Messages in this thread Patch in this message | | | From | Nikita Danilov <> | Date | Sun, 21 Nov 2004 18:44:12 +0300 | Subject | [PATCH]: 2/4 mm/swap.c cleanup |
| |
Add pagevec_for_each_page() macro to iterate over all pages in a pagevec. Non-trivial part is to keep track of page zone and relock zone->lru_lock when switching to new zone.
This simplifies functions in mm/swap.c that process pages from pvec in a batch.
(Patch is for 2.6.10-rc2)
Signed-off-by: Nikita Danilov <nikita@clusterfs.com>
include/linux/pagevec.h | 45 +++++++++++++++++++++++++++++++++++++++++++ mm/swap.c | 50 +++++++++--------------------------------------- 2 files changed, 55 insertions(+), 40 deletions(-)
diff -puN include/linux/pagevec.h~pvec-cleanup include/linux/pagevec.h --- bk-linux/include/linux/pagevec.h~pvec-cleanup 2004-11-21 17:01:02.606535952 +0300 +++ bk-linux-nikita/include/linux/pagevec.h 2004-11-21 17:01:02.611535192 +0300 @@ -83,3 +83,48 @@ static inline void pagevec_lru_add(struc if (pagevec_count(pvec)) __pagevec_lru_add(pvec); } + +/* + * Helper macro for pagevec_for_each_page(). This is called on each + * iteration before entering loop body. Checks if we are switching to + * the new zone so that ->lru_lock should be re-taken. + */ +#define __guardloop(_v, _i, _p, _z) \ +({ \ + struct zone *pagezone; \ + \ + _p = (_v)->pages[i]; \ + pagezone = page_zone(_p); \ + \ + if (pagezone != (_z)) { \ + if (_z) \ + spin_unlock_irq(&(_z)->lru_lock); \ + _z = pagezone; \ + spin_lock_irq(&(_z)->lru_lock); \ + } \ +}) + +/* + * Helper macro for pagevec_for_each_page(). This is called after last + * iteration to release zone->lru_lock if necessary. + */ +#define __postloop(_v, _i, _p, _z) \ +({ \ + if ((_z) != NULL) \ + spin_unlock_irq(&(_z)->lru_lock); \ +}) + +/* + * Macro to iterate over all pages in pvec. Body of a loop is invoked with + * page's zone ->lru_lock held. This is used by various function in mm/swap.c + * to batch per-page operations that whould otherwise had to acquire hot + * zone->lru_lock for each page. + * + * This uses ugly preprocessor magic, but that's what preprocessor is all + * about. + */ +#define pagevec_for_each_page(_v, _i, _p, _z) \ +for (_i = 0, _z = NULL; \ + ((_i) < pagevec_count(_v) && (__guardloop(_v, _i, _p, _z), 1)) || \ + (__postloop(_v, _i, _p, _z), 0); \ + (_i)++) diff -puN mm/swap.c~pvec-cleanup mm/swap.c --- bk-linux/mm/swap.c~pvec-cleanup 2004-11-21 17:01:02.609535496 +0300 +++ bk-linux-nikita/mm/swap.c 2004-11-21 17:01:02.611535192 +0300 @@ -116,19 +116,11 @@ void fastcall activate_page(struct page static void __pagevec_mark_accessed(struct pagevec *pvec) { int i; - struct zone *zone = NULL; + struct zone *zone; + struct page *page; - for (i = 0; i < pagevec_count(pvec); i++) { - struct page *page = pvec->pages[i]; - struct zone *pagezone = page_zone(page); - - if (pagezone != zone) { - if (zone) - local_unlock_irq(&zone->lru_lock); - zone = pagezone; - local_lock_irq(&zone->lru_lock); - } - if (!PageActive(page) && PageReferenced(page) && PageLRU(page)) { + pagevec_for_each_page(pvec, i, page, zone) { + if (!PageActive(page) && PageReferenced(page) && PageLRU(page)){ del_page_from_inactive_list(zone, page); SetPageActive(page); add_page_to_active_list(zone, page); @@ -138,8 +130,6 @@ static void __pagevec_mark_accessed(stru SetPageReferenced(page); } } - if (zone) - local_unlock_irq(&zone->lru_lock); release_pages(pvec->pages, pvec->nr, pvec->cold); pagevec_reinit(pvec); } @@ -322,25 +312,15 @@ void __pagevec_release_nonlru(struct pag void __pagevec_lru_add(struct pagevec *pvec) { int i; - struct zone *zone = NULL; - - for (i = 0; i < pagevec_count(pvec); i++) { - struct page *page = pvec->pages[i]; - struct zone *pagezone = page_zone(page); + struct page *page; + struct zone *zone; - if (pagezone != zone) { - if (zone) - spin_unlock_irq(&zone->lru_lock); - zone = pagezone; - spin_lock_irq(&zone->lru_lock); - } + pagevec_for_each_page(pvec, i, page, zone) { if (TestSetPageLRU(page)) BUG(); ClearPageSkipped(page); add_page_to_inactive_list(zone, page); } - if (zone) - spin_unlock_irq(&zone->lru_lock); release_pages(pvec->pages, pvec->nr, pvec->cold); pagevec_reinit(pvec); } @@ -350,26 +330,16 @@ EXPORT_SYMBOL(__pagevec_lru_add); void __pagevec_lru_add_active(struct pagevec *pvec) { int i; - struct zone *zone = NULL; - - for (i = 0; i < pagevec_count(pvec); i++) { - struct page *page = pvec->pages[i]; - struct zone *pagezone = page_zone(page); + struct page *page; + struct zone *zone; - if (pagezone != zone) { - if (zone) - spin_unlock_irq(&zone->lru_lock); - zone = pagezone; - spin_lock_irq(&zone->lru_lock); - } + pagevec_for_each_page(pvec, i, page, zone) { if (TestSetPageLRU(page)) BUG(); if (TestSetPageActive(page)) BUG(); add_page_to_active_list(zone, page); } - if (zone) - spin_unlock_irq(&zone->lru_lock); release_pages(pvec->pages, pvec->nr, pvec->cold); pagevec_reinit(pvec); } _ - 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/
| |