From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 3 Nov 2007 18:54:47 -0400 From: Rik van Riel Subject: [RFC PATCH 2/10] free swap space entries if vm_swap_full() Message-ID: <20071103185447.358b9c4a@bree.surriel.com> In-Reply-To: <20071103184229.3f20e2f0@bree.surriel.com> References: <20071103184229.3f20e2f0@bree.surriel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org List-ID: Rik van Riel's patch to free swap space on swap-in/activiation, forward ported by Lee Schermerhorn. Against: 2.6.23-rc2-mm2 atop: + lts' convert anon_vma list lock to reader/write lock patch + Nick Piggin's move and rework isolate_lru_page() patch Patch Description: quick attempt by lts 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 include/linux/pagevec.h | 1 + mm/swap.c | 18 ++++++++++++++++++ mm/vmscan.c | 16 +++++++++++----- 3 files changed, 30 insertions(+), 5 deletions(-) Index: linux-2.6.23-rc6-mm1/mm/vmscan.c =================================================================== --- linux-2.6.23-rc6-mm1.orig/mm/vmscan.c 2007-09-25 15:20:05.000000000 -0400 +++ linux-2.6.23-rc6-mm1/mm/vmscan.c 2007-09-25 15:25:04.000000000 -0400 @@ -613,6 +613,9 @@ 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: @@ -1142,14 +1145,13 @@ force_reclaim_mapped: } } __mod_zone_page_state(zone, NR_INACTIVE, pgmoved); + spin_unlock_irq(&zone->lru_lock); pgdeactivate += pgmoved; - if (buffer_heads_over_limit) { - spin_unlock_irq(&zone->lru_lock); - pagevec_strip(&pvec); - spin_lock_irq(&zone->lru_lock); - } + if (buffer_heads_over_limit) + pagevec_strip(&pvec); pgmoved = 0; + spin_lock_irq(&zone->lru_lock); while (!list_empty(&l_active)) { page = lru_to_page(&l_active); prefetchw_prev_lru_page(page, &l_active, flags); @@ -1163,6 +1165,8 @@ force_reclaim_mapped: __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); } @@ -1172,6 +1176,8 @@ force_reclaim_mapped: __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-2.6.23-rc6-mm1/mm/swap.c =================================================================== --- linux-2.6.23-rc6-mm1.orig/mm/swap.c 2007-09-25 15:20:05.000000000 -0400 +++ linux-2.6.23-rc6-mm1/mm/swap.c 2007-09-25 15:22:51.000000000 -0400 @@ -421,6 +421,24 @@ 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-2.6.23-rc6-mm1/include/linux/pagevec.h =================================================================== --- linux-2.6.23-rc6-mm1.orig/include/linux/pagevec.h 2007-09-25 15:20:02.000000000 -0400 +++ linux-2.6.23-rc6-mm1/include/linux/pagevec.h 2007-09-25 15:22:51.000000000 -0400 @@ -26,6 +26,7 @@ void __pagevec_free(struct pagevec *pvec void __pagevec_lru_add(struct pagevec *pvec); void __pagevec_lru_add_active(struct pagevec *pvec); 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, -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org