From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wanpeng Li Subject: Re: [PATCH] mm/hugetlb_cgroup: Add list_del to remove unused page from hugepage_activelist when hugepage migration Date: Wed, 11 Jul 2012 18:16:18 +0800 Message-ID: <20120711101618.GA12033@kernel> References: <1341978718-6423-1-git-send-email-liwp.linux@gmail.com> <87wr2aitpk.fsf@skywalker.in.ibm.com> <20120711091648.GA10841@kernel> <87txxeiqc0.fsf@skywalker.in.ibm.com> Reply-To: Wanpeng Li Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:subject:message-id:reply-to:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=72ZaxE9L4TheX4kfxeLxOlgBSmkoBKafDR0UVjD6XQ4=; b=atq/NjLATX9B+UlsrmgUAF/yOKND8ymO9zwAn//0xWeqgmdmBzqU2lTgfDovvVyT4c x/qJ+0YQ/nSLAmRN36EUIYuYJ0LxTQQjDj9wi4C4lbq5Lw9g29NkxD2VcraD/ZhFf2Is Dea5aSUmFL2QjdHk5A4kw3MSK2VEOBMRBXBRgx80PpLU2SdGDjzHN4Y0MpJx+5MYg3LQ x1B077xBtXmLfVEDW+An4klBVCY0jqSPUlPodOKmMMNOEG79SApZ2JFN7ity2ZNz51U1 PdfTGIT5v98RfT++lxpfOtiIS3Evqk79vAsLMKkRoZsMMYpuJ7kdkpQzGtghoGqbnHg7 S30w== Content-Disposition: inline In-Reply-To: <87txxeiqc0.fsf-6yE53ggjAfyqSkle7U1LjlaTQe2KTcn/@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "Aneesh Kumar K.V" Cc: Andrew Morton , Li Zefan , Tejun Heo , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Wanpeng Li On Wed, Jul 11, 2012 at 03:15:19PM +0530, Aneesh Kumar K.V wrote: >Wanpeng Li writes: > >> On Wed, Jul 11, 2012 at 02:02:23PM +0530, Aneesh Kumar K.V wrote: >>>Wanpeng Li writes: >>> >>>> From: Wanpeng Li >>>> >>>> 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 >>>> --- >>>> 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-u79uwXL29TY76Z2rM5mHXA@public.gmane.org >More majordomo info at http://vger.kernel.org/majordomo-info.html >Please read the FAQ at http://www.tux.org/lkml/