On Thu, 28 May 2020, Alex Shi wrote: > This is a new version which bases on linux-next > > 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 | 104 ++++++++----- > 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, 487 insertions(+), 312 deletions(-) Hi Alex, I didn't get to try v10 at all, waited until Johannes's preparatory memcg swap cleanup was in mmotm; but I have spent a while thrashing this v11, and can happily report that it is much better than v9 etc: I believe this memcg lru_lock work will soon be ready for v5.9. I've not yet found any flaw at the swapping end, but fixes are needed for isolate_migratepages_block() and mem_cgroup_move_account(): I've got a series of 4 fix patches to send you (I guess two to fold into existing patches of yours, and two to keep as separate from me). I haven't yet written the patch descriptions, will return to that tomorrow. I expect you will be preparing a v12 rebased on v5.8-rc1 or v5.8-rc2, and will be able to include these fixes in that. Tomorrow... Hugh
