[PATCH] taskstats: fix sub-threads accounting (4a279ff1) · Commits · 戴 / test

If there are no listeners, taskstats_exit_send() just returns because taskstats_exit_alloc() didn't allocate *tidstats. This is wrong, each sub-thread should do fill_tgid_exit() on exit, otherwise its ->delays is not recorded in ->signal->stats and lost. Q: We don't send TASKSTATS_TYPE_AGGR_TGID when single-threaded process exits. Is it good? How can the listener figure out that it was actually a process exit, not sub-thread? Signed-off-by:

Oleg Nesterov <oleg@tv-sign.ru> Cc: Balbir Singh <balbir@in.ibm.com> Acked-by:

Shailabh Nagar <nagar@watson.ibm.com> Signed-off-by:

Andrew Morton <akpm@osdl.org> Signed-off-by:

Linus Torvalds <torvalds@osdl.org>

kernel/taskstats.c

+10 −7

Original line number	Diff line number	Diff line
		@@ -455,10 +455,9 @@ void taskstats_exit_send(struct task_struct tsk, struct taskstats tidstats,
		int is_thread_group;
		struct nlattr *na;

		if (!family_registered \|\| !tidstats)
		if (!family_registered)
		return;

		rc = 0;
		/*
		* Size includes space for nested attributes
		*/
		@@ -466,8 +465,15 @@ void taskstats_exit_send(struct task_struct tsk, struct taskstats tidstats,
		nla_total_size(sizeof(struct taskstats)) + nla_total_size(0);

		is_thread_group = (tsk->signal->stats != NULL);
		if (is_thread_group)
		size = 2 * size; /* PID + STATS + TGID + STATS */
		if (is_thread_group) {
		/* PID + STATS + TGID + STATS */
		size = 2 * size;
		/* fill the tsk->signal->stats structure */
		fill_tgid_exit(tsk);
		}

		if (!tidstats)
		return;

		rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, &reply, size);
		if (rc < 0)
		@@ -487,11 +493,8 @@ void taskstats_exit_send(struct task_struct tsk, struct taskstats tidstats,
		goto send;

		/*
		* tsk has/had a thread group so fill the tsk->signal->stats structure
		* Doesn't matter if tsk is the leader or the last group member leaving
		*/

		fill_tgid_exit(tsk);
		if (!group_dead)
		goto send;

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