Re: [PATCH -mmotm] build fix formemcg-move-charges-of-anonymous-swap.patch

From: Daisuke Nishimura
Date: Thu Jan 07 2010 - 00:33:38 EST


On Thu, 7 Jan 2010 13:30:26 +0900, KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> On Thu, 7 Jan 2010 13:06:09 +0900
> Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> wrote:
>
> > build fix in !CONFIG_SWAP case.
> >
> > CC mm/memcontrol.o
> > mm/memcontrol.c: In function 'is_target_pte_for_mc':
> > mm/memcontrol.c:3648: error: implicit declaration of function 'mem_cgroup_count_swap_user'
> > make[1]: *** [mm/memcontrol.o] Error 1
> > make: *** [mm] Error 2
> >
> > Reported-by: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
> > Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> > Signed-off-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
>
> Hmm, this doesn't seem include fix for CONFIG_CGROUP_MEM_RES_CTLR_SWAP=n
> ==
> static int is_target_pte_for_mc(struct vm_area_struct *vma,
> unsigned long addr, pte_t ptent, union mc_target *target)
> {
> ....
> 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);
> }
> ==
> At least, !do_swap_account check is necessary, I think.
> I'm sorry if I miss something...
>
mem_cgroup_count_swap_user() is defined in CONFIG_CGROUP_MEM_RES_CTLR case,
so the build error has nothing to do with CONFIG_CGROUP_MEM_RES_CTLR_SWAP(i.e. do_swap_account).
And I think adding !do_swap_account would ignore unmaped-but-not-uncharged-yet
swapcache in CONFIG_SWAP && !CONFIG_CGROUP_MEM_RES_CTLR_SWAP case.
(it would not be a big problem though).

Anyway, I'm sorry that the first patch was wrong...
This is the correct one.

===
From: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>

build fix in !CONFIG_SWAP case.

CC mm/memcontrol.o
mm/memcontrol.c: In function 'is_target_pte_for_mc':
mm/memcontrol.c:3648: error: implicit declaration of function 'mem_cgroup_count_swap_user'
make[1]: *** [mm/memcontrol.o] Error 1
make: *** [mm] Error 2

Reported-by: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Signed-off-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
---
This can be applied after memcg-move-charges-of-anonymous-swap.patch.

include/linux/swap.h | 8 ++++++++
1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index d9b06f7..c2a4295 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -488,6 +488,14 @@ mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent)
{
}

+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+static inline int
+mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep)
+{
+ return 0;
+}
+#endif
+
#endif /* CONFIG_SWAP */
#endif /* __KERNEL__*/
#endif /* _LINUX_SWAP_H */
--
1.5.6.1
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