From patchwork Thu Jul 18 09:27:20 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Wang, Wei W" X-Patchwork-Id: 11048755 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6B84713A4 for ; Thu, 18 Jul 2019 10:10:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5B100285B0 for ; Thu, 18 Jul 2019 10:10:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4E753285F1; Thu, 18 Jul 2019 10:10:48 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EBFD8285B0 for ; Thu, 18 Jul 2019 10:10:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727131AbfGRKKn (ORCPT ); Thu, 18 Jul 2019 06:10:43 -0400 Received: from mga14.intel.com ([192.55.52.115]:2216 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726495AbfGRKKn (ORCPT ); Thu, 18 Jul 2019 06:10:43 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Jul 2019 03:10:43 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,276,1559545200"; d="scan'208";a="162031470" Received: from devel-ww.sh.intel.com ([10.239.48.128]) by orsmga008.jf.intel.com with ESMTP; 18 Jul 2019 03:10:39 -0700 From: Wei Wang To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, mst@redhat.com, xdeguillard@vmware.com, namit@vmware.com Cc: akpm@linux-foundation.org, pagupta@redhat.com, riel@surriel.com, dave.hansen@intel.com, david@redhat.com, konrad.wilk@oracle.com, yang.zhang.wz@gmail.com, nitesh@redhat.com, lcapitulino@redhat.com, aarcange@redhat.com, pbonzini@redhat.com, alexander.h.duyck@linux.intel.com, dan.j.williams@intel.com Subject: [PATCH v2] mm/balloon_compaction: avoid duplicate page removal Date: Thu, 18 Jul 2019 17:27:20 +0800 Message-Id: <1563442040-13510-1-git-send-email-wei.w.wang@intel.com> X-Mailer: git-send-email 2.7.4 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Fixes: 418a3ab1e778 (mm/balloon_compaction: List interfaces) A #GP is reported in the guest when requesting balloon inflation via virtio-balloon. The reason is that the virtio-balloon driver has removed the page from its internal page list (via balloon_page_pop), but balloon_page_enqueue_one also calls "list_del" to do the removal. This is necessary when it's used from balloon_page_enqueue_list, but not from balloon_page_enqueue_one. So remove the list_del balloon_page_enqueue_one, and update some comments as a reminder. Signed-off-by: Wei Wang Acked-by: Nadav Amit --- ChangeLong: v1->v2: updated some comments mm/balloon_compaction.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c index 83a7b61..8639bfc 100644 --- a/mm/balloon_compaction.c +++ b/mm/balloon_compaction.c @@ -21,7 +21,6 @@ static void balloon_page_enqueue_one(struct balloon_dev_info *b_dev_info, * memory corruption is possible and we should stop execution. */ BUG_ON(!trylock_page(page)); - list_del(&page->lru); balloon_page_insert(b_dev_info, page); unlock_page(page); __count_vm_event(BALLOON_INFLATE); @@ -33,7 +32,7 @@ static void balloon_page_enqueue_one(struct balloon_dev_info *b_dev_info, * @b_dev_info: balloon device descriptor where we will insert a new page to * @pages: pages to enqueue - allocated using balloon_page_alloc. * - * Driver must call it to properly enqueue a balloon pages before definitively + * Driver must call it to properly enqueue balloon pages before definitively * removing it from the guest system. * * Return: number of pages that were enqueued. @@ -47,6 +46,7 @@ size_t balloon_page_list_enqueue(struct balloon_dev_info *b_dev_info, spin_lock_irqsave(&b_dev_info->pages_lock, flags); list_for_each_entry_safe(page, tmp, pages, lru) { + list_del(&page->lru); balloon_page_enqueue_one(b_dev_info, page); n_pages++; } @@ -128,13 +128,19 @@ struct page *balloon_page_alloc(void) EXPORT_SYMBOL_GPL(balloon_page_alloc); /* - * balloon_page_enqueue - allocates a new page and inserts it into the balloon - * page list. + * balloon_page_enqueue - inserts a new page into the balloon page list. + * * @b_dev_info: balloon device descriptor where we will insert a new page to * @page: new page to enqueue - allocated using balloon_page_alloc. * * Driver must call it to properly enqueue a new allocated balloon page * before definitively removing it from the guest system. + * + * Drivers must not call balloon_page_enqueue on pages that have been + * pushed to a list with balloon_page_push before removing them with + * balloon_page_pop. To all pages on a list, use balloon_page_list_enqueue + * instead. + * * This function returns the page address for the recently enqueued page or * NULL in the case we fail to allocate a new page this turn. */