With the deployment of high-capacity CXL Type 3 memory, HBM and Nvdimm, the kernel now supports memory tiering. Building on this foundation and aiming to further enhance memory efficiency, the kernel has introduced demotion and promotion features. To provide users with a more intuitive way to observe information related to demotion, we have made several improvements to demotion profiling, primarily in two aspects: Patch 1 introduces a new interface: /sys/devices/system/node/node0/demotion_nodes This interface is used to display the target nodes to which a node can demote. Patch 2, Patch 3, and Patch 4 are improvements to demotion statistics. Patch 2 changes the granularity of demotion statistics from global to per-node. Patch 3 and Patch 4 further differentiate demotion statistics into demotion source and demotion destination. The names of the statistics are open to discussion; they could be named something like pgdemote_from/to_* etc. One issue with this patch set is that SUM(pgdemote_src_*) always equals SUM(pgdemote_dst_*) in the global statistics (/proc/vmstat). Should we hide one of them? Any feedback is welcome. TO: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> TO: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> TO: "Rafael J. Wysocki" <rafael@xxxxxxxxxx> CC: "Huang, Ying" <ying.huang@xxxxxxxxx> CC: y-goto@xxxxxxxxxxx CC: linux-kernel@xxxxxxxxxxxxxxx TO: linux-mm@xxxxxxxxx Li Zhijian (4): drivers/base/node: Add demotion_nodes sys infterface mm/vmstat: Move pgdemote_* to per-node stats mm/vmstat: rename pgdemote_* to pgdemote_dst_* and add pgdemote_src_* drivers/base/node: add demote_src and demote_dst to numastat drivers/base/node.c | 29 +++++++++++++++++++++++++++-- include/linux/memory-tiers.h | 6 ++++++ include/linux/mmzone.h | 7 +++++++ include/linux/vm_event_item.h | 3 --- mm/memory-tiers.c | 8 ++++++++ mm/vmscan.c | 14 +++++++++++--- mm/vmstat.c | 9 ++++++--- 7 files changed, 65 insertions(+), 11 deletions(-) -- 2.29.2
