On Thu, Jan 06, 2022 at 09:03:34PM +0900, DaeRo Lee wrote:
> > > @@ -4355,7 +4355,7 @@ static enum zone_type kswapd_highest_zoneidx(pg_data_t *pgdat,
> > > static void kswapd_try_to_sleep(pg_data_t *pgdat, int alloc_order, int reclaim_order,
> > > unsigned int highest_zoneidx)
> > > {
> > > - long remaining = 0;
> > > + long remaining = ~0;
> > > DEFINE_WAIT(wait);
> > >
> > > if (freezing(current) || kthread_should_stop())
> >
> > While this does avoid calling prepare_kswapd_sleep() twice if the pgdat
> > is balanced on the first try, it then does not restore the vmstat
> > thresholds and doesn't call schedul() for kswapd to go to sleep.
>
> I intended not to call prepare_kswapd_sleep() twice when the pgdat is NOT
> balanced on the first try:)
>
Stupid typo on my part.
> > @@ -4406,11 +4412,11 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int alloc_order, int reclaim_o
> > }
> >
> > /*
> > - * After a short sleep, check if it was a premature sleep. If not, then
> > - * go fully to sleep until explicitly woken up.
> > + * If balanced to the high watermark, restore vmstat thresholds and
> > + * kswapd goes to sleep. If kswapd remains awake, account whether
> > + * the low or high watermark was hit quickly.
> > */
> > - if (!remaining &&
> > - prepare_kswapd_sleep(pgdat, reclaim_order, highest_zoneidx)) {
> > + if (balanced) {
> > trace_mm_vmscan_kswapd_sleep(pgdat->node_id);
> >
> > /*
>
> But, I think what you did is more readable and nice.
> Thanks!
>
Feel free to pick it up, rerun your tests to ensure it's behaving as
expected and resend! Include something in the changelog about user-visible
effects if any (or a note saying that it reduces unnecssary overhead)
and resend with me added to the cc.
> > > @@ -4331,7 +4331,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int highest_zoneidx)
> > > /*
> > > * Return the order kswapd stopped reclaiming at as
> > > * prepare_kswapd_sleep() takes it into account. If another caller
> > > - * entered the allocator slow path while kswapd was awake, order will
> > > + * entered the allqocator slow path while kswapd was awake, order will
> > > * remain at the higher level.
> > > */
> > > return sc.order;
> >
> > This hunk just adds a typo, drop it.
>
> Sorry about that;;
No need to be sorry, it happens :)
Thanks!
--
Mel Gorman
SUSE Labs
