diff options
Diffstat (limited to 'src/kernel/tests/lib/tst_memutils.c')
-rw-r--r-- | src/kernel/tests/lib/tst_memutils.c | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/src/kernel/tests/lib/tst_memutils.c b/src/kernel/tests/lib/tst_memutils.c new file mode 100644 index 0000000..f134d90 --- /dev/null +++ b/src/kernel/tests/lib/tst_memutils.c @@ -0,0 +1,62 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (c) 2020 SUSE LLC <mdoucha@suse.cz> + */ + +#include <unistd.h> +#include <limits.h> +#include <sys/sysinfo.h> +#include <stdlib.h> + +#define TST_NO_DEFAULT_MAIN +#include "tst_test.h" + +#define BLOCKSIZE (16 * 1024 * 1024) + +void tst_pollute_memory(size_t maxsize, int fillchar) +{ + size_t i, map_count = 0, safety = 0, blocksize = BLOCKSIZE; + void **map_blocks; + struct sysinfo info; + + SAFE_SYSINFO(&info); + safety = 4096 * SAFE_SYSCONF(_SC_PAGESIZE) / info.mem_unit; + + if (info.freeswap > safety) + safety = 0; + + /* Not enough free memory to avoid invoking OOM killer */ + if (info.freeram <= safety) + return; + + if (!maxsize) + maxsize = SIZE_MAX; + + if (info.freeram - safety < maxsize / info.mem_unit) + maxsize = (info.freeram - safety) * info.mem_unit; + + blocksize = MIN(maxsize, blocksize); + map_count = maxsize / blocksize; + map_blocks = SAFE_MALLOC(map_count * sizeof(void *)); + + /* + * Keep allocating until the first failure. The address space may be + * too fragmented or just smaller than maxsize. + */ + for (i = 0; i < map_count; i++) { + map_blocks[i] = mmap(NULL, blocksize, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + + if (map_blocks[i] == MAP_FAILED) { + map_count = i; + break; + } + + memset(map_blocks[i], fillchar, blocksize); + } + + for (i = 0; i < map_count; i++) + SAFE_MUNMAP(map_blocks[i], blocksize); + + free(map_blocks); +} |