From: Martin Hicks <mort@sgi.com>
The patches introduce two different ways to free up page cache from a node:
manually through a syscall and automatically through flag modifiers to a
mempolicy.
Currently if a job is started and there is page cache lying around on a
particular node then allocations will spill onto remote nodes and page cache
won't be reclaimed until the whole system is short on memory. This can result
in a signficiant performance hit for HPC applications that planned on that
memory being allocated locally.
Just a refactoring patch that sticks a list of pages back onto the appropriate
LRU lists. This is used to return pages to the LRU lists after processing
them outside the LRU lock.
Signed-off-by: Martin Hicks <mort@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
mm/vmscan.c | 62 ++++++++++++++++++++++++++++++++++++------------------------
1 files changed, 38 insertions(+), 24 deletions(-)
diff -puN mm/vmscan.c~vm-merge_lru_pages mm/vmscan.c
--- 25/mm/vmscan.c~vm-merge_lru_pages Wed Apr 27 16:37:37 2005
+++ 25-akpm/mm/vmscan.c Wed Apr 27 16:37:37 2005
@@ -605,20 +605,50 @@ static int isolate_lru_pages(int nr_to_s
}
/*
+ * This is the opposite of isolate_lru_pages(). It puts the
+ * pages in @list back onto the lru lists in @zone.
+ */
+void merge_lru_pages(struct zone *zone, struct list_head *list)
+{
+ struct page *page;
+ struct pagevec pvec;
+
+ BUG_ON(zone == NULL);
+ BUG_ON(list == NULL);
+
+ pagevec_init(&pvec, 1);
+
+ while (!list_empty(list)) {
+ page = lru_to_page(list);
+ if (TestSetPageLRU(page))
+ BUG();
+ list_del(&page->lru);
+ if (PageActive(page))
+ add_page_to_active_list(zone, page);
+ else
+ add_page_to_inactive_list(zone, page);
+ if (!pagevec_add(&pvec, page)) {
+ spin_unlock_irq(&zone->lru_lock);
+ __pagevec_release(&pvec);
+ spin_lock_irq(&zone->lru_lock);
+ }
+ }
+ spin_unlock_irq(&zone->lru_lock);
+ pagevec_release(&pvec);
+ spin_lock_irq(&zone->lru_lock);
+}
+
+/*
* shrink_cache() adds the number of pages reclaimed to sc->nr_reclaimed
*/
static void shrink_cache(struct zone *zone, struct scan_control *sc)
{
LIST_HEAD(page_list);
- struct pagevec pvec;
int max_scan = sc->nr_to_scan;
- pagevec_init(&pvec, 1);
-
lru_add_drain();
spin_lock_irq(&zone->lru_lock);
while (max_scan > 0) {
- struct page *page;
int nr_taken;
int nr_scan;
int nr_freed;
@@ -631,7 +661,7 @@ static void shrink_cache(struct zone *zo
spin_unlock_irq(&zone->lru_lock);
if (nr_taken == 0)
- goto done;
+ return;
max_scan -= nr_scan;
if (current_is_kswapd())
@@ -644,29 +674,13 @@ static void shrink_cache(struct zone *zo
mod_page_state_zone(zone, pgsteal, nr_freed);
sc->nr_to_reclaim -= nr_freed;
- spin_lock_irq(&zone->lru_lock);
/*
* Put back any unfreeable pages.
*/
- while (!list_empty(&page_list)) {
- page = lru_to_page(&page_list);
- if (TestSetPageLRU(page))
- BUG();
- list_del(&page->lru);
- if (PageActive(page))
- add_page_to_active_list(zone, page);
- else
- add_page_to_inactive_list(zone, page);
- if (!pagevec_add(&pvec, page)) {
- spin_unlock_irq(&zone->lru_lock);
- __pagevec_release(&pvec);
- spin_lock_irq(&zone->lru_lock);
- }
- }
- }
+ spin_lock_irq(&zone->lru_lock);
+ merge_lru_pages(zone, &page_list);
+ }
spin_unlock_irq(&zone->lru_lock);
-done:
- pagevec_release(&pvec);
}
/*
_