On Mon 04-08-14 16:34:29, Johannes Weiner wrote: > Charge migration currently disables IRQs twice to update the charge > statistics for the old page and then again for the new page. > > But migration is a seemless transition of a charge from one physical > page to another one of the same size, so this should be a non-event > from an accounting point of view. Leave the statistics alone.
Moving stats to mem_cgroup_commit_charge sounds logical to me but does this work properly even for the fuse replace page cache case when old and new pages can already live in different memcgs? > Signed-off-by: Johannes Weiner <[email protected]> > --- > mm/memcontrol.c | 35 ++++++++++------------------------- > 1 file changed, 10 insertions(+), 25 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 475ecadd9646..8d65dadeec1b 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2728,7 +2728,7 @@ static void unlock_page_lru(struct page *page, int > isolated) > } > > static void commit_charge(struct page *page, struct mem_cgroup *memcg, > - unsigned int nr_pages, bool lrucare) > + bool lrucare) > { > struct page_cgroup *pc = lookup_page_cgroup(page); > int isolated; > @@ -2765,16 +2765,6 @@ static void commit_charge(struct page *page, struct > mem_cgroup *memcg, > > if (lrucare) > unlock_page_lru(page, isolated); > - > - local_irq_disable(); > - mem_cgroup_charge_statistics(memcg, page, nr_pages); > - /* > - * "charge_statistics" updated event counter. Then, check it. > - * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree. > - * if they exceeds softlimit. > - */ > - memcg_check_events(memcg, page); > - local_irq_enable(); > } > > static DEFINE_MUTEX(set_limit_mutex); > @@ -6460,12 +6450,17 @@ void mem_cgroup_commit_charge(struct page *page, > struct mem_cgroup *memcg, > if (!memcg) > return; > > + commit_charge(page, memcg, lrucare); > + > if (PageTransHuge(page)) { > nr_pages <<= compound_order(page); > VM_BUG_ON_PAGE(!PageTransHuge(page), page); > } > > - commit_charge(page, memcg, nr_pages, lrucare); > + local_irq_disable(); > + mem_cgroup_charge_statistics(memcg, page, nr_pages); > + memcg_check_events(memcg, page); > + local_irq_enable(); > > if (do_swap_account && PageSwapCache(page)) { > swp_entry_t entry = { .val = page_private(page) }; > @@ -6651,7 +6646,6 @@ void mem_cgroup_uncharge_list(struct list_head > *page_list) > void mem_cgroup_migrate(struct page *oldpage, struct page *newpage, > bool lrucare) > { > - unsigned int nr_pages = 1; > struct page_cgroup *pc; > int isolated; > > @@ -6660,6 +6654,8 @@ void mem_cgroup_migrate(struct page *oldpage, struct > page *newpage, > VM_BUG_ON_PAGE(!lrucare && PageLRU(oldpage), oldpage); > VM_BUG_ON_PAGE(!lrucare && PageLRU(newpage), newpage); > VM_BUG_ON_PAGE(PageAnon(oldpage) != PageAnon(newpage), newpage); > + VM_BUG_ON_PAGE(PageTransHuge(oldpage) != PageTransHuge(newpage), > + newpage); > > if (mem_cgroup_disabled()) > return; > @@ -6677,12 +6673,6 @@ void mem_cgroup_migrate(struct page *oldpage, struct > page *newpage, > VM_BUG_ON_PAGE(!(pc->flags & PCG_MEM), oldpage); > VM_BUG_ON_PAGE(do_swap_account && !(pc->flags & PCG_MEMSW), oldpage); > > - if (PageTransHuge(oldpage)) { > - nr_pages <<= compound_order(oldpage); > - VM_BUG_ON_PAGE(!PageTransHuge(oldpage), oldpage); > - VM_BUG_ON_PAGE(!PageTransHuge(newpage), newpage); > - } > - > if (lrucare) > lock_page_lru(oldpage, &isolated); > > @@ -6691,12 +6681,7 @@ void mem_cgroup_migrate(struct page *oldpage, struct > page *newpage, > if (lrucare) > unlock_page_lru(oldpage, isolated); > > - local_irq_disable(); > - mem_cgroup_charge_statistics(pc->mem_cgroup, oldpage, -nr_pages); > - memcg_check_events(pc->mem_cgroup, oldpage); > - local_irq_enable(); > - > - commit_charge(newpage, pc->mem_cgroup, nr_pages, lrucare); > + commit_charge(newpage, pc->mem_cgroup, lrucare); > } > > /* > -- > 2.0.3 > -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
