Messages in this thread | | | Date | Tue, 27 Mar 2012 16:10:49 +0200 | Subject | Re: [PATCH 21/32] nohz/cpuset: Flush cputime on threads in nohz cpusets when waiting leader | From | Gilad Ben-Yossef <> |
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On Wed, Mar 21, 2012 at 3:58 PM, Frederic Weisbecker <fweisbec@gmail.com> wrote: > When we wait for a zombie task, flush the cputimes on nohz cpusets > in case we are waiting for a group leader that has threads running > in nohz CPUs. This way thread_group_times() doesn't report stale > values. > > <doubts> > If I understood well the code, by the time we call that thread_group_times(), > we may have childs that are still running, so this is necessary. > But I need to check deeper. > </doubts> > ... > > diff --git a/kernel/exit.c b/kernel/exit.c > index 4b4042f..c194662 100644 > --- a/kernel/exit.c > +++ b/kernel/exit.c > @@ -52,6 +52,7 @@ > #include <linux/hw_breakpoint.h> > #include <linux/oom.h> > #include <linux/writeback.h> > +#include <linux/cpuset.h> > > #include <asm/uaccess.h> > #include <asm/unistd.h> > @@ -1712,6 +1713,13 @@ repeat: > (!wo->wo_pid || hlist_empty(&wo->wo_pid->tasks[wo->wo_type]))) > goto notask; > > + /* > + * For cputime in sub-threads before adding them. > + * Must be called outside tasklist_lock lock because write lock > + * can be acquired under irqs disabled. > + */ > + cpuset_nohz_flush_cputimes(); > + > set_current_state(TASK_INTERRUPTIBLE); > read_lock(&tasklist_lock); > tsk = current; > -- > 1.7.5.4 >
I believe this patch is not needed because after this point we call do_wait_thread /ptrace_do_wait, which both call wait_consider_task, which calls wait_task_stopped/zombie/continued, which all eventually calls getrusage, which calls k_getrusage where you added a call to cpuset_noz_flush_cputimes() in another patch :-)
Gilad
-- Gilad Ben-Yossef Chief Coffee Drinker gilad@benyossef.com Israel Cell: +972-52-8260388 US Cell: +1-973-8260388 http://benyossef.com
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