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Diffstat (limited to 'mm/vmscan.c')
-rw-r--r--mm/vmscan.c64
1 files changed, 41 insertions, 23 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index eea668d9cff6..90c4075d8d75 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -281,17 +281,34 @@ shrink_slab_node(struct shrink_control *shrinkctl, struct shrinker *shrinker,
nr_pages_scanned, lru_pages,
max_pass, delta, total_scan);
- while (total_scan >= batch_size) {
+ /*
+ * Normally, we should not scan less than batch_size objects in one
+ * pass to avoid too frequent shrinker calls, but if the slab has less
+ * than batch_size objects in total and we are really tight on memory,
+ * we will try to reclaim all available objects, otherwise we can end
+ * up failing allocations although there are plenty of reclaimable
+ * objects spread over several slabs with usage less than the
+ * batch_size.
+ *
+ * We detect the "tight on memory" situations by looking at the total
+ * number of objects we want to scan (total_scan). If it is greater
+ * than the total number of objects on slab (max_pass), we must be
+ * scanning at high prio and therefore should try to reclaim as much as
+ * possible.
+ */
+ while (total_scan >= batch_size ||
+ total_scan >= max_pass) {
unsigned long ret;
+ unsigned long nr_to_scan = min(batch_size, total_scan);
- shrinkctl->nr_to_scan = batch_size;
+ shrinkctl->nr_to_scan = nr_to_scan;
ret = shrinker->scan_objects(shrinker, shrinkctl);
if (ret == SHRINK_STOP)
break;
freed += ret;
- count_vm_events(SLABS_SCANNED, batch_size);
- total_scan -= batch_size;
+ count_vm_events(SLABS_SCANNED, nr_to_scan);
+ total_scan -= nr_to_scan;
cond_resched();
}
@@ -352,16 +369,17 @@ unsigned long shrink_slab(struct shrink_control *shrinkctl,
}
list_for_each_entry(shrinker, &shrinker_list, list) {
- for_each_node_mask(shrinkctl->nid, shrinkctl->nodes_to_scan) {
- if (!node_online(shrinkctl->nid))
- continue;
-
- if (!(shrinker->flags & SHRINKER_NUMA_AWARE) &&
- (shrinkctl->nid != 0))
- break;
-
+ if (!(shrinker->flags & SHRINKER_NUMA_AWARE)) {
+ shrinkctl->nid = 0;
freed += shrink_slab_node(shrinkctl, shrinker,
- nr_pages_scanned, lru_pages);
+ nr_pages_scanned, lru_pages);
+ continue;
+ }
+
+ for_each_node_mask(shrinkctl->nid, shrinkctl->nodes_to_scan) {
+ if (node_online(shrinkctl->nid))
+ freed += shrink_slab_node(shrinkctl, shrinker,
+ nr_pages_scanned, lru_pages);
}
}
@@ -603,7 +621,7 @@ void putback_lru_page(struct page *page)
bool is_unevictable;
int was_unevictable = PageUnevictable(page);
- VM_BUG_ON(PageLRU(page));
+ VM_BUG_ON_PAGE(PageLRU(page), page);
redo:
ClearPageUnevictable(page);
@@ -794,8 +812,8 @@ static unsigned long shrink_page_list(struct list_head *page_list,
if (!trylock_page(page))
goto keep;
- VM_BUG_ON(PageActive(page));
- VM_BUG_ON(page_zone(page) != zone);
+ VM_BUG_ON_PAGE(PageActive(page), page);
+ VM_BUG_ON_PAGE(page_zone(page) != zone, page);
sc->nr_scanned++;
@@ -1079,14 +1097,14 @@ activate_locked:
/* Not a candidate for swapping, so reclaim swap space. */
if (PageSwapCache(page) && vm_swap_full())
try_to_free_swap(page);
- VM_BUG_ON(PageActive(page));
+ VM_BUG_ON_PAGE(PageActive(page), page);
SetPageActive(page);
pgactivate++;
keep_locked:
unlock_page(page);
keep:
list_add(&page->lru, &ret_pages);
- VM_BUG_ON(PageLRU(page) || PageUnevictable(page));
+ VM_BUG_ON_PAGE(PageLRU(page) || PageUnevictable(page), page);
}
free_hot_cold_page_list(&free_pages, 1);
@@ -1240,7 +1258,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
page = lru_to_page(src);
prefetchw_prev_lru_page(page, src, flags);
- VM_BUG_ON(!PageLRU(page));
+ VM_BUG_ON_PAGE(!PageLRU(page), page);
switch (__isolate_lru_page(page, mode)) {
case 0:
@@ -1295,7 +1313,7 @@ int isolate_lru_page(struct page *page)
{
int ret = -EBUSY;
- VM_BUG_ON(!page_count(page));
+ VM_BUG_ON_PAGE(!page_count(page), page);
if (PageLRU(page)) {
struct zone *zone = page_zone(page);
@@ -1366,7 +1384,7 @@ putback_inactive_pages(struct lruvec *lruvec, struct list_head *page_list)
struct page *page = lru_to_page(page_list);
int lru;
- VM_BUG_ON(PageLRU(page));
+ VM_BUG_ON_PAGE(PageLRU(page), page);
list_del(&page->lru);
if (unlikely(!page_evictable(page))) {
spin_unlock_irq(&zone->lru_lock);
@@ -1586,7 +1604,7 @@ static void move_active_pages_to_lru(struct lruvec *lruvec,
page = lru_to_page(list);
lruvec = mem_cgroup_page_lruvec(page, zone);
- VM_BUG_ON(PageLRU(page));
+ VM_BUG_ON_PAGE(PageLRU(page), page);
SetPageLRU(page);
nr_pages = hpage_nr_pages(page);
@@ -3701,7 +3719,7 @@ void check_move_unevictable_pages(struct page **pages, int nr_pages)
if (page_evictable(page)) {
enum lru_list lru = page_lru_base_type(page);
- VM_BUG_ON(PageActive(page));
+ VM_BUG_ON_PAGE(PageActive(page), page);
ClearPageUnevictable(page);
del_page_from_lru_list(page, lruvec, LRU_UNEVICTABLE);
add_page_to_lru_list(page, lruvec, lru);