Messages in this thread | | | Date | Fri, 29 May 2015 14:25:04 +0530 | From | "Naveen N. Rao" <> | Subject | Re: [PATCH] proc/schedstat: Expose /proc/<pid>/schedstat if delay accounting is enabled |
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On 2015/05/29 10:04AM, Ingo Molnar wrote: > > * Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> wrote: > > > /proc/<pid>/schedstat is currently only available if CONFIG_SCHEDSTATS is > > enabled. But, all the fields that this exposes are available and valid > > if CONFIG_TASK_DELAY_ACCT is enabled as well. > > > > Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> > > --- > > fs/proc/base.c | 11 +++++++---- > > 1 file changed, 7 insertions(+), 4 deletions(-) > > > > diff --git a/fs/proc/base.c b/fs/proc/base.c > > index 093ca14..3ece303 100644 > > --- a/fs/proc/base.c > > +++ b/fs/proc/base.c > > @@ -304,14 +304,17 @@ static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns, > > } > > #endif > > > > +#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) > > +#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) > > +#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) >
Hi Ingo, Thanks for the review.
> So such #ifdef parades are ugly and are usually a sign of some problem with the > patch - as in this case. > > But there's deeper problems as well: > > /* > * Provides /proc/PID/schedstat > */ > static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns, > struct pid *pid, struct task_struct *task) > { > seq_printf(m, "%llu %llu %lu\n", > (unsigned long long)task->se.sum_exec_runtime, > (unsigned long long)task->sched_info.run_delay, > task->sched_info.pcount); > > return 0; > } > > - The sum_exec_runtime field is available unconditionally. > > - But the sched_info.run_delay field is only maintained if CONFIG_SCHEDSTATS is > enabled. > > - Also, the sched_info.pcount field is again only maintained if CONFIG_SCHEDSTATS > is enabled.
I may be missing something, but from my reading of the code, the above are maintained if any one of CONFIG_SCHEDSTATS or CONFIG_TASK_DELAY_ACCT are enabled (from kernel/sched/stats.h).
Only the runqueue-specific sched_info is tracked with CONFIG_SCHEDSTATS separately [kernel/sched/stats.c and the corresponding global /proc/schedstat]
Regards, Naveen
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