From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with SMTP id A734A6B003D for ; Tue, 10 Feb 2009 05:57:03 -0500 (EST) Received: by yw-out-1718.google.com with SMTP id 9so520916ywk.26 for ; Tue, 10 Feb 2009 02:57:01 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20090210184055.6FCB.KOSAKI.MOTOHIRO@jp.fujitsu.com> References: <20090210184055.6FCB.KOSAKI.MOTOHIRO@jp.fujitsu.com> Date: Tue, 10 Feb 2009 19:57:01 +0900 Message-ID: <28c262360902100257o6a8e2374v42f1ae906c53bcec@mail.gmail.com> Subject: Re: [PATCH] mm: remove zone->prev_prioriy From: MinChan Kim Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: KAMEZAWA Hiroyuki , LKML , linux-mm , Rik van Riel , Andrew Morton List-ID: Hi, Kosaki-san. As you know, prev_priority is used as a measure of how much stress page reclaim. But now we doesn't need it due to split-lru's way. I think it would be better to remain why prev_priority isn't needed any more and how split-lru can replace prev_priority's role in changelog. In future, it help mm newbies understand change history, I think. On Tue, Feb 10, 2009 at 6:42 PM, KOSAKI Motohiro wrote: > > KAMEZAWA Hiroyuki sugessted to remove zone->prev_priority. > it's because Split-LRU VM doesn't use this parameter at all. > > > Signed-off-by: KOSAKI Motohiro > Cc: KAMEZAWA Hiroyuki > --- > include/linux/memcontrol.h | 27 ------------------------- > include/linux/mmzone.h | 15 -------------- > mm/memcontrol.c | 31 ----------------------------- > mm/page_alloc.c | 2 - > mm/vmscan.c | 48 ++------------------------------------------- > mm/vmstat.c | 2 - > 6 files changed, 3 insertions(+), 122 deletions(-) > > Index: b/mm/memcontrol.c > =================================================================== > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -150,8 +150,6 @@ struct mem_cgroup { > */ > spinlock_t reclaim_param_lock; > > - int prev_priority; /* for recording reclaim priority */ > - > /* > * While reclaiming in a hiearchy, we cache the last child we > * reclaimed from. Protected by hierarchy_mutex > @@ -464,35 +462,6 @@ int mem_cgroup_calc_mapped_ratio(struct > return (int)((rss * 100L) / total); > } > > -/* > - * prev_priority control...this will be used in memory reclaim path. > - */ > -int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem) > -{ > - int prev_priority; > - > - spin_lock(&mem->reclaim_param_lock); > - prev_priority = mem->prev_priority; > - spin_unlock(&mem->reclaim_param_lock); > - > - return prev_priority; > -} > - > -void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority) > -{ > - spin_lock(&mem->reclaim_param_lock); > - if (priority < mem->prev_priority) > - mem->prev_priority = priority; > - spin_unlock(&mem->reclaim_param_lock); > -} > - > -void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority) > -{ > - spin_lock(&mem->reclaim_param_lock); > - mem->prev_priority = priority; > - spin_unlock(&mem->reclaim_param_lock); > -} > - > static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages) > { > unsigned long active; > Index: b/mm/vmscan.c > =================================================================== > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -1174,20 +1174,6 @@ done: > } > > /* > - * We are about to scan this zone at a certain priority level. If that priority > - * level is smaller (ie: more urgent) than the previous priority, then note > - * that priority level within the zone. This is done so that when the next > - * process comes in to scan this zone, it will immediately start out at this > - * priority level rather than having to build up its own scanning priority. > - * Here, this priority affects only the reclaim-mapped threshold. > - */ > -static inline void note_zone_scanning_priority(struct zone *zone, int priority) > -{ > - if (priority < zone->prev_priority) > - zone->prev_priority = priority; > -} > - > -/* > * This moves pages from the active list to the inactive list. > * > * We move them the other way if the page is referenced by one or more > @@ -1553,22 +1539,18 @@ static void shrink_zones(int priority, s > if (scanning_global_lru(sc)) { > if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) > continue; > - note_zone_scanning_priority(zone, priority); > > if (zone_is_all_unreclaimable(zone) && > priority != DEF_PRIORITY) > continue; /* Let kswapd poll it */ > - sc->all_unreclaimable = 0; > + > } else { > /* > * Ignore cpuset limitation here. We just want to reduce > * # of used pages by us regardless of memory shortage. > */ > - sc->all_unreclaimable = 0; > - mem_cgroup_note_reclaim_priority(sc->mem_cgroup, > - priority); > } > - > + sc->all_unreclaimable = 0; > shrink_zone(priority, zone, sc); > } > } > @@ -1676,11 +1658,8 @@ out: > > if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) > continue; > - > - zone->prev_priority = priority; > } > - } else > - mem_cgroup_record_reclaim_priority(sc->mem_cgroup, priority); > + } > > delayacct_freepages_end(); > > @@ -1769,11 +1748,6 @@ static unsigned long balance_pgdat(pg_da > .mem_cgroup = NULL, > .isolate_pages = isolate_pages_global, > }; > - /* > - * temp_priority is used to remember the scanning priority at which > - * this zone was successfully refilled to free_pages == pages_high. > - */ > - int temp_priority[MAX_NR_ZONES]; > > loop_again: > total_scanned = 0; > @@ -1781,9 +1755,6 @@ loop_again: > sc.may_writepage = !laptop_mode; > count_vm_event(PAGEOUTRUN); > > - for (i = 0; i < pgdat->nr_zones; i++) > - temp_priority[i] = DEF_PRIORITY; > - > for (priority = DEF_PRIORITY; priority >= 0; priority--) { > int end_zone = 0; /* Inclusive. 0 = ZONE_DMA */ > unsigned long lru_pages = 0; > @@ -1854,9 +1825,7 @@ loop_again: > if (!zone_watermark_ok(zone, order, zone->pages_high, > end_zone, 0)) > all_zones_ok = 0; > - temp_priority[i] = priority; > sc.nr_scanned = 0; > - note_zone_scanning_priority(zone, priority); > /* > * We put equal pressure on every zone, unless one > * zone has way too many pages free already. > @@ -1903,16 +1872,6 @@ loop_again: > break; > } > out: > - /* > - * Note within each zone the priority level at which this zone was > - * brought into a happy state. So that the next thread which scans this > - * zone will start out at that priority level. > - */ > - for (i = 0; i < pgdat->nr_zones; i++) { > - struct zone *zone = pgdat->node_zones + i; > - > - zone->prev_priority = temp_priority[i]; > - } > if (!all_zones_ok) { > cond_resched(); > > @@ -2321,7 +2280,6 @@ static int __zone_reclaim(struct zone *z > */ > priority = ZONE_RECLAIM_PRIORITY; > do { > - note_zone_scanning_priority(zone, priority); > shrink_zone(priority, zone, &sc); > priority--; > } while (priority >= 0 && sc.nr_reclaimed < nr_pages); > Index: b/include/linux/mmzone.h > =================================================================== > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -337,21 +337,6 @@ struct zone { > atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS]; > > /* > - * prev_priority holds the scanning priority for this zone. It is > - * defined as the scanning priority at which we achieved our reclaim > - * target at the previous try_to_free_pages() or balance_pgdat() > - * invokation. > - * > - * We use prev_priority as a measure of how much stress page reclaim is > - * under - it drives the swappiness decision: whether to unmap mapped > - * pages. > - * > - * Access to both this field is quite racy even on uniprocessor. But > - * it is expected to average out OK. > - */ > - int prev_priority; > - > - /* > * The target ratio of ACTIVE_ANON to INACTIVE_ANON pages on > * this zone's LRU. Maintained by the pageout code. > */ > Index: b/mm/page_alloc.c > =================================================================== > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -3516,8 +3516,6 @@ static void __paginginit free_area_init_ > zone_seqlock_init(zone); > zone->zone_pgdat = pgdat; > > - zone->prev_priority = DEF_PRIORITY; > - > zone_pcp_init(zone); > for_each_lru(l) { > INIT_LIST_HEAD(&zone->lru[l].list); > Index: b/mm/vmstat.c > =================================================================== > --- a/mm/vmstat.c > +++ b/mm/vmstat.c > @@ -775,11 +775,9 @@ static void zoneinfo_show_print(struct s > } > seq_printf(m, > "\n all_unreclaimable: %u" > - "\n prev_priority: %i" > "\n start_pfn: %lu" > "\n inactive_ratio: %u", > zone_is_all_unreclaimable(zone), > - zone->prev_priority, > zone->zone_start_pfn, > zone->inactive_ratio); > seq_putc(m, '\n'); > Index: b/include/linux/memcontrol.h > =================================================================== > --- a/include/linux/memcontrol.h > +++ b/include/linux/memcontrol.h > @@ -88,14 +88,7 @@ extern void mem_cgroup_end_migration(str > /* > * For memory reclaim. > */ > -extern int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem); > extern long mem_cgroup_reclaim_imbalance(struct mem_cgroup *mem); > - > -extern int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem); > -extern void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, > - int priority); > -extern void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, > - int priority); > int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg); > unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg, > struct zone *zone, > @@ -209,31 +202,11 @@ static inline void mem_cgroup_end_migrat > { > } > > -static inline int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem) > -{ > - return 0; > -} > - > static inline int mem_cgroup_reclaim_imbalance(struct mem_cgroup *mem) > { > return 0; > } > > -static inline int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem) > -{ > - return 0; > -} > - > -static inline void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, > - int priority) > -{ > -} > - > -static inline void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, > - int priority) > -{ > -} > - > static inline bool mem_cgroup_disabled(void) > { > return true; > > > > -- > 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 > -- Kinds regards, MinChan Kim -- 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