#include <trace/events/vmscan.h>
/*
- * lumpy_mode determines how the inactive list is shrunk
- * LUMPY_MODE_SINGLE: Reclaim only order-0 pages
- * LUMPY_MODE_ASYNC: Do not block
- * LUMPY_MODE_SYNC: Allow blocking e.g. call wait_on_page_writeback
- * LUMPY_MODE_CONTIGRECLAIM: For high-order allocations, take a reference
+ * reclaim_mode determines how the inactive list is shrunk
+ * RECLAIM_MODE_SINGLE: Reclaim only order-0 pages
+ * RECLAIM_MODE_ASYNC: Do not block
+ * RECLAIM_MODE_SYNC: Allow blocking e.g. call wait_on_page_writeback
+ * RECLAIM_MODE_LUMPYRECLAIM: For high-order allocations, take a reference
* page from the LRU and reclaim all pages within a
* naturally aligned range
- * LUMPY_MODE_COMPACTION: For high-order allocations, reclaim a number of
+ * RECLAIM_MODE_COMPACTION: For high-order allocations, reclaim a number of
* order-0 pages and then compact the zone
*/
-typedef unsigned __bitwise__ lumpy_mode;
-#define LUMPY_MODE_SINGLE ((__force lumpy_mode)0x01u)
-#define LUMPY_MODE_ASYNC ((__force lumpy_mode)0x02u)
-#define LUMPY_MODE_SYNC ((__force lumpy_mode)0x04u)
-#define LUMPY_MODE_CONTIGRECLAIM ((__force lumpy_mode)0x08u)
-#define LUMPY_MODE_COMPACTION ((__force lumpy_mode)0x10u)
+typedef unsigned __bitwise__ reclaim_mode_t;
+#define RECLAIM_MODE_SINGLE ((__force reclaim_mode_t)0x01u)
+#define RECLAIM_MODE_ASYNC ((__force reclaim_mode_t)0x02u)
+#define RECLAIM_MODE_SYNC ((__force reclaim_mode_t)0x04u)
+#define RECLAIM_MODE_LUMPYRECLAIM ((__force reclaim_mode_t)0x08u)
+#define RECLAIM_MODE_COMPACTION ((__force reclaim_mode_t)0x10u)
struct scan_control {
/* Incremented by the number of inactive pages that were scanned */
* Intend to reclaim enough continuous memory rather than reclaim
* enough amount of memory. i.e, mode for high order allocation.
*/
- lumpy_mode lumpy_reclaim_mode;
+ reclaim_mode_t reclaim_mode;
/* Which cgroup do we reclaim from */
struct mem_cgroup *mem_cgroup;
return ret;
}
-static void set_lumpy_reclaim_mode(int priority, struct scan_control *sc,
+static void set_reclaim_mode(int priority, struct scan_control *sc,
bool sync)
{
- lumpy_mode syncmode = sync ? LUMPY_MODE_SYNC : LUMPY_MODE_ASYNC;
+ reclaim_mode_t syncmode = sync ? RECLAIM_MODE_SYNC : RECLAIM_MODE_ASYNC;
/*
* Initially assume we are entering either lumpy reclaim or
* sync mode or just reclaim order-0 pages later.
*/
if (COMPACTION_BUILD)
- sc->lumpy_reclaim_mode = LUMPY_MODE_COMPACTION;
+ sc->reclaim_mode = RECLAIM_MODE_COMPACTION;
else
- sc->lumpy_reclaim_mode = LUMPY_MODE_CONTIGRECLAIM;
+ sc->reclaim_mode = RECLAIM_MODE_LUMPYRECLAIM;
/*
* Avoid using lumpy reclaim or reclaim/compaction if possible by
* under memory pressure
*/
if (sc->order > PAGE_ALLOC_COSTLY_ORDER)
- sc->lumpy_reclaim_mode |= syncmode;
+ sc->reclaim_mode |= syncmode;
else if (sc->order && priority < DEF_PRIORITY - 2)
- sc->lumpy_reclaim_mode |= syncmode;
+ sc->reclaim_mode |= syncmode;
else
- sc->lumpy_reclaim_mode = LUMPY_MODE_SINGLE | LUMPY_MODE_ASYNC;
+ sc->reclaim_mode = RECLAIM_MODE_SINGLE | RECLAIM_MODE_ASYNC;
}
-static void disable_lumpy_reclaim_mode(struct scan_control *sc)
+static void reset_reclaim_mode(struct scan_control *sc)
{
- sc->lumpy_reclaim_mode = LUMPY_MODE_SINGLE | LUMPY_MODE_ASYNC;
+ sc->reclaim_mode = RECLAIM_MODE_SINGLE | RECLAIM_MODE_ASYNC;
}
static inline int is_page_cache_freeable(struct page *page)
* first attempt to free a range of pages fails.
*/
if (PageWriteback(page) &&
- (sc->lumpy_reclaim_mode & LUMPY_MODE_SYNC))
+ (sc->reclaim_mode & RECLAIM_MODE_SYNC))
wait_on_page_writeback(page);
if (!PageWriteback(page)) {
ClearPageReclaim(page);
}
trace_mm_vmscan_writepage(page,
- trace_reclaim_flags(page, sc->lumpy_reclaim_mode));
+ trace_reclaim_flags(page, sc->reclaim_mode));
inc_zone_page_state(page, NR_VMSCAN_WRITE);
return PAGE_SUCCESS;
}
referenced_page = TestClearPageReferenced(page);
/* Lumpy reclaim - ignore references */
- if (sc->lumpy_reclaim_mode & LUMPY_MODE_CONTIGRECLAIM)
+ if (sc->reclaim_mode & RECLAIM_MODE_LUMPYRECLAIM)
return PAGEREF_RECLAIM;
/*
* for any page for which writeback has already
* started.
*/
- if ((sc->lumpy_reclaim_mode & LUMPY_MODE_SYNC) &&
+ if ((sc->reclaim_mode & RECLAIM_MODE_SYNC) &&
may_enter_fs)
wait_on_page_writeback(page);
else {
try_to_free_swap(page);
unlock_page(page);
putback_lru_page(page);
- disable_lumpy_reclaim_mode(sc);
+ reset_reclaim_mode(sc);
continue;
activate_locked:
keep_locked:
unlock_page(page);
keep:
- disable_lumpy_reclaim_mode(sc);
+ reset_reclaim_mode(sc);
keep_lumpy:
list_add(&page->lru, &ret_pages);
VM_BUG_ON(PageLRU(page) || PageUnevictable(page));
case 0:
list_move(&page->lru, dst);
mem_cgroup_del_lru(page);
- nr_taken++;
+ nr_taken += hpage_nr_pages(page);
break;
case -EBUSY:
if (__isolate_lru_page(cursor_page, mode, file) == 0) {
list_move(&cursor_page->lru, dst);
mem_cgroup_del_lru(cursor_page);
- nr_taken++;
+ nr_taken += hpage_nr_pages(page);
nr_lumpy_taken++;
if (PageDirty(cursor_page))
nr_lumpy_dirty++;
struct page *page;
list_for_each_entry(page, page_list, lru) {
+ int numpages = hpage_nr_pages(page);
lru = page_lru_base_type(page);
if (PageActive(page)) {
lru += LRU_ACTIVE;
ClearPageActive(page);
- nr_active++;
+ nr_active += numpages;
}
if (count)
- count[lru]++;
+ count[lru] += numpages;
}
return nr_active;
add_page_to_lru_list(zone, page, lru);
if (is_active_lru(lru)) {
int file = is_file_lru(lru);
- reclaim_stat->recent_rotated[file]++;
+ int numpages = hpage_nr_pages(page);
+ reclaim_stat->recent_rotated[file] += numpages;
}
if (!pagevec_add(&pvec, page)) {
spin_unlock_irq(&zone->lru_lock);
return false;
/* Only stall on lumpy reclaim */
- if (sc->lumpy_reclaim_mode & LUMPY_MODE_SINGLE)
+ if (sc->reclaim_mode & RECLAIM_MODE_SINGLE)
return false;
/* If we have relaimed everything on the isolated list, no stall */
return SWAP_CLUSTER_MAX;
}
- set_lumpy_reclaim_mode(priority, sc, false);
+ set_reclaim_mode(priority, sc, false);
lru_add_drain();
spin_lock_irq(&zone->lru_lock);
if (scanning_global_lru(sc)) {
nr_taken = isolate_pages_global(nr_to_scan,
&page_list, &nr_scanned, sc->order,
- sc->lumpy_reclaim_mode & LUMPY_MODE_CONTIGRECLAIM ?
+ sc->reclaim_mode & RECLAIM_MODE_LUMPYRECLAIM ?
ISOLATE_BOTH : ISOLATE_INACTIVE,
zone, 0, file);
zone->pages_scanned += nr_scanned;
} else {
nr_taken = mem_cgroup_isolate_pages(nr_to_scan,
&page_list, &nr_scanned, sc->order,
- sc->lumpy_reclaim_mode & LUMPY_MODE_CONTIGRECLAIM ?
+ sc->reclaim_mode & RECLAIM_MODE_LUMPYRECLAIM ?
ISOLATE_BOTH : ISOLATE_INACTIVE,
zone, sc->mem_cgroup,
0, file);
/* 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);
+ set_reclaim_mode(priority, sc, true);
nr_reclaimed += shrink_page_list(&page_list, zone, sc);
}
zone_idx(zone),
nr_scanned, nr_reclaimed,
priority,
- trace_shrink_flags(file, sc->lumpy_reclaim_mode));
+ trace_shrink_flags(file, sc->reclaim_mode));
return nr_reclaimed;
}
list_move(&page->lru, &zone->lru[lru].list);
mem_cgroup_add_lru_list(page, lru);
- pgmoved++;
+ pgmoved += hpage_nr_pages(page);
if (!pagevec_add(&pvec, page) || list_empty(list)) {
spin_unlock_irq(&zone->lru_lock);
}
if (page_referenced(page, 0, sc->mem_cgroup, &vm_flags)) {
- nr_rotated++;
+ nr_rotated += hpage_nr_pages(page);
/*
* Identify referenced, file-backed active pages and
* give them one more trip around the active list. So
unsigned long inactive_lru_pages;
/* If not in reclaim/compaction mode, stop */
- if (!(sc->lumpy_reclaim_mode & LUMPY_MODE_COMPACTION))
+ if (!(sc->reclaim_mode & RECLAIM_MODE_COMPACTION))
return false;
/*
}
#endif
+/*
+ * pgdat_balanced is used when checking if a node is balanced for high-order
+ * allocations. Only zones that meet watermarks and are in a zone allowed
+ * by the callers classzone_idx are added to balanced_pages. The total of
+ * balanced pages must be at least 25% of the zones allowed by classzone_idx
+ * for the node to be considered balanced. Forcing all zones to be balanced
+ * for high orders can cause excessive reclaim when there are imbalanced zones.
+ * The choice of 25% is due to
+ * o a 16M DMA zone that is balanced will not balance a zone on any
+ * reasonable sized machine
+ * o On all other machines, the top zone must be at least a reasonable
+ * precentage of the middle zones. For example, on 32-bit x86, highmem
+ * would need to be at least 256M for it to be balance a whole node.
+ * Similarly, on x86-64 the Normal zone would need to be at least 1G
+ * to balance a node on its own. These seemed like reasonable ratios.
+ */
+static bool pgdat_balanced(pg_data_t *pgdat, unsigned long balanced_pages,
+ int classzone_idx)
+{
+ unsigned long present_pages = 0;
+ int i;
+
+ for (i = 0; i <= classzone_idx; i++)
+ present_pages += pgdat->node_zones[i].present_pages;
+
+ return balanced_pages > (present_pages >> 2);
+}
+
/* is kswapd sleeping prematurely? */
-static int sleeping_prematurely(pg_data_t *pgdat, int order, long remaining)
+static bool sleeping_prematurely(pg_data_t *pgdat, int order, long remaining,
+ int classzone_idx)
{
int i;
+ unsigned long balanced = 0;
+ bool all_zones_ok = true;
/* If a direct reclaimer woke kswapd within HZ/10, it's premature */
if (remaining)
- return 1;
+ return true;
- /* If after HZ/10, a zone is below the high mark, it's premature */
+ /* Check the watermark levels */
for (i = 0; i < pgdat->nr_zones; i++) {
struct zone *zone = pgdat->node_zones + i;
if (!populated_zone(zone))
continue;
- if (zone->all_unreclaimable)
+ /*
+ * balance_pgdat() skips over all_unreclaimable after
+ * DEF_PRIORITY. Effectively, it considers them balanced so
+ * they must be considered balanced here as well if kswapd
+ * is to sleep
+ */
+ if (zone->all_unreclaimable) {
+ balanced += zone->present_pages;
continue;
+ }
if (!zone_watermark_ok_safe(zone, order, high_wmark_pages(zone),
- 0, 0))
- return 1;
+ classzone_idx, 0))
+ all_zones_ok = false;
+ else
+ balanced += zone->present_pages;
}
- return 0;
+ /*
+ * For high-order requests, the balanced zones must contain at least
+ * 25% of the nodes pages for kswapd to sleep. For order-0, all zones
+ * must be balanced
+ */
+ if (order)
+ return pgdat_balanced(pgdat, balanced, classzone_idx);
+ else
+ return !all_zones_ok;
}
/*
* For kswapd, balance_pgdat() will work across all this node's zones until
* they are all at high_wmark_pages(zone).
*
- * Returns the number of pages which were actually freed.
+ * Returns the final order kswapd was reclaiming at
*
* There is special handling here for zones which are full of pinned pages.
* This can happen if the pages are all mlocked, or if they are all used by
* interoperates with the page allocator fallback scheme to ensure that aging
* of pages is balanced across the zones.
*/
-static unsigned long balance_pgdat(pg_data_t *pgdat, int order)
+static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
+ int *classzone_idx)
{
int all_zones_ok;
+ unsigned long balanced;
int priority;
int i;
+ int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */
unsigned long total_scanned;
struct reclaim_state *reclaim_state = current->reclaim_state;
struct scan_control sc = {
count_vm_event(PAGEOUTRUN);
for (priority = DEF_PRIORITY; priority >= 0; priority--) {
- int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */
unsigned long lru_pages = 0;
int has_under_min_watermark_zone = 0;
disable_swap_token();
all_zones_ok = 1;
+ balanced = 0;
/*
* Scan in the highmem->dma direction for the highest
if (!zone_watermark_ok_safe(zone, order,
high_wmark_pages(zone), 0, 0)) {
end_zone = i;
+ *classzone_idx = i;
break;
}
}
* cause too much scanning of the lower zones.
*/
for (i = 0; i <= end_zone; i++) {
+ int compaction;
struct zone *zone = pgdat->node_zones + i;
int nr_slab;
lru_pages);
sc.nr_reclaimed += reclaim_state->reclaimed_slab;
total_scanned += sc.nr_scanned;
+
+ compaction = 0;
+ if (order &&
+ zone_watermark_ok(zone, 0,
+ high_wmark_pages(zone),
+ end_zone, 0) &&
+ !zone_watermark_ok(zone, order,
+ high_wmark_pages(zone),
+ end_zone, 0)) {
+ compact_zone_order(zone,
+ order,
+ sc.gfp_mask, false,
+ COMPACT_MODE_KSWAPD);
+ compaction = 1;
+ }
+
if (zone->all_unreclaimable)
continue;
- if (nr_slab == 0 && !zone_reclaimable(zone))
+ if (!compaction && nr_slab == 0 &&
+ !zone_reclaimable(zone))
zone->all_unreclaimable = 1;
/*
* If we've done a decent amount of scanning and
total_scanned > sc.nr_reclaimed + sc.nr_reclaimed / 2)
sc.may_writepage = 1;
- /*
- * Compact the zone for higher orders to reduce
- * latencies for higher-order allocations that
- * would ordinarily call try_to_compact_pages()
- */
- if (sc.order > PAGE_ALLOC_COSTLY_ORDER)
- compact_zone_order(zone, sc.order, sc.gfp_mask);
-
if (!zone_watermark_ok_safe(zone, order,
high_wmark_pages(zone), end_zone, 0)) {
all_zones_ok = 0;
* spectulatively avoid congestion waits
*/
zone_clear_flag(zone, ZONE_CONGESTED);
+ if (i <= *classzone_idx)
+ balanced += zone->present_pages;
}
}
- if (all_zones_ok)
+ if (all_zones_ok || (order && pgdat_balanced(pgdat, balanced, *classzone_idx)))
break; /* kswapd: all done */
/*
* OK, kswapd is getting into trouble. Take a nap, then take
break;
}
out:
- if (!all_zones_ok) {
+
+ /*
+ * order-0: All zones must meet high watermark for a balanced node
+ * high-order: Balanced zones must make up at least 25% of the node
+ * for the node to be balanced
+ */
+ if (!(all_zones_ok || (order && pgdat_balanced(pgdat, balanced, *classzone_idx)))) {
cond_resched();
try_to_freeze();
goto loop_again;
}
- return sc.nr_reclaimed;
+ /*
+ * If kswapd was reclaiming at a higher order, it has the option of
+ * sleeping without all zones being balanced. Before it does, it must
+ * ensure that the watermarks for order-0 on *all* zones are met and
+ * that the congestion flags are cleared. The congestion flag must
+ * be cleared as kswapd is the only mechanism that clears the flag
+ * and it is potentially going to sleep here.
+ */
+ if (order) {
+ for (i = 0; i <= end_zone; i++) {
+ struct zone *zone = pgdat->node_zones + i;
+
+ if (!populated_zone(zone))
+ continue;
+
+ if (zone->all_unreclaimable && priority != DEF_PRIORITY)
+ continue;
+
+ /* Confirm the zone is balanced for order-0 */
+ if (!zone_watermark_ok(zone, 0,
+ high_wmark_pages(zone), 0, 0)) {
+ order = sc.order = 0;
+ goto loop_again;
+ }
+
+ /* If balanced, clear the congested flag */
+ zone_clear_flag(zone, ZONE_CONGESTED);
+ }
+ }
+
+ /*
+ * Return the order we were reclaiming at so sleeping_prematurely()
+ * makes a decision on the order we were last reclaiming at. However,
+ * if another caller entered the allocator slow path while kswapd
+ * was awake, order will remain at the higher level
+ */
+ *classzone_idx = end_zone;
+ return order;
}
-static void kswapd_try_to_sleep(pg_data_t *pgdat, int order)
+static void kswapd_try_to_sleep(pg_data_t *pgdat, int order, int classzone_idx)
{
long remaining = 0;
DEFINE_WAIT(wait);
prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
/* Try to sleep for a short interval */
- if (!sleeping_prematurely(pgdat, order, remaining)) {
+ if (!sleeping_prematurely(pgdat, order, remaining, classzone_idx)) {
remaining = schedule_timeout(HZ/10);
finish_wait(&pgdat->kswapd_wait, &wait);
prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
* After a short sleep, check if it was a premature sleep. If not, then
* go fully to sleep until explicitly woken up.
*/
- if (!sleeping_prematurely(pgdat, order, remaining)) {
+ if (!sleeping_prematurely(pgdat, order, remaining, classzone_idx)) {
trace_mm_vmscan_kswapd_sleep(pgdat->node_id);
/*
static int kswapd(void *p)
{
unsigned long order;
+ int classzone_idx;
pg_data_t *pgdat = (pg_data_t*)p;
struct task_struct *tsk = current;
set_freezable();
order = 0;
+ classzone_idx = MAX_NR_ZONES - 1;
for ( ; ; ) {
unsigned long new_order;
+ int new_classzone_idx;
int ret;
new_order = pgdat->kswapd_max_order;
+ new_classzone_idx = pgdat->classzone_idx;
pgdat->kswapd_max_order = 0;
- if (order < new_order) {
+ pgdat->classzone_idx = MAX_NR_ZONES - 1;
+ if (order < new_order || classzone_idx > new_classzone_idx) {
/*
* Don't sleep if someone wants a larger 'order'
- * allocation
+ * allocation or has tigher zone constraints
*/
order = new_order;
+ classzone_idx = new_classzone_idx;
} else {
- kswapd_try_to_sleep(pgdat, order);
+ kswapd_try_to_sleep(pgdat, order, classzone_idx);
order = pgdat->kswapd_max_order;
+ classzone_idx = pgdat->classzone_idx;
+ pgdat->kswapd_max_order = 0;
+ pgdat->classzone_idx = MAX_NR_ZONES - 1;
}
ret = try_to_freeze();
*/
if (!ret) {
trace_mm_vmscan_kswapd_wake(pgdat->node_id, order);
- balance_pgdat(pgdat, order);
+ order = balance_pgdat(pgdat, order, &classzone_idx);
}
}
return 0;
/*
* A zone is low on free memory, so wake its kswapd task to service it.
*/
-void wakeup_kswapd(struct zone *zone, int order)
+void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx)
{
pg_data_t *pgdat;
if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
return;
pgdat = zone->zone_pgdat;
- if (pgdat->kswapd_max_order < order)
+ if (pgdat->kswapd_max_order < order) {
pgdat->kswapd_max_order = order;
+ pgdat->classzone_idx = min(pgdat->classzone_idx, classzone_idx);
+ }
if (!waitqueue_active(&pgdat->kswapd_wait))
return;
if (zone_watermark_ok_safe(zone, order, low_wmark_pages(zone), 0, 0))
git.openpandora.org / pandora-kernel.git / blobdiff