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-rw-r--r--mm/vmscan.c63
1 files changed, 49 insertions, 14 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 277a36de11c1..f8e3dcd527b8 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1118,6 +1118,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
int may_enter_fs;
enum page_references references = PAGEREF_RECLAIM_CLEAN;
bool dirty, writeback;
+ unsigned int nr_pages;
cond_resched();
@@ -1129,7 +1130,10 @@ static unsigned long shrink_page_list(struct list_head *page_list,
VM_BUG_ON_PAGE(PageActive(page), page);
- sc->nr_scanned++;
+ nr_pages = 1 << compound_order(page);
+
+ /* Account the number of base pages even though THP */
+ sc->nr_scanned += nr_pages;
if (unlikely(!page_evictable(page)))
goto activate_locked;
@@ -1250,7 +1254,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
case PAGEREF_ACTIVATE:
goto activate_locked;
case PAGEREF_KEEP:
- stat->nr_ref_keep++;
+ stat->nr_ref_keep += nr_pages;
goto keep_locked;
case PAGEREF_RECLAIM:
case PAGEREF_RECLAIM_CLEAN:
@@ -1282,7 +1286,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
}
if (!add_to_swap(page)) {
if (!PageTransHuge(page))
- goto activate_locked;
+ goto activate_locked_split;
/* Fallback to swap normal pages */
if (split_huge_page_to_list(page,
page_list))
@@ -1291,7 +1295,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
count_vm_event(THP_SWPOUT_FALLBACK);
#endif
if (!add_to_swap(page))
- goto activate_locked;
+ goto activate_locked_split;
}
may_enter_fs = 1;
@@ -1306,6 +1310,18 @@ static unsigned long shrink_page_list(struct list_head *page_list,
}
/*
+ * THP may get split above, need minus tail pages and update
+ * nr_pages to avoid accounting tail pages twice.
+ *
+ * The tail pages that are added into swap cache successfully
+ * reach here.
+ */
+ if ((nr_pages > 1) && !PageTransHuge(page)) {
+ sc->nr_scanned -= (nr_pages - 1);
+ nr_pages = 1;
+ }
+
+ /*
* The page is mapped into the page tables of one or more
* processes. Try to unmap it here.
*/
@@ -1315,7 +1331,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
if (unlikely(PageTransHuge(page)))
flags |= TTU_SPLIT_HUGE_PMD;
if (!try_to_unmap(page, flags)) {
- stat->nr_unmap_fail++;
+ stat->nr_unmap_fail += nr_pages;
goto activate_locked;
}
}
@@ -1442,7 +1458,11 @@ static unsigned long shrink_page_list(struct list_head *page_list,
unlock_page(page);
free_it:
- nr_reclaimed++;
+ /*
+ * THP may get swapped out in a whole, need account
+ * all base pages.
+ */
+ nr_reclaimed += nr_pages;
/*
* Is there need to periodically free_page_list? It would
@@ -1455,6 +1475,15 @@ free_it:
list_add(&page->lru, &free_pages);
continue;
+activate_locked_split:
+ /*
+ * The tail pages that are failed to add into swap cache
+ * reach here. Fixup nr_scanned and nr_pages.
+ */
+ if (nr_pages > 1) {
+ sc->nr_scanned -= (nr_pages - 1);
+ nr_pages = 1;
+ }
activate_locked:
/* Not a candidate for swapping, so reclaim swap space. */
if (PageSwapCache(page) && (mem_cgroup_swap_full(page) ||
@@ -1464,8 +1493,7 @@ activate_locked:
if (!PageMlocked(page)) {
int type = page_is_file_cache(page);
SetPageActive(page);
- pgactivate++;
- stat->nr_activate[type] += hpage_nr_pages(page);
+ stat->nr_activate[type] += nr_pages;
count_memcg_page_event(page, PGACTIVATE);
}
keep_locked:
@@ -1475,6 +1503,8 @@ keep:
VM_BUG_ON_PAGE(PageLRU(page) || PageUnevictable(page), page);
}
+ pgactivate = stat->nr_activate[0] + stat->nr_activate[1];
+
mem_cgroup_uncharge_list(&free_pages);
try_to_unmap_flush();
free_unref_page_list(&free_pages);
@@ -1646,10 +1676,9 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
LIST_HEAD(pages_skipped);
isolate_mode_t mode = (sc->may_unmap ? 0 : ISOLATE_UNMAPPED);
+ total_scan = 0;
scan = 0;
- for (total_scan = 0;
- scan < nr_to_scan && nr_taken < nr_to_scan && !list_empty(src);
- total_scan++) {
+ while (scan < nr_to_scan && !list_empty(src)) {
struct page *page;
page = lru_to_page(src);
@@ -1657,9 +1686,12 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
VM_BUG_ON_PAGE(!PageLRU(page), page);
+ nr_pages = 1 << compound_order(page);
+ total_scan += nr_pages;
+
if (page_zonenum(page) > sc->reclaim_idx) {
list_move(&page->lru, &pages_skipped);
- nr_skipped[page_zonenum(page)]++;
+ nr_skipped[page_zonenum(page)] += nr_pages;
continue;
}
@@ -1668,11 +1700,14 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
* return with no isolated pages if the LRU mostly contains
* ineligible pages. This causes the VM to not reclaim any
* pages, triggering a premature OOM.
+ *
+ * Account all tail pages of THP. This would not cause
+ * premature OOM since __isolate_lru_page() returns -EBUSY
+ * only when the page is being freed somewhere else.
*/
- scan++;
+ scan += nr_pages;
switch (__isolate_lru_page(page, mode)) {
case 0:
- nr_pages = hpage_nr_pages(page);
nr_taken += nr_pages;
nr_zone_taken[page_zonenum(page)] += nr_pages;
list_move(&page->lru, dst);