2833 }
2834 
2835 bool os::unguard_memory(char* addr, size_t size) {
2836   return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
2837 }
2838 
2839 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
2840   bool result = false;
2841   void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE,
2842                   MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
2843                   -1, 0);
2844 
2845   if (p != (void *) -1) {
2846     // We don't know if this really is a huge page or not.
2847     FILE *fp = fopen("/proc/self/maps", "r");
2848     if (fp) {
2849       while (!feof(fp)) {
2850         char chars[257];
2851         long x = 0;
2852         if (fgets(chars, sizeof(chars), fp)) {
2853           if (sscanf(chars, "%lx-%*lx", &x) == 1
2854               && x == (long)p) {
2855             if (strstr (chars, "hugepage")) {
2856               result = true;
2857               break;
2858             }
2859           }
2860         }
2861       }
2862       fclose(fp);
2863     }
2864     munmap (p, page_size);
2865     if (result)
2866       return true;
2867   }
2868 
2869   if (warn) {
2870     warning("HugeTLBFS is not supported by the operating system.");
2871   }
2872 
2873   return result;

2833 }
2834 
2835 bool os::unguard_memory(char* addr, size_t size) {
2836   return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
2837 }
2838 
2839 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
2840   bool result = false;
2841   void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE,
2842                   MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
2843                   -1, 0);
2844 
2845   if (p != (void *) -1) {
2846     // We don't know if this really is a huge page or not.
2847     FILE *fp = fopen("/proc/self/maps", "r");
2848     if (fp) {
2849       while (!feof(fp)) {
2850         char chars[257];
2851         long x = 0;
2852         if (fgets(chars, sizeof(chars), fp)) {
2853           if (sscanf(chars, "%lx-%*x", &x) == 1
2854               && x == (long)p) {
2855             if (strstr (chars, "hugepage")) {
2856               result = true;
2857               break;
2858             }
2859           }
2860         }
2861       }
2862       fclose(fp);
2863     }
2864     munmap (p, page_size);
2865     if (result)
2866       return true;
2867   }
2868 
2869   if (warn) {
2870     warning("HugeTLBFS is not supported by the operating system.");
2871   }
2872 
2873   return result;