]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
mm/migrate: update node demotion order on hotplug events
authorDave Hansen <dave.hansen@linux.intel.com>
Thu, 2 Sep 2021 21:59:09 +0000 (14:59 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 3 Sep 2021 16:58:16 +0000 (09:58 -0700)
commit884a6e5d1f93b5032e5d6dd2a183f8b3f008416b
treec44eb9149b246eb27ade53abde2829ef9ec1f0ca
parent79c28a41672278283fa72e03d0bf80e6644d4ac4
mm/migrate: update node demotion order on hotplug events

Reclaim-based migration is attempting to optimize data placement in memory
based on the system topology.  If the system changes, so must the
migration ordering.

The implementation is conceptually simple and entirely unoptimized.  On
any memory or CPU hotplug events, assume that a node was added or removed
and recalculate all migration targets.  This ensures that the
node_demotion[] array is always ready to be used in case the new reclaim
mode is enabled.

This recalculation is far from optimal, most glaringly that it does not
even attempt to figure out the hotplug event would have some *actual*
effect on the demotion order.  But, given the expected paucity of hotplug
events, this should be fine.

Link: https://lkml.kernel.org/r/20210721063926.3024591-2-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20210715055145.195411-3-ying.huang@intel.com
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/migrate.c