Use MAP_POPULATE to reduce pagefault when available

[lttng-ust.git] / libringbuffer / shm.c

diff --git a/libringbuffer/shm.c b/libringbuffer/shm.c
index 10b3bcef110a979ce2169ccf10417e470e122ba9..909991ed27c6f1ada4a04426e396d232d126df8e 100644 (file)
--- a/libringbuffer/shm.c
+++ b/libringbuffer/shm.c
@@ -40,6 +40,7 @@
 #endif
 #include <helper.h>
 #include <ust-fd.h>
+#include "mmap.h"
 
 /*
  * Ensure we have the required amount of space available by writing 0
@@ -154,7 +155,7 @@ struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table,
 
        /* memory_map: mmap */
        memory_map = mmap(NULL, memory_map_size, PROT_READ | PROT_WRITE,
-                         MAP_SHARED, shmfd, 0);
+                         MAP_SHARED | LTTNG_MAP_POPULATE, shmfd, 0);
        if (memory_map == MAP_FAILED) {
                PERROR("mmap");
                goto error_mmap;
@@ -341,7 +342,7 @@ struct shm_object *shm_object_table_append_shm(struct shm_object_table *table,
 
        /* memory_map: mmap */
        memory_map = mmap(NULL, memory_map_size, PROT_READ | PROT_WRITE,
-                         MAP_SHARED, shm_fd, 0);
+                         MAP_SHARED | LTTNG_MAP_POPULATE, shm_fd, 0);
        if (memory_map == MAP_FAILED) {
                PERROR("mmap");
                goto error_mmap;