Free swap cache entries when swapping in pages if vm_swap_full() [swap space > 1/2 used]. Uses new pagevec to reduce pressure on locks. Signed-off-by: Rik van Riel Signed-off-by: Lee Schermerhorn Index: linux-2.6.25-rc3-mm1/mm/vmscan.c =================================================================== --- linux-2.6.25-rc3-mm1.orig/mm/vmscan.c 2008-03-04 15:25:52.000000000 -0500 +++ linux-2.6.25-rc3-mm1/mm/vmscan.c 2008-03-04 15:29:50.000000000 -0500 @@ -632,6 +632,9 @@ free_it: continue; activate_locked: + /* Not a candidate for swapping, so reclaim swap space. */ + if (PageSwapCache(page) && vm_swap_full()) + remove_exclusive_swap_page(page); SetPageActive(page); pgactivate++; keep_locked: @@ -1216,6 +1219,8 @@ static void shrink_active_list(unsigned __mod_zone_page_state(zone, NR_ACTIVE, pgmoved); pgmoved = 0; spin_unlock_irq(&zone->lru_lock); + if (vm_swap_full()) + pagevec_swap_free(&pvec); __pagevec_release(&pvec); spin_lock_irq(&zone->lru_lock); } @@ -1225,6 +1230,8 @@ static void shrink_active_list(unsigned __count_zone_vm_events(PGREFILL, zone, pgscanned); __count_vm_events(PGDEACTIVATE, pgdeactivate); spin_unlock_irq(&zone->lru_lock); + if (vm_swap_full()) + pagevec_swap_free(&pvec); pagevec_release(&pvec); } Index: linux-2.6.25-rc3-mm1/mm/swap.c =================================================================== --- linux-2.6.25-rc3-mm1.orig/mm/swap.c 2008-03-04 15:28:39.000000000 -0500 +++ linux-2.6.25-rc3-mm1/mm/swap.c 2008-03-04 15:29:50.000000000 -0500 @@ -457,6 +457,24 @@ void pagevec_strip(struct pagevec *pvec) } } +/* + * Try to free swap space from the pages in a pagevec + */ +void pagevec_swap_free(struct pagevec *pvec) +{ + int i; + + for (i = 0; i < pagevec_count(pvec); i++) { + struct page *page = pvec->pages[i]; + + if (PageSwapCache(page) && !TestSetPageLocked(page)) { + if (PageSwapCache(page)) + remove_exclusive_swap_page(page); + unlock_page(page); + } + } +} + /** * pagevec_lookup - gang pagecache lookup * @pvec: Where the resulting pages are placed Index: linux-2.6.25-rc3-mm1/include/linux/pagevec.h =================================================================== --- linux-2.6.25-rc3-mm1.orig/include/linux/pagevec.h 2008-03-04 15:26:18.000000000 -0500 +++ linux-2.6.25-rc3-mm1/include/linux/pagevec.h 2008-03-04 15:29:50.000000000 -0500 @@ -25,6 +25,7 @@ void __pagevec_release_nonlru(struct pag void __pagevec_free(struct pagevec *pvec); void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru); void pagevec_strip(struct pagevec *pvec); +void pagevec_swap_free(struct pagevec *pvec); unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping, pgoff_t start, unsigned nr_pages); unsigned pagevec_lookup_tag(struct pagevec *pvec, -- All Rights Reversed -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/