From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C4C6C3F2D1 for ; Mon, 2 Mar 2020 13:52:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EE3F120656 for ; Mon, 2 Mar 2020 13:52:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="SdF4HhRS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727262AbgCBNwf (ORCPT ); Mon, 2 Mar 2020 08:52:35 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:37111 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726872AbgCBNwf (ORCPT ); Mon, 2 Mar 2020 08:52:35 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1583157153; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VciLBaV7pUjkHDnp5otMw2hIIXH26cxj8VOXjFbvJwY=; b=SdF4HhRSm1YZ5Pqyw4/mqVKIzitbWtcHLsslSwfnlvZvuMMOfi95LtJmBnfDub3DWSw/W8 SxgatwvxGSB8Hm34Fgfzm9DMXG0fnwktDPyXKSQcJpLSyURJJn1V9QmBccU6IM5LNJuFY2 1H4+l4flfy8DUl1eGo8PZLC4BeDyGzc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-328-YSTvRB3mNKaadRmgcuPvpg-1; Mon, 02 Mar 2020 08:52:31 -0500 X-MC-Unique: YSTvRB3mNKaadRmgcuPvpg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9A62918FE86A; Mon, 2 Mar 2020 13:52:28 +0000 (UTC) Received: from t480s.redhat.com (ovpn-116-114.ams2.redhat.com [10.36.116.114]) by smtp.corp.redhat.com (Postfix) with ESMTP id 19E1E19C4F; Mon, 2 Mar 2020 13:52:14 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, virtio-dev@lists.oasis-open.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, Michal Hocko , Andrew Morton , "Michael S . Tsirkin" , David Hildenbrand , Juergen Gross , Konrad Rzeszutek Wilk , Pavel Tatashin , Alexander Duyck , Vlastimil Babka , Johannes Weiner , Anthony Yznaga , Michal Hocko , Oscar Salvador , Mel Gorman , Mike Rapoport , Dan Williams , Anshuman Khandual , Qian Cai , Pingfan Liu Subject: [PATCH v1 06/11] mm: Allow to offline unmovable PageOffline() pages via MEM_GOING_OFFLINE Date: Mon, 2 Mar 2020 14:49:36 +0100 Message-Id: <20200302134941.315212-7-david@redhat.com> In-Reply-To: <20200302134941.315212-1-david@redhat.com> References: <20200302134941.315212-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org virtio-mem wants to allow to offline memory blocks of which some parts were unplugged (allocated via alloc_contig_range()), especially, to later offline and remove completely unplugged memory blocks. The important part is that PageOffline() has to remain set until the section is offline, so these pages will never get accessed (e.g., when dumping). The pages shoul= d not be handed back to the buddy (which would require clearing PageOffline= () and result in issues if offlining fails and the pages are suddenly in the buddy). Let's allow to do that by allowing to isolate any PageOffline() page when offlining. This way, we can reach the memory hotplug notifier MEM_GOING_OFFLINE, where the driver can signal that he is fine with offlining this page by dropping its reference count. PageOffline() pages with a reference count of 0 can then be skipped when offlining the pages (like if they were free, however they are not in the buddy). Anybody who uses PageOffline() pages and does not agree to offline them (e.g., Hyper-V balloon, XEN balloon, VMWare balloon for 2MB pages) will n= ot decrement the reference count and make offlining fail when trying to migrate such an unmovable page. So there should be no observable change. Same applies to balloon compaction users (movable PageOffline() pages), t= he pages will simply be migrated. Note 1: If offlining fails, a driver has to increment the reference count again in MEM_CANCEL_OFFLINE. Note 2: A driver that makes use of this has to be aware that re-onlining the memory block has to be handled by hooking into onlining code (online_page_callback_t), resetting the page PageOffline() and not giving them to the buddy. Cc: Andrew Morton Cc: Juergen Gross Cc: Konrad Rzeszutek Wilk Cc: Pavel Tatashin Cc: Alexander Duyck Cc: Vlastimil Babka Cc: Johannes Weiner Cc: Anthony Yznaga Cc: Michal Hocko Cc: Oscar Salvador Cc: Mel Gorman Cc: Mike Rapoport Cc: Dan Williams Cc: Anshuman Khandual Cc: Qian Cai Cc: Pingfan Liu Signed-off-by: David Hildenbrand --- include/linux/page-flags.h | 10 +++++++++ mm/memory_hotplug.c | 44 +++++++++++++++++++++++++++++--------- mm/page_alloc.c | 24 +++++++++++++++++++++ mm/page_isolation.c | 9 ++++++++ 4 files changed, 77 insertions(+), 10 deletions(-) diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 49c2697046b9..fd6d4670ccc3 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -772,6 +772,16 @@ PAGE_TYPE_OPS(Buddy, buddy) * not onlined when onlining the section). * The content of these pages is effectively stale. Such pages should no= t * be touched (read/write/dump/save) except by their owner. + * + * If a driver wants to allow to offline unmovable PageOffline() pages w= ithout + * putting them back to the buddy, it can do so via the memory notifier = by + * decrementing the reference count in MEM_GOING_OFFLINE and incrementin= g the + * reference count in MEM_CANCEL_OFFLINE. When offlining, the PageOfflin= e() + * pages (now with a reference count of zero) are treated like free page= s, + * allowing the containing memory block to get offlined. A driver that + * relies on this feature is aware that re-onlining the memory block wil= l + * require to re-set the pages PageOffline() and not giving them to the + * buddy via online_page_callback_t. */ PAGE_TYPE_OPS(Offline, offline) =20 diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 1a00b5a37ef6..ab1c31e67fd1 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1221,11 +1221,17 @@ struct zone *test_pages_in_a_zone(unsigned long s= tart_pfn, =20 /* * Scan pfn range [start,end) to find movable/migratable pages (LRU page= s, - * non-lru movable pages and hugepages). We scan pfn because it's much - * easier than scanning over linked list. This function returns the pfn - * of the first found movable page if it's found, otherwise 0. + * non-lru movable pages and hugepages). Will skip over most unmovable + * pages (esp., pages that can be skipped when offlining), but bail out = on + * definitely unmovable pages. + * + * Returns: + * 0 in case a movable page is found and movable_pfn was updated. + * -ENOENT in case no movable page was found. + * -EBUSY in case a definitely unmovable page was found. */ -static unsigned long scan_movable_pages(unsigned long start, unsigned lo= ng end) +static int scan_movable_pages(unsigned long start, unsigned long end, + unsigned long *movable_pfn) { unsigned long pfn; =20 @@ -1237,18 +1243,30 @@ static unsigned long scan_movable_pages(unsigned = long start, unsigned long end) continue; page =3D pfn_to_page(pfn); if (PageLRU(page)) - return pfn; + goto found; if (__PageMovable(page)) - return pfn; + goto found; + + /* + * PageOffline() pages that are not marked __PageMovable() and + * have a reference count > 0 (after MEM_GOING_OFFLINE) are + * definitely unmovable. If their reference count would be 0, + * they could at least be skipped when offlining memory. + */ + if (PageOffline(page) && page_count(page)) + return -EBUSY; =20 if (!PageHuge(page)) continue; head =3D compound_head(page); if (page_huge_active(head)) - return pfn; + goto found; skip =3D compound_nr(head) - (page - head); pfn +=3D skip - 1; } + return -ENOENT; +found: + *movable_pfn =3D pfn; return 0; } =20 @@ -1515,7 +1533,8 @@ static int __ref __offline_pages(unsigned long star= t_pfn, } =20 do { - for (pfn =3D start_pfn; pfn;) { + pfn =3D start_pfn; + do { if (signal_pending(current)) { ret =3D -EINTR; reason =3D "signal backoff"; @@ -1525,14 +1544,19 @@ static int __ref __offline_pages(unsigned long st= art_pfn, cond_resched(); lru_add_drain_all(); =20 - pfn =3D scan_movable_pages(pfn, end_pfn); - if (pfn) { + ret =3D scan_movable_pages(pfn, end_pfn, &pfn); + if (!ret) { /* * TODO: fatal migration failures should bail * out */ do_migrate_range(pfn, end_pfn); } + } while (!ret); + + if (ret !=3D -ENOENT) { + reason =3D "unmovable page"; + goto failed_removal_isolated; } =20 /* diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 8d7be3f33e26..baa60222215f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -8366,6 +8366,19 @@ struct page *has_unmovable_pages(struct zone *zone= , struct page *page, if ((flags & MEMORY_OFFLINE) && PageHWPoison(page)) continue; =20 + /* + * We treat all PageOffline() pages as movable when offlining + * to give drivers a chance to decrement their reference count + * in MEM_GOING_OFFLINE in order to indicate that these pages + * can be offlined as there are no direct references anymore. + * For actually unmovable PageOffline() where the driver does + * not support this, we will fail later when trying to actually + * move these pages that still have a reference count > 0. + * (false negatives in this function only) + */ + if ((flags & MEMORY_OFFLINE) && PageOffline(page)) + continue; + if (__PageMovable(page) || PageLRU(page)) continue; =20 @@ -8786,6 +8799,17 @@ __offline_isolated_pages(unsigned long start_pfn, = unsigned long end_pfn) offlined_pages++; continue; } + /* + * At this point all remaining PageOffline() pages have a + * reference count of 0 and can simply be skipped. + */ + if (PageOffline(page)) { + BUG_ON(page_count(page)); + BUG_ON(PageBuddy(page)); + pfn++; + offlined_pages++; + continue; + } =20 BUG_ON(page_count(page)); BUG_ON(!PageBuddy(page)); diff --git a/mm/page_isolation.c b/mm/page_isolation.c index 2c11a38d6e87..f6d07c5f0d34 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -151,6 +151,7 @@ __first_valid_page(unsigned long pfn, unsigned long n= r_pages) * a bit mask) * MEMORY_OFFLINE - isolate to offline (!allocate) memory * e.g., skip over PageHWPoison() pages + * and PageOffline() pages. * REPORT_FAILURE - report details about the failure to * isolate the range * @@ -259,6 +260,14 @@ __test_page_isolated_in_pageblock(unsigned long pfn,= unsigned long end_pfn, else if ((flags & MEMORY_OFFLINE) && PageHWPoison(page)) /* A HWPoisoned page cannot be also PageBuddy */ pfn++; + else if ((flags & MEMORY_OFFLINE) && PageOffline(page) && + !page_count(page)) + /* + * The responsible driver agreed to skip PageOffline() + * pages when offlining memory by dropping its + * reference in MEM_GOING_OFFLINE. + */ + pfn++; else break; } --=20 2.24.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-6859-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 8C98A985CDE for ; Mon, 2 Mar 2020 13:52:36 +0000 (UTC) From: David Hildenbrand Date: Mon, 2 Mar 2020 14:49:36 +0100 Message-Id: <20200302134941.315212-7-david@redhat.com> In-Reply-To: <20200302134941.315212-1-david@redhat.com> References: <20200302134941.315212-1-david@redhat.com> MIME-Version: 1.0 Subject: [virtio-dev] [PATCH v1 06/11] mm: Allow to offline unmovable PageOffline() pages via MEM_GOING_OFFLINE Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, virtio-dev@lists.oasis-open.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, Michal Hocko , Andrew Morton , "Michael S . Tsirkin" , David Hildenbrand , Juergen Gross , Konrad Rzeszutek Wilk , Pavel Tatashin , Alexander Duyck , Vlastimil Babka , Johannes Weiner , Anthony Yznaga , Michal Hocko , Oscar Salvador , Mel Gorman , Mike Rapoport , Dan Williams , Anshuman Khandual , Qian Cai , Pingfan Liu List-ID: virtio-mem wants to allow to offline memory blocks of which some parts were unplugged (allocated via alloc_contig_range()), especially, to later offline and remove completely unplugged memory blocks. The important part is that PageOffline() has to remain set until the section is offline, so these pages will never get accessed (e.g., when dumping). The pages should not be handed back to the buddy (which would require clearing PageOffline() and result in issues if offlining fails and the pages are suddenly in the buddy). Let's allow to do that by allowing to isolate any PageOffline() page when offlining. This way, we can reach the memory hotplug notifier MEM_GOING_OFFLINE, where the driver can signal that he is fine with offlining this page by dropping its reference count. PageOffline() pages with a reference count of 0 can then be skipped when offlining the pages (like if they were free, however they are not in the buddy). Anybody who uses PageOffline() pages and does not agree to offline them (e.g., Hyper-V balloon, XEN balloon, VMWare balloon for 2MB pages) will not decrement the reference count and make offlining fail when trying to migrate such an unmovable page. So there should be no observable change. Same applies to balloon compaction users (movable PageOffline() pages), the pages will simply be migrated. Note 1: If offlining fails, a driver has to increment the reference =09count again in MEM_CANCEL_OFFLINE. Note 2: A driver that makes use of this has to be aware that re-onlining =09the memory block has to be handled by hooking into onlining code =09(online_page_callback_t), resetting the page PageOffline() and =09not giving them to the buddy. Cc: Andrew Morton Cc: Juergen Gross Cc: Konrad Rzeszutek Wilk Cc: Pavel Tatashin Cc: Alexander Duyck Cc: Vlastimil Babka Cc: Johannes Weiner Cc: Anthony Yznaga Cc: Michal Hocko Cc: Oscar Salvador Cc: Mel Gorman Cc: Mike Rapoport Cc: Dan Williams Cc: Anshuman Khandual Cc: Qian Cai Cc: Pingfan Liu Signed-off-by: David Hildenbrand --- include/linux/page-flags.h | 10 +++++++++ mm/memory_hotplug.c | 44 +++++++++++++++++++++++++++++--------- mm/page_alloc.c | 24 +++++++++++++++++++++ mm/page_isolation.c | 9 ++++++++ 4 files changed, 77 insertions(+), 10 deletions(-) diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 49c2697046b9..fd6d4670ccc3 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -772,6 +772,16 @@ PAGE_TYPE_OPS(Buddy, buddy) * not onlined when onlining the section). * The content of these pages is effectively stale. Such pages should not * be touched (read/write/dump/save) except by their owner. + * + * If a driver wants to allow to offline unmovable PageOffline() pages wit= hout + * putting them back to the buddy, it can do so via the memory notifier by + * decrementing the reference count in MEM_GOING_OFFLINE and incrementing = the + * reference count in MEM_CANCEL_OFFLINE. When offlining, the PageOffline(= ) + * pages (now with a reference count of zero) are treated like free pages, + * allowing the containing memory block to get offlined. A driver that + * relies on this feature is aware that re-onlining the memory block will + * require to re-set the pages PageOffline() and not giving them to the + * buddy via online_page_callback_t. */ PAGE_TYPE_OPS(Offline, offline) =20 diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 1a00b5a37ef6..ab1c31e67fd1 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1221,11 +1221,17 @@ struct zone *test_pages_in_a_zone(unsigned long sta= rt_pfn, =20 /* * Scan pfn range [start,end) to find movable/migratable pages (LRU pages, - * non-lru movable pages and hugepages). We scan pfn because it's much - * easier than scanning over linked list. This function returns the pfn - * of the first found movable page if it's found, otherwise 0. + * non-lru movable pages and hugepages). Will skip over most unmovable + * pages (esp., pages that can be skipped when offlining), but bail out on + * definitely unmovable pages. + * + * Returns: + *=090 in case a movable page is found and movable_pfn was updated. + *=09-ENOENT in case no movable page was found. + *=09-EBUSY in case a definitely unmovable page was found. */ -static unsigned long scan_movable_pages(unsigned long start, unsigned long= end) +static int scan_movable_pages(unsigned long start, unsigned long end, +=09=09=09 unsigned long *movable_pfn) { =09unsigned long pfn; =20 @@ -1237,18 +1243,30 @@ static unsigned long scan_movable_pages(unsigned lo= ng start, unsigned long end) =09=09=09continue; =09=09page =3D pfn_to_page(pfn); =09=09if (PageLRU(page)) -=09=09=09return pfn; +=09=09=09goto found; =09=09if (__PageMovable(page)) -=09=09=09return pfn; +=09=09=09goto found; + +=09=09/* +=09=09 * PageOffline() pages that are not marked __PageMovable() and +=09=09 * have a reference count > 0 (after MEM_GOING_OFFLINE) are +=09=09 * definitely unmovable. If their reference count would be 0, +=09=09 * they could at least be skipped when offlining memory. +=09=09 */ +=09=09if (PageOffline(page) && page_count(page)) +=09=09=09return -EBUSY; =20 =09=09if (!PageHuge(page)) =09=09=09continue; =09=09head =3D compound_head(page); =09=09if (page_huge_active(head)) -=09=09=09return pfn; +=09=09=09goto found; =09=09skip =3D compound_nr(head) - (page - head); =09=09pfn +=3D skip - 1; =09} +=09return -ENOENT; +found: +=09*movable_pfn =3D pfn; =09return 0; } =20 @@ -1515,7 +1533,8 @@ static int __ref __offline_pages(unsigned long start_= pfn, =09} =20 =09do { -=09=09for (pfn =3D start_pfn; pfn;) { +=09=09pfn =3D start_pfn; +=09=09do { =09=09=09if (signal_pending(current)) { =09=09=09=09ret =3D -EINTR; =09=09=09=09reason =3D "signal backoff"; @@ -1525,14 +1544,19 @@ static int __ref __offline_pages(unsigned long star= t_pfn, =09=09=09cond_resched(); =09=09=09lru_add_drain_all(); =20 -=09=09=09pfn =3D scan_movable_pages(pfn, end_pfn); -=09=09=09if (pfn) { +=09=09=09ret =3D scan_movable_pages(pfn, end_pfn, &pfn); +=09=09=09if (!ret) { =09=09=09=09/* =09=09=09=09 * TODO: fatal migration failures should bail =09=09=09=09 * out =09=09=09=09 */ =09=09=09=09do_migrate_range(pfn, end_pfn); =09=09=09} +=09=09} while (!ret); + +=09=09if (ret !=3D -ENOENT) { +=09=09=09reason =3D "unmovable page"; +=09=09=09goto failed_removal_isolated; =09=09} =20 =09=09/* diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 8d7be3f33e26..baa60222215f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -8366,6 +8366,19 @@ struct page *has_unmovable_pages(struct zone *zone, = struct page *page, =09=09if ((flags & MEMORY_OFFLINE) && PageHWPoison(page)) =09=09=09continue; =20 +=09=09/* +=09=09 * We treat all PageOffline() pages as movable when offlining +=09=09 * to give drivers a chance to decrement their reference count +=09=09 * in MEM_GOING_OFFLINE in order to indicate that these pages +=09=09 * can be offlined as there are no direct references anymore. +=09=09 * For actually unmovable PageOffline() where the driver does +=09=09 * not support this, we will fail later when trying to actually +=09=09 * move these pages that still have a reference count > 0. +=09=09 * (false negatives in this function only) +=09=09 */ +=09=09if ((flags & MEMORY_OFFLINE) && PageOffline(page)) +=09=09=09continue; + =09=09if (__PageMovable(page) || PageLRU(page)) =09=09=09continue; =20 @@ -8786,6 +8799,17 @@ __offline_isolated_pages(unsigned long start_pfn, un= signed long end_pfn) =09=09=09offlined_pages++; =09=09=09continue; =09=09} +=09=09/* +=09=09 * At this point all remaining PageOffline() pages have a +=09=09 * reference count of 0 and can simply be skipped. +=09=09 */ +=09=09if (PageOffline(page)) { +=09=09=09BUG_ON(page_count(page)); +=09=09=09BUG_ON(PageBuddy(page)); +=09=09=09pfn++; +=09=09=09offlined_pages++; +=09=09=09continue; +=09=09} =20 =09=09BUG_ON(page_count(page)); =09=09BUG_ON(!PageBuddy(page)); diff --git a/mm/page_isolation.c b/mm/page_isolation.c index 2c11a38d6e87..f6d07c5f0d34 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -151,6 +151,7 @@ __first_valid_page(unsigned long pfn, unsigned long nr_= pages) *=09=09=09a bit mask) *=09=09=09MEMORY_OFFLINE - isolate to offline (!allocate) memory *=09=09=09=09=09 e.g., skip over PageHWPoison() pages + *=09=09=09=09=09 and PageOffline() pages. *=09=09=09REPORT_FAILURE - report details about the failure to *=09=09=09isolate the range * @@ -259,6 +260,14 @@ __test_page_isolated_in_pageblock(unsigned long pfn, u= nsigned long end_pfn, =09=09else if ((flags & MEMORY_OFFLINE) && PageHWPoison(page)) =09=09=09/* A HWPoisoned page cannot be also PageBuddy */ =09=09=09pfn++; +=09=09else if ((flags & MEMORY_OFFLINE) && PageOffline(page) && +=09=09=09 !page_count(page)) +=09=09=09/* +=09=09=09 * The responsible driver agreed to skip PageOffline() +=09=09=09 * pages when offlining memory by dropping its +=09=09=09 * reference in MEM_GOING_OFFLINE. +=09=09=09 */ +=09=09=09pfn++; =09=09else =09=09=09break; =09} --=20 2.24.1 --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org