Messages in this thread |  | | | Date | Mon, 20 Jul 2009 23:30:48 +0900 (JST) | | From | KOSAKI Motohiro <> | | Subject | Re: [PATCH 4/5] Use add_page_to_lru_list() helper function |
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> On Mon, 2009-07-20 at 14:37 +0900, KOSAKI Motohiro wrote: > > > > @@ -1241,7 +1241,6 @@ static void move_active_pages_to_lru(str > > > > spin_lock_irq(&zone->lru_lock); > > > > } > > > > } > > > > - __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved); > > > > if (!is_active_lru(lru)) > > > > __count_vm_events(PGDEACTIVATE, pgmoved); > > > > } > > > > > > This is a net loss, you introduce pgmoved calls to __inc_zone_state, > > > instead of the one __mod_zone_page_state() call. > > > > max pgmoved is 32. 32 times __inc_zone_state() make 0 or 1 time > > atomic operation (not much than two). > > I don't think it reduce performance. > > its not just atomics, count calls and branches too. It simply adds a ton > of code for no particular reason.
hm, I don't think it's tons penalty. I mean vmscan makes tons cache miss and function calling penalty is hidden by it. But, I agreed this patch doesn't have strong motivation. I can drop this.
Andrew, Can you please drop this patch?
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