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SubjectRe: [PATCH 00/31] numa/core patches
On 10/29/2012 01:56 AM, Johannes Weiner wrote:
> On Fri, Oct 26, 2012 at 11:08:00AM +0200, Peter Zijlstra wrote:
>> On Fri, 2012-10-26 at 17:07 +0800, Zhouping Liu wrote:
>>> [ 180.918591] RIP: 0010:[<ffffffff8118c39a>] [<ffffffff8118c39a>] mem_cgroup_prepare_migration+0xba/0xd0
>>> [ 182.681450] [<ffffffff81183b60>] do_huge_pmd_numa_page+0x180/0x500
>>> [ 182.775090] [<ffffffff811585c9>] handle_mm_fault+0x1e9/0x360
>>> [ 182.863038] [<ffffffff81632b62>] __do_page_fault+0x172/0x4e0
>>> [ 182.950574] [<ffffffff8101c283>] ? __switch_to_xtra+0x163/0x1a0
>>> [ 183.041512] [<ffffffff8101281e>] ? __switch_to+0x3ce/0x4a0
>>> [ 183.126832] [<ffffffff8162d686>] ? __schedule+0x3c6/0x7a0
>>> [ 183.211216] [<ffffffff81632ede>] do_page_fault+0xe/0x10
>>> [ 183.293705] [<ffffffff8162f518>] page_fault+0x28/0x30
>> Johannes, this looks like the thp migration memcg hookery gone bad,
>> could you have a look at this?
> Oops. Here is an incremental fix, feel free to fold it into #31.

Hi Johannes,

Tested the below patch, and I'm sure it has fixed the above issue, thank
you.

Zhouping

>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
> ---
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 5c30a14..0d7ebd3 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -801,8 +801,6 @@ void do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
> if (!new_page)
> goto alloc_fail;
>
> - mem_cgroup_prepare_migration(page, new_page, &memcg);
> -
> lru = PageLRU(page);
>
> if (lru && isolate_lru_page(page)) /* does an implicit get_page() */
> @@ -835,6 +833,14 @@ void do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
>
> return;
> }
> + /*
> + * Traditional migration needs to prepare the memcg charge
> + * transaction early to prevent the old page from being
> + * uncharged when installing migration entries. Here we can
> + * save the potential rollback and start the charge transfer
> + * only when migration is already known to end successfully.
> + */
> + mem_cgroup_prepare_migration(page, new_page, &memcg);
>
> entry = mk_pmd(new_page, vma->vm_page_prot);
> entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
> @@ -845,6 +851,12 @@ void do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
> set_pmd_at(mm, haddr, pmd, entry);
> update_mmu_cache_pmd(vma, address, entry);
> page_remove_rmap(page);
> + /*
> + * Finish the charge transaction under the page table lock to
> + * prevent split_huge_page() from dividing up the charge
> + * before it's fully transferred to the new page.
> + */
> + mem_cgroup_end_migration(memcg, page, new_page, true);
> spin_unlock(&mm->page_table_lock);
>
> put_page(page); /* Drop the rmap reference */
> @@ -856,18 +868,14 @@ void do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
>
> unlock_page(new_page);
>
> - mem_cgroup_end_migration(memcg, page, new_page, true);
> -
> unlock_page(page);
> put_page(page); /* Drop the local reference */
>
> return;
>
> alloc_fail:
> - if (new_page) {
> - mem_cgroup_end_migration(memcg, page, new_page, false);
> + if (new_page)
> put_page(new_page);
> - }
>
> unlock_page(page);
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 7acf43b..011e510 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -3255,15 +3255,18 @@ void mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
> struct mem_cgroup **memcgp)
> {
> struct mem_cgroup *memcg = NULL;
> + unsigned int nr_pages = 1;
> struct page_cgroup *pc;
> enum charge_type ctype;
>
> *memcgp = NULL;
>
> - VM_BUG_ON(PageTransHuge(page));
> if (mem_cgroup_disabled())
> return;
>
> + if (PageTransHuge(page))
> + nr_pages <<= compound_order(page);
> +
> pc = lookup_page_cgroup(page);
> lock_page_cgroup(pc);
> if (PageCgroupUsed(pc)) {
> @@ -3325,7 +3328,7 @@ void mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
> * charged to the res_counter since we plan on replacing the
> * old one and only one page is going to be left afterwards.
> */
> - __mem_cgroup_commit_charge(memcg, newpage, 1, ctype, false);
> + __mem_cgroup_commit_charge(memcg, newpage, nr_pages, ctype, false);
> }
>
> /* remove redundant charge if migration failed*/



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