Messages in this thread | | | Date | Fri, 29 May 2015 11:18:37 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] proc/schedstat: Expose /proc/<pid>/schedstat if delay accounting is enabled |
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* Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> wrote:
> 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).
Hm, indeed - I mis-read the rq-specific code - sorry.
So all this should really be cleaned up:
include/linux/sched.h:#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) include/linux/sched.h:#endif /* defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) */ include/linux/sched.h:#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) kernel/sched/core.c:#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) kernel/sched/stats.h:#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) kernel/sched/stats.h:#endif /* CONFIG_SCHEDSTATS || CONFIG_TASK_DELAY_ACCT */
by introducing an intermediate Kconfig variable, named CONFIG_SCHED_INFO or so, and selected by both SCHEDSTATS and TASK_DELAY_ACCT.
Please make it two patches: the first one adds CONFIG_SCHED_INFO and cleans up the code to use it, the second one uses it for the procps change.
Thanks,
Ingo
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