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[209.132.183.28]) by mx.google.com with ESMTPS id 4si18296957uat.189.2019.07.24.12.56.56 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Jul 2019 12:56:56 -0700 (PDT) Received-SPF: pass (google.com: domain of david@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of david@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D582A330272; Wed, 24 Jul 2019 19:56:55 +0000 (UTC) Received: from [10.36.116.35] (ovpn-116-35.ams2.redhat.com [10.36.116.35]) by smtp.corp.redhat.com (Postfix) with ESMTP id E7AFB605C3; Wed, 24 Jul 2019 19:56:44 +0000 (UTC) Subject: Re: [RFC][Patch v11 2/2] virtio-balloon: page_hinting: reporting to the host To: "Michael S. Tsirkin" , Nitesh Narayan Lal Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, pbonzini@redhat.com, lcapitulino@redhat.com, pagupta@redhat.com, wei.w.wang@intel.com, yang.zhang.wz@gmail.com, riel@surriel.com, dodgen@google.com, konrad.wilk@oracle.com, dhildenb@redhat.com, aarcange@redhat.com, alexander.duyck@gmail.com, john.starks@microsoft.com, dave.hansen@intel.com, mhocko@suse.com References: <20190710195158.19640-1-nitesh@redhat.com> <20190710195158.19640-3-nitesh@redhat.com> <20190724153951-mutt-send-email-mst@kernel.org> From: David Hildenbrand Openpgp: preference=signencrypt Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwX4EEwECACgFAljj9eoCGwMFCQlmAYAGCwkI BwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEE3eEPcA/4Na5IIP/3T/FIQMxIfNzZshIq687qgG 8UbspuE/YSUDdv7r5szYTK6KPTlqN8NAcSfheywbuYD9A4ZeSBWD3/NAVUdrCaRP2IvFyELj xoMvfJccbq45BxzgEspg/bVahNbyuBpLBVjVWwRtFCUEXkyazksSv8pdTMAs9IucChvFmmq3 jJ2vlaz9lYt/lxN246fIVceckPMiUveimngvXZw21VOAhfQ+/sofXF8JCFv2mFcBDoa7eYob s0FLpmqFaeNRHAlzMWgSsP80qx5nWWEvRLdKWi533N2vC/EyunN3HcBwVrXH4hxRBMco3jvM m8VKLKao9wKj82qSivUnkPIwsAGNPdFoPbgghCQiBjBe6A75Z2xHFrzo7t1jg7nQfIyNC7ez MZBJ59sqA9EDMEJPlLNIeJmqslXPjmMFnE7Mby/+335WJYDulsRybN+W5rLT5aMvhC6x6POK z55fMNKrMASCzBJum2Fwjf/VnuGRYkhKCqqZ8gJ3OvmR50tInDV2jZ1DQgc3i550T5JDpToh dPBxZocIhzg+MBSRDXcJmHOx/7nQm3iQ6iLuwmXsRC6f5FbFefk9EjuTKcLMvBsEx+2DEx0E UnmJ4hVg7u1PQ+2Oy+Lh/opK/BDiqlQ8Pz2jiXv5xkECvr/3Sv59hlOCZMOaiLTTjtOIU7Tq 7ut6OL64oAq+zsFNBFXLn5EBEADn1959INH2cwYJv0tsxf5MUCghCj/CA/lc/LMthqQ773ga uB9mN+F1rE9cyyXb6jyOGn+GUjMbnq1o121Vm0+neKHUCBtHyseBfDXHA6m4B3mUTWo13nid 0e4AM71r0DS8+KYh6zvweLX/LL5kQS9GQeT+QNroXcC1NzWbitts6TZ+IrPOwT1hfB4WNC+X 2n4AzDqp3+ILiVST2DT4VBc11Gz6jijpC/KI5Al8ZDhRwG47LUiuQmt3yqrmN63V9wzaPhC+ xbwIsNZlLUvuRnmBPkTJwwrFRZvwu5GPHNndBjVpAfaSTOfppyKBTccu2AXJXWAE1Xjh6GOC 8mlFjZwLxWFqdPHR1n2aPVgoiTLk34LR/bXO+e0GpzFXT7enwyvFFFyAS0Nk1q/7EChPcbRb hJqEBpRNZemxmg55zC3GLvgLKd5A09MOM2BrMea+l0FUR+PuTenh2YmnmLRTro6eZ/qYwWkC u8FFIw4pT0OUDMyLgi+GI1aMpVogTZJ70FgV0pUAlpmrzk/bLbRkF3TwgucpyPtcpmQtTkWS gDS50QG9DR/1As3LLLcNkwJBZzBG6PWbvcOyrwMQUF1nl4SSPV0LLH63+BrrHasfJzxKXzqg rW28CTAE2x8qi7e/6M/+XXhrsMYG+uaViM7n2je3qKe7ofum3s4vq7oFCPsOgwARAQABwsFl BBgBAgAPBQJVy5+RAhsMBQkJZgGAAAoJEE3eEPcA/4NagOsP/jPoIBb/iXVbM+fmSHOjEshl KMwEl/m5iLj3iHnHPVLBUWrXPdS7iQijJA/VLxjnFknhaS60hkUNWexDMxVVP/6lbOrs4bDZ NEWDMktAeqJaFtxackPszlcpRVkAs6Msn9tu8hlvB517pyUgvuD7ZS9gGOMmYwFQDyytpepo YApVV00P0u3AaE0Cj/o71STqGJKZxcVhPaZ+LR+UCBZOyKfEyq+ZN311VpOJZ1IvTExf+S/5 lqnciDtbO3I4Wq0ArLX1gs1q1XlXLaVaA3yVqeC8E7kOchDNinD3hJS4OX0e1gdsx/e6COvy qNg5aL5n0Kl4fcVqM0LdIhsubVs4eiNCa5XMSYpXmVi3HAuFyg9dN+x8thSwI836FoMASwOl C7tHsTjnSGufB+D7F7ZBT61BffNBBIm1KdMxcxqLUVXpBQHHlGkbwI+3Ye+nE6HmZH7IwLwV W+Ajl7oYF+jeKaH4DZFtgLYGLtZ1LDwKPjX7VAsa4Yx7S5+EBAaZGxK510MjIx6SGrZWBrrV TEvdV00F2MnQoeXKzD7O4WFbL55hhyGgfWTHwZ457iN9SgYi1JLPqWkZB0JRXIEtjd4JEQcx +8Umfre0Xt4713VxMygW0PnQt5aSQdMD58jHFxTk092mU+yIHj5LeYgvwSgZN4airXk5yRXl SE+xAvmumFBY Organization: Red Hat GmbH Message-ID: Date: Wed, 24 Jul 2019 21:56:44 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20190724153951-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Wed, 24 Jul 2019 19:56:56 +0000 (UTC) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 24.07.19 21:47, Michael S. Tsirkin wrote: > On Wed, Jul 10, 2019 at 03:51:58PM -0400, Nitesh Narayan Lal wrote: >> Enables the kernel to negotiate VIRTIO_BALLOON_F_HINTING feature with the >> host. If it is available and page_hinting_flag is set to true, page_hinting >> is enabled and its callbacks are configured along with the max_pages count >> which indicates the maximum number of pages that can be isolated and hinted >> at a time. Currently, only free pages of order >= (MAX_ORDER - 2) are >> reported. To prevent any false OOM max_pages count is set to 16. >> >> By default page_hinting feature is enabled and gets loaded as soon >> as the virtio-balloon driver is loaded. However, it could be disabled >> by writing the page_hinting_flag which is a virtio-balloon parameter. >> >> Signed-off-by: Nitesh Narayan Lal >> --- >> drivers/virtio/Kconfig | 1 + >> drivers/virtio/virtio_balloon.c | 91 ++++++++++++++++++++++++++++- >> include/uapi/linux/virtio_balloon.h | 11 ++++ >> 3 files changed, 102 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig >> index 023fc3bc01c6..dcc0cb4269a5 100644 >> --- a/drivers/virtio/Kconfig >> +++ b/drivers/virtio/Kconfig >> @@ -47,6 +47,7 @@ config VIRTIO_BALLOON >> tristate "Virtio balloon driver" >> depends on VIRTIO >> select MEMORY_BALLOON >> + select PAGE_HINTING >> ---help--- >> This driver supports increasing and decreasing the amount >> of memory within a KVM guest. >> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c >> index 44339fc87cc7..1fb0eb0b2c20 100644 >> --- a/drivers/virtio/virtio_balloon.c >> +++ b/drivers/virtio/virtio_balloon.c >> @@ -18,6 +18,7 @@ >> #include >> #include >> #include >> +#include >> >> /* >> * Balloon device works in 4K page units. So each page is pointed to by >> @@ -35,6 +36,12 @@ >> /* The size of a free page block in bytes */ >> #define VIRTIO_BALLOON_FREE_PAGE_SIZE \ >> (1 << (VIRTIO_BALLOON_FREE_PAGE_ORDER + PAGE_SHIFT)) >> +/* Number of isolated pages to be reported to the host at a time. >> + * TODO: >> + * 1. Set it via host. >> + * 2. Find an optimal value for this. >> + */ >> +#define PAGE_HINTING_MAX_PAGES 16 >> >> #ifdef CONFIG_BALLOON_COMPACTION >> static struct vfsmount *balloon_mnt; >> @@ -45,6 +52,7 @@ enum virtio_balloon_vq { >> VIRTIO_BALLOON_VQ_DEFLATE, >> VIRTIO_BALLOON_VQ_STATS, >> VIRTIO_BALLOON_VQ_FREE_PAGE, >> + VIRTIO_BALLOON_VQ_HINTING, >> VIRTIO_BALLOON_VQ_MAX >> }; >> >> @@ -54,7 +62,8 @@ enum virtio_balloon_config_read { >> >> struct virtio_balloon { >> struct virtio_device *vdev; >> - struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq; >> + struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq, >> + *hinting_vq; >> >> /* Balloon's own wq for cpu-intensive work items */ >> struct workqueue_struct *balloon_wq; >> @@ -112,6 +121,9 @@ struct virtio_balloon { >> >> /* To register a shrinker to shrink memory upon memory pressure */ >> struct shrinker shrinker; >> + >> + /* Array object pointing at the isolated pages ready for hinting */ >> + struct isolated_memory isolated_pages[PAGE_HINTING_MAX_PAGES]; >> }; >> >> static struct virtio_device_id id_table[] = { >> @@ -119,6 +131,66 @@ static struct virtio_device_id id_table[] = { >> { 0 }, >> }; >> >> +static struct page_hinting_config page_hinting_conf; >> +bool page_hinting_flag = true; >> +struct virtio_balloon *hvb; >> +module_param(page_hinting_flag, bool, 0444); >> +MODULE_PARM_DESC(page_hinting_flag, "Enable page hinting"); >> + >> +static int page_hinting_report(void) >> +{ >> + struct virtqueue *vq = hvb->hinting_vq; >> + struct scatterlist sg; >> + int err = 0, unused; >> + >> + mutex_lock(&hvb->balloon_lock); >> + sg_init_one(&sg, hvb->isolated_pages, sizeof(hvb->isolated_pages[0]) * >> + PAGE_HINTING_MAX_PAGES); >> + err = virtqueue_add_outbuf(vq, &sg, 1, hvb, GFP_KERNEL); > > In Alex's patch, I really like it that he's passing pages as sg > entries. IMHO that's both cleaner and allows seamless > support for arbitrary page sizes. > +1 I especially like passing full addresses and sizes instead of PFNs and orders (compared to Alex's v1, where he would pass PFNs and orders). -- Thanks, David / dhildenb