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authorShailabh Nagar <nagar@watson.ibm.com>2006-07-14 07:24:46 (GMT)
committerLinus Torvalds <torvalds@g5.osdl.org>2006-07-15 04:53:57 (GMT)
commitc8924363da07aec213e5d359f23eeae1fff91951 (patch)
treebef390d55719cf3f4b0d02c7efe03dd9ebc7321a /include
parent9e06d3f9f6b14f6e3120923ed215032726246c98 (diff)
[PATCH] per-task delay accounting: avoid send without listeners
Don't send taskstats (per-pid or per-tgid) on thread exit when no one is listening for such data. Currently the taskstats interface allocates a structure, fills it in and calls netlink to send out per-pid and per-tgid stats regardless of whether a userspace listener for the data exists (netlink layer would check for that and avoid the multicast). As a result of this patch, the check for the no-listener case is performed early, avoiding the redundant allocation and filling up of the taskstats structures. Signed-off-by: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com> Cc: Jay Lan <jlan@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/taskstats_kern.h13
1 files changed, 12 insertions, 1 deletions
diff --git a/include/linux/taskstats_kern.h b/include/linux/taskstats_kern.h
index 0ae8f67..2b6adec 100644
--- a/include/linux/taskstats_kern.h
+++ b/include/linux/taskstats_kern.h
@@ -9,6 +9,7 @@
#include <linux/taskstats.h>
#include <linux/sched.h>
+#include <net/genetlink.h>
enum {
TASKSTATS_MSG_UNICAST, /* send data only to requester */
@@ -19,9 +20,19 @@ enum {
extern kmem_cache_t *taskstats_cache;
extern struct mutex taskstats_exit_mutex;
+static inline int taskstats_has_listeners(void)
+{
+ if (!genl_sock)
+ return 0;
+ return netlink_has_listeners(genl_sock, TASKSTATS_LISTEN_GROUP);
+}
+
+
static inline void taskstats_exit_alloc(struct taskstats **ptidstats)
{
- *ptidstats = kmem_cache_zalloc(taskstats_cache, SLAB_KERNEL);
+ *ptidstats = NULL;
+ if (taskstats_has_listeners())
+ *ptidstats = kmem_cache_zalloc(taskstats_cache, SLAB_KERNEL);
}
static inline void taskstats_exit_free(struct taskstats *tidstats)

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