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-rw-r--r--mm/vmscan.c66
1 files changed, 39 insertions, 27 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 32c661d66a45..7901cb749e17 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1866,6 +1866,8 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
bool force_scan = false;
unsigned long ap, fp;
enum lru_list lru;
+ bool some_scanned;
+ int pass;
/*
* If the zone or memcg is small, nr[l] can be 0. This
@@ -1989,39 +1991,49 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
fraction[1] = fp;
denominator = ap + fp + 1;
out:
- for_each_evictable_lru(lru) {
- int file = is_file_lru(lru);
- unsigned long size;
- unsigned long scan;
+ some_scanned = false;
+ /* Only use force_scan on second pass. */
+ for (pass = 0; !some_scanned && pass < 2; pass++) {
+ for_each_evictable_lru(lru) {
+ int file = is_file_lru(lru);
+ unsigned long size;
+ unsigned long scan;
- size = get_lru_size(lruvec, lru);
- scan = size >> sc->priority;
+ size = get_lru_size(lruvec, lru);
+ scan = size >> sc->priority;
- if (!scan && force_scan)
- scan = min(size, SWAP_CLUSTER_MAX);
+ if (!scan && pass && force_scan)
+ scan = min(size, SWAP_CLUSTER_MAX);
- switch (scan_balance) {
- case SCAN_EQUAL:
- /* Scan lists relative to size */
- break;
- case SCAN_FRACT:
+ switch (scan_balance) {
+ case SCAN_EQUAL:
+ /* Scan lists relative to size */
+ break;
+ case SCAN_FRACT:
+ /*
+ * Scan types proportional to swappiness and
+ * their relative recent reclaim efficiency.
+ */
+ scan = div64_u64(scan * fraction[file],
+ denominator);
+ break;
+ case SCAN_FILE:
+ case SCAN_ANON:
+ /* Scan one type exclusively */
+ if ((scan_balance == SCAN_FILE) != file)
+ scan = 0;
+ break;
+ default:
+ /* Look ma, no brain */
+ BUG();
+ }
+ nr[lru] = scan;
/*
- * Scan types proportional to swappiness and
- * their relative recent reclaim efficiency.
+ * Skip the second pass and don't force_scan,
+ * if we found something to scan.
*/
- scan = div64_u64(scan * fraction[file], denominator);
- break;
- case SCAN_FILE:
- case SCAN_ANON:
- /* Scan one type exclusively */
- if ((scan_balance == SCAN_FILE) != file)
- scan = 0;
- break;
- default:
- /* Look ma, no brain */
- BUG();
+ some_scanned |= !!scan;
}
- nr[lru] = scan;
}
}