From 31ab38be5f3c4b826db89ff3cd4f32f988747f06 Mon Sep 17 00:00:00 2001
From: Qi Wang <interwq@gwu.edu>
Date: Thu, 5 Oct 2017 16:28:55 -0700
Subject: [PATCH] Define MADV_FREE on our own when needed.

On x86 Linux, we define our own MADV_FREE if madvise(2) is available, but no
MADV_FREE is detected.  This allows the feature to be built in and enabled with
runtime detection.
---
 configure.ac                                          | 9 +++++++++
 include/jemalloc/internal/jemalloc_internal_defs.h.in | 3 +++
 include/jemalloc/internal/jemalloc_preamble.h.in      | 4 ++++
 src/pages.c                                           | 8 +++++++-
 4 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index f957377b..b4c66fb8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1824,6 +1824,15 @@ if test "x${je_cv_madvise}" = "xyes" ; then
 ], [je_cv_madv_free])
   if test "x${je_cv_madv_free}" = "xyes" ; then
     AC_DEFINE([JEMALLOC_PURGE_MADVISE_FREE], [ ])
+  elif test "x${je_cv_madvise}" = "xyes" ; then
+    case "${host_cpu}" in i686|x86_64)
+        case "${host}" in *-*-linux*)
+            AC_DEFINE([JEMALLOC_PURGE_MADVISE_FREE], [ ])
+            AC_DEFINE([JEMALLOC_DEFINE_MADVISE_FREE], [ ])
+	    ;;
+        esac
+        ;;
+    esac
   fi
 
   dnl Check for madvise(..., MADV_DONTNEED).
diff --git a/include/jemalloc/internal/jemalloc_internal_defs.h.in b/include/jemalloc/internal/jemalloc_internal_defs.h.in
index 31262fb2..b56f21f8 100644
--- a/include/jemalloc/internal/jemalloc_internal_defs.h.in
+++ b/include/jemalloc/internal/jemalloc_internal_defs.h.in
@@ -285,6 +285,9 @@
 #undef JEMALLOC_PURGE_MADVISE_DONTNEED
 #undef JEMALLOC_PURGE_MADVISE_DONTNEED_ZEROS
 
+/* Defined if madvise(2) is available but MADV_FREE is not (x86 Linux only). */
+#undef JEMALLOC_DEFINE_MADVISE_FREE
+
 /*
  * Defined if transparent huge pages (THPs) are supported via the
  * MADV_[NO]HUGEPAGE arguments to madvise(2), and THP support is enabled.
diff --git a/include/jemalloc/internal/jemalloc_preamble.h.in b/include/jemalloc/internal/jemalloc_preamble.h.in
index f6ed731c..f81f3a40 100644
--- a/include/jemalloc/internal/jemalloc_preamble.h.in
+++ b/include/jemalloc/internal/jemalloc_preamble.h.in
@@ -47,6 +47,10 @@
 #endif
 #include "jemalloc/internal/hooks.h"
 
+#ifdef JEMALLOC_DEFINE_MADVISE_FREE
+#  define JEMALLOC_MADV_FREE 8
+#endif
+
 static const bool config_debug =
 #ifdef JEMALLOC_DEBUG
     true
diff --git a/src/pages.c b/src/pages.c
index 84691883..e8112f74 100644
--- a/src/pages.c
+++ b/src/pages.c
@@ -269,7 +269,13 @@ pages_purge_lazy(void *addr, size_t size) {
 	VirtualAlloc(addr, size, MEM_RESET, PAGE_READWRITE);
 	return false;
 #elif defined(JEMALLOC_PURGE_MADVISE_FREE)
-	return (madvise(addr, size, MADV_FREE) != 0);
+	return (madvise(addr, size,
+#  ifdef MADV_FREE
+	    MADV_FREE
+#  else
+	    JEMALLOC_MADV_FREE
+#  endif
+	    ) != 0);
 #elif defined(JEMALLOC_PURGE_MADVISE_DONTNEED) && \
     !defined(JEMALLOC_PURGE_MADVISE_DONTNEED_ZEROS)
 	return (madvise(addr, size, MADV_DONTNEED) != 0);