Implemented madvise() for journal mapped entries.

Used SEQUENTIAL advise.

configure.ac

@@ -159,7 +159,7 @@ AC_DEFINE([DSFMT_MEXP], [521], [DSFMT parameters.])
 # Checks for library functions.
 AC_FUNC_FORK
 AC_FUNC_MMAP
-AC_CHECK_FUNCS([gethostbyname gettimeofday clock_gettime memalign memmove memset munmap regcomp pselect select socket sqrt strcasecmp strchr strdup strerror strncasecmp strtol strtoul poll epoll_wait kqueue setgroups sendmmsg])
+AC_CHECK_FUNCS([gethostbyname gettimeofday clock_gettime memalign memmove memset munmap regcomp pselect select socket sqrt strcasecmp strchr strdup strerror strncasecmp strtol strtoul poll epoll_wait kqueue setgroups sendmmsg madvise])
 
 AC_CONFIG_FILES([Makefile
 		 samples/Makefile

src/knot/server/journal.c

@@ -14,6 +14,7 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <config.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
@@ -775,6 +776,10 @@ int journal_map(journal_t *journal, uint64_t id, char **dst, size_t size)
 		return KNOTD_ERROR;
 	}
 	
+	/* Advise usage of memory. */
+#ifdef HAVE_MADVISE
+	madvise(*dst, n->len + ps_delta, MADV_SEQUENTIAL);
+#endif
 	/* Correct dst pointer to alignment. */
 	*dst += ps_delta;