On Tue, 30 Mar 2010 10:33:01 +0900
Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> wrote:
> On Mon, 29 Mar 2010 13:36:45 +0900, KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> > Hmm...then, a shmem page is moved even if the task doesn't do page-fault.
> > Could you clarify
> > "All pages in the range mapped by a task will be moved to the new group
> > even if the task doesn't do page fault, i.e. not tasks' RSS."
> > ?
> I see.
>
> This is the updated version.
>
Ah, sorry. one more quesiton.
> ===
> From: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
>
> This patch adds support for moving charge of shmem and swap of it. It's enabled
> by setting bit 2 of <target cgroup>/memory.move_charge_at_immigrate.
>
> Signed-off-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
> ---
> v1->v2
> - update a documentation.
>
> Documentation/cgroups/memory.txt | 9 +++++-
> include/linux/swap.h | 5 +++
> mm/memcontrol.c | 52 +++++++++++++++++++++++++------------
> mm/shmem.c | 37 +++++++++++++++++++++++++++
> 4 files changed, 84 insertions(+), 19 deletions(-)
>
> diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
> index c624cd2..4755d5e 100644
> --- a/Documentation/cgroups/memory.txt
> +++ b/Documentation/cgroups/memory.txt
> @@ -465,13 +465,18 @@ charges should be moved.
> 1 | A charge of page cache mapped by the target task. Pages mapped by
> | multiple processes will not be moved. This "page cache" doesn't include
> | tmpfs.
> + -----+------------------------------------------------------------------------
> + 2 | A charge of a tmpfs page(or swap of it) mapped by the target task. A
> + | typical use case of it is ipc shared memory. Unlike above 2 cases, all
> + | pages(and swaps) in the range mapped by the task will be moved even if
> + | the task hasn't done page fault, i.e. they might not be the task's
> + | "RSS", but other task's "RSS" that maps the shared memory. You must
> + | enable Swap Extension(see 2.4) to enable move of swap charges.
>
> Note: Those pages and swaps must be charged to the old cgroup.
> -Note: More type of pages(e.g. shmem) will be supported by other bits in future.
>
> 8.3 TODO
>
> -- Add support for other types of pages(e.g. file cache, shmem, etc.).
> - Implement madvise(2) to let users decide the vma to be moved or not to be
> moved.
> - All of moving charge operations are done under cgroup_mutex. It's not good
> diff --git a/include/linux/swap.h b/include/linux/swap.h
> index 1f59d93..94ec325 100644
> --- a/include/linux/swap.h
> +++ b/include/linux/swap.h
> @@ -285,6 +285,11 @@ extern void kswapd_stop(int nid);
> extern int shmem_unuse(swp_entry_t entry, struct page *page);
> #endif /* CONFIG_MMU */
>
> +#ifdef CONFIG_CGROUP_MEM_RES_CTLR
> +extern void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
> + struct page **pagep, swp_entry_t *ent);
> +#endif
> +
> extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *);
>
> #ifdef CONFIG_SWAP
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 66d2704..99a496c 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -251,6 +251,7 @@ struct mem_cgroup {
> enum move_type {
> MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */
> MOVE_CHARGE_TYPE_FILE, /* private file caches */
> + MOVE_CHARGE_TYPE_SHMEM, /* shared memory and swap of it */
> NR_MOVE_TYPE,
> };
>
> @@ -4195,12 +4196,30 @@ static int is_target_pte_for_mc(struct vm_area_struct *vma,
> &mc.to->move_charge_at_immigrate);
> bool move_file = test_bit(MOVE_CHARGE_TYPE_FILE,
> &mc.to->move_charge_at_immigrate);
> + bool move_shmem = test_bit(MOVE_CHARGE_TYPE_SHMEM,
> + &mc.to->move_charge_at_immigrate);
> + bool is_shmem = false;
>
> 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)) {
> + if (pte_none(ptent) || pte_file(ptent)) {
> + struct inode *inode;
> + struct address_space *mapping;
> + pgoff_t pgoff = 0;
> +
> + if (!vma->vm_file)
> + return 0;
> + mapping = vma->vm_file->f_mapping;
> + if (!move_shmem || !mapping_cap_swap_backed(mapping))
> + return 0;
> +
> + if (pte_none(ptent))
> + pgoff = linear_page_index(vma, addr);
> + if (pte_file(ptent))
> + pgoff = pte_to_pgoff(ptent);
> + inode = vma->vm_file->f_path.dentry->d_inode;
> + mem_cgroup_get_shmem_target(inode, pgoff, &page, &ent);
> + is_shmem = true;
> + } else if (is_swap_pte(ptent)) {
> ent = pte_to_swp_entry(ptent);
> if (!move_anon || non_swap_entry(ent))
> return 0;
> @@ -4210,26 +4229,22 @@ static int is_target_pte_for_mc(struct vm_area_struct *vma,
> page = vm_normal_page(vma, addr, ptent);
> if (!page || !page_mapped(page))
> return 0;
> - /*
> - * TODO: We don't move charges of shmem/tmpfs pages for now.
> - */
> if (PageAnon(page)) {
> if (!move_anon)
> return 0;
> } else if (page_is_file_cache(page)) {
> if (!move_file)
> return 0;
> - } else
> - return 0;
> + } else {
> + if (!move_shmem)
> + return 0;
> + is_shmem = true;
> + }
> 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.
> - */
> + if (usage_count > 1 && !is_shmem) {
> if (page)
> put_page(page);
> return 0;
> @@ -4284,6 +4299,8 @@ static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
>
> down_read(&mm->mmap_sem);
> for (vma = mm->mmap; vma; vma = vma->vm_next) {
> + bool move_shmem = test_bit(MOVE_CHARGE_TYPE_SHMEM,
> + &mc.to->move_charge_at_immigrate);
> struct mm_walk mem_cgroup_count_precharge_walk = {
> .pmd_entry = mem_cgroup_count_precharge_pte_range,
> .mm = mm,
> @@ -4292,7 +4309,7 @@ static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
> if (is_vm_hugetlb_page(vma))
> continue;
> /* TODO: We don't move charges of shmem/tmpfs pages for now. */
> - if (vma->vm_flags & VM_SHARED)
> + if ((vma->vm_flags & VM_SHARED) && !move_shmem)
> continue;
SHARED mapped file cache is not moved by patch [1/2] ???
It sounds strange.
Thanks,
-Kame
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