Messages in this thread |  | | | Subject | [PATCH RFC 00/15] mm: memory book keeping and lru_lock splitting | | From | Konstantin Khlebnikov <> | | Date | Thu, 16 Feb 2012 02:57:04 +0400 |
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There should be no logic changes in this patchset, this is only tossing bits around. [ This patchset is on top some memcg cleanup/rework patches, which I sent to linux-mm@ today/yesterday ]
Most of things in this patchset are self-descriptive, so here brief plan:
* Transmute struct lruvec into struct book. Like real book this struct will store set of pages for one zone. It will be working unit for reclaimer code. [ If memcg is disabled in config there will only one book embedded into struct zone ]
* move page-lru counters to struct book [ this adds extra overhead in add_page_to_lru_list()/del_page_from_lru_list() for non-memcg case, but I believe it will be invisible, only one non-atomic add/sub in the same cacheline with lru list ]
* unify inactive_list_is_low_global() and cleanup reclaimer code * replace struct mem_cgroup_zone with single pointer to struct book * optimize page to book translations, move it upper in the call stack, replace some struct zone arguments with struct book pointer.
page -> book dereference become main operation, page (even free) will always points to one book in its zone. so page->flags bits may contains direct reference to book. Maybe we can replace page_zone(page) with book_zone(page_book(page)), without mem cgroups book -> zone dereference will be simple container_of().
Finally, there appears some new locking primitives for decorating lru_lock splitting logic. Final patch actually splits zone->lru_lock into small per-book pieces. All this code currently *completely untested*, but seems like it already can work.
After that, there two options how manage struct book on mem-cgroup create/destroy: a) [ currently implemented ] allocate and release by rcu. Thus lock_page_book() will be protected with rcu_read_lock(). b) allocate and never release struct book, reuse them after rcu grace period. It allows to avoid some rcu_read_lock()/rcu_read_unlock() calls on hot paths.
Motivation: I wrote the similar memory controller for our rhel6-based openvz/virtuozzo kernel, including splitted lru-locks and some other [patented LOL] cool stuff. [ common descrioption without techical details: http://wiki.openvz.org/VSwap ] That kernel already in production and rather stable for a long time.
--- Konstantin Khlebnikov (15): mm: rename struct lruvec into struct book mm: memory bookkeeping core mm: add book->pages_count mm: unify inactive_list_is_low() mm: add book->reclaim_stat mm: kill struct mem_cgroup_zone mm: move page-to-book translation upper mm: introduce book locking primitives mm: handle book relocks on lumpy reclaim mm: handle book relocks in compaction mm: handle book relock in memory controller mm: optimize books in update_page_reclaim_stat() mm: optimize books in pagevec_lru_move_fn() mm: optimize putback for 0-order reclaim mm: split zone->lru_lock
include/linux/memcontrol.h | 52 ------- include/linux/mm_inline.h | 222 ++++++++++++++++++++++++++++- include/linux/mmzone.h | 26 ++- include/linux/swap.h | 2 init/Kconfig | 4 + mm/compaction.c | 35 +++-- mm/huge_memory.c | 10 + mm/memcontrol.c | 238 ++++++++++--------------------- mm/page_alloc.c | 20 ++- mm/swap.c | 128 ++++++----------- mm/vmscan.c | 334 +++++++++++++++++++------------------------- 11 files changed, 554 insertions(+), 517 deletions(-) -- Signature
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