linux-kernel - Re: [PATCH] mm/hugetlb_cgroup: Add list_del to remove unused page from hugepage

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Wed, 11 Jul 2012 18:16:18 +0800
From:	Wanpeng Li <liwp.linux@...il.com>
To:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Li Zefan <lizefan@...wei.com>, Tejun Heo <tj@...nel.org>,
	cgroups@...r.kernel.org, linux-kernel@...r.kernel.org,
	Wanpeng Li <liwp.linux@...il.com>
Subject: Re: [PATCH] mm/hugetlb_cgroup: Add list_del to remove unused page
 from hugepage_activelist when hugepage migration

On Wed, Jul 11, 2012 at 03:15:19PM +0530, Aneesh Kumar K.V wrote:
>Wanpeng Li <liwp.linux@...il.com> writes:
>
>> On Wed, Jul 11, 2012 at 02:02:23PM +0530, Aneesh Kumar K.V wrote:
>>>Wanpeng Li <liwp.linux@...il.com> writes:
>>>
>>>> From: Wanpeng Li <liwp@...ux.vnet.ibm.com>
>>>>
>>>> hugepage_activelist is used to track currently used HugeTLB pages.
>>>> We can find the in-use HugeTLB pages to support HugeTLB cgroup
>>>> removal. Don't keep unused page in hugetlb_activelist too long.
>>>> Otherwise, on cgroup removal we should update the unused page's 
>>>> charge to parent count. To reduce this overhead, remove unused page 
>>>> from hugepage_activelist immediately.
>>>>
>>>> Signed-off-by: Wanpeng Li <liwp.linux@...il.com>
>>>> ---
>>>>  mm/hugetlb_cgroup.c |    1 +
>>>>  1 files changed, 1 insertions(+), 0 deletions(-)
>>>>
>>>> diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
>>>> index b834e8d..d819d66 100644
>>>> --- a/mm/hugetlb_cgroup.c
>>>> +++ b/mm/hugetlb_cgroup.c
>>>> @@ -398,6 +398,7 @@ void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
>>>>  	spin_lock(&hugetlb_lock);
>>>>  	h_cg = hugetlb_cgroup_from_page(oldhpage);
>>>>  	set_hugetlb_cgroup(oldhpage, NULL);
>>>> +	list_del(&oldhpage->lru);
>>>>
>>>>  	/* move the h_cg details to new cgroup */
>>>>  	set_hugetlb_cgroup(newhpage, h_cg);
>>>
>>>put_page on the oldhpage will do that. If we do list_del here
>>>free_huge_page() will have error list_move().
>>
>> I don't know if move the page to other lists when migration in order 
>> to reduce overhead I mentioned make sense. :-)
>>
>
>Even if we are in the active_list, we don't get anything wrong because
>hugetlb cgroup is set to NULL for the old hugetlb page. The above patch is
>wrong and will result in crash when we try to put_page the oldhpage.

Hi aneesh, I am happy we are in the same company. I am a guy in LTC
China. I want to know if there any features or works about hugetlb
cgroup I can do with you!

Regards,
Wanpeng Li

>
>-aneesh
>
>--
>To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>the body of a message to majordomo@...r.kernel.org
>More majordomo info at  http://vger.kernel.org/majordomo-info.html
>Please read the FAQ at  http://www.tux.org/lkml/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/