Thin out scan_control: remove nr_to_scan and priority Make nr_to_scan and priority a parameter instead of putting it into scan control. This allows various small optimizations and IMHO makes the code easier to read. Signed-off-by: Christoph Lameter Index: linux-2.6.16-rc1-mm1/mm/vmscan.c =================================================================== --- linux-2.6.16-rc1-mm1.orig/mm/vmscan.c 2006-01-19 17:52:20.000000000 -0800 +++ linux-2.6.16-rc1-mm1/mm/vmscan.c 2006-01-19 20:07:42.000000000 -0800 @@ -52,9 +52,6 @@ typedef enum { } pageout_t; struct scan_control { - /* Ask refill_inactive_zone, or shrink_cache to scan this many pages */ - unsigned long nr_to_scan; - /* Incremented by the number of inactive pages that were scanned */ unsigned long nr_scanned; @@ -63,9 +60,6 @@ struct scan_control { unsigned long nr_mapped; /* From page_state */ - /* Ask shrink_caches, or shrink_zone to scan at this priority */ - unsigned int priority; - /* This context's GFP mask */ gfp_t gfp_mask; @@ -1084,11 +1078,10 @@ static int isolate_lru_pages(int nr_to_s /* * shrink_cache() adds the number of pages reclaimed to sc->nr_reclaimed */ -static void shrink_cache(struct zone *zone, struct scan_control *sc) +static void shrink_cache(int max_scan, struct zone *zone, struct scan_control *sc) { LIST_HEAD(page_list); struct pagevec pvec; - int max_scan = sc->nr_to_scan; pagevec_init(&pvec, 1); @@ -1164,12 +1157,11 @@ done: * But we had to alter page->flags anyway. */ static void -refill_inactive_zone(struct zone *zone, struct scan_control *sc) +refill_inactive_zone(int nr_pages, struct zone *zone, struct scan_control *sc) { int pgmoved; int pgdeactivate = 0; int pgscanned; - int nr_pages = sc->nr_to_scan; LIST_HEAD(l_hold); /* The pages which were snipped off */ LIST_HEAD(l_inactive); /* Pages to go onto the inactive_list */ LIST_HEAD(l_active); /* Pages to go onto the active_list */ @@ -1296,10 +1288,11 @@ refill_inactive_zone(struct zone *zone, * This is a basic per-zone page freer. Used by both kswapd and direct reclaim. */ static void -shrink_zone(struct zone *zone, struct scan_control *sc) +shrink_zone(int priority, struct zone *zone, struct scan_control *sc) { unsigned long nr_active; unsigned long nr_inactive; + unsigned long nr_to_scan; atomic_inc(&zone->reclaim_in_progress); @@ -1307,14 +1300,14 @@ shrink_zone(struct zone *zone, struct sc * Add one to `nr_to_scan' just to make sure that the kernel will * slowly sift through the active list. */ - zone->nr_scan_active += (zone->nr_active >> sc->priority) + 1; + zone->nr_scan_active += (zone->nr_active >> priority) + 1; nr_active = zone->nr_scan_active; if (nr_active >= sc->swap_cluster_max) zone->nr_scan_active = 0; else nr_active = 0; - zone->nr_scan_inactive += (zone->nr_inactive >> sc->priority) + 1; + zone->nr_scan_inactive += (zone->nr_inactive >> priority) + 1; nr_inactive = zone->nr_scan_inactive; if (nr_inactive >= sc->swap_cluster_max) zone->nr_scan_inactive = 0; @@ -1323,17 +1316,17 @@ shrink_zone(struct zone *zone, struct sc while (nr_active || nr_inactive) { if (nr_active) { - sc->nr_to_scan = min(nr_active, + nr_to_scan = min(nr_active, (unsigned long)sc->swap_cluster_max); - nr_active -= sc->nr_to_scan; - refill_inactive_zone(zone, sc); + nr_active -= nr_to_scan; + refill_inactive_zone(nr_to_scan, zone, sc); } if (nr_inactive) { - sc->nr_to_scan = min(nr_inactive, + nr_to_scan = min(nr_inactive, (unsigned long)sc->swap_cluster_max); - nr_inactive -= sc->nr_to_scan; - shrink_cache(zone, sc); + nr_inactive -= nr_to_scan; + shrink_cache(nr_to_scan, zone, sc); } } @@ -1359,7 +1352,7 @@ shrink_zone(struct zone *zone, struct sc * scan then give up on it. */ static void -shrink_caches(struct zone **zones, struct scan_control *sc) +shrink_caches(int priority, struct zone **zones, struct scan_control *sc) { int i; @@ -1372,14 +1365,14 @@ shrink_caches(struct zone **zones, struc if (!cpuset_zone_allowed(zone, __GFP_HARDWALL)) continue; - zone->temp_priority = sc->priority; - if (zone->prev_priority > sc->priority) - zone->prev_priority = sc->priority; + zone->temp_priority = priority; + if (zone->prev_priority > priority) + zone->prev_priority = priority; - if (zone->all_unreclaimable && sc->priority != DEF_PRIORITY) + if (zone->all_unreclaimable && priority != DEF_PRIORITY) continue; /* Let kswapd poll it */ - shrink_zone(zone, sc); + shrink_zone(priority, zone, sc); } } @@ -1426,11 +1419,10 @@ int try_to_free_pages(struct zone **zone sc.nr_mapped = read_page_state(nr_mapped); sc.nr_scanned = 0; sc.nr_reclaimed = 0; - sc.priority = priority; sc.swap_cluster_max = SWAP_CLUSTER_MAX; if (!priority) disable_swap_token(); - shrink_caches(zones, &sc); + shrink_caches(priority, zones, &sc); shrink_slab(sc.nr_scanned, gfp_mask, lru_pages); if (reclaim_state) { sc.nr_reclaimed += reclaim_state->reclaimed_slab; @@ -1593,10 +1585,9 @@ scan: zone->prev_priority = priority; sc.nr_scanned = 0; sc.nr_reclaimed = 0; - sc.priority = priority; sc.swap_cluster_max = nr_pages? nr_pages : SWAP_CLUSTER_MAX; atomic_inc(&zone->reclaim_in_progress); - shrink_zone(zone, &sc); + shrink_zone(priority, zone, &sc); atomic_dec(&zone->reclaim_in_progress); reclaim_state->reclaimed_slab = 0; nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL, @@ -1852,7 +1843,6 @@ int zone_reclaim(struct zone *zone, gfp_ sc.may_swap = 0; sc.nr_scanned = 0; sc.nr_reclaimed = 0; - sc.priority = 0; sc.nr_mapped = read_page_state(nr_mapped); sc.gfp_mask = gfp_mask; @@ -1868,7 +1858,7 @@ int zone_reclaim(struct zone *zone, gfp_ p->flags |= PF_MEMALLOC; reclaim_state.reclaimed_slab = 0; p->reclaim_state = &reclaim_state; - shrink_zone(zone, &sc); + shrink_zone(0, zone, &sc); p->reclaim_state = NULL; current->flags &= ~PF_MEMALLOC;