stress-daemon: add --daemon-bloat option to simulte memory usage

This new option adds memory bloat to a daemon process by mmap'ping
a user specified amount of memory (with MAP_POPULATE where possible).
This simulates memory bloated daemon processes.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>

Author: ColinIanKing

core-opts.c

@@ -245,6 +245,7 @@ const struct option stress_long_options[] = {
 	{ "cyclic-sleep",	1,	NULL,	OPT_cyclic_sleep },
 
 	{ "daemon",		1,	NULL,	OPT_daemon },
+	{ "daemon-bloat",	1,	NULL,	OPT_daemon_bloat },
 	{ "daemon-ops",		1,	NULL,	OPT_daemon_ops },
 	{ "daemon-wait",	0,	NULL,	OPT_daemon_wait },
 

core-opts.h

@@ -372,6 +372,7 @@ typedef enum {
 	OPT_cyclic_sleep,
 
 	OPT_daemon,
+	OPT_daemon_bloat,
 	OPT_daemon_ops,
 	OPT_daemon_wait,
 

stress-daemon.c

@@ -20,6 +20,8 @@
 #include "stress-ng.h"
 #include "core-capabilities.h"
 #include "core-signal.h"
+#include "core-mmap.h"
+#include "core-put.h"
 
 #if defined(NSIG)
 #define MAX_SIGNUM      NSIG
@@ -32,10 +34,11 @@
 #define MAX_BACKOFF	(10000)
 
 static const stress_help_t help[] = {
-	{ NULL,	"daemon N",	"start N workers creating multiple daemons" },
-	{ NULL,	"daemon-ops N",	"stop when N daemons have been created" },
-	{ NULL, "daemon-wait",	"stressor wait for daemon to exit and not init" },
-	{ NULL,	NULL,		NULL }
+	{ NULL,	"daemon N",       "start N workers creating multiple daemons" },
+	{ NULL, "daemon-bloat N", "specify N bytes of daemon child process memory bloat" },
+	{ NULL,	"daemon-ops N",   "stop when N daemons have been created" },
+	{ NULL, "daemon-wait",    "stressor wait for daemon to exit and not init" },
+	{ NULL,	NULL,              NULL }
 };
 
 /*
@@ -58,6 +61,7 @@ static void daemon_wait_pid(const pid_t pid, const bool daemon_wait)
 static int stress_make_daemon(
 	stress_args_t *args,
 	const int fd,
+	const size_t daemon_bloat,
 	const bool daemon_wait)
 {
 	int fds[3];
@@ -134,6 +138,15 @@ static int stress_make_daemon(
 			VOID_RET(int, stress_capabilities_drop(args->name));
 			stress_proc_state_set(args->name, STRESS_STATE_RUN);
 
+			if (daemon_bloat) {
+				void *ptr;
+
+				ptr = stress_mmap_populate(NULL, daemon_bloat,
+						PROT_READ | PROT_WRITE,
+						MAP_PRIVATE | MAP_ANONYMOUS,
+						-1, 0);
+				stress_put_void_ptr(ptr);
+			}
 			sz = write(fd, &rc, sizeof(rc));
 			if (sz != sizeof(rc))
 				goto err_close_fds2;
@@ -143,7 +156,6 @@ static int stress_make_daemon(
 			break;
 		}
 	}
-
 err_close_fds2:
 	(void)close(fds[2]);
 err_close_fds1:
@@ -166,7 +178,9 @@ static int stress_daemon(stress_args_t *args)
 	int rc = EXIT_SUCCESS;
 	pid_t pid;
 	bool daemon_wait = false;
+	size_t daemon_bloat = 0;
 
+	(void)stress_setting_get("daemon-bloat", &daemon_bloat);
 	(void)stress_setting_get("daemon-wait", &daemon_wait);
 
 	if (stress_signal_stop_stressing(args->name, SIGALRM) < 0)
@@ -198,7 +212,7 @@ static int stress_daemon(stress_args_t *args)
 		/* Children */
 		stress_make_it_fail_set();
 		(void)close(fds[0]);
-		rc = stress_make_daemon(args, fds[1], daemon_wait);
+		rc = stress_make_daemon(args, fds[1], daemon_bloat, daemon_wait);
 		shim_exit_group(rc);
 	} else {
 		/* Parent */
@@ -233,7 +247,8 @@ static int stress_daemon(stress_args_t *args)
 }
 
 static const stress_opt_t opts[] = {
-	{ OPT_daemon_wait, "daemon-wait", TYPE_ID_BOOL, 0, 1, NULL },
+	{ OPT_daemon_bloat, "daemon-bloat", TYPE_ID_SIZE_T_BYTES, 4096, 64 * MB, NULL },
+	{ OPT_daemon_wait,  "daemon-wait",  TYPE_ID_BOOL, 0, 1, NULL },
 	END_OPT,
 };
 

stress-ng.1

@@ -2795,6 +2795,10 @@ This puts pressure on init to do rapid child reaping. The daemon processes
 perform the usual mix of calls to turn into typical UNIX daemons, so this
 artificially mimics very heavy daemon system stress.
 .TP
+.B \-\-daemon\-bloat N
+specify daemon's memory mapping bloat size in bytes. This simulates memory usage
+by a deameon process, default is zero (no memory mapping), range 4K to 64MB.
+.TP
 .B \-\-daemon\-ops N
 stop daemon workers after N daemons have been created.
 .TP