Re: [PATCH 39 of 66] memcg huge memory

KAMEZAWA Hiroyuki
2010-11-19T01:25:25Z

On Wed, 03 Nov 2010 16:28:14 +0100
Andrea Arcangeli <aarcange@redhat.com> wrote:

> From: Andrea Arcangeli <aarcange@redhat.com>
>
> Add memcg charge/uncharge to hugepage faults in huge_memory.c.
>
> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
> Acked-by: Rik van Riel <riel@redhat.com>
> ---
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -233,6 +233,7 @@ static int __do_huge_pmd_anonymous_page(
> VM_BUG_ON(!PageCompound(page));
> pgtable = pte_alloc_one(mm, haddr);
> if (unlikely(!pgtable)) {
> + mem_cgroup_uncharge_page(page);
> put_page(page);
> return VM_FAULT_OOM;
> }
> @@ -243,6 +244,7 @@ static int __do_huge_pmd_anonymous_page(
> spin_lock(&mm->page_table_lock);
> if (unlikely(!pmd_none(*pmd))) {
> spin_unlock(&mm->page_table_lock);
> + mem_cgroup_uncharge_page(page);
> put_page(page);
> pte_free(mm, pgtable);
> } else {
> @@ -286,6 +288,10 @@ int do_huge_pmd_anonymous_page(struct mm
> page = alloc_hugepage(transparent_hugepage_defrag(vma));
> if (unlikely(!page))
> goto out;
> + if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) {
> + put_page(page);
> + goto out;
> + }
>
> return __do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, page);
> }
> @@ -402,9 +408,15 @@ static int do_huge_pmd_wp_page_fallback(
> for (i = 0; i < HPAGE_PMD_NR; i++) {
> pages[i] = alloc_page_vma(GFP_HIGHUSER_MOVABLE,
> vma, address);
> - if (unlikely(!pages[i])) {
> - while (--i >= 0)
> + if (unlikely(!pages[i] ||
> + mem_cgroup_newpage_charge(pages[i], mm,
> + GFP_KERNEL))) {
> + if (pages[i])
> put_page(pages[i]);
> + while (--i >= 0) {
> + mem_cgroup_uncharge_page(pages[i]);
> + put_page(pages[i]);
> + }

Maybe you can use batched-uncharge here.
==
mem_cgroup_uncharge_start()
{
do loop;
}
mem_cgroup_uncharge_end();
==
Then, many atomic ops can be reduced.

> kfree(pages);
> ret |= VM_FAULT_OOM;
> goto out;
> @@ -455,8 +467,10 @@ out:
>
> out_free_pages:
> spin_unlock(&mm->page_table_lock);
> - for (i = 0; i < HPAGE_PMD_NR; i++)
> + for (i = 0; i < HPAGE_PMD_NR; i++) {
> + mem_cgroup_uncharge_page(pages[i]);
> put_page(pages[i]);
> + }

here, too.

> kfree(pages);
> goto out;
> }
> @@ -501,14 +515,22 @@ int do_huge_pmd_wp_page(struct mm_struct
> goto out;
> }
>
> + if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) {
> + put_page(new_page);
> + put_page(page);
> + ret |= VM_FAULT_OOM;
> + goto out;
> + }
> +
> copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR);
> __SetPageUptodate(new_page);
>
> spin_lock(&mm->page_table_lock);
> put_page(page);
> - if (unlikely(!pmd_same(*pmd, orig_pmd)))
> + if (unlikely(!pmd_same(*pmd, orig_pmd))) {
> + mem_cgroup_uncharge_page(new_page);
> put_page(new_page);
> - else {
> + } else {
> pmd_t entry;
> VM_BUG_ON(!PageHead(page));
> entry = mk_pmd(new_page, vma->vm_page_prot);

Hmm...it seems there are no codes for move_account() hugepage in series.
I think it needs some complicated work to walk page table.

Thanks,
-Kame