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authorShailabh Nagar <nagar@watson.ibm.com>2006-07-14 00:24:44 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-07-14 21:53:57 -0700
commitad4ecbcba72855a2b5319b96e2a3a65ed1ca3bfd (patch)
treea2f5b98598948525de77ab594e4432f09a230388 /kernel/exit.c
parent25890454667b3295f67b3372352be90705f8667c (diff)
downloadlinux-ad4ecbcba72855a2b5319b96e2a3a65ed1ca3bfd.tar.gz
[PATCH] delay accounting taskstats interface send tgid once
Send per-tgid data only once during exit of a thread group instead of once with each member thread exit. Currently, when a thread exits, besides its per-tid data, the per-tgid data of its thread group is also sent out, if its thread group is non-empty. The per-tgid data sent consists of the sum of per-tid stats for all *remaining* threads of the thread group. This patch modifies this sending in two ways: - the per-tgid data is sent only when the last thread of a thread group exits. This cuts down heavily on the overhead of sending/receiving per-tgid data, especially when other exploiters of the taskstats interface aren't interested in per-tgid stats - the semantics of the per-tgid data sent are changed. Instead of being the sum of per-tid data for remaining threads, the value now sent is the true total accumalated statistics for all threads that are/were part of the thread group. The patch also addresses a minor issue where failure of one accounting subsystem to fill in the taskstats structure was causing the send of taskstats to not be sent at all. The patch has been tested for stability and run cerberus for over 4 hours on an SMP. [akpm@osdl.org: bugfixes] Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com> Signed-off-by: Balbir Singh <balbir@in.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 'kernel/exit.c')
-rw-r--r--kernel/exit.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 9852ed8c298..67c1e9a4f81 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -845,7 +845,7 @@ static void exit_notify(struct task_struct *tsk)
fastcall NORET_TYPE void do_exit(long code)
{
struct task_struct *tsk = current;
- struct taskstats *tidstats, *tgidstats;
+ struct taskstats *tidstats;
int group_dead;
profile_task_exit(tsk);
@@ -884,7 +884,7 @@ fastcall NORET_TYPE void do_exit(long code)
current->comm, current->pid,
preempt_count());
- taskstats_exit_alloc(&tidstats, &tgidstats);
+ taskstats_exit_alloc(&tidstats);
acct_update_integrals(tsk);
if (tsk->mm) {
@@ -905,8 +905,8 @@ fastcall NORET_TYPE void do_exit(long code)
#endif
if (unlikely(tsk->audit_context))
audit_free(tsk);
- taskstats_exit_send(tsk, tidstats, tgidstats);
- taskstats_exit_free(tidstats, tgidstats);
+ taskstats_exit_send(tsk, tidstats, group_dead);
+ taskstats_exit_free(tidstats);
delayacct_tsk_exit(tsk);
exit_mm(tsk);