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powerpc/numa: Associate numa node to its cpu earlier

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powerpc is the only platform that do not rely on
cpu_up()->try_online_node() to bring up a numa node,
and special cases it, instead, deep in its own machinery:

dlpar_online_cpu
 find_and_online_cpu_nid
  try_online_node

This should not be needed, but the thing is that the try_online_node()
from cpu_up() will not apply on the right node, because cpu_to_node()
will return the old mapping numa<->cpu that gets set on boot stage
for all possible cpus.

That can be seen easily if we try to print out the numa node passed
to try_online_node() in cpu_up().

The thing is that the numa<->cpu mapping does not get updated till a much
later stage in start_secondary:

start_secondary:
 set_numa_node(numa_cpu_lookup_table[cpu])

But we do not really care, as we already now the
CPU <-> NUMA associativity back in find_and_online_cpu_nid(),
so let us make use of that and set the proper numa<->cpu mapping,
so cpu_to_node() in cpu_up() returns the right node and
try_online_node() can do its work.

Signed-off-by: Oscar Salvador <osalvador@suse.de>
Tested-by: Geetika Moolchandani <Geetika.Moolchandani1@ibm.com>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220411074934.4632-1-osalvador@suse.de
This commit is contained in:
Oscar Salvador 2022-04-11 09:49:34 +02:00 committed by Michael Ellerman
parent 9a9c5ff5ff
commit 48b63961c8
3 changed files with 11 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
arch/powerpc/include/asm/topology.h
View File

@ -111,14 +111,10 @@ static inline void unmap_cpu_from_node(unsigned long cpu) {}
#endif /* CONFIG_NUMA */
#if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)
extern int find_and_online_cpu_nid(int cpu);
void find_and_update_cpu_nid(int cpu);
extern int cpu_to_coregroup_id(int cpu);
#else
static inline int find_and_online_cpu_nid(int cpu)
{
return 0;
}
static inline void find_and_update_cpu_nid(int cpu) {}
static inline int cpu_to_coregroup_id(int cpu)
{
#ifdef CONFIG_SMP

32
arch/powerpc/mm/numa.c
View File

@ -1422,42 +1422,26 @@ out:
return rc;
}
int find_and_online_cpu_nid(int cpu)
void find_and_update_cpu_nid(int cpu)
{
__be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};
int new_nid;
/* Use associativity from first thread for all siblings */
if (vphn_get_associativity(cpu, associativity))
return cpu_to_node(cpu);
return;
/* Do not have previous associativity, so find it now. */
new_nid = associativity_to_nid(associativity);
if (new_nid < 0 || !node_possible(new_nid))
new_nid = first_online_node;
if (!node_online(new_nid)) {
#ifdef CONFIG_MEMORY_HOTPLUG
/*
* Need to ensure that NODE_DATA is initialized for a node from
* available memory (see memblock_alloc_try_nid). If unable to
* init the node, then default to nearest node that has memory
* installed. Skip onlining a node if the subsystems are not
* yet initialized.
*/
if (!topology_inited || try_online_node(new_nid))
new_nid = first_online_node;
#else
/*
* Default to using the nearest node that has memory installed.
* Otherwise, it would be necessary to patch the kernel MM code
* to deal with more memoryless-node error conditions.
*/
new_nid = first_online_node;
#endif
}
else
// Associate node <-> cpu, so cpu_up() calls
// try_online_node() on the right node.
set_cpu_numa_node(cpu, new_nid);
pr_debug("%s:%d cpu %d nid %d\n", __func__, __LINE__, cpu, new_nid);
return new_nid;
}
int cpu_to_coregroup_id(int cpu)

2
arch/powerpc/platforms/pseries/hotplug-cpu.c
View File

@ -398,7 +398,7 @@ static int dlpar_online_cpu(struct device_node *dn)
if (get_hard_smp_processor_id(cpu) != thread)
continue;
cpu_maps_update_done();
find_and_online_cpu_nid(cpu);
find_and_update_cpu_nid(cpu);
rc = device_online(get_cpu_device(cpu));
if (rc) {
dlpar_offline_cpu(dn);