From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx160.postini.com [74.125.245.160]) by kanga.kvack.org (Postfix) with SMTP id BDCF26B0033 for ; Thu, 18 Jul 2013 23:20:08 -0400 (EDT) Received: from /spool/local by e28smtp05.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 19 Jul 2013 08:44:27 +0530 Received: from d28relay04.in.ibm.com (d28relay04.in.ibm.com [9.184.220.61]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id 960661258051 for ; Fri, 19 Jul 2013 08:49:24 +0530 (IST) Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay04.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r6J3JxDC22478852 for ; Fri, 19 Jul 2013 08:49:59 +0530 Received: from d28av05.in.ibm.com (loopback [127.0.0.1]) by d28av05.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r6J3K2cg023418 for ; Fri, 19 Jul 2013 13:20:03 +1000 From: "Aneesh Kumar K.V" Subject: Re: hugepage related lockdep trace. In-Reply-To: References: <20130717153223.GD27731@redhat.com> <20130718000901.GA31972@blaptop> <87hafrdatb.fsf@linux.vnet.ibm.com> Date: Fri, 19 Jul 2013 08:50:02 +0530 Message-ID: <87d2qfck2l.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: Hillf Danton Cc: Minchan Kim , Dave Jones , Linux Kernel , linux-mm@kvack.org, Rik van Riel , Michal Hocko , KAMEZAWA Hiroyuki , Andrew Morton Hillf Danton writes: > On Fri, Jul 19, 2013 at 1:42 AM, Aneesh Kumar K.V > wrote: >> Minchan Kim writes: >>> IMHO, it's a false positive because i_mmap_mutex was held by kswapd >>> while one in the middle of fault path could be never on kswapd context. >>> >>> It seems lockdep for reclaim-over-fs isn't enough smart to identify >>> between background and direct reclaim. >>> >>> Wait for other's opinion. >> >> Is that reasoning correct ?. We may not deadlock because hugetlb pages >> cannot be reclaimed. So the fault path in hugetlb won't end up >> reclaiming pages from same inode. But the report is correct right ? >> >> >> Looking at the hugetlb code we have in huge_pmd_share >> >> out: >> pte = (pte_t *)pmd_alloc(mm, pud, addr); >> mutex_unlock(&mapping->i_mmap_mutex); >> return pte; >> >> I guess we should move that pmd_alloc outside i_mmap_mutex. Otherwise >> that pmd_alloc can result in a reclaim which can call shrink_page_list ? >> > Hm, can huge pages be reclaimed, say by kswapd currently? No we don't reclaim hugetlb pages. -aneesh -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org