vmstat: add pcp remote node draining via cpu_vm_stats_fold

vmstat: add pcp remote node draining via cpu_vm_stats_fold

Large NUMA systems might have significant portions of system memory to be
trapped in pcp queues.  The number of pcp is determined by the number of
processors and nodes in a system.  A system with 4 processors and 2 nodes
has 8 pcps which is okay.  But a system with 1024 processors and 512 nodes
has 512k pcps with a high potential for large amount of memory being
caught in them.

Enable remote node draining for the CONFIG_HAVE_CMPXCHG_LOCAL case, where
vmstat_shepherd will perform the aging and draining via cpu_vm_stats_fold.

Link: https://lkml.kernel.org/r/20230320180745.858515310@redhat.com
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Aaron Tomlin <atomlin@atomlin.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: "Russell King (Oracle)" <linux@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>