Commit-ID: 90ed9cbe765ad358b3151a12b8bf889a3cbcd573 Gitweb: http://git.kernel.org/tip/90ed9cbe765ad358b3151a12b8bf889a3cbcd573 Author: Rik van Riel <r...@redhat.com> AuthorDate: Fri, 15 Aug 2014 16:05:36 -0400 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Mon, 8 Sep 2014 08:17:00 +0200
exit: Always reap resource stats in __exit_signal() Oleg pointed out that wait_task_zombie adds a task's usage statistics to the parent's signal struct, but the task's own signal struct should also propagate the statistics at exit time. This allows thread_group_cputime(reaped_zombie) to get the statistics after __unhash_process() has made the task invisible to for_each_thread, but before the thread has actually been rcu freed, making sure no non-monotonic results are returned inside that window. Suggested-by: Oleg Nesterov <o...@redhat.com> Signed-off-by: Rik van Riel <r...@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: Andrew Morton <a...@linux-foundation.org> Cc: David Rientjes <rient...@google.com> Cc: Guillaume Morin <guilla...@morinfr.org> Cc: Ionut Alexa <ionut.m.al...@gmail.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Li Zefan <lize...@huawei.com> Cc: Michal Hocko <mho...@suse.cz> Cc: Michal Schmidt <mschm...@redhat.com> Cc: Oleg Nesterov <o...@redhat.com> Cc: umgwanakikb...@gmail.com Cc: fweis...@gmail.com Cc: s...@redhat.com Cc: lwood...@redhat.com Cc: atheu...@redhat.com Link: http://lkml.kernel.org/r/1408133138-22048-2-git-send-email-r...@redhat.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/exit.c | 43 +++++++++++++++++++++---------------------- 1 file changed, 21 insertions(+), 22 deletions(-) diff --git a/kernel/exit.c b/kernel/exit.c index 32c58f7..b93d46d 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -115,30 +115,29 @@ static void __exit_signal(struct task_struct *tsk) if (tsk == sig->curr_target) sig->curr_target = next_thread(tsk); - /* - * Accumulate here the counters for all threads but the - * group leader as they die, so they can be added into - * the process-wide totals when those are taken. - * The group leader stays around as a zombie as long - * as there are other threads. When it gets reaped, - * the exit.c code will add its counts into these totals. - * We won't ever get here for the group leader, since it - * will have been the last reference on the signal_struct. - */ - task_cputime(tsk, &utime, &stime); - sig->utime += utime; - sig->stime += stime; - sig->gtime += task_gtime(tsk); - sig->min_flt += tsk->min_flt; - sig->maj_flt += tsk->maj_flt; - sig->nvcsw += tsk->nvcsw; - sig->nivcsw += tsk->nivcsw; - sig->inblock += task_io_get_inblock(tsk); - sig->oublock += task_io_get_oublock(tsk); - task_io_accounting_add(&sig->ioac, &tsk->ioac); - sig->sum_sched_runtime += tsk->se.sum_exec_runtime; } + /* + * Accumulate here the counters for all threads but the group leader + * as they die, so they can be added into the process-wide totals + * when those are taken. The group leader stays around as a zombie as + * long as there are other threads. When it gets reaped, the exit.c + * code will add its counts into these totals. We won't ever get here + * for the group leader, since it will have been the last reference on + * the signal_struct. + */ + task_cputime(tsk, &utime, &stime); + sig->utime += utime; + sig->stime += stime; + sig->gtime += task_gtime(tsk); + sig->min_flt += tsk->min_flt; + sig->maj_flt += tsk->maj_flt; + sig->nvcsw += tsk->nvcsw; + sig->nivcsw += tsk->nivcsw; + sig->inblock += task_io_get_inblock(tsk); + sig->oublock += task_io_get_oublock(tsk); + task_io_accounting_add(&sig->ioac, &tsk->ioac); + sig->sum_sched_runtime += tsk->se.sum_exec_runtime; sig->nr_threads--; __unhash_process(tsk, group_dead); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
