Re: [PATCH 03/25] mm, vmscan: Move LRU lists to node

[Mel Gorman <mgorman@suse.de>]

On Thu, Jun 11, 2015 at 03:12:12PM +0800, Hillf Danton wrote:
> > @@ -774,6 +764,21 @@ typedef struct pglist_data {
> >  	ZONE_PADDING(_pad1_)
> >  	spinlock_t		lru_lock;
> > 
> > +	/* Fields commonly accessed by the page reclaim scanner */
> > +	struct lruvec		lruvec;
> > +
> > +	/* Evictions & activations on the inactive file list */
> > +	atomic_long_t		inactive_age;
> > +
> > +	/*
> > +	 * The target ratio of ACTIVE_ANON to INACTIVE_ANON pages on
> > +	 * this zone's LRU.  Maintained by the pageout code.
> > +	 */
> 
> The comment has to be updated.
> 

Yes it does. Fixed.

> > +	unsigned int inactive_ratio;
> > +
> > +	unsigned long		flags;
> > +
> > +	ZONE_PADDING(_pad2_)
> >  	struct per_cpu_nodestat __percpu *per_cpu_nodestats;
> >  	atomic_long_t		vm_stat[NR_VM_NODE_STAT_ITEMS];
> >  } pg_data_t;
> > @@ -1185,7 +1185,7 @@ struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
> >  	struct lruvec *lruvec;
> > 
> >  	if (mem_cgroup_disabled()) {
> > -		lruvec = &zone->lruvec;
> > +		lruvec = zone_lruvec(zone);
> >  		goto out;
> >  	}
> > 
> > @@ -1197,8 +1197,8 @@ out:
> >  	 * we have to be prepared to initialize lruvec->zone here;
> >  	 * and if offlined then reonlined, we need to reinitialize it.
> >  	 */
> > -	if (unlikely(lruvec->zone != zone))
> > -		lruvec->zone = zone;
> > +	if (unlikely(lruvec->pgdat != zone->zone_pgdat))
> > +		lruvec->pgdat = zone->zone_pgdat;
> 
> See below please.
> 
> >  	return lruvec;
> >  }
> > 
> > @@ -1211,14 +1211,14 @@ out:
> >   * and putback protocol: the LRU lock must be held, and the page must
> >   * either be PageLRU() or the caller must have isolated/allocated it.
> >   */
> > -struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct zone *zone)
> > +struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgdat)
> >  {
> >  	struct mem_cgroup_per_zone *mz;
> >  	struct mem_cgroup *memcg;
> >  	struct lruvec *lruvec;
> > 
> >  	if (mem_cgroup_disabled()) {
> > -		lruvec = &zone->lruvec;
> > +		lruvec = &pgdat->lruvec;
> >  		goto out;
> >  	}
> > 
> > @@ -1238,8 +1238,8 @@ out:
> >  	 * we have to be prepared to initialize lruvec->zone here;
> >  	 * and if offlined then reonlined, we need to reinitialize it.
> >  	 */
> > -	if (unlikely(lruvec->zone != zone))
> > -		lruvec->zone = zone;
> > +	if (unlikely(lruvec->pgdat != pgdat))
> > +		lruvec->pgdat = pgdat;
> 
> Given &pgdat->lruvec, we no longer need(or are able) to set lruvec->pgdat.
> 

I do not understand your comment. This is setting a mapping between lruvec
and pgdat, not the other way around. It's a straight-forward conversion
of zone to pgdat.

-- 
Mel Gorman
SUSE Labs

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