Support AutoConf for posix_madvise and POSIX_MADV_DONTNEED

configure.ac

@@ -2204,6 +2204,26 @@ case "${host_cpu}" in
   fi
   ;;
 esac
+else
+  dnl Check for posix_madvise.
+  JE_COMPILABLE([posix_madvise], [
+  #include <sys/mman.h>
+  ], [
+    posix_madvise((void *)0, 0, 0);
+  ], [je_cv_posix_madvise])
+  if test "x${je_cv_posix_madvise}" = "xyes" ; then
+    AC_DEFINE([JEMALLOC_HAVE_POSIX_MADVISE], [ ])
+
+    dnl Check for posix_madvise(..., POSIX_MADV_DONTNEED).
+    JE_COMPILABLE([posix_madvise(..., POSIX_MADV_DONTNEED)], [
+  #include <sys/mman.h>
+  ], [
+    posix_madvise((void *)0, 0, POSIX_MADV_DONTNEED);
+  ], [je_cv_posix_madv_dontneed])
+    if test "x${je_cv_posix_madv_dontneed}" = "xyes" ; then
+      AC_DEFINE([JEMALLOC_PURGE_POSIX_MADVISE_DONTNEED], [ ])
+    fi
+  fi
 fi
 
 dnl ============================================================================

include/jemalloc/internal/jemalloc_internal_defs.h.in

@@ -318,6 +318,17 @@
  */
 #undef JEMALLOC_THP
 
+/* Defined if posix_madvise is available. */
+#undef JEMALLOC_HAVE_POSIX_MADVISE
+
+/*
+ * Method for purging unused pages using posix_madvise.
+ *
+ *   posix_madvise(..., POSIX_MADV_DONTNEED)
+ */
+#undef JEMALLOC_PURGE_POSIX_MADVISE_DONTNEED
+#undef JEMALLOC_PURGE_POSIX_MADVISE_DONTNEED_ZEROS
+
 /*
  * Defined if memcntl page admin call is supported
  */