Messages in this thread Patch in this message | | | Date | Fri, 30 Jan 2004 15:44:12 +1100 | From | Nick Piggin <> | Subject | Re: [PATCH][CFT] mm swapping improvements |
| |
Nick Piggin wrote:
> Hi list, > > Attached is a patchset against 2.6.2-rc2-mm1 which includes two of > Nikita's patches and one of my own, and backs out the RSS limit patch > due to some problems (discussion of these patches on linux-mm). > The patchset improves VM performance under swapping quite significantly > for kbuild - its now close 2.4 or better in some cases. > > I haven't done many other tests so I would like anyone who's had > swapping related slowdowns when moving from 2.4 to 2.6, and is > interested in helping improve it to test out the patch please. > I can make a patch against the -linus kernel if anyone would like. > > Some benchmarks: http://www.kerneltrap.org/~npiggin/vm/3/ > Green is 2.6, red is 2.4, purple is 2.6 with this patch. >
OK here is the patch for 2.6.2-rc2. Only compile tested but there isn't much difference between -linus and -mm in this area so it should be fine.
linux-2.6-npiggin/include/linux/mmzone.h | 6 + linux-2.6-npiggin/mm/page_alloc.c | 20 ++++ linux-2.6-npiggin/mm/vmscan.c | 152 +++++++++++++++++++------------ 3 files changed, 124 insertions(+), 54 deletions(-)
diff -puN include/linux/mmzone.h~rollup include/linux/mmzone.h --- linux-2.6/include/linux/mmzone.h~rollup 2004-01-30 15:40:02.000000000 +1100 +++ linux-2.6-npiggin/include/linux/mmzone.h 2004-01-30 15:40:02.000000000 +1100 @@ -149,6 +149,12 @@ struct zone { unsigned long zone_start_pfn; /* + * dummy page used as place holder during scanning of + * active_list in refill_inactive_zone() + */ + struct page *scan_page; + + /* * rarely used fields: */ char *name; diff -puN mm/page_alloc.c~rollup mm/page_alloc.c --- linux-2.6/mm/page_alloc.c~rollup 2004-01-30 15:40:02.000000000 +1100 +++ linux-2.6-npiggin/mm/page_alloc.c 2004-01-30 15:40:02.000000000 +1100 @@ -1230,6 +1230,9 @@ void __init memmap_init_zone(struct page memmap_init_zone((start), (size), (nid), (zone), (start_pfn)) #endif +/* dummy pages used to scan active lists */ +static struct page scan_pages[MAX_NUMNODES][MAX_NR_ZONES]; + /* * Set up the zone data structures: * - mark all pages reserved @@ -1252,6 +1255,7 @@ static void __init free_area_init_core(s struct zone *zone = pgdat->node_zones + j; unsigned long size, realsize; unsigned long batch; + struct page *scan_page; zone_table[NODEZONE(nid, j)] = zone; realsize = size = zones_size[j]; @@ -1306,6 +1310,22 @@ static void __init free_area_init_core(s atomic_set(&zone->refill_counter, 0); zone->nr_active = 0; zone->nr_inactive = 0; + + /* initialize dummy page used for scanning */ + scan_page = &scan_pages[nid][j]; + zone->scan_page = scan_page; + memset(scan_page, 0, sizeof *scan_page); + scan_page->flags = + (1 << PG_locked) | + (1 << PG_error) | + (1 << PG_lru) | + (1 << PG_active) | + (1 << PG_reserved); + set_page_zone(scan_page, j); + page_cache_get(scan_page); + INIT_LIST_HEAD(&scan_page->list); + list_add(&scan_page->lru, &zone->active_list); + if (!size) continue; diff -puN mm/vmscan.c~rollup mm/vmscan.c --- linux-2.6/mm/vmscan.c~rollup 2004-01-30 15:40:02.000000000 +1100 +++ linux-2.6-npiggin/mm/vmscan.c 2004-01-30 15:40:02.000000000 +1100 @@ -43,14 +43,15 @@ int vm_swappiness = 60; static long total_memory; +#define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru)) + #ifdef ARCH_HAS_PREFETCH #define prefetch_prev_lru_page(_page, _base, _field) \ do { \ if ((_page)->lru.prev != _base) { \ struct page *prev; \ \ - prev = list_entry(_page->lru.prev, \ - struct page, lru); \ + prev = lru_to_page(&(_page)->lru); \ prefetch(&prev->_field); \ } \ } while (0) @@ -64,8 +65,7 @@ static long total_memory; if ((_page)->lru.prev != _base) { \ struct page *prev; \ \ - prev = list_entry(_page->lru.prev, \ - struct page, lru); \ + prev = lru_to_page(&(_page)->lru); \ prefetchw(&prev->_field); \ } \ } while (0) @@ -260,7 +260,7 @@ shrink_list(struct list_head *page_list, int may_enter_fs; int referenced; - page = list_entry(page_list->prev, struct page, lru); + page = lru_to_page(page_list); list_del(&page->lru); if (TestSetPageLocked(page)) @@ -504,8 +504,7 @@ shrink_cache(const int nr_pages, struct while (nr_scan++ < nr_to_process && !list_empty(&zone->inactive_list)) { - page = list_entry(zone->inactive_list.prev, - struct page, lru); + page = lru_to_page(&zone->inactive_list); prefetchw_prev_lru_page(page, &zone->inactive_list, flags); @@ -543,7 +542,7 @@ shrink_cache(const int nr_pages, struct * Put back any unfreeable pages. */ while (!list_empty(&page_list)) { - page = list_entry(page_list.prev, struct page, lru); + page = lru_to_page(&page_list); if (TestSetPageLRU(page)) BUG(); list_del(&page->lru); @@ -564,6 +563,39 @@ done: return ret; } + +/* move pages from @page_list to the @spot, that should be somewhere on the + * @zone->active_list */ +static int +spill_on_spot(struct zone *zone, + struct list_head *page_list, struct list_head *spot, + struct pagevec *pvec) +{ + struct page *page; + int moved; + + moved = 0; + while (!list_empty(page_list)) { + page = lru_to_page(page_list); + prefetchw_prev_lru_page(page, page_list, flags); + if (TestSetPageLRU(page)) + BUG(); + BUG_ON(!PageActive(page)); + list_move(&page->lru, spot); + moved++; + if (!pagevec_add(pvec, page)) { + zone->nr_active += moved; + moved = 0; + spin_unlock_irq(&zone->lru_lock); + __pagevec_release(pvec); + spin_lock_irq(&zone->lru_lock); + } + } + return moved; +} + + + /* * This moves pages from the active list to the inactive list. * @@ -590,37 +622,18 @@ refill_inactive_zone(struct zone *zone, int nr_pages = nr_pages_in; LIST_HEAD(l_hold); /* The pages which were snipped off */ LIST_HEAD(l_inactive); /* Pages to go onto the inactive_list */ - LIST_HEAD(l_active); /* Pages to go onto the active_list */ + LIST_HEAD(l_ignore); /* Pages to be returned to the active_list */ + LIST_HEAD(l_active); /* Pages to go onto the head of the + * active_list */ + struct page *page; + struct page *scan; struct pagevec pvec; int reclaim_mapped = 0; long mapped_ratio; long distress; long swap_tendency; - lru_add_drain(); - pgmoved = 0; - spin_lock_irq(&zone->lru_lock); - while (nr_pages && !list_empty(&zone->active_list)) { - page = list_entry(zone->active_list.prev, struct page, lru); - prefetchw_prev_lru_page(page, &zone->active_list, flags); - if (!TestClearPageLRU(page)) - BUG(); - list_del(&page->lru); - if (page_count(page) == 0) { - /* It is currently in pagevec_release() */ - SetPageLRU(page); - list_add(&page->lru, &zone->active_list); - } else { - page_cache_get(page); - list_add(&page->lru, &l_hold); - pgmoved++; - } - nr_pages--; - } - zone->nr_active -= pgmoved; - spin_unlock_irq(&zone->lru_lock); - /* * `distress' is a measure of how much trouble we're having reclaiming * pages. 0 -> no problems. 100 -> great trouble. @@ -652,10 +665,59 @@ refill_inactive_zone(struct zone *zone, if (swap_tendency >= 100) reclaim_mapped = 1; + scan = zone->scan_page; + lru_add_drain(); + pgmoved = 0; + spin_lock_irq(&zone->lru_lock); + if (reclaim_mapped) { + /* + * When scanning active_list with !reclaim_mapped mapped + * inactive pages are left behind zone->scan_page. If zone is + * switched to reclaim_mapped mode reset zone->scan_page to + * the end of inactive list so that inactive mapped pages are + * re-scanned. + */ + list_move_tail(&scan->lru, &zone->active_list); + } + while (nr_pages && zone->active_list.prev != zone->active_list.next) { + /* + * if head of active list reached---wrap to the tail + */ + if (scan->lru.prev == &zone->active_list) + list_move_tail(&scan->lru, &zone->active_list); + page = lru_to_page(&scan->lru); + prefetchw_prev_lru_page(page, &zone->active_list, flags); + if (!TestClearPageLRU(page)) + BUG(); + list_del(&page->lru); + if (page_count(page) == 0) { + /* It is currently in pagevec_release() */ + SetPageLRU(page); + list_add(&page->lru, &zone->active_list); + } else { + page_cache_get(page); + list_add(&page->lru, &l_hold); + pgmoved++; + } + nr_pages--; + } + zone->nr_active -= pgmoved; + spin_unlock_irq(&zone->lru_lock); + while (!list_empty(&l_hold)) { - page = list_entry(l_hold.prev, struct page, lru); + page = lru_to_page(&l_hold); list_del(&page->lru); if (page_mapped(page)) { + + if (!reclaim_mapped) { + list_add(&page->lru, &l_ignore); + continue; + } + + /* + * probably it would be useful to transfer dirty bit + * from pte to the @page here. + */ pte_chain_lock(page); if (page_mapped(page) && page_referenced(page)) { pte_chain_unlock(page); @@ -663,10 +725,6 @@ refill_inactive_zone(struct zone *zone, continue; } pte_chain_unlock(page); - if (!reclaim_mapped) { - list_add(&page->lru, &l_active); - continue; - } } /* * FIXME: need to consider page_count(page) here if/when we @@ -684,7 +742,7 @@ refill_inactive_zone(struct zone *zone, pgmoved = 0; spin_lock_irq(&zone->lru_lock); while (!list_empty(&l_inactive)) { - page = list_entry(l_inactive.prev, struct page, lru); + page = lru_to_page(&l_inactive); prefetchw_prev_lru_page(page, &l_inactive, flags); if (TestSetPageLRU(page)) BUG(); @@ -711,23 +769,9 @@ refill_inactive_zone(struct zone *zone, spin_lock_irq(&zone->lru_lock); } - pgmoved = 0; - while (!list_empty(&l_active)) { - page = list_entry(l_active.prev, struct page, lru); - prefetchw_prev_lru_page(page, &l_active, flags); - if (TestSetPageLRU(page)) - BUG(); - BUG_ON(!PageActive(page)); - list_move(&page->lru, &zone->active_list); - pgmoved++; - if (!pagevec_add(&pvec, page)) { + pgmoved = spill_on_spot(zone, &l_active, &zone->active_list, &pvec); zone->nr_active += pgmoved; - pgmoved = 0; - spin_unlock_irq(&zone->lru_lock); - __pagevec_release(&pvec); - spin_lock_irq(&zone->lru_lock); - } - } + pgmoved = spill_on_spot(zone, &l_ignore, &scan->lru, &pvec); zone->nr_active += pgmoved; spin_unlock_irq(&zone->lru_lock); pagevec_release(&pvec); _
| |