On Thu, 22 May 2008 15:20:05 +0900
Daisuke Nishimura <[EMAIL PROTECTED]> wrote:
> +#ifdef CONFIG_CGROUP_SWAP_RES_CTLR
> +int swap_cgroup_charge(struct page *page,
> + struct swap_info_struct *si,
> + unsigned long offset)
> +{
> + int ret;
> + struct page_cgroup *pc;
> + struct mem_cgroup *mem;
> +
> + lock_page_cgroup(page);
> + pc = page_get_page_cgroup(page);
> + if (unlikely(!pc))
> + mem = &init_mem_cgroup;
> + else
> + mem = pc->mem_cgroup;
> + unlock_page_cgroup(page);
If !pc, the page is used before memory controller is available. But is it
good to be charged to init_mem_cgroup() ?
How about returning 'failure' in this case ? I think returning 'failure' here
is not so bad.
> +
> + css_get(&mem->css);
move this css_get() before unlock_page_cgroup() is safer.
> + ret = res_counter_charge(&mem->swap_res, PAGE_SIZE);
> + if (!ret)
> + si->memcg[offset] = mem;
> + else
> + css_put(&mem->css);
> +
> + return ret;
> +}
> +
> +void swap_cgroup_uncharge(struct swap_info_struct *si,
> + unsigned long offset)
> +{
> + struct mem_cgroup *mem = si->memcg[offset];
> +
> + /* "mem" would be NULL:
> + * 1. when get_swap_page() failed at charging swap_cgroup,
> + * and called swap_entry_free().
> + * 2. when this swap entry had been assigned by
> + * get_swap_page_of_type() (via SWSUSP?).
> + */
> + if (mem) {
> + res_counter_uncharge(&mem->swap_res, PAGE_SIZE);
> + si->memcg[offset] = NULL;
> + css_put(&mem->css);
> + }
> +}
> +#endif
> +
> diff --git a/mm/shmem.c b/mm/shmem.c
> index 95b056d..69f8909 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -1029,7 +1029,7 @@ static int shmem_writepage(struct page *page, struct
> writeback_control *wbc)
> * want to check if there's a redundant swappage to be discarded.
> */
> if (wbc->for_reclaim)
> - swap = get_swap_page();
> + swap = get_swap_page(page);
> else
> swap.val = 0;
>
> diff --git a/mm/swap_state.c b/mm/swap_state.c
> index 676e191..a78d617 100644
> --- a/mm/swap_state.c
> +++ b/mm/swap_state.c
> @@ -130,7 +130,7 @@ int add_to_swap(struct page * page, gfp_t gfp_mask)
> BUG_ON(!PageUptodate(page));
>
> for (;;) {
> - entry = get_swap_page();
> + entry = get_swap_page(page);
> if (!entry.val)
> return 0;
>
> diff --git a/mm/swapfile.c b/mm/swapfile.c
> index 232bf20..682b71e 100644
> --- a/mm/swapfile.c
> +++ b/mm/swapfile.c
> @@ -172,7 +172,10 @@ no_page:
> return 0;
> }
>
> -swp_entry_t get_swap_page(void)
> +/* get_swap_page() calls this */
> +static int swap_entry_free(struct swap_info_struct *, unsigned long);
> +
> +swp_entry_t get_swap_page(struct page *page)
> {
> struct swap_info_struct *si;
> pgoff_t offset;
> @@ -201,6 +204,14 @@ swp_entry_t get_swap_page(void)
> swap_list.next = next;
> offset = scan_swap_map(si);
> if (offset) {
> + /*
> + * This should be the first use of this swap entry.
> + * So, charge this swap entry here.
> + */
> + if (swap_cgroup_charge(page, si, offset)) {
> + swap_entry_free(si, offset);
> + goto noswap;
> + }
> spin_unlock(&swap_lock);
> return swp_entry(type, offset);
> }
> @@ -285,6 +296,7 @@ static int swap_entry_free(struct swap_info_struct *p,
> unsigned long offset)
> swap_list.next = p - swap_info;
> nr_swap_pages++;
> p->inuse_pages--;
> + swap_cgroup_uncharge(p, offset);
> }
> }
> return count;
>
>
> --
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> the body to [EMAIL PROTECTED] For more info on Linux MM,
> see: http://www.linux-mm.org/ .
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>
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