On Tue, 19 Oct 2010 09:45:12 +0900 KAMEZAWA Hiroyuki <[email protected]> wrote:
> On Mon, 18 Oct 2010 17:39:37 -0700 > Greg Thelen <[email protected]> wrote: > > > Performance Impact: moving a 8G anon process. > > > > Before: > > real 0m0.792s > > user 0m0.000s > > sys 0m0.780s > > > > After: > > real 0m0.854s > > user 0m0.000s > > sys 0m0.842s > > > > This score is bad but planned patches for optimization can reduce > > this impact. > > > > I'll post optimization patches after this set goes to -mm. > RFC version will be posted soon. > This is a RFC and based on dirty-limit v3 patch. Then, I'll post again this when dirty-limit patches are queued. == From: KAMEZAWA Hiroyuki <[email protected]> At moving account, a major source of cost is put/get_page(). This patch reduces cost of put/get page by the fact all operations are done under pte_lock(). Because move_account() is done under pte_lock, pages present on page table are never be freed. Then, we don't need to do get/put_page at isolating pages from LRU. Cost of moving 8G anon process. [mmotm] real 0m0.792s user 0m0.000s sys 0m0.780s [dirty] real 0m0.854s user 0m0.000s sys 0m0.842s [get/put] real 0m0.757s user 0m0.000s sys 0m0.746s seems nice. Signed-off-by: KAMEZAWA Hiroyuki <[email protected]> --- mm/memcontrol.c | 59 +++++++++++++++++++++++++++++++++----------------------- 1 file changed, 35 insertions(+), 24 deletions(-) Index: dirty_limit_new/mm/memcontrol.c =================================================================== --- dirty_limit_new.orig/mm/memcontrol.c +++ dirty_limit_new/mm/memcontrol.c @@ -4844,9 +4844,13 @@ one_by_one: * Returns * 0(MC_TARGET_NONE): if the pte is not a target for move charge. * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for - * move charge. if @target is not NULL, the page is stored in target->page - * with extra refcnt got(Callers should handle it). - * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a + * move charge and it's mapped. If @target is not NULL, the page is stored, + * in target->ent. We expect pte_lock is held throughout the operation and + * no extra page_get() is done. + * 2.(MC_TARGET_UNMAPPED_PAGE): if the page corresponding to this pte is a + * target for move charge and it's not mapped. If @target is not NULL, the + * page is stored in target->ent with extra refcnt got. + * 3(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a * target for charge migration. if @target is not NULL, the entry is stored * in target->ent. * @@ -4859,7 +4863,8 @@ union mc_target { enum mc_target_type { MC_TARGET_NONE, /* not used */ - MC_TARGET_PAGE, + MC_TARGET_PAGE, /* page mapped */ + MC_TARGET_UNMAPPED_PAGE, /* page not mapped*/ MC_TARGET_SWAP, }; @@ -4877,8 +4882,6 @@ static struct page *mc_handle_present_pt } else if (!move_file()) /* we ignore mapcount for file pages */ return NULL; - if (!get_page_unless_zero(page)) - return NULL; return page; } @@ -4944,13 +4947,17 @@ static int is_target_pte_for_mc(struct v struct page_cgroup *pc; int ret = 0; swp_entry_t ent = { .val = 0 }; + bool mapped = true; - if (pte_present(ptent)) + if (pte_present(ptent)) { page = mc_handle_present_pte(vma, addr, ptent); - else if (is_swap_pte(ptent)) - page = mc_handle_swap_pte(vma, addr, ptent, &ent); - else if (pte_none(ptent) || pte_file(ptent)) - page = mc_handle_file_pte(vma, addr, ptent, &ent); + } else { + mapped = false; + if (is_swap_pte(ptent)) + page = mc_handle_swap_pte(vma, addr, ptent, &ent); + else if (pte_none(ptent) || pte_file(ptent)) + page = mc_handle_file_pte(vma, addr, ptent, &ent); + } if (!page && !ent.val) return 0; @@ -4962,11 +4969,14 @@ static int is_target_pte_for_mc(struct v * the lock. */ if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) { - ret = MC_TARGET_PAGE; + if (mapped) + ret = MC_TARGET_PAGE; + else + ret = MC_TARGET_UNMAPPED_PAGE; if (target) target->page = page; } - if (!ret || !target) + if (!mapped && (!ret || !target)) put_page(page); } /* There is a swap entry and a page doesn't exist or isn't charged */ @@ -5153,19 +5163,20 @@ retry: type = is_target_pte_for_mc(vma, addr, ptent, &target); switch (type) { case MC_TARGET_PAGE: + case MC_TARGET_UNMAPPED_PAGE: page = target.page; - if (isolate_lru_page(page)) - goto put; - pc = lookup_page_cgroup(page); - if (!mem_cgroup_move_account(pc, - mc.from, mc.to, false)) { - mc.precharge--; - /* we uncharge from mc.from later. */ - mc.moved_charge++; + if (!isolate_lru_page(page)) { + pc = lookup_page_cgroup(page); + if (!mem_cgroup_move_account(pc, mc.from, + mc.to, false)) { + mc.precharge--; + /* we uncharge from mc.from later. */ + mc.moved_charge++; + } + putback_lru_page(page); } - putback_lru_page(page); -put: /* is_target_pte_for_mc() gets the page */ - put_page(page); + if (type == MC_TARGET_UNMAPPED_PAGE) + put_page(page); break; case MC_TARGET_SWAP: ent = target.ent; _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
