[0/3] Recalculate per-cpu page allocator batch and high limits after deferred meminit v2

Message

Mel Gorman Oct. 21, 2019, 9:48 a.m. UTC

This is an updated series that addresses some review feedback and an
LKP warning.  I did not preserve Michal Hocko's ack for the fix as it
has changed.  This series replaces the following patches in mmotm

mm-pcp-share-common-code-between-memory-hotplug-and-percpu-sysctl-handler.patch
mm-meminit-recalculate-pcpu-batch-and-high-limits-after-init-completes.patch
mm-pcpu-make-zone-pcp-updates-and-reset-internal-to-the-mm.patch

Changelog since V1
o Fix a "might sleep" warning
o Reorder for easier backporting

A private report stated that system CPU usage was excessive on an AMD
EPYC 2 machine while building kernels with much longer build times than
expected. The issue is partially explained by high zone lock contention
due to the per-cpu page allocator batch and high limits being calculated
incorrectly. This series addresses a large chunk of the problem. Patch
1 is the real fix and the other two are cosmetic issues noticed while
implementing the fix.

 include/linux/mm.h |  3 ---
 mm/internal.h      |  3 +++
 mm/page_alloc.c    | 31 ++++++++++++++++++++-----------
 3 files changed, 23 insertions(+), 14 deletions(-)