On Fri, Aug 03, 2018 at 11:43:57AM +0530, Srikar Dronamraju wrote: > diff --git a/mm/migrate.c b/mm/migrate.c > index 8c0af0f..dbc2cb7 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1868,16 +1868,24 @@ static struct page *alloc_misplaced_dst_page(struct > page *page, > static bool numamigrate_update_ratelimit(pg_data_t *pgdat, > unsigned long nr_pages) > { > + unsigned long next_window, interval; > + > + next_window = READ_ONCE(pgdat->numabalancing_migrate_next_window); > + interval = msecs_to_jiffies(migrate_interval_millisecs); > + > /* > * Rate-limit the amount of data that is being migrated to a node. > * Optimal placement is no good if the memory bus is saturated and > * all the time is being spent migrating! > */ > - if (time_after(jiffies, next_window)) { > - spin_lock(&pgdat->numabalancing_migrate_lock); > + if (time_after(jiffies, next_window) && > + spin_trylock(&pgdat->numabalancing_migrate_lock)) {
This patch doesn't apply cleanly; also you introduce @next_window with this patch, so how can it remove a user of it. I fixed this up, still weird.