On Mon, 10 May 2010 15:25:54 -0700
Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Thu, 8 Apr 2010 14:10:20 +0900
> Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> wrote:
>
> > This patch cleans up move charge code by:
> >
> > - define functions to handle pte for each types, and make is_target_pte_for_mc()
> > cleaner.
> > - instead of checking the MOVE_CHARGE_TYPE_ANON bit, define a function that
> > checks the bit.
> >
> > ...
> >
>
> > @@ -4241,13 +4263,15 @@ static int is_target_pte_for_mc(struct vm_area_struct *vma,
> > if (!ret || !target)
> > put_page(page);
> > }
> > - /* throught */
> > - if (ent.val && do_swap_account && !ret &&
> > - css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
> > - ret = MC_TARGET_SWAP;
> > - if (target)
> > - target->ent = ent;
> > + /* Threre is a swap entry and a page doesn't exist or isn't charged */
> > + if (ent.val && !ret) {
> > + if (css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
> > + ret = MC_TARGET_SWAP;
> > + if (target)
> > + target->ent = ent;
> > + }
> > }
> > +
> > return ret;
> > }
>
> Are you sure that the test of do_swap_account should be removed here?
> it didn't seem to be covered in the changelog.
>
Hmmm...thank you for pointing out. I think it should be checked.
Nishimura-san ?
> This patch got somewaht trashed by
> memcg-fix-css_id-rcu-locking-for-real.patch, which is was sent under the
> not-very-useful title "[BUGFIX][PATCH 2/2] cgroup/cssid/memcg rcu
> fixes. (Was Re: [PATCH tip/core/urgent 08/10] memcg: css_id() must be
> called under rcu_read_lock()". (the same title as [patch 1/1]).
>
yes, sorry. I sent a revert+new-fix patch...
I'm sorry if it adds more confusion..
> I reworked memcg-clean-up-move-charge.patch as below:
>
>
>
> From: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
>
> This patch cleans up move charge code by:
>
> - define functions to handle pte for each types, and make
> is_target_pte_for_mc() cleaner.
>
> - instead of checking the MOVE_CHARGE_TYPE_ANON bit, define a function
> that checks the bit.
>
> Signed-off-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> Cc: Balbir Singh <balbir@xxxxxxxxxx>
> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> ---
>
> mm/memcontrol.c | 96 ++++++++++++++++++++++++++++------------------
> 1 file changed, 59 insertions(+), 37 deletions(-)
>
> diff -puN mm/memcontrol.c~memcg-clean-up-move-charge mm/memcontrol.c
> --- a/mm/memcontrol.c~memcg-clean-up-move-charge
> +++ a/mm/memcontrol.c
> @@ -266,6 +266,12 @@ static struct move_charge_struct {
> .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
> };
>
> +static bool move_anon(void)
> +{
> + return test_bit(MOVE_CHARGE_TYPE_ANON,
> + &mc.to->move_charge_at_immigrate);
> +}
> +
> /*
> * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
> * limit reclaim to prevent infinite loops, if they ever occur.
> @@ -4185,50 +4191,66 @@ enum mc_target_type {
> MC_TARGET_SWAP,
> };
>
> -static int is_target_pte_for_mc(struct vm_area_struct *vma,
> - unsigned long addr, pte_t ptent, union mc_target *target)
> +static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
> + unsigned long addr, pte_t ptent)
> {
> - struct page *page = NULL;
> - struct page_cgroup *pc;
> - int ret = 0;
> - swp_entry_t ent = { .val = 0 };
> - int usage_count = 0;
> - bool move_anon = test_bit(MOVE_CHARGE_TYPE_ANON,
> - &mc.to->move_charge_at_immigrate);
> + struct page *page = vm_normal_page(vma, addr, ptent);
>
> - if (!pte_present(ptent)) {
> - /* TODO: handle swap of shmes/tmpfs */
> - if (pte_none(ptent) || pte_file(ptent))
> - return 0;
> - else if (is_swap_pte(ptent)) {
> - ent = pte_to_swp_entry(ptent);
> - if (!move_anon || non_swap_entry(ent))
> - return 0;
> - usage_count = mem_cgroup_count_swap_user(ent, &page);
> - }
> - } else {
> - page = vm_normal_page(vma, addr, ptent);
> - if (!page || !page_mapped(page))
> - return 0;
> + if (!page || !page_mapped(page))
> + return NULL;
> + if (PageAnon(page)) {
> + /* we don't move shared anon */
> + if (!move_anon() || page_mapcount(page) > 2)
> + return NULL;
> + } else
> /*
> * TODO: We don't move charges of file(including shmem/tmpfs)
> * pages for now.
> */
> - if (!move_anon || !PageAnon(page))
> - return 0;
> - if (!get_page_unless_zero(page))
> - return 0;
> - usage_count = page_mapcount(page);
> - }
> - if (usage_count > 1) {
> - /*
> - * TODO: We don't move charges of shared(used by multiple
> - * processes) pages for now.
> - */
> + return NULL;
> + if (!get_page_unless_zero(page))
> + return NULL;
> +
> + return page;
> +}
> +
> +static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
> + unsigned long addr, pte_t ptent, swp_entry_t *entry)
> +{
> + int usage_count;
> + struct page *page = NULL;
> + swp_entry_t ent = pte_to_swp_entry(ptent);
> +
> + if (!move_anon() || non_swap_entry(ent))
> + return NULL;
> + usage_count = mem_cgroup_count_swap_user(ent, &page);
> + if (usage_count > 1) { /* we don't move shared anon */
> if (page)
> put_page(page);
> - return 0;
> + return NULL;
> }
> + if (do_swap_account)
> + entry->val = ent.val;
Maybe page should be set to NULL here. if !do_swap_account....
Thanks,
-Kame
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