#include <linux/mm.h>
#include <linux/module.h>
-#include <linux/slab.h>
+#include <linux/gfp.h>
#include <linux/kernel_stat.h>
#include <linux/swap.h>
#include <linux/pagemap.h>
return ret;
}
-/* Called without lock on whether page is mapped, so answer is unstable */
-static inline int page_mapping_inuse(struct page *page)
-{
- struct address_space *mapping;
-
- /* Page is in somebody's page tables. */
- if (page_mapped(page))
- return 1;
-
- /* Be more reluctant to reclaim swapcache than pagecache */
- if (PageSwapCache(page))
- return 1;
-
- mapping = page_mapping(page);
- if (!mapping)
- return 0;
-
- /* File is mmap'd by somebody? */
- return mapping_mapped(mapping);
-}
-
static inline int is_page_cache_freeable(struct page *page)
{
/*
enum page_references {
PAGEREF_RECLAIM,
PAGEREF_RECLAIM_CLEAN,
+ PAGEREF_KEEP,
PAGEREF_ACTIVATE,
};
static enum page_references page_check_references(struct page *page,
struct scan_control *sc)
{
+ int referenced_ptes, referenced_page;
unsigned long vm_flags;
- int referenced;
- referenced = page_referenced(page, 1, sc->mem_cgroup, &vm_flags);
- if (!referenced)
- return PAGEREF_RECLAIM;
+ referenced_ptes = page_referenced(page, 1, sc->mem_cgroup, &vm_flags);
+ referenced_page = TestClearPageReferenced(page);
/* Lumpy reclaim - ignore references */
if (sc->order > PAGE_ALLOC_COSTLY_ORDER)
if (vm_flags & VM_LOCKED)
return PAGEREF_RECLAIM;
- if (page_mapping_inuse(page))
- return PAGEREF_ACTIVATE;
+ if (referenced_ptes) {
+ if (PageAnon(page))
+ return PAGEREF_ACTIVATE;
+ /*
+ * All mapped pages start out with page table
+ * references from the instantiating fault, so we need
+ * to look twice if a mapped file page is used more
+ * than once.
+ *
+ * Mark it and spare it for another trip around the
+ * inactive list. Another page table reference will
+ * lead to its activation.
+ *
+ * Note: the mark is set for activated pages as well
+ * so that recently deactivated but used pages are
+ * quickly recovered.
+ */
+ SetPageReferenced(page);
+
+ if (referenced_page)
+ return PAGEREF_ACTIVATE;
+
+ return PAGEREF_KEEP;
+ }
/* Reclaim if clean, defer dirty pages to writeback */
- return PAGEREF_RECLAIM_CLEAN;
+ if (referenced_page)
+ return PAGEREF_RECLAIM_CLEAN;
+
+ return PAGEREF_RECLAIM;
}
/*
switch (references) {
case PAGEREF_ACTIVATE:
goto activate_locked;
+ case PAGEREF_KEEP:
+ goto keep_locked;
case PAGEREF_RECLAIM:
case PAGEREF_RECLAIM_CLEAN:
; /* try to reclaim the page below */
continue;
}
- /* page_referenced clears PageReferenced */
- if (page_mapping_inuse(page) &&
- page_referenced(page, 0, sc->mem_cgroup, &vm_flags)) {
+ if (page_referenced(page, 0, sc->mem_cgroup, &vm_flags)) {
nr_rotated++;
/*
* Identify referenced, file-backed active pages and
unsigned long ap, fp;
struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
- /* If we have no swap space, do not bother scanning anon pages. */
- if (!sc->may_swap || (nr_swap_pages <= 0)) {
- percent[0] = 0;
- percent[1] = 100;
- return;
- }
-
anon = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_ANON) +
zone_nr_lru_pages(zone, sc, LRU_INACTIVE_ANON);
file = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_FILE) +
unsigned long nr_reclaimed = sc->nr_reclaimed;
unsigned long nr_to_reclaim = sc->nr_to_reclaim;
struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
+ int noswap = 0;
- get_scan_ratio(zone, sc, percent);
+ /* If we have no swap space, do not bother scanning anon pages. */
+ if (!sc->may_swap || (nr_swap_pages <= 0)) {
+ noswap = 1;
+ percent[0] = 0;
+ percent[1] = 100;
+ } else
+ get_scan_ratio(zone, sc, percent);
for_each_evictable_lru(l) {
int file = is_file_lru(l);
unsigned long scan;
- if (percent[file] == 0) {
- nr[l] = 0;
- continue;
- }
-
scan = zone_nr_lru_pages(zone, sc, l);
- if (priority) {
+ if (priority || noswap) {
scan >>= priority;
scan = (scan * percent[file]) / 100;
}