X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=mm%2Fvmscan.c;h=10f9c59aed5536b88addea2a99bd4539ebf5a9f2;hp=9fdfce7ba4039a19026d39db3bae3c6f0bd18f97;hb=ee72886d8ed5d9de3fa0ed3b99a7ca7702576a96;hpb=d630ba565f3d806d64df4415d4a8457b4ab23db6

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 9fdfce7ba403..10f9c59aed55 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -865,6 +865,15 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 		if (PageDirty(page)) {
 			nr_dirty++;
 
+			/*
+			 * Only kswapd can writeback filesystem pages to
+			 * avoid risk of stack overflow
+			 */
+			if (page_is_file_cache(page) && !current_is_kswapd()) {
+				inc_zone_page_state(page, NR_VMSCAN_WRITE_SKIP);
+				goto keep_locked;
+			}
+
 			if (references == PAGEREF_RECLAIM_CLEAN)
 				goto keep_locked;
 			if (!may_enter_fs)
@@ -1012,23 +1021,27 @@ keep_lumpy:
  *
  * returns 0 on success, -ve errno on failure.
  */
-int __isolate_lru_page(struct page *page, int mode, int file)
+int __isolate_lru_page(struct page *page, isolate_mode_t mode, int file)
 {
+	bool all_lru_mode;
 	int ret = -EINVAL;
 
 	/* Only take pages on the LRU. */
 	if (!PageLRU(page))
 		return ret;
 
+	all_lru_mode = (mode & (ISOLATE_ACTIVE|ISOLATE_INACTIVE)) ==
+		(ISOLATE_ACTIVE|ISOLATE_INACTIVE);
+
 	/*
 	 * When checking the active state, we need to be sure we are
 	 * dealing with comparible boolean values.  Take the logical not
 	 * of each.
 	 */
-	if (mode != ISOLATE_BOTH && (!PageActive(page) != !mode))
+	if (!all_lru_mode && !PageActive(page) != !(mode & ISOLATE_ACTIVE))
 		return ret;
 
-	if (mode != ISOLATE_BOTH && page_is_file_cache(page) != file)
+	if (!all_lru_mode && !!page_is_file_cache(page) != file)
 		return ret;
 
 	/*
@@ -1041,6 +1054,12 @@ int __isolate_lru_page(struct page *page, int mode, int file)
 
 	ret = -EBUSY;
 
+	if ((mode & ISOLATE_CLEAN) && (PageDirty(page) || PageWriteback(page)))
+		return ret;
+
+	if ((mode & ISOLATE_UNMAPPED) && page_mapped(page))
+		return ret;
+
 	if (likely(get_page_unless_zero(page))) {
 		/*
 		 * Be careful not to clear PageLRU until after we're
@@ -1076,7 +1095,8 @@ int __isolate_lru_page(struct page *page, int mode, int file)
  */
 static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
 		struct list_head *src, struct list_head *dst,
-		unsigned long *scanned, int order, int mode, int file)
+		unsigned long *scanned, int order, isolate_mode_t mode,
+		int file)
 {
 	unsigned long nr_taken = 0;
 	unsigned long nr_lumpy_taken = 0;
@@ -1201,8 +1221,8 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
 static unsigned long isolate_pages_global(unsigned long nr,
 					struct list_head *dst,
 					unsigned long *scanned, int order,
-					int mode, struct zone *z,
-					int active, int file)
+					isolate_mode_t mode,
+					struct zone *z,	int active, int file)
 {
 	int lru = LRU_BASE;
 	if (active)
@@ -1448,6 +1468,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct zone *zone,
 	unsigned long nr_taken;
 	unsigned long nr_anon;
 	unsigned long nr_file;
+	isolate_mode_t reclaim_mode = ISOLATE_INACTIVE;
 
 	while (unlikely(too_many_isolated(zone, file, sc))) {
 		congestion_wait(BLK_RW_ASYNC, HZ/10);
@@ -1458,15 +1479,21 @@ shrink_inactive_list(unsigned long nr_to_scan, struct zone *zone,
 	}
 
 	set_reclaim_mode(priority, sc, false);
+	if (sc->reclaim_mode & RECLAIM_MODE_LUMPYRECLAIM)
+		reclaim_mode |= ISOLATE_ACTIVE;
+
 	lru_add_drain();
+
+	if (!sc->may_unmap)
+		reclaim_mode |= ISOLATE_UNMAPPED;
+	if (!sc->may_writepage)
+		reclaim_mode |= ISOLATE_CLEAN;
+
 	spin_lock_irq(&zone->lru_lock);
 
 	if (scanning_global_lru(sc)) {
-		nr_taken = isolate_pages_global(nr_to_scan,
-			&page_list, &nr_scanned, sc->order,
-			sc->reclaim_mode & RECLAIM_MODE_LUMPYRECLAIM ?
-					ISOLATE_BOTH : ISOLATE_INACTIVE,
-			zone, 0, file);
+		nr_taken = isolate_pages_global(nr_to_scan, &page_list,
+			&nr_scanned, sc->order, reclaim_mode, zone, 0, file);
 		zone->pages_scanned += nr_scanned;
 		if (current_is_kswapd())
 			__count_zone_vm_events(PGSCAN_KSWAPD, zone,
@@ -1475,12 +1502,9 @@ shrink_inactive_list(unsigned long nr_to_scan, struct zone *zone,
 			__count_zone_vm_events(PGSCAN_DIRECT, zone,
 					       nr_scanned);
 	} else {
-		nr_taken = mem_cgroup_isolate_pages(nr_to_scan,
-			&page_list, &nr_scanned, sc->order,
-			sc->reclaim_mode & RECLAIM_MODE_LUMPYRECLAIM ?
-					ISOLATE_BOTH : ISOLATE_INACTIVE,
-			zone, sc->mem_cgroup,
-			0, file);
+		nr_taken = mem_cgroup_isolate_pages(nr_to_scan, &page_list,
+			&nr_scanned, sc->order, reclaim_mode, zone,
+			sc->mem_cgroup, 0, file);
 		/*
 		 * mem_cgroup_isolate_pages() keeps track of
 		 * scanned pages on its own.
@@ -1582,19 +1606,26 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
 	struct page *page;
 	struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
 	unsigned long nr_rotated = 0;
+	isolate_mode_t reclaim_mode = ISOLATE_ACTIVE;
 
 	lru_add_drain();
+
+	if (!sc->may_unmap)
+		reclaim_mode |= ISOLATE_UNMAPPED;
+	if (!sc->may_writepage)
+		reclaim_mode |= ISOLATE_CLEAN;
+
 	spin_lock_irq(&zone->lru_lock);
 	if (scanning_global_lru(sc)) {
 		nr_taken = isolate_pages_global(nr_pages, &l_hold,
 						&pgscanned, sc->order,
-						ISOLATE_ACTIVE, zone,
+						reclaim_mode, zone,
 						1, file);
 		zone->pages_scanned += pgscanned;
 	} else {
 		nr_taken = mem_cgroup_isolate_pages(nr_pages, &l_hold,
 						&pgscanned, sc->order,
-						ISOLATE_ACTIVE, zone,
+						reclaim_mode, zone,
 						sc->mem_cgroup, 1, file);
 		/*
 		 * mem_cgroup_isolate_pages() keeps track of
@@ -1795,12 +1826,19 @@ static void get_scan_count(struct zone *zone, struct scan_control *sc,
 	enum lru_list l;
 	int noswap = 0;
 	bool force_scan = false;
-	unsigned long nr_force_scan[2];
 
-	/* kswapd does zone balancing and needs to scan this zone */
+	/*
+	 * If the zone or memcg is small, nr[l] can be 0.  This
+	 * results in no scanning on this priority and a potential
+	 * priority drop.  Global direct reclaim can go to the next
+	 * zone and tends to have no problems. Global kswapd is for
+	 * zone balancing and it needs to scan a minimum amount. When
+	 * reclaiming for a memcg, a priority drop can cause high
+	 * latencies, so it's better to scan a minimum amount there as
+	 * well.
+	 */
 	if (scanning_global_lru(sc) && current_is_kswapd())
 		force_scan = true;
-	/* memcg may have small limit and need to avoid priority drop */
 	if (!scanning_global_lru(sc))
 		force_scan = true;
 
@@ -1810,8 +1848,6 @@ static void get_scan_count(struct zone *zone, struct scan_control *sc,
 		fraction[0] = 0;
 		fraction[1] = 1;
 		denominator = 1;
-		nr_force_scan[0] = 0;
-		nr_force_scan[1] = SWAP_CLUSTER_MAX;
 		goto out;
 	}
 
@@ -1828,8 +1864,6 @@ static void get_scan_count(struct zone *zone, struct scan_control *sc,
 			fraction[0] = 1;
 			fraction[1] = 0;
 			denominator = 1;
-			nr_force_scan[0] = SWAP_CLUSTER_MAX;
-			nr_force_scan[1] = 0;
 			goto out;
 		}
 	}
@@ -1878,11 +1912,6 @@ static void get_scan_count(struct zone *zone, struct scan_control *sc,
 	fraction[0] = ap;
 	fraction[1] = fp;
 	denominator = ap + fp + 1;
-	if (force_scan) {
-		unsigned long scan = SWAP_CLUSTER_MAX;
-		nr_force_scan[0] = div64_u64(scan * ap, denominator);
-		nr_force_scan[1] = div64_u64(scan * fp, denominator);
-	}
 out:
 	for_each_evictable_lru(l) {
 		int file = is_file_lru(l);
@@ -1891,20 +1920,10 @@ out:
 		scan = zone_nr_lru_pages(zone, sc, l);
 		if (priority || noswap) {
 			scan >>= priority;
+			if (!scan && force_scan)
+				scan = SWAP_CLUSTER_MAX;
 			scan = div64_u64(scan * fraction[file], denominator);
 		}
-
-		/*
-		 * If zone is small or memcg is small, nr[l] can be 0.
-		 * This results no-scan on this priority and priority drop down.
-		 * For global direct reclaim, it can visit next zone and tend
-		 * not to have problems. For global kswapd, it's for zone
-		 * balancing and it need to scan a small amounts. When using
-		 * memcg, priority drop can cause big latency. So, it's better
-		 * to scan small amount. See may_noscan above.
-		 */
-		if (!scan && force_scan)
-			scan = nr_force_scan[file];
 		nr[l] = scan;
 	}
 }
@@ -1983,12 +2002,14 @@ static void shrink_zone(int priority, struct zone *zone,
 	enum lru_list l;
 	unsigned long nr_reclaimed, nr_scanned;
 	unsigned long nr_to_reclaim = sc->nr_to_reclaim;
+	struct blk_plug plug;
 
 restart:
 	nr_reclaimed = 0;
 	nr_scanned = sc->nr_scanned;
 	get_scan_count(zone, sc, nr, priority);
 
+	blk_start_plug(&plug);
 	while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] ||
 					nr[LRU_INACTIVE_FILE]) {
 		for_each_evictable_lru(l) {
@@ -2012,6 +2033,7 @@ restart:
 		if (nr_reclaimed >= nr_to_reclaim && priority < DEF_PRIORITY)
 			break;
 	}
+	blk_finish_plug(&plug);
 	sc->nr_reclaimed += nr_reclaimed;
 
 	/*