Re: [BUGFIX][PATCH] oom-kill: fix NUMA consraint check with nodemask v2

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

On Tue, 10 Nov 2009 16:24:22 +0900 (JST)
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote:

> Hi
> 
> > ===================================================================
> > --- mmotm-2.6.32-Nov2.orig/mm/oom_kill.c
> > +++ mmotm-2.6.32-Nov2/mm/oom_kill.c
> > @@ -196,27 +196,40 @@ unsigned long badness(struct task_struct
> >  /*
> >   * Determine the type of allocation constraint.
> >   */
> > +#ifdef CONFIG_NUMA
> >  static inline enum oom_constraint constrained_alloc(struct zonelist *zonelist,
> > -						    gfp_t gfp_mask)
> > +				    gfp_t gfp_mask, nodemask_t *nodemask)
> >  {
> > -#ifdef CONFIG_NUMA
> >  	struct zone *zone;
> >  	struct zoneref *z;
> >  	enum zone_type high_zoneidx = gfp_zone(gfp_mask);
> > -	nodemask_t nodes = node_states[N_HIGH_MEMORY];
> > +	int ret = CONSTRAINT_NONE;
> >  
> > -	for_each_zone_zonelist(zone, z, zonelist, high_zoneidx)
> > -		if (cpuset_zone_allowed_softwall(zone, gfp_mask))
> > -			node_clear(zone_to_nid(zone), nodes);
> > -		else
> > +	/*
> > + 	 * The nodemask here is a nodemask passed to alloc_pages(). Now,
> > + 	 * cpuset doesn't use this nodemask for its hardwall/softwall/hierarchy
> > + 	 * feature. Then, only mempolicy use this nodemask.
> > + 	 */
> > +	if (nodemask && nodes_equal(*nodemask, node_states[N_HIGH_MEMORY]))
> > +		ret = CONSTRAINT_MEMORY_POLICY;
> 
> !nodes_equal() ?
> 
yes. will fix.

> 
> > +
> > +	/* Check this allocation failure is caused by cpuset's wall function */
> > +	for_each_zone_zonelist_nodemask(zone, z, zonelist,
> > +			high_zoneidx, nodemask)
> > +		if (!cpuset_zone_allowed_softwall(zone, gfp_mask))
> >  			return CONSTRAINT_CPUSET;
> 
> If cpuset and MPOL_BIND are both used, Probably CONSTRAINT_MEMORY_POLICY is
> better choice.
> 

No. this memory allocation is failed by limitation of cpuset's alloc mask.
Not from mempolicy.


Thanks,
-Kame

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