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[209.132.183.28]) by mx.google.com with ESMTPS id s47si14402464qth.305.2019.07.24.13.07.04 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Jul 2019 13:07:04 -0700 (PDT) Received-SPF: pass (google.com: domain of nitesh@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 nitesh@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=nitesh@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 728B1308FBAC; Wed, 24 Jul 2019 20:07:03 +0000 (UTC) Received: from [10.18.17.163] (dhcp-17-163.bos.redhat.com [10.18.17.163]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 194C11843C; Wed, 24 Jul 2019 20:06:52 +0000 (UTC) Subject: Re: [RFC][Patch v11 2/2] virtio-balloon: page_hinting: reporting to the host To: "Michael S. Tsirkin" 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, david@redhat.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: Nitesh Narayan Lal Openpgp: preference=signencrypt Autocrypt: addr=nitesh@redhat.com; prefer-encrypt=mutual; keydata= mQINBFl4pQoBEADT/nXR2JOfsCjDgYmE2qonSGjkM1g8S6p9UWD+bf7YEAYYYzZsLtbilFTe z4nL4AV6VJmC7dBIlTi3Mj2eymD/2dkKP6UXlliWkq67feVg1KG+4UIp89lFW7v5Y8Muw3Fm uQbFvxyhN8n3tmhRe+ScWsndSBDxYOZgkbCSIfNPdZrHcnOLfA7xMJZeRCjqUpwhIjxQdFA7 n0s0KZ2cHIsemtBM8b2WXSQG9CjqAJHVkDhrBWKThDRF7k80oiJdEQlTEiVhaEDURXq+2XmG jpCnvRQDb28EJSsQlNEAzwzHMeplddfB0vCg9fRk/kOBMDBtGsTvNT9OYUZD+7jaf0gvBvBB lbKmmMMX7uJB+ejY7bnw6ePNrVPErWyfHzR5WYrIFUtgoR3LigKnw5apzc7UIV9G8uiIcZEn C+QJCK43jgnkPcSmwVPztcrkbC84g1K5v2Dxh9amXKLBA1/i+CAY8JWMTepsFohIFMXNLj+B RJoOcR4HGYXZ6CAJa3Glu3mCmYqHTOKwezJTAvmsCLd3W7WxOGF8BbBjVaPjcZfavOvkin0u DaFvhAmrzN6lL0msY17JCZo046z8oAqkyvEflFbC0S1R/POzehKrzQ1RFRD3/YzzlhmIowkM BpTqNBeHEzQAlIhQuyu1ugmQtfsYYq6FPmWMRfFPes/4JUU/PQARAQABtCVOaXRlc2ggTmFy YXlhbiBMYWwgPG5pbGFsQHJlZGhhdC5jb20+iQI9BBMBCAAnBQJZeKUKAhsjBQkJZgGABQsJ CAcCBhUICQoLAgQWAgMBAh4BAheAAAoJEKOGQNwGMqM56lEP/A2KMs/pu0URcVk/kqVwcBhU SnvB8DP3lDWDnmVrAkFEOnPX7GTbactQ41wF/xwjwmEmTzLrMRZpkqz2y9mV0hWHjqoXbOCS 6RwK3ri5e2ThIPoGxFLt6TrMHgCRwm8YuOSJ97o+uohCTN8pmQ86KMUrDNwMqRkeTRW9wWIQ EdDqW44VwelnyPwcmWHBNNb1Kd8j3xKlHtnS45vc6WuoKxYRBTQOwI/5uFpDZtZ1a5kq9Ak/ MOPDDZpd84rqd+IvgMw5z4a5QlkvOTpScD21G3gjmtTEtyfahltyDK/5i8IaQC3YiXJCrqxE r7/4JMZeOYiKpE9iZMtS90t4wBgbVTqAGH1nE/ifZVAUcCtycD0f3egX9CHe45Ad4fsF3edQ ESa5tZAogiA4Hc/yQpnnf43a3aQ67XPOJXxS0Qptzu4vfF9h7kTKYWSrVesOU3QKYbjEAf95 NewF9FhAlYqYrwIwnuAZ8TdXVDYt7Z3z506//sf6zoRwYIDA8RDqFGRuPMXUsoUnf/KKPrtR ceLcSUP/JCNiYbf1/QtW8S6Ca/4qJFXQHp0knqJPGmwuFHsarSdpvZQ9qpxD3FnuPyo64S2N Dfq8TAeifNp2pAmPY2PAHQ3nOmKgMG8Gn5QiORvMUGzSz8Lo31LW58NdBKbh6bci5+t/HE0H pnyVf5xhNC/FuQINBFl4pQoBEACr+MgxWHUP76oNNYjRiNDhaIVtnPRqxiZ9v4H5FPxJy9UD Bqr54rifr1E+K+yYNPt/Po43vVL2cAyfyI/LVLlhiY4yH6T1n+Di/hSkkviCaf13gczuvgz4 KVYLwojU8+naJUsiCJw01MjO3pg9GQ+47HgsnRjCdNmmHiUQqksMIfd8k3reO9SUNlEmDDNB XuSzkHjE5y/R/6p8uXaVpiKPfHoULjNRWaFc3d2JGmxJpBdpYnajoz61m7XJlgwl/B5Ql/6B dHGaX3VHxOZsfRfugwYF9CkrPbyO5PK7yJ5vaiWre7aQ9bmCtXAomvF1q3/qRwZp77k6i9R3 tWfXjZDOQokw0u6d6DYJ0Vkfcwheg2i/Mf/epQl7Pf846G3PgSnyVK6cRwerBl5a68w7xqVU 4KgAh0DePjtDcbcXsKRT9D63cfyfrNE+ea4i0SVik6+N4nAj1HbzWHTk2KIxTsJXypibOKFX 2VykltxutR1sUfZBYMkfU4PogE7NjVEU7KtuCOSAkYzIWrZNEQrxYkxHLJsWruhSYNRsqVBy KvY6JAsq/i5yhVd5JKKU8wIOgSwC9P6mXYRgwPyfg15GZpnw+Fpey4bCDkT5fMOaCcS+vSU1 UaFmC4Ogzpe2BW2DOaPU5Ik99zUFNn6cRmOOXArrryjFlLT5oSOe4IposgWzdwARAQABiQIl BBgBCAAPBQJZeKUKAhsMBQkJZgGAAAoJEKOGQNwGMqM5ELoP/jj9d9gF1Al4+9bngUlYohYu 0sxyZo9IZ7Yb7cHuJzOMqfgoP4tydP4QCuyd9Q2OHHL5AL4VFNb8SvqAxxYSPuDJTI3JZwI7 d8JTPKwpulMSUaJE8ZH9n8A/+sdC3CAD4QafVBcCcbFe1jifHmQRdDrvHV9Es14QVAOTZhnJ vweENyHEIxkpLsyUUDuVypIo6y/Cws+EBCWt27BJi9GH/EOTB0wb+2ghCs/i3h8a+bi+bS7L FCCm/AxIqxRurh2UySn0P/2+2eZvneJ1/uTgfxnjeSlwQJ1BWzMAdAHQO1/lnbyZgEZEtUZJ x9d9ASekTtJjBMKJXAw7GbB2dAA/QmbA+Q+Xuamzm/1imigz6L6sOt2n/X/SSc33w8RJUyor SvAIoG/zU2Y76pKTgbpQqMDmkmNYFMLcAukpvC4ki3Sf086TdMgkjqtnpTkEElMSFJC8npXv 3QnGGOIfFug/qs8z03DLPBz9VYS26jiiN7QIJVpeeEdN/LKnaz5LO+h5kNAyj44qdF2T2AiF HxnZnxO5JNP5uISQH3FjxxGxJkdJ8jKzZV7aT37sC+Rp0o3KNc+GXTR+GSVq87Xfuhx0LRST NK9ZhT0+qkiN7npFLtNtbzwqaqceq3XhafmCiw8xrtzCnlB/C4SiBr/93Ip4kihXJ0EuHSLn VujM7c/b4pps Organization: Red Hat Inc, Message-ID: <74181cce-5db2-3d0a-00d6-16966c876dcc@redhat.com> Date: Wed, 24 Jul 2019 16:06:52 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190724153951-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Wed, 24 Jul 2019 20:07:03 +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 7/24/19 3:47 PM, 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. > > In particular .... +1. I will also incorporate this change. > >> + if (!err) >> + virtqueue_kick(hvb->hinting_vq); >> + wait_event(hvb->acked, virtqueue_get_buf(vq, &unused)); >> + mutex_unlock(&hvb->balloon_lock); >> + return err; >> +} >> + >> +void hint_pages(struct list_head *pages) >> +{ >> + struct device *dev = &hvb->vdev->dev; >> + struct page *page, *next; >> + int idx = 0, order, err; >> + unsigned long pfn; >> + >> + list_for_each_entry_safe(page, next, pages, lru) { >> + pfn = page_to_pfn(page); >> + order = page_private(page); >> + hvb->isolated_pages[idx].phys_addr = pfn << PAGE_SHIFT; >> + hvb->isolated_pages[idx].size = (1 << order) * PAGE_SIZE; >> + idx++; > ... passing native endian-ness values to host creates pain for > cross-endian configurations. > >> + } >> + err = page_hinting_report(); >> + if (err < 0) >> + dev_err(dev, "Failed to hint pages, err = %d\n", err); >> +} >> + >> +static void page_hinting_init(struct virtio_balloon *vb) >> +{ >> + struct device *dev = &vb->vdev->dev; >> + int err; >> + >> + page_hinting_conf.hint_pages = hint_pages; >> + page_hinting_conf.max_pages = PAGE_HINTING_MAX_PAGES; >> + err = page_hinting_enable(&page_hinting_conf); >> + if (err < 0) { >> + dev_err(dev, "Failed to enable page-hinting, err = %d\n", err); > It would be nicer to disable the feature bit then, or fail probe > completely. Makes sense. Thanks. >> + page_hinting_flag = false; >> + page_hinting_conf.hint_pages = NULL; >> + page_hinting_conf.max_pages = 0; >> + return; >> + } >> + hvb = vb; >> +} >> + >> static u32 page_to_balloon_pfn(struct page *page) >> { >> unsigned long pfn = page_to_pfn(page); >> @@ -475,6 +547,7 @@ static int init_vqs(struct virtio_balloon *vb) >> names[VIRTIO_BALLOON_VQ_DEFLATE] = "deflate"; >> names[VIRTIO_BALLOON_VQ_STATS] = NULL; >> names[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; >> + names[VIRTIO_BALLOON_VQ_HINTING] = NULL; >> >> if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { >> names[VIRTIO_BALLOON_VQ_STATS] = "stats"; >> @@ -486,11 +559,18 @@ static int init_vqs(struct virtio_balloon *vb) >> callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; >> } >> >> + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HINTING)) { >> + names[VIRTIO_BALLOON_VQ_HINTING] = "hinting_vq"; >> + callbacks[VIRTIO_BALLOON_VQ_HINTING] = balloon_ack; >> + } >> err = vb->vdev->config->find_vqs(vb->vdev, VIRTIO_BALLOON_VQ_MAX, >> vqs, callbacks, names, NULL, NULL); >> if (err) >> return err; >> >> + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HINTING)) >> + vb->hinting_vq = vqs[VIRTIO_BALLOON_VQ_HINTING]; >> + >> vb->inflate_vq = vqs[VIRTIO_BALLOON_VQ_INFLATE]; >> vb->deflate_vq = vqs[VIRTIO_BALLOON_VQ_DEFLATE]; >> if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { >> @@ -929,6 +1009,9 @@ static int virtballoon_probe(struct virtio_device *vdev) >> if (err) >> goto out_del_balloon_wq; >> } >> + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HINTING) && >> + page_hinting_flag) >> + page_hinting_init(vb); >> virtio_device_ready(vdev); >> >> if (towards_target(vb)) >> @@ -976,6 +1059,10 @@ static void virtballoon_remove(struct virtio_device *vdev) >> destroy_workqueue(vb->balloon_wq); >> } >> >> + if (!page_hinting_flag) { >> + hvb = NULL; >> + page_hinting_disable(); >> + } >> remove_common(vb); >> #ifdef CONFIG_BALLOON_COMPACTION >> if (vb->vb_dev_info.inode) >> @@ -1030,8 +1117,10 @@ static unsigned int features[] = { >> VIRTIO_BALLOON_F_MUST_TELL_HOST, >> VIRTIO_BALLOON_F_STATS_VQ, >> VIRTIO_BALLOON_F_DEFLATE_ON_OOM, >> + VIRTIO_BALLOON_F_HINTING, >> VIRTIO_BALLOON_F_FREE_PAGE_HINT, >> VIRTIO_BALLOON_F_PAGE_POISON, >> + VIRTIO_BALLOON_F_HINTING, >> }; >> >> static struct virtio_driver virtio_balloon_driver = { >> diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h >> index a1966cd7b677..29eed0ec83d3 100644 >> --- a/include/uapi/linux/virtio_balloon.h >> +++ b/include/uapi/linux/virtio_balloon.h >> @@ -36,6 +36,8 @@ >> #define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */ >> #define VIRTIO_BALLOON_F_FREE_PAGE_HINT 3 /* VQ to report free pages */ >> #define VIRTIO_BALLOON_F_PAGE_POISON 4 /* Guest is using page poisoning */ >> +/* TODO: Find a better name to avoid any confusion with FREE_PAGE_HINT */ >> +#define VIRTIO_BALLOON_F_HINTING 5 /* Page hinting virtqueue */ >> >> /* Size of a PFN in the balloon interface. */ >> #define VIRTIO_BALLOON_PFN_SHIFT 12 >> @@ -108,4 +110,13 @@ struct virtio_balloon_stat { >> __virtio64 val; >> } __attribute__((packed)); >> >> +/* >> + * struct isolated_memory- holds the pages which will be reported to the host. >> + * @phys_add: physical address associated with a page. >> + * @size: total size of memory to be reported. >> + */ >> +struct isolated_memory { >> + __virtio64 phys_addr; >> + __virtio64 size; >> +}; >> #endif /* _LINUX_VIRTIO_BALLOON_H */ >> -- >> 2.21.0 -- Thanks Nitesh