large shared segment optimisation (in TEST_MMAP mode)
for FreeBSD supporting such feature.
Grabbing the first kind which fit the needed size otherwise
falling back to the classic shared segment allocation.
MODIFY
src/afl-sharedmem.c
src/afl-sharedmem.c
@@ -153,6 +153,8 @@ u8 *afl_shm_init(sharedmem_t *shm, size_t map_size,
shm->g_shm_fd = -1;
shm->cmplog_g_shm_fd = -1;
+ const int shmflags = O_RDWR | O_EXCL;
+
/* ======
generate random file name for multi instance
@@ -161,9 +163,37 @@ u8 *afl_shm_init(sharedmem_t *shm, size_t map_size,
so we do this worse workaround */
snprintf(shm->g_shm_file_path, L_tmpnam, "/afl_%d_%ld", getpid(), random());
+#ifdef SHM_LARGEPAGE_ALLOC_DEFAULT
+ /* trying to get large memory segment optimised and monitorable separately as such */
+ static size_t sizes[4] = {(size_t)-1};
+ static int psizes = 0;
+ int i;
+ if (sizes[0] == (size_t)-1) { psizes = getpagesizes(sizes, 4); }
+
+ /* very unlikely to fail even if the arch supports only two sizes */
+ if (likely(psizes > 0)) {
+
+ for (i = psizes - 1; shm->g_shm_fd == -1 && i >= 0; --i) {
+
+ if (sizes[i] == 0 || map_size % sizes[i]) { continue; }
+
+ shm->g_shm_fd = shm_create_largepage(shm->g_shm_file_path, shmflags, i,
+ SHM_LARGEPAGE_ALLOC_DEFAULT, DEFAULT_PERMISSION);
+
+ }
+
+ }
+#endif
+
+
/* create the shared memory segment as if it was a file */
- shm->g_shm_fd = shm_open(shm->g_shm_file_path, O_CREAT | O_RDWR | O_EXCL,
+ if (shm->g_shm_fd == -1) {
+
+ shm->g_shm_fd = shm_open(shm->g_shm_file_path, shmflags | O_CREAT,
DEFAULT_PERMISSION);
+
+ }
+
if (shm->g_shm_fd == -1) { PFATAL("shm_open() failed"); }
/* configure the size of the shared memory segment */

large shared segment optimisation (in TEST_MMAP mode)
for FreeBSD supporting such feature.

Grabbing the first kind which fit the needed size otherwise
falling back to the classic shared segment allocation.