Hi,
Since I am responsible for messing up some aspects of vm
(when fixing others)
here is a patch that tries to solve the introduced problems.
* no more periodic wake up of kswapd - not needed anymore
* no more freeing all zones to (free_pages > pages_high)
* always wakes kswapd up after try_to_free_pages
* always wakes kswapd up when (free_pages < pages_low)
* remove keep_kswapd_awake() function - not needed anymore
/RogerL
Note: Includes Riels "[PATCH] 2.4.0-test4 kswapd rebalancing fix"
-- Home page: http://www.norran.net/nra02596/
--- linux/mm/vmscan.c.orig Sat Jul 15 23:44:34 2000 +++ linux/mm/vmscan.c Sun Jul 16 00:57:00 2000 @@ -439,26 +439,6 @@ static inline int memory_pressure(void) return 0; } -/* - * Check if there recently has been memory pressure (zone_wake_kswapd) - */ -static inline int keep_kswapd_awake(void) -{ - pg_data_t *pgdat = pgdat_list; - - do { - int i; - for(i = 0; i < MAX_NR_ZONES; i++) { - zone_t *zone = pgdat->node_zones+ i; - if (zone->size && - zone->zone_wake_kswapd) - return 1; - } - pgdat = pgdat->node_next; - } while (pgdat); - - return 0; -} /* * We need to make the locks finer granularity, but right @@ -499,7 +479,7 @@ static int do_try_to_free_pages(unsigned /* not (been) low on memory - it is * pointless to try to swap out. */ - if (!keep_kswapd_awake()) + if (!memory_pressure()) goto done; /* Try to get rid of some shared memory pages.. */ @@ -520,7 +500,7 @@ static int do_try_to_free_pages(unsigned * if (count <= 0) * goto done; */ - if (!keep_kswapd_awake()) + if (!memory_pressure()) goto done; while (shm_swap(priority, gfp_mask)) { @@ -595,11 +575,8 @@ int kswapd(void *unused) tsk->flags |= PF_MEMALLOC; for (;;) { - if (!keep_kswapd_awake()) { - /* wake up regulary to do an early attempt too free - * pages - pages will not actually be freed. - */ - interruptible_sleep_on_timeout(&kswapd_wait, HZ); + if (!memory_pressure()) { + interruptible_sleep_on(&kswapd_wait); } do_try_to_free_pages(GFP_KSWAPD); @@ -631,18 +608,18 @@ int try_to_free_pages(unsigned int gfp_m retval = do_try_to_free_pages(gfp_mask); current->flags &= ~PF_MEMALLOC; } - else { - /* make sure kswapd runs */ - if (waitqueue_active(&kswapd_wait)) - wake_up_interruptible(&kswapd_wait); - } + + /* someone needed memory that kswapd had not provided + * make sure kswapd runs, should not happen often */ + if (waitqueue_active(&kswapd_wait)) + wake_up_interruptible(&kswapd_wait); return retval; } static int __init kswapd_init(void) { - printk("Starting kswapd v1.6\n"); + printk("Starting kswapd v1.7\n"); swap_setup(); kernel_thread(kswapd, NULL, CLONE_FS | CLONE_FILES | CLONE_SIGHAND); return 0; --- linux/mm/page_alloc.c.orig Sat Jul 15 23:44:46 2000 +++ linux/mm/page_alloc.c Sat Jul 15 23:55:55 2000 @@ -275,8 +275,16 @@ struct page * __alloc_pages(zonelist_t * break; if (!z->low_on_memory) { struct page *page = rmqueue(z, order); - if (z->free_pages < z->pages_min) + if (z->free_pages < z->pages_min) { z->low_on_memory = 1; + /* Suppose all zones have zone_wake_kswapd set + * but kswapd has stopped running due to + * no memory_pressure() + */ + z->zone_wake_kswapd = 1; /* should be set already */ + if (waitqueue_active(&kswapd_wait)) + wake_up_interruptible(&kswapd_wait); + } if (page) return page; }
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This archive was generated by hypermail 2b29 : Sat Jul 15 2000 - 21:00:22 EST