On Thu, 8 Apr 2010 17:08:58 +0900
Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> wrote:
> On Thu, 8 Apr 2010 15:44:34 +0900, KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> > On Thu, 8 Apr 2010 14:11:31 +0900
> > Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> wrote:
> >
> > > This patch adds support for moving charge of file pages, which include normal
> > > file, tmpfs file and swaps of tmpfs file. It's enabled by setting bit 1 of
> > > <target cgroup>/memory.move_charge_at_immigrate. Unlike the case of anonymous
> > > pages, file pages(and swaps) in the range mmapped 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 same file. And mapcount of the page is
> > > ignored(the page can be moved even if page_mapcount(page) > 1). So, conditions
> > > that the page/swap should be met to be moved is that it must be in the range
> > > mmapped by the target task and it must be charged to the old cgroup.
> > >
> > > Signed-off-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
> > > ---
> > > Documentation/cgroups/memory.txt | 12 ++++++--
> > > include/linux/swap.h | 5 +++
> > > mm/memcontrol.c | 55 +++++++++++++++++++++++++++++--------
> > > mm/shmem.c | 37 +++++++++++++++++++++++++
> > > 4 files changed, 94 insertions(+), 15 deletions(-)
> > >
> > > diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
> > > index 1b5bd04..13d40e7 100644
> > > --- a/Documentation/cgroups/memory.txt
> > > +++ b/Documentation/cgroups/memory.txt
> > > @@ -461,14 +461,20 @@ charges should be moved.
> > > 0 | A charge of an anonymous page(or swap of it) used by the target task.
> > > | Those pages and swaps must be used only by the target task. You must
> > > | enable Swap Extension(see 2.4) to enable move of swap charges.
> > > + -----+------------------------------------------------------------------------
> > > + 1 | A charge of file pages(normal file, tmpfs file(e.g. ipc shared memory)
> > > + | and swaps of tmpfs file) mmaped by the target task. Unlike the case of
> > > + | anonymous pages, file pages(and swaps) in the range mmapped 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 same file.
> > > + | And mapcount of the page is ignored(the page can be moved even if
> > > + | page_mapcount(page) > 1). 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. file cache, shmem,) will be supported by other
> > > - bits in future.
> > >
> >
> > About both of documenataion for 0 and 1, I think following information is omitted.
> >
> > "An account of a page of task is moved only when it's under task's current memory cgroup."
> >
> > Plz add somewhere easy-to-be-found.
> >
> hmm, I intended to say it by "Note: Those pages and swaps must be charged
> to the old cgroup.".
> But okey, I updated the documentation. How about this ?
>
seems very clearer to me.
Thank you.
-Kame
> ===
> From: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
>
> This patch adds support for moving charge of file pages, which include normal
> file, tmpfs file and swaps of tmpfs file. It's enabled by setting bit 1 of
> <target cgroup>/memory.move_charge_at_immigrate. Unlike the case of anonymous
> pages, file pages(and swaps) in the range mmapped 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 same file. And mapcount of the page is
> ignored(the page can be moved even if page_mapcount(page) > 1). So, conditions
> that the page/swap should be met to be moved is that it must be in the range
> mmapped by the target task and it must be charged to the old cgroup.
>
> Signed-off-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
> ---
> v3->v3.1: updated documentation.
>
> Documentation/cgroups/memory.txt | 18 ++++++++----
> include/linux/swap.h | 5 +++
> mm/memcontrol.c | 55 +++++++++++++++++++++++++++++--------
> mm/shmem.c | 37 +++++++++++++++++++++++++
> 4 files changed, 97 insertions(+), 18 deletions(-)
>
> diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
> index 1b5bd04..374582c 100644
> --- a/Documentation/cgroups/memory.txt
> +++ b/Documentation/cgroups/memory.txt
> @@ -454,21 +454,27 @@ And if you want disable it again:
> 8.2 Type of charges which can be move
>
> Each bits of move_charge_at_immigrate has its own meaning about what type of
> -charges should be moved.
> +charges should be moved. But in any cases, it must be noted that an account of
> +a page or a swap can be moved only when it is charged to the task's current(old)
> +memory cgroup.
>
> bit | what type of charges would be moved ?
> -----+------------------------------------------------------------------------
> 0 | A charge of an anonymous page(or swap of it) used by the target task.
> | Those pages and swaps must be used only by the target task. 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. file cache, shmem,) will be supported by other
> - bits in future.
> + -----+------------------------------------------------------------------------
> + 1 | A charge of file pages(normal file, tmpfs file(e.g. ipc shared memory)
> + | and swaps of tmpfs file) mmaped by the target task. Unlike the case of
> + | anonymous pages, file pages(and swaps) in the range mmapped 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 same file.
> + | And mapcount of the page is ignored(the page can be moved even if
> + | page_mapcount(page) > 1). You must enable Swap Extension(see 2.4) to
> + | enable move of swap charges.
>
> 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 95a1706..225a658 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -250,6 +250,7 @@ struct mem_cgroup {
> */
> enum move_type {
> MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */
> + MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */
> NR_MOVE_TYPE,
> };
>
> @@ -271,6 +272,11 @@ static bool move_anon(void)
> return test_bit(MOVE_CHARGE_TYPE_ANON,
> &mc.to->move_charge_at_immigrate);
> }
> +static bool move_file(void)
> +{
> + return test_bit(MOVE_CHARGE_TYPE_FILE,
> + &mc.to->move_charge_at_immigrate);
> +}
>
> /*
> * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
> @@ -4199,11 +4205,8 @@ static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
> /* 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.
> - */
> + } else if (!move_file())
> + /* we ignore mapcount for file pages */
> return NULL;
> if (!get_page_unless_zero(page))
> return NULL;
> @@ -4232,6 +4235,39 @@ static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
> return page;
> }
>
> +static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
> + unsigned long addr, pte_t ptent, swp_entry_t *entry)
> +{
> + struct page *page = NULL;
> + struct inode *inode;
> + struct address_space *mapping;
> + pgoff_t pgoff;
> +
> + if (!vma->vm_file) /* anonymous vma */
> + return NULL;
> + if (!move_file())
> + return NULL;
> +
> + inode = vma->vm_file->f_path.dentry->d_inode;
> + mapping = vma->vm_file->f_mapping;
> + if (pte_none(ptent))
> + pgoff = linear_page_index(vma, addr);
> + if (pte_file(ptent))
> + pgoff = pte_to_pgoff(ptent);
> +
> + /* page is moved even if it's not RSS of this task(page-faulted). */
> + if (!mapping_cap_swap_backed(mapping)) { /* normal file */
> + page = find_get_page(mapping, pgoff);
> + } else { /* shmem/tmpfs file. we should take account of swap too. */
> + swp_entry_t ent;
> + mem_cgroup_get_shmem_target(inode, pgoff, &page, &ent);
> + if (do_swap_account)
> + entry->val = ent.val;
> + }
> +
> + return page;
> +}
> +
> static int is_target_pte_for_mc(struct vm_area_struct *vma,
> unsigned long addr, pte_t ptent, union mc_target *target)
> {
> @@ -4244,7 +4280,8 @@ static int is_target_pte_for_mc(struct vm_area_struct *vma,
> page = mc_handle_present_pte(vma, addr, ptent);
> else if (is_swap_pte(ptent))
> page = mc_handle_swap_pte(vma, addr, ptent, &ent);
> - /* TODO: handle swap of shmes/tmpfs */
> + else if (pte_none(ptent) || pte_file(ptent))
> + page = mc_handle_file_pte(vma, addr, ptent, &ent);
>
> if (!page && !ent.val)
> return 0;
> @@ -4307,9 +4344,6 @@ 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)
> - continue;
> walk_page_range(vma->vm_start, vma->vm_end,
> &mem_cgroup_count_precharge_walk);
> }
> @@ -4506,9 +4540,6 @@ static void mem_cgroup_move_charge(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)
> - continue;
> ret = walk_page_range(vma->vm_start, vma->vm_end,
> &mem_cgroup_move_charge_walk);
> if (ret)
> diff --git a/mm/shmem.c b/mm/shmem.c
> index dde4363..cb87365 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -2701,3 +2701,40 @@ int shmem_zero_setup(struct vm_area_struct *vma)
> vma->vm_ops = &shmem_vm_ops;
> return 0;
> }
> +
> +#ifdef CONFIG_CGROUP_MEM_RES_CTLR
> +/**
> + * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file
> + * @inode: the inode to be searched
> + * @pgoff: the offset to be searched
> + * @pagep: the pointer for the found page to be stored
> + * @ent: the pointer for the found swap entry to be stored
> + *
> + * If a page is found, refcount of it is incremented. Callers should handle
> + * these refcount.
> + */
> +void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
> + struct page **pagep, swp_entry_t *ent)
> +{
> + swp_entry_t entry = { .val = 0 }, *ptr;
> + struct page *page = NULL;
> + struct shmem_inode_info *info = SHMEM_I(inode);
> +
> + if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode))
> + goto out;
> +
> + spin_lock(&info->lock);
> + ptr = shmem_swp_entry(info, pgoff, NULL);
> + if (ptr && ptr->val) {
> + entry.val = ptr->val;
> + page = find_get_page(&swapper_space, entry.val);
> + } else
> + page = find_get_page(inode->i_mapping, pgoff);
> + if (ptr)
> + shmem_swp_unmap(ptr);
> + spin_unlock(&info->lock);
> +out:
> + *pagep = page;
> + *ent = entry;
> +}
> +#endif
> --
> 1.6.4
>
>
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