Re: [RFC][PATCH 2/2] quicklist shouldn't be proportional to # of CPUs

[KOSAKI Motohiro]

Hi Peter,

Thank you good point out!

> > @@ -41,8 +41,8 @@ static unsigned long max_pages(unsigned 
> >  
> >  	max = node_free_pages / FRACTION_OF_NODE_MEM;
> >  
> > -	num_cpus_per_node = cpus_weight_nr(node_to_cpumask(node));
> > -	max /= num_cpus_per_node;
> > +	node_cpumask = node_to_cpumask(node);
> > +	max /= cpus_weight_nr(node_cpumask);
> >  
> >  	return max(max, min_pages);
> >  }
> 
> humm, I thought we wanted to keep cpumask_t stuff away from our stack -
> since on insanely large SGI boxen (/me looks at mike) the thing becomes
> 512 bytes.

Hm, interesting.
I think following patch fill your point, right?

but I worry about it works on sparc64...


Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>

---
 mm/quicklist.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

Index: b/mm/quicklist.c
===================================================================
--- a/mm/quicklist.c
+++ b/mm/quicklist.c
@@ -26,7 +26,10 @@ DEFINE_PER_CPU(struct quicklist, quickli
 static unsigned long max_pages(unsigned long min_pages)
 {
 	unsigned long node_free_pages, max;
-	struct zone *zones = NODE_DATA(numa_node_id())->node_zones;
+	int node = numa_node_id();
+	struct zone *zones = NODE_DATA(node)->node_zones;
+	int num_cpus_on_node;
+	node_to_cpumask_ptr(cpumask_on_node, node);
 
 	node_free_pages =
 #ifdef CONFIG_ZONE_DMA
@@ -38,6 +41,10 @@ static unsigned long max_pages(unsigned 
 		zone_page_state(&zones[ZONE_NORMAL], NR_FREE_PAGES);
 
 	max = node_free_pages / FRACTION_OF_NODE_MEM;
+
+	num_cpus_on_node = cpus_weight_nr(*cpumask_on_node);
+	max /= num_cpus_on_node;
+
 	return max(max, min_pages);
 }
 


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