From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Sat, 7 Jan 2012 19:56:55 +0000 (-0500)
Subject: runas: use CLONE_VM flag
X-Git-Tag: v2.0-pre17~38
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=10d32e930a6b67c3f196ca3bf4f247d444d8c2b6;hp=47fb756380d79f439e0650841048cd2550d48903

runas: use CLONE_VM flag

Having to clone the vma each time runas is executed brings a significant
slowdown to the "start" operation when done with attached application,
and to the file creation needed when an application is attaching to the
sessiond. Use CLONE_VM flag to speed this up.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/librunas/runas.c b/librunas/runas.c
index b3fa81469..f612ccc75 100644
--- a/librunas/runas.c
+++ b/librunas/runas.c
@@ -230,7 +230,7 @@ int run_as(int (*cmd)(void *data), void *data, uid_t uid, gid_t gid)
 	 * where the stack grows up (HPPA).
 	 */
 	pid = clone(child_run_as, child_stack + (CHILD_STACK_SIZE / 2),
-		CLONE_FILES | SIGCHLD,
+		CLONE_FILES | SIGCHLD | CLONE_VM,
 		&run_as_data, NULL);
 	if (pid < 0) {
 		perror("clone");