Re: [PATCH 04/10] mm: vmscan: Decide whether to compact the pgdatbased on reclaim progress

[Mel Gorman]

On Mon, Mar 18, 2013 at 07:11:30PM +0800, Wanpeng Li wrote:
> >@@ -2864,46 +2879,21 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
> > 		if (try_to_freeze() || kthread_should_stop())
> > 			break;
> >
> >-		/* If no reclaim progress then increase scanning priority */
> >-		if (sc.nr_reclaimed - nr_reclaimed == 0)
> >-			raise_priority = true;
> >+		/* Compact if necessary and kswapd is reclaiming efficiently */
> >+		this_reclaimed = sc.nr_reclaimed - nr_reclaimed;
> >+		if (order && pgdat_needs_compaction &&
> >+				this_reclaimed > nr_to_reclaim)
> >+			compact_pgdat(pgdat, order);
> >
> 
> Hi Mel,
> 
> If you should check compaction_suitable here to confirm it's not because
> other reasons like large number of pages under writeback to avoid blind
> compaction. :-)
> 

This starts as a question but it is not a question so I am not sure how
I should respond.

Checking compaction_suitable here is unnecessary because compact_pgdat()
makes the same check when it calls compact_zone().

-- 
Mel Gorman
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/