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-rw-r--r--mm/vmscan.c27
1 files changed, 22 insertions, 5 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index b7d868c..1b85217 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -70,6 +70,13 @@ struct scan_control {
int order;
+ /*
+ * Pages that have (or should have) IO pending. If we run into
+ * a lot of these, we're better off waiting a little for IO to
+ * finish rather than scanning more pages in the VM.
+ */
+ int nr_io_pages;
+
/* Which cgroup do we reclaim from */
struct mem_cgroup *mem_cgroup;
@@ -499,8 +506,10 @@ static unsigned long shrink_page_list(struct list_head *page_list,
*/
if (sync_writeback == PAGEOUT_IO_SYNC && may_enter_fs)
wait_on_page_writeback(page);
- else
+ else {
+ sc->nr_io_pages++;
goto keep_locked;
+ }
}
referenced = page_referenced(page, 1, sc->mem_cgroup);
@@ -539,8 +548,10 @@ static unsigned long shrink_page_list(struct list_head *page_list,
if (PageDirty(page)) {
if (sc->order <= PAGE_ALLOC_COSTLY_ORDER && referenced)
goto keep_locked;
- if (!may_enter_fs)
+ if (!may_enter_fs) {
+ sc->nr_io_pages++;
goto keep_locked;
+ }
if (!sc->may_writepage)
goto keep_locked;
@@ -551,8 +562,10 @@ static unsigned long shrink_page_list(struct list_head *page_list,
case PAGE_ACTIVATE:
goto activate_locked;
case PAGE_SUCCESS:
- if (PageWriteback(page) || PageDirty(page))
+ if (PageWriteback(page) || PageDirty(page)) {
+ sc->nr_io_pages++;
goto keep;
+ }
/*
* A synchronous write - probably a ramdisk. Go
* ahead and try to reclaim the page.
@@ -1259,6 +1272,7 @@ static unsigned long do_try_to_free_pages(struct zone **zones, gfp_t gfp_mask,
for (priority = DEF_PRIORITY; priority >= 0; priority--) {
sc->nr_scanned = 0;
+ sc->nr_io_pages = 0;
if (!priority)
disable_swap_token();
nr_reclaimed += shrink_zones(priority, zones, sc);
@@ -1292,7 +1306,8 @@ static unsigned long do_try_to_free_pages(struct zone **zones, gfp_t gfp_mask,
}
/* Take a nap, wait for some writeback to complete */
- if (sc->nr_scanned && priority < DEF_PRIORITY - 2)
+ if (sc->nr_scanned && priority < DEF_PRIORITY - 2 &&
+ sc->nr_io_pages > sc->swap_cluster_max)
congestion_wait(WRITE, HZ/10);
}
/* top priority shrink_caches still had more to do? don't OOM, then */
@@ -1424,6 +1439,7 @@ loop_again:
if (!priority)
disable_swap_token();
+ sc.nr_io_pages = 0;
all_zones_ok = 1;
/*
@@ -1516,7 +1532,8 @@ loop_again:
* OK, kswapd is getting into trouble. Take a nap, then take
* another pass across the zones.
*/
- if (total_scanned && priority < DEF_PRIORITY - 2)
+ if (total_scanned && priority < DEF_PRIORITY - 2 &&
+ sc.nr_io_pages > sc.swap_cluster_max)
congestion_wait(WRITE, HZ/10);
/*
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