From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932420Ab2LFWgz (ORCPT ); Thu, 6 Dec 2012 17:36:55 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:59422 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753998Ab2LFWgy (ORCPT ); Thu, 6 Dec 2012 17:36:54 -0500 Date: Thu, 6 Dec 2012 14:36:52 -0800 From: Andrew Morton To: Naoya Horiguchi Cc: Andi Kleen , Tony Luck , Wu Fengguang , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/3] HWPOISON, hugetlbfs: fix warning on freeing hwpoisoned hugepage Message-Id: <20121206143652.29c4922f.akpm@linux-foundation.org> In-Reply-To: <1354744058-26373-2-git-send-email-n-horiguchi@ah.jp.nec.com> References: <1354744058-26373-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1354744058-26373-2-git-send-email-n-horiguchi@ah.jp.nec.com> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 5 Dec 2012 16:47:36 -0500 Naoya Horiguchi wrote: > This patch fixes the warning from __list_del_entry() which is triggered > when a process tries to do free_huge_page() for a hwpoisoned hugepage. > > Originally, page->lru of hugetlbfs head page was dangling when the > hugepage was in use. This behavior has changed by commit 0edaecfab218d7 > ("hugetlb: add a list for tracking in-use HugeTLB pages"), where hugepages > in use are linked to hugepage_activelist. HWpoisoned hugepages should not > be charged to any process, so we introduce another list to link hwpoisoned > hugepages. > > ... > > --- v3.7-rc8.orig/include/linux/hugetlb.h > +++ v3.7-rc8/include/linux/hugetlb.h > @@ -230,6 +230,9 @@ struct hstate { > unsigned long nr_overcommit_huge_pages; > struct list_head hugepage_activelist; > struct list_head hugepage_freelists[MAX_NUMNODES]; > +#ifdef CONFIG_MEMORY_FAILURE > + struct list_head hugepage_hwpoisonedlist; > +#endif > unsigned int nr_huge_pages_node[MAX_NUMNODES]; > unsigned int free_huge_pages_node[MAX_NUMNODES]; > unsigned int surplus_huge_pages_node[MAX_NUMNODES]; > diff --git v3.7-rc8.orig/mm/hugetlb.c v3.7-rc8/mm/hugetlb.c > index 59a0059..e61a749 100644 > --- v3.7-rc8.orig/mm/hugetlb.c > +++ v3.7-rc8/mm/hugetlb.c > @@ -1939,6 +1939,7 @@ void __init hugetlb_add_hstate(unsigned order) > for (i = 0; i < MAX_NUMNODES; ++i) > INIT_LIST_HEAD(&h->hugepage_freelists[i]); > INIT_LIST_HEAD(&h->hugepage_activelist); > + INIT_LIST_HEAD(&h->hugepage_hwpoisonedlist); > h->next_nid_to_alloc = first_node(node_states[N_HIGH_MEMORY]); > h->next_nid_to_free = first_node(node_states[N_HIGH_MEMORY]); > snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", > @@ -3170,7 +3171,7 @@ int dequeue_hwpoisoned_huge_page(struct page *hpage) > > spin_lock(&hugetlb_lock); > if (is_hugepage_on_freelist(hpage)) { > - list_del(&hpage->lru); > + list_move(&hpage->lru, &h->hugepage_hwpoisonedlist); > set_page_refcounted(hpage); > h->free_huge_pages--; > h->free_huge_pages_node[nid]--; Do we actually need to new list? We could use list_del_init() to leave the page's list_head pointing at itself. In this state, it is its own list_head and further list_del()s are a no-op. I don't know whether this would trigger list-debug warnings.