diff options
| author | Shailabh Nagar <nagar@watson.ibm.com> | 2006-07-14 00:24:46 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-07-14 21:53:57 -0700 |
| commit | c8924363da07aec213e5d359f23eeae1fff91951 (patch) | |
| tree | bef390d55719cf3f4b0d02c7efe03dd9ebc7321a | |
| parent | 9e06d3f9f6b14f6e3120923ed215032726246c98 (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>
| -rw-r--r-- | include/linux/taskstats_kern.h | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/include/linux/taskstats_kern.h b/include/linux/taskstats_kern.h index 0ae8f67af1f..2b6adec3a2e 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) |