- ret = mmap(req, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+ if (need_exec)
+ prot |= PROT_EXEC;
+ /* avoid MAP_FIXED, it overrides existing mappings..
+ if (is_fixed)
+ flags |= MAP_FIXED;
+ */
+ if (size >= HUGETLB_THRESHOLD)
+ flags |= MAP_HUGETLB;
+#ifdef MAP_JIT
+ if (need_exec)
+ flags |= MAP_JIT;
+#endif
+
+ ret = mmap(req, size, prot, flags, -1, 0);
+ if (ret == MAP_FAILED && (flags & MAP_HUGETLB)) {
+ if (!hugetlb_warned) {
+ fprintf(stderr,
+ "warning: failed to do hugetlb mmap (%p, %zu): %d\n",
+ req, size, errno);
+ hugetlb_warned = 1;
+ }
+ flags &= ~MAP_HUGETLB;
+ ret = mmap(req, size, prot, flags, -1, 0);
+#ifdef MADV_HUGEPAGE
+ if (ret != MAP_FAILED && ((uintptr_t)ret & (2*1024*1024 - 1))) {
+ // try to manually realign assuming bottom-to-top alloc
+ munmap(ret, size);
+ ret = (void *)((uintptr_t)ret & ~(2*1024*1024 - 1));
+ ret = mmap(ret, size, prot, flags, -1, 0);
+ }
+ if (ret != MAP_FAILED)
+ madvise(ret, size, MADV_HUGEPAGE);
+#endif
+ }