summaryrefslogtreecommitdiffstats
path: root/mm/vmscan.c
diff options
context:
space:
mode:
Diffstat (limited to 'mm/vmscan.c')
-rw-r--r--mm/vmscan.c42
1 files changed, 35 insertions, 7 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 130ad0239f52..30fd658bb289 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -401,10 +401,8 @@ static pageout_t pageout(struct page *page, struct address_space *mapping,
}
if (mapping->a_ops->writepage == NULL)
return PAGE_ACTIVATE;
- if (!may_write_to_queue(mapping->backing_dev_info, sc)) {
- disable_lumpy_reclaim_mode(sc);
+ if (!may_write_to_queue(mapping->backing_dev_info, sc))
return PAGE_KEEP;
- }
if (clear_page_dirty_for_io(page)) {
int res;
@@ -681,11 +679,14 @@ static noinline_for_stack void free_page_list(struct list_head *free_pages)
* shrink_page_list() returns the number of reclaimed pages
*/
static unsigned long shrink_page_list(struct list_head *page_list,
+ struct zone *zone,
struct scan_control *sc)
{
LIST_HEAD(ret_pages);
LIST_HEAD(free_pages);
int pgactivate = 0;
+ unsigned long nr_dirty = 0;
+ unsigned long nr_congested = 0;
unsigned long nr_reclaimed = 0;
cond_resched();
@@ -705,6 +706,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
goto keep;
VM_BUG_ON(PageActive(page));
+ VM_BUG_ON(page_zone(page) != zone);
sc->nr_scanned++;
@@ -782,6 +784,8 @@ static unsigned long shrink_page_list(struct list_head *page_list,
}
if (PageDirty(page)) {
+ nr_dirty++;
+
if (references == PAGEREF_RECLAIM_CLEAN)
goto keep_locked;
if (!may_enter_fs)
@@ -792,6 +796,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
/* Page is dirty, try to write it out here */
switch (pageout(page, mapping, sc)) {
case PAGE_KEEP:
+ nr_congested++;
goto keep_locked;
case PAGE_ACTIVATE:
goto activate_locked;
@@ -902,6 +907,15 @@ keep_lumpy:
VM_BUG_ON(PageLRU(page) || PageUnevictable(page));
}
+ /*
+ * Tag a zone as congested if all the dirty pages encountered were
+ * backed by a congested BDI. In this case, reclaimers should just
+ * back off and wait for congestion to clear because further reclaim
+ * will encounter the same problem
+ */
+ if (nr_dirty == nr_congested)
+ zone_set_flag(zone, ZONE_CONGESTED);
+
free_page_list(&free_pages);
list_splice(&ret_pages, page_list);
@@ -1386,12 +1400,12 @@ shrink_inactive_list(unsigned long nr_to_scan, struct zone *zone,
spin_unlock_irq(&zone->lru_lock);
- nr_reclaimed = shrink_page_list(&page_list, sc);
+ nr_reclaimed = shrink_page_list(&page_list, zone, sc);
/* Check if we should syncronously wait for writeback */
if (should_reclaim_stall(nr_taken, nr_reclaimed, priority, sc)) {
set_lumpy_reclaim_mode(priority, sc, true);
- nr_reclaimed += shrink_page_list(&page_list, sc);
+ nr_reclaimed += shrink_page_list(&page_list, zone, sc);
}
local_irq_disable();
@@ -1982,8 +1996,13 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
/* Take a nap, wait for some writeback to complete */
if (!sc->hibernation_mode && sc->nr_scanned &&
- priority < DEF_PRIORITY - 2)
- congestion_wait(BLK_RW_ASYNC, HZ/10);
+ priority < DEF_PRIORITY - 2) {
+ struct zone *preferred_zone;
+
+ first_zones_zonelist(zonelist, gfp_zone(sc->gfp_mask),
+ NULL, &preferred_zone);
+ wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/10);
+ }
}
out:
@@ -2282,6 +2301,15 @@ loop_again:
if (!zone_watermark_ok(zone, order,
min_wmark_pages(zone), end_zone, 0))
has_under_min_watermark_zone = 1;
+ } else {
+ /*
+ * If a zone reaches its high watermark,
+ * consider it to be no longer congested. It's
+ * possible there are dirty pages backed by
+ * congested BDIs but as pressure is relieved,
+ * spectulatively avoid congestion waits
+ */
+ zone_clear_flag(zone, ZONE_CONGESTED);
}
}