return is_migrate_cma(migratetype) || migratetype == MIGRATE_MOVABLE;
}
+#ifdef CONFIG_COMPACTION
+/* Returns true if the pageblock should be scanned for pages to isolate. */
+static inline bool isolation_suitable(struct compact_control *cc,
+ struct page *page)
+{
+ if (cc->ignore_skip_hint)
+ return true;
+
+ return !get_pageblock_skip(page);
+}
+
+/*
+ * This function is called to clear all cached information on pageblocks that
+ * should be skipped for page isolation when the migrate and free page scanner
+ * meet.
+ */
+static void __reset_isolation_suitable(struct zone *zone)
+{
+ unsigned long start_pfn = zone->zone_start_pfn;
+ unsigned long end_pfn = zone->zone_start_pfn + zone->spanned_pages;
+ unsigned long pfn;
+
+ zone->compact_cached_migrate_pfn = start_pfn;
+ zone->compact_cached_free_pfn = end_pfn;
+ zone->compact_blockskip_flush = false;
+
+ /* Walk the zone and mark every pageblock as suitable for isolation */
+ for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
+ struct page *page;
+
+ cond_resched();
+
+ if (!pfn_valid(pfn))
+ continue;
+
+ page = pfn_to_page(pfn);
+ if (zone != page_zone(page))
+ continue;
+
+ clear_pageblock_skip(page);
+ }
+}
+
+void reset_isolation_suitable(pg_data_t *pgdat)
+{
+ int zoneid;
+
+ for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) {
+ struct zone *zone = &pgdat->node_zones[zoneid];
+ if (!populated_zone(zone))
+ continue;
+
+ /* Only flush if a full compaction finished recently */
+ if (zone->compact_blockskip_flush)
+ __reset_isolation_suitable(zone);
+ }
+}
+
+/*
+ * If no pages were isolated then mark this pageblock to be skipped in the
+ * future. The information is later cleared by __reset_isolation_suitable().
+ */
+static void update_pageblock_skip(struct compact_control *cc,
+ struct page *page, unsigned long nr_isolated,
+ bool migrate_scanner)
+{
+ struct zone *zone = cc->zone;
+ if (!page)
+ return;
+
+ if (!nr_isolated) {
+ unsigned long pfn = page_to_pfn(page);
+ set_pageblock_skip(page);
+
+ /* Update where compaction should restart */
+ if (migrate_scanner) {
+ if (!cc->finished_update_migrate &&
+ pfn > zone->compact_cached_migrate_pfn)
+ zone->compact_cached_migrate_pfn = pfn;
+ } else {
+ if (!cc->finished_update_free &&
+ pfn < zone->compact_cached_free_pfn)
+ zone->compact_cached_free_pfn = pfn;
+ }
+ }
+}
+#else
+static inline bool isolation_suitable(struct compact_control *cc,
+ struct page *page)
+{
+ return true;
+}
+
+static void update_pageblock_skip(struct compact_control *cc,
+ struct page *page, unsigned long nr_isolated,
+ bool migrate_scanner)
+{
+}
+#endif /* CONFIG_COMPACTION */
+
static inline bool should_release_lock(spinlock_t *lock)
{
return need_resched() || spin_is_contended(lock);
bool strict)
{
int nr_scanned = 0, total_isolated = 0;
- struct page *cursor;
+ struct page *cursor, *valid_page = NULL;
unsigned long nr_strict_required = end_pfn - blockpfn;
unsigned long flags;
bool locked = false;
nr_scanned++;
if (!pfn_valid_within(blockpfn))
continue;
+ if (!valid_page)
+ valid_page = page;
if (!PageBuddy(page))
continue;
if (locked)
spin_unlock_irqrestore(&cc->zone->lock, flags);
+ /* Update the pageblock-skip if the whole pageblock was scanned */
+ if (blockpfn == end_pfn)
+ update_pageblock_skip(cc, valid_page, total_isolated, false);
+
return total_isolated;
}
* a free page).
*/
unsigned long
-isolate_freepages_range(unsigned long start_pfn, unsigned long end_pfn)
+isolate_freepages_range(struct compact_control *cc,
+ unsigned long start_pfn, unsigned long end_pfn)
{
unsigned long isolated, pfn, block_end_pfn;
- struct zone *zone = NULL;
LIST_HEAD(freelist);
- /* cc needed for isolate_freepages_block to acquire zone->lock */
- struct compact_control cc = {
- .sync = true,
- };
-
- if (pfn_valid(start_pfn))
- cc.zone = zone = page_zone(pfn_to_page(start_pfn));
-
for (pfn = start_pfn; pfn < end_pfn; pfn += isolated) {
- if (!pfn_valid(pfn) || zone != page_zone(pfn_to_page(pfn)))
+ if (!pfn_valid(pfn) || cc->zone != page_zone(pfn_to_page(pfn)))
break;
/*
block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
block_end_pfn = min(block_end_pfn, end_pfn);
- isolated = isolate_freepages_block(&cc, pfn, block_end_pfn,
+ isolated = isolate_freepages_block(cc, pfn, block_end_pfn,
&freelist, true);
/*
* @cc: Compaction control structure.
* @low_pfn: The first PFN of the range.
* @end_pfn: The one-past-the-last PFN of the range.
+ * @unevictable: true if it allows to isolate unevictable pages
*
* Isolate all pages that can be migrated from the range specified by
* [low_pfn, end_pfn). Returns zero if there is a fatal signal
*/
unsigned long
isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
- unsigned long low_pfn, unsigned long end_pfn)
+ unsigned long low_pfn, unsigned long end_pfn, bool unevictable)
{
unsigned long last_pageblock_nr = 0, pageblock_nr;
unsigned long nr_scanned = 0, nr_isolated = 0;
struct lruvec *lruvec;
unsigned long flags;
bool locked = false;
+ struct page *page = NULL, *valid_page = NULL;
/*
* Ensure that there are not too many pages isolated from the LRU
/* Time to isolate some pages for migration */
cond_resched();
for (; low_pfn < end_pfn; low_pfn++) {
- struct page *page;
-
/* give a chance to irqs before checking need_resched() */
if (locked && !((low_pfn+1) % SWAP_CLUSTER_MAX)) {
if (should_release_lock(&zone->lru_lock)) {
if (page_zone(page) != zone)
continue;
+ if (!valid_page)
+ valid_page = page;
+
+ /* If isolation recently failed, do not retry */
+ pageblock_nr = low_pfn >> pageblock_order;
+ if (!isolation_suitable(cc, page))
+ goto next_pageblock;
+
/* Skip if free */
if (PageBuddy(page))
continue;
* migration is optimistic to see if the minimum amount of work
* satisfies the allocation
*/
- pageblock_nr = low_pfn >> pageblock_order;
if (!cc->sync && last_pageblock_nr != pageblock_nr &&
!migrate_async_suitable(get_pageblock_migratetype(page))) {
+ cc->finished_update_migrate = true;
goto next_pageblock;
}
if (!cc->sync)
mode |= ISOLATE_ASYNC_MIGRATE;
+ if (unevictable)
+ mode |= ISOLATE_UNEVICTABLE;
+
lruvec = mem_cgroup_page_lruvec(page, zone);
/* Try isolate the page */
VM_BUG_ON(PageTransCompound(page));
/* Successfully isolated */
+ cc->finished_update_migrate = true;
del_page_from_lru_list(page, lruvec, page_lru(page));
list_add(&page->lru, migratelist);
cc->nr_migratepages++;
if (locked)
spin_unlock_irqrestore(&zone->lru_lock, flags);
+ /* Update the pageblock-skip if the whole pageblock was scanned */
+ if (low_pfn == end_pfn)
+ update_pageblock_skip(cc, valid_page, nr_isolated, true);
+
trace_mm_compaction_isolate_migratepages(nr_scanned, nr_isolated);
return low_pfn;
if (!suitable_migration_target(page))
continue;
+ /* If isolation recently failed, do not retry */
+ if (!isolation_suitable(cc, page))
+ continue;
+
/* Found a block suitable for isolating free pages from */
isolated = 0;
end_pfn = min(pfn + pageblock_nr_pages, zone_end_pfn);
* looking for free pages, the search will restart here as
* page migration may have returned some pages to the allocator
*/
- if (isolated)
+ if (isolated) {
+ cc->finished_update_free = true;
high_pfn = max(high_pfn, pfn);
+ }
}
/* split_free_page does not map the pages */
}
/* Perform the isolation */
- low_pfn = isolate_migratepages_range(zone, cc, low_pfn, end_pfn);
+ low_pfn = isolate_migratepages_range(zone, cc, low_pfn, end_pfn, false);
if (!low_pfn || cc->contended)
return ISOLATE_ABORT;
return COMPACT_PARTIAL;
/* Compaction run completes if the migrate and free scanner meet */
- if (cc->free_pfn <= cc->migrate_pfn)
+ if (cc->free_pfn <= cc->migrate_pfn) {
+ /*
+ * Mark that the PG_migrate_skip information should be cleared
+ * by kswapd when it goes to sleep. kswapd does not set the
+ * flag itself as the decision to be clear should be directly
+ * based on an allocation request.
+ */
+ if (!current_is_kswapd())
+ zone->compact_blockskip_flush = true;
+
return COMPACT_COMPLETE;
+ }
/*
* order == -1 is expected when compacting via
static int compact_zone(struct zone *zone, struct compact_control *cc)
{
int ret;
+ unsigned long start_pfn = zone->zone_start_pfn;
+ unsigned long end_pfn = zone->zone_start_pfn + zone->spanned_pages;
ret = compaction_suitable(zone, cc->order);
switch (ret) {
;
}
- /* Setup to move all movable pages to the end of the zone */
- cc->migrate_pfn = zone->zone_start_pfn;
- cc->free_pfn = cc->migrate_pfn + zone->spanned_pages;
- cc->free_pfn &= ~(pageblock_nr_pages-1);
+ /*
+ * Setup to move all movable pages to the end of the zone. Used cached
+ * information on where the scanners should start but check that it
+ * is initialised by ensuring the values are within zone boundaries.
+ */
+ cc->migrate_pfn = zone->compact_cached_migrate_pfn;
+ cc->free_pfn = zone->compact_cached_free_pfn;
+ if (cc->free_pfn < start_pfn || cc->free_pfn > end_pfn) {
+ cc->free_pfn = end_pfn & ~(pageblock_nr_pages-1);
+ zone->compact_cached_free_pfn = cc->free_pfn;
+ }
+ if (cc->migrate_pfn < start_pfn || cc->migrate_pfn > end_pfn) {
+ cc->migrate_pfn = start_pfn;
+ zone->compact_cached_migrate_pfn = cc->migrate_pfn;
+ }
+
+ /*
+ * Clear pageblock skip if there were failures recently and compaction
+ * is about to be retried after being deferred. kswapd does not do
+ * this reset as it'll reset the cached information when going to sleep.
+ */
+ if (compaction_restarting(zone, cc->order) && !current_is_kswapd())
+ __reset_isolation_suitable(zone);
migrate_prep_local();
projects / cascardo / linux.git / blobdiff