From 8b45b1c4907b4b2186441e02edd3b0c37f8b3269 Mon Sep 17 00:00:00 2001
From: Joost VandeVondele <Joost.VandeVondele@gmail.com>
Date: Fri, 21 Aug 2020 07:42:19 +0200
Subject: [PATCH] Deal with very old linux kernels

MADV_HUGEPAGE might not be available, for kernels before 2.6.38 (released 2011). Just skip the madvise.

closes https://github.com/official-stockfish/Stockfish/pull/3039

No functional change
---
 src/misc.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/misc.cpp b/src/misc.cpp
index 459ea100..56a3dcad 100644
--- a/src/misc.cpp
+++ b/src/misc.cpp
@@ -367,7 +367,9 @@ void* aligned_ttmem_alloc(size_t allocSize, void*& mem) {
   size_t size = ((allocSize + alignment - 1) / alignment) * alignment; // multiple of alignment
   if (posix_memalign(&mem, alignment, size))
      mem = nullptr;
+#if defined(MADV_HUGEPAGE)
   madvise(mem, allocSize, MADV_HUGEPAGE);
+#endif
   return mem;
 }
 
-- 
2.39.2