Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759614Ab3GSDUM (ORCPT ); Thu, 18 Jul 2013 23:20:12 -0400 Received: from e28smtp07.in.ibm.com ([122.248.162.7]:56884 "EHLO e28smtp07.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759599Ab3GSDUK (ORCPT ); Thu, 18 Jul 2013 23:20:10 -0400 From: "Aneesh Kumar K.V" To: Hillf Danton Cc: Minchan Kim , Dave Jones , Linux Kernel , linux-mm@kvack.org, Rik van Riel , Michal Hocko , KAMEZAWA Hiroyuki , Andrew Morton Subject: Re: hugepage related lockdep trace. In-Reply-To: References: <20130717153223.GD27731@redhat.com> <20130718000901.GA31972@blaptop> <87hafrdatb.fsf@linux.vnet.ibm.com> User-Agent: Notmuch/0.15.2+167~g5306b2b (http://notmuchmail.org) Emacs/24.3.50.1 (x86_64-unknown-linux-gnu) 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 X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13071903-8878-0000-0000-000008053799 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1399 Lines: 39 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 from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/