. Code assumes a hugetlbfs filesystem is mounted - * at './huge'. The code will use 10MB worth of huge pages. + * mremap system call. The path to a file in a hugetlbfs filesystem must + * be passed as the last argument to this test. The amount of memory used + * by this test in MBs can optionally be passed as an argument. If no memory + * amount is passed, the default amount is 10MB. + * + * To make sure the test triggers pmd sharing and goes through the 'unshare' + * path in the mremap code use 1GB (1024) or more. */ #define _GNU_SOURCE @@ -18,7 +23,8 @@ #include <linux/userfaultfd.h> #include <sys/ioctl.h> -#define LENGTH (1UL * 1024 * 1024 * 1024) +#define DEFAULT_LENGTH_MB 10UL +#define MB_TO_BYTES(x) (x * 1024 * 1024) #define PROTECTION (PROT_READ | PROT_WRITE | PROT_EXEC) #define FLAGS (MAP_SHARED | MAP_ANONYMOUS) @@ -28,20 +34,20 @@ static void check_bytes(char *addr) printf("First hex is %x\n", *((unsigned int *)addr)); } -static void write_bytes(char *addr) +static void write_bytes(char *addr, size_t len) { unsigned long i; - for (i = 0; i < LENGTH; i++) + for (i = 0; i < len; i++) *(addr + i) = (char)i; } -static int read_bytes(char *addr) +static int read_bytes(char *addr, size_t len) { unsigned long i; check_bytes(addr); - for (i = 0; i < LENGTH; i++) + for (i = 0; i < len; i++) if (*(addr + i) != (char)i) { printf("Mismatch at %lu\n", i); return 1; @@ -99,11 +105,28 @@ static void register_region_with_uffd(char *addr, size_t len) } } -int main(void) +int main(int argc, char *argv[]) { + size_t length = 0; + + if (argc != 2 && argc != 3) { + printf("Usage: %s [length_in_MB] <hugetlb_file>\n", argv[0]); + exit(1); + } + + /* Read memory length as the first arg if valid, otherwise fallback to + * the default length. + */ + if (argc == 3) + length = argc > 2 ? (size_t)atoi(argv[1]) : 0UL; + + length = length > 0 ? length : DEFAULT_LENGTH_MB; + length = MB_TO_BYTES(length); + int ret = 0; - int fd = open("/huge/test", O_CREAT | O_RDWR, 0755); + /* last arg is the hugetlb file name */ + int fd = open(argv[argc-1], O_CREAT | O_RDWR, 0755); if (fd < 0) { perror("Open failed"); @@ -112,7 +135,7 @@ int main(void) /* mmap to a PUD aligned address to hopefully trigger pmd sharing. */ unsigned long suggested_addr = 0x7eaa40000000; - void *haddr = mmap((void *)suggested_addr, LENGTH, PROTECTION, + void *haddr = mmap((void *)suggested_addr, length, PROTECTION, MAP_HUGETLB | MAP_SHARED | MAP_POPULATE, fd, 0); printf("Map haddr: Returned address is %p\n", haddr); if (haddr == MAP_FAILED) { @@ -122,7 +145,7 @@ int main(void) /* mmap again to a dummy address to hopefully trigger pmd sharing. */ suggested_addr = 0x7daa40000000; - void *daddr = mmap((void *)suggested_addr, LENGTH, PROTECTION, + void *daddr = mmap((void *)suggested_addr, length, PROTECTION, MAP_HUGETLB | MAP_SHARED | MAP_POPULATE, fd, 0); printf("Map daddr: Returned address is %p\n", daddr); if (daddr == MAP_FAILED) { @@ -132,16 +155,16 @@ int main(void) suggested_addr = 0x7faa40000000; void *vaddr = - mmap((void *)suggested_addr, LENGTH, PROTECTION, FLAGS, -1, 0); + mmap((void *)suggested_addr, length, PROTECTION, FLAGS, -1, 0); printf("Map vaddr: Returned address is %p\n", vaddr); if (vaddr == MAP_FAILED) { perror("mmap2"); exit(1); } - register_region_with_uffd(haddr, LENGTH); + register_region_with_uffd(haddr, length); - void *addr = mremap(haddr, LENGTH, LENGTH, + void *addr = mremap(haddr, length, length, MREMAP_MAYMOVE | MREMAP_FIXED, vaddr); if (addr == MAP_FAILED) { perror("mremap"); @@ -150,10 +173,19 @@ int main(void) printf("Mremap: Returned address is %p\n", addr); check_bytes(addr); - write_bytes(addr); - ret = read_bytes(addr); + write_bytes(addr, length); + ret = read_bytes(addr, length); + + munmap(addr, length); + + addr = mremap(addr, length, length, 0); + if (addr != MAP_FAILED) { + printf("mremap: Expected failure, but call succeeded\n"); + exit(1); + } - munmap(addr, LENGTH); + close(fd); + unlink(argv[argc-1]); return ret; } |