Messages in this thread | | | Date | Fri, 23 Mar 2012 09:18:46 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [PATCH] memcg: change behavior of moving charges at task move |
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(2012/03/23 6:36), Andrew Morton wrote:
> On Wed, 21 Mar 2012 18:52:04 +0900 > KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote: > >> 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 NULL; >> - } >> +#ifdef CONFIG_SWAP >> + /* >> + * Avoid lookup_swap_cache() not to update statistics. >> + */ > > I don't understand this comment - what is it trying to tell us? >
High Dickins advised me to use find_get_page() rather than lookup_swap_cache() because lookup_swap_cache() has some statistics with swap.
>> + page = find_get_page(&swapper_space, ent.val); > > The code won't even compile if CONFIG_SWAP=n? >
mm/built-in.o: In function `mc_handle_swap_pte': /home/kamezawa/Kernel/next/linux/mm/memcontrol.c:5172: undefined reference to `swapper_space' make: *** [.tmp_vmlinux1] Error 1
Ah...but I think this function (mc_handle_swap_pte) itself should be under CONFIG_SWAP. I'll post v2.
Thank you for review! -Kame
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