Re: [RFC PATCH 2/10] free swap space entries if vm_swap_full()

Christoph Lameter
2007-11-07T02:20:44Z

On Sat, 3 Nov 2007, Rik van Riel wrote:

> @@ -1142,14 +1145,13 @@ force_reclaim_mapped:
> }
> }
> __mod_zone_page_state(zone, NR_INACTIVE, pgmoved);
> + spin_unlock_irq(&zone->lru_lock);
> pgdeactivate += pgmoved;
> - if (buffer_heads_over_limit) {
> - spin_unlock_irq(&zone->lru_lock);
> - pagevec_strip(&pvec);
> - spin_lock_irq(&zone->lru_lock);
> - }
>
> + if (buffer_heads_over_limit)
> + pagevec_strip(&pvec);
> pgmoved = 0;
> + spin_lock_irq(&zone->lru_lock);
> while (!list_empty(&l_active)) {
> page = lru_to_page(&l_active);
> prefetchw_prev_lru_page(page, &l_active, flags);

Why are we dropping the lock here now? There would be less activity
on the lru_lock if we would only drop it if necessary.

> @@ -1163,6 +1165,8 @@ force_reclaim_mapped:
> __mod_zone_page_state(zone, NR_ACTIVE, pgmoved);
> pgmoved = 0;
> spin_unlock_irq(&zone->lru_lock);
> + if (vm_swap_full())
> + pagevec_swap_free(&pvec);
> __pagevec_release(&pvec);
> spin_lock_irq(&zone->lru_lock);
> }

Same here. Maybe the spin_unlock and the spin_lock can go into
pagevec_swap_free?