SWDEV-419034 - Use MADV_HUGEPAGE for large host allocations

Change-Id: I80bb1839cdd47eb64a97467c8b01fcdf37195ad5

rocclr/os/os_posix.cpp

@@ -1,4 +1,4 @@
-/* Copyright (c) 2008 - 2021 Advanced Micro Devices, Inc.
+/* Copyright (c) 2008 - 2023 Advanced Micro Devices, Inc.
 
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
@@ -233,6 +233,17 @@ address Os::reserveMemory(address start, size_t size, size_t alignment, MemProt
     }
   }
 
+  // Hint to enable THP for large host allocations which can help in performance gain
+  constexpr size_t kLargePageSize = 2 * Mi;
+  if (size >= kLargePageSize) {
+    int status = madvise(aligned, size, MADV_HUGEPAGE);
+    if (status) {
+      ClPrint(amd::LOG_DEBUG, amd::LOG_CODE, "madvise with advice MADV_HUGEPAGE"
+              " starting at address %p and page size 0x%zx, returned %d, errno: %s",
+              aligned, size, status, strerror(errno));
+    }
+  }
+
   return aligned;
 }