1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. 4 */ 5 6 #include <assert.h> 7 #include <stdbool.h> 8 #include <stdint.h> 9 #include <stdio.h> 10 #include <stdlib.h> 11 #include <unistd.h> 12 #include <signal.h> 13 #include <sys/mman.h> 14 #include <linux/mman.h> 15 16 #include "kselftest.h" 17 18 int main(int argc, char *argv[]) 19 { 20 const size_t alloc_size = 2 * 1024 * 1024; 21 int retry_count = 10; 22 bool dropped; 23 void *alloc; 24 25 ksft_print_header(); 26 ksft_set_plan(1); 27 28 alloc = mmap(0, alloc_size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_DROPPABLE, -1, 0); 29 if (alloc == MAP_FAILED) { 30 if ((errno == EOPNOTSUPP) || (errno == EINVAL)) { 31 ksft_test_result_skip("MAP_DROPPABLE not supported\n"); 32 exit(KSFT_SKIP); 33 } 34 ksft_test_result_fail("mmap error: %s\n", strerror(errno)); 35 exit(KSFT_FAIL); 36 } 37 memset(alloc, 'A', alloc_size); 38 39 while (retry_count--) { 40 if (madvise(alloc, alloc_size, MADV_PAGEOUT)) { 41 if (errno == EINVAL) { 42 ksft_test_result_skip("madvise(MADV_PAGEOUT) not supported\n"); 43 exit(KSFT_SKIP); 44 } 45 ksft_test_result_fail("madvise(MADV_PAGEOUT) error: %s\n", strerror(errno)); 46 exit(KSFT_FAIL); 47 } 48 49 dropped = memchr(alloc, 'A', alloc_size) == NULL; 50 51 /* 52 * Speculative reference can temporarily prevent some 53 * pages from getting dropped. So sleep and retry. 54 * 55 * If a page is not droppable for 10s, something 56 * is seriously messed up and we want to fail. 57 */ 58 if (dropped) 59 break; 60 sleep(1); 61 } 62 63 ksft_test_result(dropped, "madvise(MADV_PAGEOUT) behavior\n"); 64 65 ksft_finished(); 66 } 67