lib/test_free_pages.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * test_free_pages.c: Check that free_pages() doesn't leak memory
   4  * Copyright (c) 2020 Oracle
   5  * Author: Matthew Wilcox <willy@infradead.org>
   6  */
   7
   8 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/gfp.h>
  11 #include <linux/mm.h>
  12 #include <linux/module.h>
  13
  14 static void test_free_pages(gfp_t gfp)
  15 {
  16         unsigned int i;
  17
  18         for (i = 0; i < 1000 * 1000; i++) {
  19                 unsigned long addr = __get_free_pages(gfp, 3);
  20                 struct page *page = virt_to_page((void *)addr);
  21
  22                 /* Simulate page cache getting a speculative reference */
  23                 get_page(page);
  24                 free_pages(addr, 3);
  25                 put_page(page);
  26         }
  27 }
  28
  29 static int m_in(void)
  30 {
  31         pr_info("Testing with GFP_KERNEL\n");
  32         test_free_pages(GFP_KERNEL);
  33         pr_info("Testing with GFP_KERNEL | __GFP_COMP\n");
  34         test_free_pages(GFP_KERNEL | __GFP_COMP);
  35         pr_info("Test completed\n");
  36
  37         return 0;
  38 }
  39
  40 static void m_ex(void)
  41 {
  42 }
  43
  44 module_init(m_in);
  45 module_exit(m_ex);
  46 MODULE_AUTHOR("Matthew Wilcox <willy@infradead.org>");
  47 MODULE_LICENSE("GPL");