On Fri, Dec 14, 2018 at 09:15:06AM -0800, Suren Baghdasaryan wrote: > The psi monitoring patches will need to determine the same states as > record_times(). To avoid calculating them twice, maintain a state mask > that can be consulted cheaply. Do this in a separate patch to keep the > churn in the main feature patch at a minimum. > > Signed-off-by: Suren Baghdasaryan <[email protected]> > --- > include/linux/psi_types.h | 3 +++ > kernel/sched/psi.c | 29 +++++++++++++++++++---------- > 2 files changed, 22 insertions(+), 10 deletions(-) > > diff --git a/include/linux/psi_types.h b/include/linux/psi_types.h > index 2cf422db5d18..2c6e9b67b7eb 100644 > --- a/include/linux/psi_types.h > +++ b/include/linux/psi_types.h > @@ -53,6 +53,9 @@ struct psi_group_cpu { > /* States of the tasks belonging to this group */ > unsigned int tasks[NR_PSI_TASK_COUNTS]; > > + /* Aggregate pressure state derived from the tasks */ > + u32 state_mask; > + > /* Period time sampling buckets for each state of interest (ns) */ > u32 times[NR_PSI_STATES]; >
Since we spend so much time counting space in that line, maybe add a note to the Changlog about how this fits. Also, since I just had to re-count, you might want to add explicit numbers to the psi_res and psi_states enums. > + if (state_mask & (1 << s)) We have the BIT() macro, but I'm honestly not sure that will improve things.
