+#ifdef MADV_HUGEPAGE
+ if (size >= 2*1024*1024) {
+ if (ptr != MAP_FAILED && ((uintptr_t)ptr & (2*1024*1024 - 1))) {
+ // try to manually realign assuming bottom-to-top alloc
+ munmap(ptr, size);
+ addr = (uintptr_t)ptr & ~(2*1024*1024 - 1);
+ ptr = mmap((void *)(uintptr_t)addr, size,
+ PROT_READ | PROT_WRITE, flags, -1, 0);
+ }
+ if (ptr != MAP_FAILED)
+ madvise(ptr, size, MADV_HUGEPAGE);
+ }
+#endif
+ return ptr;
+#endif