Commit 6e08a369 authored by Wu Fengguang's avatar Wu Fengguang Committed by Linus Torvalds

vmscan: cleanup the scan batching code

The vmscan batching logic is twisting.  Move it into a standalone function
nr_scan_try_batch() and document it.  No behavior change.
Signed-off-by: default avatarWu Fengguang <fengguang.wu@intel.com>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Christoph Lameter <cl@linux-foundation.org>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 56e49d21
......@@ -334,9 +334,9 @@ struct zone {
/* Fields commonly accessed by the page reclaim scanner */
spinlock_t lru_lock;
struct {
struct zone_lru {
struct list_head list;
unsigned long nr_scan;
unsigned long nr_saved_scan; /* accumulated for batching */
} lru[NR_LRU_LISTS];
struct zone_reclaim_stat reclaim_stat;
......
......@@ -3657,7 +3657,7 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat,
zone_pcp_init(zone);
for_each_lru(l) {
INIT_LIST_HEAD(&zone->lru[l].list);
zone->lru[l].nr_scan = 0;
zone->lru[l].nr_saved_scan = 0;
}
zone->reclaim_stat.recent_rotated[0] = 0;
zone->reclaim_stat.recent_rotated[1] = 0;
......
......@@ -1492,6 +1492,26 @@ static void get_scan_ratio(struct zone *zone, struct scan_control *sc,
percent[1] = 100 - percent[0];
}
/*
* Smallish @nr_to_scan's are deposited in @nr_saved_scan,
* until we collected @swap_cluster_max pages to scan.
*/
static unsigned long nr_scan_try_batch(unsigned long nr_to_scan,
unsigned long *nr_saved_scan,
unsigned long swap_cluster_max)
{
unsigned long nr;
*nr_saved_scan += nr_to_scan;
nr = *nr_saved_scan;
if (nr >= swap_cluster_max)
*nr_saved_scan = 0;
else
nr = 0;
return nr;
}
/*
* This is a basic per-zone page freer. Used by both kswapd and direct reclaim.
......@@ -1517,14 +1537,11 @@ static void shrink_zone(int priority, struct zone *zone,
scan >>= priority;
scan = (scan * percent[file]) / 100;
}
if (scanning_global_lru(sc)) {
zone->lru[l].nr_scan += scan;
nr[l] = zone->lru[l].nr_scan;
if (nr[l] >= swap_cluster_max)
zone->lru[l].nr_scan = 0;
else
nr[l] = 0;
} else
if (scanning_global_lru(sc))
nr[l] = nr_scan_try_batch(scan,
&zone->lru[l].nr_saved_scan,
swap_cluster_max);
else
nr[l] = scan;
}
......@@ -2124,11 +2141,11 @@ static void shrink_all_zones(unsigned long nr_pages, int prio,
l == LRU_ACTIVE_FILE))
continue;
zone->lru[l].nr_scan += (lru_pages >> prio) + 1;
if (zone->lru[l].nr_scan >= nr_pages || pass > 3) {
zone->lru[l].nr_saved_scan += (lru_pages >> prio) + 1;
if (zone->lru[l].nr_saved_scan >= nr_pages || pass > 3) {
unsigned long nr_to_scan;
zone->lru[l].nr_scan = 0;
zone->lru[l].nr_saved_scan = 0;
nr_to_scan = min(nr_pages, lru_pages);
nr_reclaimed += shrink_list(l, nr_to_scan, zone,
sc, prio);
......
......@@ -718,10 +718,10 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
low_wmark_pages(zone),
high_wmark_pages(zone),
zone->pages_scanned,
zone->lru[LRU_ACTIVE_ANON].nr_scan,
zone->lru[LRU_INACTIVE_ANON].nr_scan,
zone->lru[LRU_ACTIVE_FILE].nr_scan,
zone->lru[LRU_INACTIVE_FILE].nr_scan,
zone->lru[LRU_ACTIVE_ANON].nr_saved_scan,
zone->lru[LRU_INACTIVE_ANON].nr_saved_scan,
zone->lru[LRU_ACTIVE_FILE].nr_saved_scan,
zone->lru[LRU_INACTIVE_FILE].nr_saved_scan,
zone->spanned_pages,
zone->present_pages);
......
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