On Thu, 16 Feb 2012 02:57:04 +0400 Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx> wrote: > 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: > AFAIK, Hugh Dickins said he has per-zone-per-lru-lock and is testing it. So, please CC him and Johannes, at least. > * 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 ] > Why you need to add new structure rahter than enhancing lruvec ? "book" means a binder of pages ? > * 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 ] > This seems straightforward. > * unify inactive_list_is_low_global() and cleanup reclaimer code > * replace struct mem_cgroup_zone with single pointer to struct book Hm, ok. > * optimize page to book translations, move it upper in the call stack, > replace some struct zone arguments with struct book pointer. > a page->book transrater from patch 2/15 +struct book *page_book(struct page *page) +{ + struct mem_cgroup_per_zone *mz; + struct page_cgroup *pc; + + if (mem_cgroup_disabled()) + return &page_zone(page)->book; + + pc = lookup_page_cgroup(page); + if (!PageCgroupUsed(pc)) + return &page_zone(page)->book; + /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ + smp_rmb(); + mz = mem_cgroup_zoneinfo(pc->mem_cgroup, + page_to_nid(page), page_zonenum(page)); + return &mz->book; +} What happens when pc->mem_cgroup is rewritten by move_account() ? Where is the guard for lockless access of this ? Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>