[PATCH v12 00/16] per memcg lru lock

Alex Shi
2020-06-11T06:17:09Z

This is a new version which bases on v5.8, only change mm/compaction.c
since mm-compaction-avoid-vm_bug_onpageslab-in-page_mapcount.patch
removed.

Johannes Weiner has suggested:
"So here is a crazy idea that may be worth exploring:

Right now, pgdat->lru_lock protects both PageLRU *and* the lruvec's
linked list.

Can we make PageLRU atomic and use it to stabilize the lru_lock
instead, and then use the lru_lock only serialize list operations?
..."

With new memcg charge path and this solution, we could isolate
LRU pages to exclusive visit them in compaction, page migration, reclaim,
memcg move_accunt, huge page split etc scenarios while keeping pages'
memcg stable. Then possible to change per node lru locking to per memcg
lru locking. As to pagevec_lru_move_fn funcs, it would be safe to let
pages remain on lru list, lru lock could guard them for list integrity.

The patchset includes 3 parts:
1, some code cleanup and minimum optimization as a preparation.
2, use TestCleanPageLRU as page isolation's precondition
3, replace per node lru_lock with per memcg per node lru_lock

The 3rd part moves per node lru_lock into lruvec, thus bring a lru_lock for
each of memcg per node. So on a large machine, each of memcg don't
have to suffer from per node pgdat->lru_lock competition. They could go
fast with their self lru_lock

Following Daniel Jordan's suggestion, I have run 208 'dd' with on 104
containers on a 2s * 26cores * HT box with a modefied case:
https://git.kernel.org/pub/scm/linux/kernel/git/wfg/vm-scalability.git/tree/case-lru-file-readtwice

With this patchset, the readtwice performance increased about 80%
in concurrent containers.

Thanks Hugh Dickins and Konstantin Khlebnikov, they both brought this
idea 8 years ago, and others who give comments as well: Daniel Jordan,
Mel Gorman, Shakeel Butt, Matthew Wilcox etc.

Thanks for Testing support from Intel 0day and Rong Chen, Fengguang Wu,
and Yun Wang. Hugh Dickins also shared his kbuild-swap case. Thanks!

Alex Shi (14):
mm/vmscan: remove unnecessary lruvec adding
mm/page_idle: no unlikely double check for idle page counting
mm/compaction: correct the comments of compact_defer_shift
mm/compaction: rename compact_deferred as compact_should_defer
mm/thp: move lru_add_page_tail func to huge_memory.c
mm/thp: clean up lru_add_page_tail
mm/thp: narrow lru locking
mm/memcg: add debug checking in lock_page_memcg
mm/lru: introduce TestClearPageLRU
mm/compaction: do page isolation first in compaction
mm/mlock: reorder isolation sequence during munlock
mm/lru: replace pgdat lru_lock with lruvec lock
mm/lru: introduce the relock_page_lruvec function
mm/pgdat: remove pgdat lru_lock

Hugh Dickins (2):
mm/vmscan: use relock for move_pages_to_lru
mm/lru: revise the comments of lru_lock

Documentation/admin-guide/cgroup-v1/memcg_test.rst | 15 +-
Documentation/admin-guide/cgroup-v1/memory.rst | 8 +-
Documentation/trace/events-kmem.rst | 2 +-
Documentation/vm/unevictable-lru.rst | 22 +--
include/linux/compaction.h | 4 +-
include/linux/memcontrol.h | 92 +++++++++++
include/linux/mm_types.h | 2 +-
include/linux/mmzone.h | 6 +-
include/linux/page-flags.h | 1 +
include/linux/swap.h | 4 +-
include/trace/events/compaction.h | 2 +-
mm/compaction.c | 96 +++++++-----
mm/filemap.c | 4 +-
mm/huge_memory.c | 51 +++++--
mm/memcontrol.c | 87 ++++++++++-
mm/mlock.c | 93 ++++++------
mm/mmzone.c | 1 +
mm/page_alloc.c | 1 -
mm/page_idle.c | 8 -
mm/rmap.c | 2 +-
mm/swap.c | 112 ++++----------
mm/swap_state.c | 6 +-
mm/vmscan.c | 168 +++++++++++----------
mm/workingset.c | 4 +-
24 files changed, 481 insertions(+), 310 deletions(-)

--
1.8.3.1