From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-2736-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 [66.179.20.138]) by lists.oasis-open.org (Postfix) with ESMTP id 88D985818FE7 for ; Fri, 1 Dec 2017 07:49:58 -0800 (PST) Date: Fri, 1 Dec 2017 17:49:36 +0200 From: "Michael S. Tsirkin" Message-ID: <20171201173951-mutt-send-email-mst@kernel.org> References: <1511963726-34070-1-git-send-email-wei.w.wang@intel.com> <1511963726-34070-11-git-send-email-wei.w.wang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1511963726-34070-11-git-send-email-wei.w.wang@intel.com> Subject: [virtio-dev] Re: [PATCH v18 10/10] virtio-balloon: don't report free pages when page poisoning is enabled To: Wei Wang Cc: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, linux-mm@kvack.org, mhocko@kernel.org, akpm@linux-foundation.org, mawilcox@microsoft.com, david@redhat.com, penguin-kernel@I-love.SAKURA.ne.jp, cornelia.huck@de.ibm.com, mgorman@techsingularity.net, aarcange@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com, willy@infradead.org, liliang.opensource@gmail.com, yang.zhang.wz@gmail.com, quan.xu@aliyun.com, nilal@redhat.com, riel@redhat.com List-ID: On Wed, Nov 29, 2017 at 09:55:26PM +0800, Wei Wang wrote: > The guest free pages should not be discarded by the live migration thread > when page poisoning is enabled with PAGE_POISONING_NO_SANITY=n, because > skipping the transfer of such poisoned free pages will trigger false > positive when new pages are allocated and checked on the destination. > This patch skips the reporting of free pages in the above case. > > Reported-by: Michael S. Tsirkin > Signed-off-by: Wei Wang > Cc: Michal Hocko > --- > drivers/virtio/virtio_balloon.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index 035bd3a..6ac4cff 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -652,7 +652,9 @@ static void report_free_page(struct work_struct *work) > /* Start by sending the obtained cmd id to the host with an outbuf */ > send_one_desc(vb, vb->free_page_vq, virt_to_phys(&vb->start_cmd_id), > sizeof(uint32_t), false, true, false); > - walk_free_mem_block(vb, 0, &virtio_balloon_send_free_pages); > + if (!(page_poisoning_enabled() && > + !IS_ENABLED(CONFIG_PAGE_POISONING_NO_SANITY))) > + walk_free_mem_block(vb, 0, &virtio_balloon_send_free_pages); > /* > * End by sending the stop id to the host with an outbuf. Use the > * non-batching mode here to trigger a kick after adding the stop id. PAGE_POISONING_ZERO is actually OK. But I really would prefer it that we still send pages to host, otherwise debugging becomes much harder. And it does not have to be completely useless, even though you can not discard them as they would be zero-filled then. How about a config field telling host what should be there in the free pages? This way even though host can not discard them, host can send them out without reading them, still a win. > -- > 2.7.4 --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH v18 10/10] virtio-balloon: don't report free pages when page poisoning is enabled Date: Fri, 1 Dec 2017 17:49:36 +0200 Message-ID: <20171201173951-mutt-send-email-mst@kernel.org> References: <1511963726-34070-1-git-send-email-wei.w.wang@intel.com> <1511963726-34070-11-git-send-email-wei.w.wang@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, linux-mm@kvack.org, mhocko@kernel.org, akpm@linux-foundation.org, mawilcox@microsoft.com, david@redhat.com, penguin-kernel@I-love.SAKURA.ne.jp, cornelia.huck@de.ibm.com, mgorman@techsingularity.net, aarcange@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com, willy@infradead.org, liliang.opensource@gmail.com, yang.zhang.wz@gmail.com, quan.xu@aliyun.com, nilal@redhat.com, riel@redhat.com To: Wei Wang Return-path: Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Content-Disposition: inline In-Reply-To: <1511963726-34070-11-git-send-email-wei.w.wang@intel.com> List-Id: kvm.vger.kernel.org On Wed, Nov 29, 2017 at 09:55:26PM +0800, Wei Wang wrote: > The guest free pages should not be discarded by the live migration thread > when page poisoning is enabled with PAGE_POISONING_NO_SANITY=n, because > skipping the transfer of such poisoned free pages will trigger false > positive when new pages are allocated and checked on the destination. > This patch skips the reporting of free pages in the above case. > > Reported-by: Michael S. Tsirkin > Signed-off-by: Wei Wang > Cc: Michal Hocko > --- > drivers/virtio/virtio_balloon.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index 035bd3a..6ac4cff 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -652,7 +652,9 @@ static void report_free_page(struct work_struct *work) > /* Start by sending the obtained cmd id to the host with an outbuf */ > send_one_desc(vb, vb->free_page_vq, virt_to_phys(&vb->start_cmd_id), > sizeof(uint32_t), false, true, false); > - walk_free_mem_block(vb, 0, &virtio_balloon_send_free_pages); > + if (!(page_poisoning_enabled() && > + !IS_ENABLED(CONFIG_PAGE_POISONING_NO_SANITY))) > + walk_free_mem_block(vb, 0, &virtio_balloon_send_free_pages); > /* > * End by sending the stop id to the host with an outbuf. Use the > * non-batching mode here to trigger a kick after adding the stop id. PAGE_POISONING_ZERO is actually OK. But I really would prefer it that we still send pages to host, otherwise debugging becomes much harder. And it does not have to be completely useless, even though you can not discard them as they would be zero-filled then. How about a config field telling host what should be there in the free pages? This way even though host can not discard them, host can send them out without reading them, still a win. > -- > 2.7.4 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ot0-f200.google.com (mail-ot0-f200.google.com [74.125.82.200]) by kanga.kvack.org (Postfix) with ESMTP id 780A36B025E for ; Fri, 1 Dec 2017 10:49:58 -0500 (EST) Received: by mail-ot0-f200.google.com with SMTP id s10so5317579oth.14 for ; Fri, 01 Dec 2017 07:49:58 -0800 (PST) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id d37si2257894oic.368.2017.12.01.07.49.56 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 01 Dec 2017 07:49:57 -0800 (PST) Date: Fri, 1 Dec 2017 17:49:36 +0200 From: "Michael S. Tsirkin" Subject: Re: [PATCH v18 10/10] virtio-balloon: don't report free pages when page poisoning is enabled Message-ID: <20171201173951-mutt-send-email-mst@kernel.org> References: <1511963726-34070-1-git-send-email-wei.w.wang@intel.com> <1511963726-34070-11-git-send-email-wei.w.wang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1511963726-34070-11-git-send-email-wei.w.wang@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Wei Wang Cc: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, linux-mm@kvack.org, mhocko@kernel.org, akpm@linux-foundation.org, mawilcox@microsoft.com, david@redhat.com, penguin-kernel@I-love.SAKURA.ne.jp, cornelia.huck@de.ibm.com, mgorman@techsingularity.net, aarcange@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com, willy@infradead.org, liliang.opensource@gmail.com, yang.zhang.wz@gmail.com, quan.xu@aliyun.com, nilal@redhat.com, riel@redhat.com On Wed, Nov 29, 2017 at 09:55:26PM +0800, Wei Wang wrote: > The guest free pages should not be discarded by the live migration thread > when page poisoning is enabled with PAGE_POISONING_NO_SANITY=n, because > skipping the transfer of such poisoned free pages will trigger false > positive when new pages are allocated and checked on the destination. > This patch skips the reporting of free pages in the above case. > > Reported-by: Michael S. Tsirkin > Signed-off-by: Wei Wang > Cc: Michal Hocko > --- > drivers/virtio/virtio_balloon.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index 035bd3a..6ac4cff 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -652,7 +652,9 @@ static void report_free_page(struct work_struct *work) > /* Start by sending the obtained cmd id to the host with an outbuf */ > send_one_desc(vb, vb->free_page_vq, virt_to_phys(&vb->start_cmd_id), > sizeof(uint32_t), false, true, false); > - walk_free_mem_block(vb, 0, &virtio_balloon_send_free_pages); > + if (!(page_poisoning_enabled() && > + !IS_ENABLED(CONFIG_PAGE_POISONING_NO_SANITY))) > + walk_free_mem_block(vb, 0, &virtio_balloon_send_free_pages); > /* > * End by sending the stop id to the host with an outbuf. Use the > * non-batching mode here to trigger a kick after adding the stop id. PAGE_POISONING_ZERO is actually OK. But I really would prefer it that we still send pages to host, otherwise debugging becomes much harder. And it does not have to be completely useless, even though you can not discard them as they would be zero-filled then. How about a config field telling host what should be there in the free pages? This way even though host can not discard them, host can send them out without reading them, still a win. > -- > 2.7.4 -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53473) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eKnah-0004CM-UU for qemu-devel@nongnu.org; Fri, 01 Dec 2017 10:51:51 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eKnZd-0003o3-Tz for qemu-devel@nongnu.org; Fri, 01 Dec 2017 10:51:03 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41306) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eKnZd-0003nO-Jt for qemu-devel@nongnu.org; Fri, 01 Dec 2017 10:49:57 -0500 Date: Fri, 1 Dec 2017 17:49:36 +0200 From: "Michael S. Tsirkin" Message-ID: <20171201173951-mutt-send-email-mst@kernel.org> References: <1511963726-34070-1-git-send-email-wei.w.wang@intel.com> <1511963726-34070-11-git-send-email-wei.w.wang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1511963726-34070-11-git-send-email-wei.w.wang@intel.com> Subject: Re: [Qemu-devel] [PATCH v18 10/10] virtio-balloon: don't report free pages when page poisoning is enabled List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Wei Wang Cc: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, linux-mm@kvack.org, mhocko@kernel.org, akpm@linux-foundation.org, mawilcox@microsoft.com, david@redhat.com, penguin-kernel@I-love.SAKURA.ne.jp, cornelia.huck@de.ibm.com, mgorman@techsingularity.net, aarcange@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com, willy@infradead.org, liliang.opensource@gmail.com, yang.zhang.wz@gmail.com, quan.xu@aliyun.com, nilal@redhat.com, riel@redhat.com On Wed, Nov 29, 2017 at 09:55:26PM +0800, Wei Wang wrote: > The guest free pages should not be discarded by the live migration thread > when page poisoning is enabled with PAGE_POISONING_NO_SANITY=n, because > skipping the transfer of such poisoned free pages will trigger false > positive when new pages are allocated and checked on the destination. > This patch skips the reporting of free pages in the above case. > > Reported-by: Michael S. Tsirkin > Signed-off-by: Wei Wang > Cc: Michal Hocko > --- > drivers/virtio/virtio_balloon.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index 035bd3a..6ac4cff 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -652,7 +652,9 @@ static void report_free_page(struct work_struct *work) > /* Start by sending the obtained cmd id to the host with an outbuf */ > send_one_desc(vb, vb->free_page_vq, virt_to_phys(&vb->start_cmd_id), > sizeof(uint32_t), false, true, false); > - walk_free_mem_block(vb, 0, &virtio_balloon_send_free_pages); > + if (!(page_poisoning_enabled() && > + !IS_ENABLED(CONFIG_PAGE_POISONING_NO_SANITY))) > + walk_free_mem_block(vb, 0, &virtio_balloon_send_free_pages); > /* > * End by sending the stop id to the host with an outbuf. Use the > * non-batching mode here to trigger a kick after adding the stop id. PAGE_POISONING_ZERO is actually OK. But I really would prefer it that we still send pages to host, otherwise debugging becomes much harder. And it does not have to be completely useless, even though you can not discard them as they would be zero-filled then. How about a config field telling host what should be there in the free pages? This way even though host can not discard them, host can send them out without reading them, still a win. > -- > 2.7.4