Re: [PATCH v2 4/5] page_alloc: Make movablecore_map has higher priority

[Tang Chen]

On 12/05/2012 11:43 PM, Jiang Liu wrote:
> If we make "movablecore_map" take precedence over "movablecore/kernelcore",
> the logic could be simplified. I think it's not so attractive to support
> both "movablecore_map" and "movablecore/kernelcore" at the same time.

Hi Liu,

Thanks for you advice. :)

Memory hotplug needs different support on different hardware. We are
trying to figure out a way to satisfy as many users as we can.
Since it is a little difficult, it may take sometime. :)

But I still think we need a boot option to support it. Just a metter of
how to make it easier to use. :)

Thanks. :)

> On 11/23/2012 06:44 PM, Tang Chen wrote:
> > If kernelcore or movablecore is specified at the same time
> > with movablecore_map, movablecore_map will have higher
> > priority to be satisfied.
> > This patch will make find_zone_movable_pfns_for_nodes()
> > calculate zone_movable_pfn[] with the limit from
> > zone_movable_limit[].
> >
> > Signed-off-by: Tang Chen<tangchen@xxxxxxxxxxxxxx>
> > Reviewed-by: Wen Congyang<wency@xxxxxxxxxxxxxx>
> > Reviewed-by: Lai Jiangshan<laijs@xxxxxxxxxxxxxx>
> > Tested-by: Lin Feng<linfeng@xxxxxxxxxxxxxx>
> > ---
> >   mm/page_alloc.c |   35 +++++++++++++++++++++++++++++++----
> >   1 files changed, 31 insertions(+), 4 deletions(-)
> >
> > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> > index f23d76a..05bafbb 100644
> > --- a/mm/page_alloc.c
> > +++ b/mm/page_alloc.c
> > @@ -4800,12 +4800,25 @@ static void __init find_zone_movable_pfns_for_nodes(void)
> >   		required_kernelcore = max(required_kernelcore, corepages);
> >   	}
> >
> > -	/* If kernelcore was not specified, there is no ZONE_MOVABLE */
> > -	if (!required_kernelcore)
> > +	/*
> > +	 * No matter kernelcore/movablecore was limited or not, movable_zone
> > +	 * should always be set to a usable zone index.
> > +	 */
> > +	find_usable_zone_for_movable();
> > +
> > +	/*
> > +	 * If neither kernelcore/movablecore nor movablecore_map is specified,
> > +	 * there is no ZONE_MOVABLE. But if movablecore_map is specified, the
> > +	 * start pfn of ZONE_MOVABLE has been stored in zone_movable_limit[].
> > +	 */
> > +	if (!required_kernelcore) {
> > +		if (movablecore_map.nr_map)
> > +			memcpy(zone_movable_pfn, zone_movable_limit,
> > +				sizeof(zone_movable_pfn));
> >   		goto out;
> > +	}
> >
> >   	/* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
> > -	find_usable_zone_for_movable();
> >   	usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
> >
> >   restart:
> > @@ -4833,10 +4846,24 @@ restart:
> >   		for_each_mem_pfn_range(i, nid,&start_pfn,&end_pfn, NULL) {
> >   			unsigned long size_pages;
> >
> > +			/*
> > +			 * Find more memory for kernelcore in
> > +			 * [zone_movable_pfn[nid], zone_movable_limit[nid]).
> > +			 */
> >   			start_pfn = max(start_pfn, zone_movable_pfn[nid]);
> >   			if (start_pfn>= end_pfn)
> >   				continue;
> >
> > +			if (zone_movable_limit[nid]) {
> > +				end_pfn = min(end_pfn, zone_movable_limit[nid]);
> > +				/* No range left for kernelcore in this node */
> > +				if (start_pfn>= end_pfn) {
> > +					zone_movable_pfn[nid] =
> > +							zone_movable_limit[nid];
> > +					break;
> > +				}
> > +			}
> > +
> >   			/* Account for what is only usable for kernelcore */
> >   			if (start_pfn<  usable_startpfn) {
> >   				unsigned long kernel_pages;
> > @@ -4896,12 +4923,12 @@ restart:
> >   	if (usable_nodes&&  required_kernelcore>  usable_nodes)
> >   		goto restart;
> >
> > +out:
> >   	/* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
> >   	for (nid = 0; nid<  MAX_NUMNODES; nid++)
> >   		zone_movable_pfn[nid] =
> >   			roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
> >
> > -out:
> >   	/* restore the node_state */
> >   	node_states[N_HIGH_MEMORY] = saved_node_state;
> >   }

--
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/