From: Wei Wang <wei.w.wang@intel.com> To: Peter Xu <peterx@redhat.com> Cc: qemu-devel@nongnu.org, virtio-dev@lists.oasis-open.org, mst@redhat.com, quintela@redhat.com, dgilbert@redhat.com, yang.zhang.wz@gmail.com, quan.xu0@gmail.com, liliang.opensource@gmail.com, pbonzini@redhat.com, nilal@redhat.com Subject: Re: [Qemu-devel] [PATCH v7 4/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT Date: Wed, 06 Jun 2018 18:11:50 +0800 [thread overview] Message-ID: <5B17B366.5030802@intel.com> (raw) In-Reply-To: <20180606064315.GB7815@xz-mi> On 06/06/2018 02:43 PM, Peter Xu wrote: > On Tue, Apr 24, 2018 at 02:13:47PM +0800, Wei Wang wrote: > > [...] > > + if (elem->out_num) { > + size = iov_to_buf(elem->out_sg, elem->out_num, 0, &id, sizeof(id)); > + virtqueue_push(vq, elem, size); > Silly question: is this sending the same id back to guest? Why? No. It's just giving back the used buffer. > >> + g_free(elem); >> + >> + virtio_tswap32s(vdev, &id); >> + if (unlikely(size != sizeof(id))) { >> + virtio_error(vdev, "received an incorrect cmd id"); > Forgot to unlock? > > Maybe we can just move the lock operations outside: > > mutex_lock(); > while (1) { > ... > if (block) { > qemu_cond_wait(); > } > ... > if (skip) { > continue; > } > ... > if (error) { > break; > } > ... > } > mutex_unlock(); I got similar comments from Michael, and it will be while (1) { lock; func(); unlock(); } All the unlock inside the body will be gone. > [...] >> +static const VMStateDescription vmstate_virtio_balloon_free_page_report = { >> + .name = "virtio-balloon-device/free-page-report", >> + .version_id = 1, >> + .minimum_version_id = 1, >> + .needed = virtio_balloon_free_page_support, >> + .fields = (VMStateField[]) { >> + VMSTATE_UINT32(free_page_report_cmd_id, VirtIOBalloon), >> + VMSTATE_UINT32(poison_val, VirtIOBalloon), > (could we move all the poison-related lines into another patch or > postpone? after all we don't support it yet, do we?) > We don't support migrating poison value, but guest maybe use it, so we are actually disabling this feature in that case. Probably good to leave the code together to handle that case. >> + if (virtio_has_feature(s->host_features, >> + VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { >> + s->free_page_vq = virtio_add_queue(vdev, VIRTQUEUE_MAX_SIZE, NULL); >> + s->free_page_report_status = FREE_PAGE_REPORT_S_STOP; >> + s->free_page_report_cmd_id = >> + VIRTIO_BALLOON_FREE_PAGE_REPORT_CMD_ID_MIN - 1; > Why explicitly -1? I thought ID_MIN would be fine too? Yes, that will also be fine. Since we states that the cmd id will be from [MIN, MAX], and we make s->free_page_report_cmd_id++ in start(), using VIRTIO_BALLOON_FREE_PAGE_REPORT_CMD_ID_MIN here will make it [MIN + 1, MAX]. > >> + if (s->iothread) { >> + object_ref(OBJECT(s->iothread)); >> + s->free_page_bh = aio_bh_new(iothread_get_aio_context(s->iothread), >> + virtio_balloon_poll_free_page_hints, s); > Just to mention that now we can create internal iothreads. Please > have a look at iothread_create(). Thanks. I noticed that, but I think configuring via the cmd line can let people share the iothread with other devices that need it. Best, Wei
WARNING: multiple messages have this Message-ID (diff)
From: Wei Wang <wei.w.wang@intel.com> To: Peter Xu <peterx@redhat.com> Cc: qemu-devel@nongnu.org, virtio-dev@lists.oasis-open.org, mst@redhat.com, quintela@redhat.com, dgilbert@redhat.com, yang.zhang.wz@gmail.com, quan.xu0@gmail.com, liliang.opensource@gmail.com, pbonzini@redhat.com, nilal@redhat.com Subject: [virtio-dev] Re: [Qemu-devel] [PATCH v7 4/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT Date: Wed, 06 Jun 2018 18:11:50 +0800 [thread overview] Message-ID: <5B17B366.5030802@intel.com> (raw) In-Reply-To: <20180606064315.GB7815@xz-mi> On 06/06/2018 02:43 PM, Peter Xu wrote: > On Tue, Apr 24, 2018 at 02:13:47PM +0800, Wei Wang wrote: > > [...] > > + if (elem->out_num) { > + size = iov_to_buf(elem->out_sg, elem->out_num, 0, &id, sizeof(id)); > + virtqueue_push(vq, elem, size); > Silly question: is this sending the same id back to guest? Why? No. It's just giving back the used buffer. > >> + g_free(elem); >> + >> + virtio_tswap32s(vdev, &id); >> + if (unlikely(size != sizeof(id))) { >> + virtio_error(vdev, "received an incorrect cmd id"); > Forgot to unlock? > > Maybe we can just move the lock operations outside: > > mutex_lock(); > while (1) { > ... > if (block) { > qemu_cond_wait(); > } > ... > if (skip) { > continue; > } > ... > if (error) { > break; > } > ... > } > mutex_unlock(); I got similar comments from Michael, and it will be while (1) { lock; func(); unlock(); } All the unlock inside the body will be gone. > [...] >> +static const VMStateDescription vmstate_virtio_balloon_free_page_report = { >> + .name = "virtio-balloon-device/free-page-report", >> + .version_id = 1, >> + .minimum_version_id = 1, >> + .needed = virtio_balloon_free_page_support, >> + .fields = (VMStateField[]) { >> + VMSTATE_UINT32(free_page_report_cmd_id, VirtIOBalloon), >> + VMSTATE_UINT32(poison_val, VirtIOBalloon), > (could we move all the poison-related lines into another patch or > postpone? after all we don't support it yet, do we?) > We don't support migrating poison value, but guest maybe use it, so we are actually disabling this feature in that case. Probably good to leave the code together to handle that case. >> + if (virtio_has_feature(s->host_features, >> + VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { >> + s->free_page_vq = virtio_add_queue(vdev, VIRTQUEUE_MAX_SIZE, NULL); >> + s->free_page_report_status = FREE_PAGE_REPORT_S_STOP; >> + s->free_page_report_cmd_id = >> + VIRTIO_BALLOON_FREE_PAGE_REPORT_CMD_ID_MIN - 1; > Why explicitly -1? I thought ID_MIN would be fine too? Yes, that will also be fine. Since we states that the cmd id will be from [MIN, MAX], and we make s->free_page_report_cmd_id++ in start(), using VIRTIO_BALLOON_FREE_PAGE_REPORT_CMD_ID_MIN here will make it [MIN + 1, MAX]. > >> + if (s->iothread) { >> + object_ref(OBJECT(s->iothread)); >> + s->free_page_bh = aio_bh_new(iothread_get_aio_context(s->iothread), >> + virtio_balloon_poll_free_page_hints, s); > Just to mention that now we can create internal iothreads. Please > have a look at iothread_create(). Thanks. I noticed that, but I think configuring via the cmd line can let people share the iothread with other devices that need it. Best, Wei --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org
next prev parent reply other threads:[~2018-06-06 10:08 UTC|newest] Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-04-24 6:13 [Qemu-devel] [PATCH v7 0/5] virtio-balloon: free page hint reporting support Wei Wang 2018-04-24 6:13 ` [virtio-dev] " Wei Wang 2018-04-24 6:13 ` [Qemu-devel] [PATCH v7 1/5] bitmap: bitmap_count_one_with_offset Wei Wang 2018-04-24 6:13 ` [virtio-dev] " Wei Wang 2018-04-24 6:13 ` [Qemu-devel] [PATCH v7 2/5] migration: use bitmap_mutex in migration_bitmap_clear_dirty Wei Wang 2018-04-24 6:13 ` [virtio-dev] " Wei Wang 2018-06-01 3:37 ` [Qemu-devel] " Peter Xu 2018-04-24 6:13 ` [Qemu-devel] [PATCH v7 3/5] migration: API to clear bits of guest free pages from the dirty bitmap Wei Wang 2018-04-24 6:13 ` [virtio-dev] " Wei Wang 2018-06-01 4:00 ` [Qemu-devel] " Peter Xu 2018-06-01 7:36 ` Wei Wang 2018-06-01 7:36 ` [virtio-dev] " Wei Wang 2018-06-01 10:06 ` Peter Xu 2018-06-01 12:32 ` Wei Wang 2018-06-01 12:32 ` [virtio-dev] " Wei Wang 2018-06-04 2:49 ` Peter Xu 2018-06-04 7:43 ` Wei Wang 2018-06-04 7:43 ` [virtio-dev] " Wei Wang 2018-04-24 6:13 ` [Qemu-devel] [PATCH v7 4/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT Wei Wang 2018-04-24 6:13 ` [virtio-dev] " Wei Wang 2018-05-29 15:24 ` [Qemu-devel] " Michael S. Tsirkin 2018-05-29 15:24 ` [virtio-dev] " Michael S. Tsirkin 2018-05-30 9:12 ` [Qemu-devel] " Wei Wang 2018-05-30 9:12 ` [virtio-dev] " Wei Wang 2018-05-30 12:47 ` [Qemu-devel] " Michael S. Tsirkin 2018-05-30 12:47 ` [virtio-dev] " Michael S. Tsirkin 2018-05-31 2:27 ` [Qemu-devel] " Wei Wang 2018-05-31 2:27 ` [virtio-dev] " Wei Wang 2018-05-31 17:42 ` [Qemu-devel] " Michael S. Tsirkin 2018-05-31 17:42 ` [virtio-dev] " Michael S. Tsirkin 2018-06-01 3:18 ` [Qemu-devel] " Wei Wang 2018-06-01 3:18 ` [virtio-dev] " Wei Wang 2018-06-04 8:04 ` [Qemu-devel] " Wei Wang 2018-06-04 8:04 ` [virtio-dev] " Wei Wang 2018-06-05 6:58 ` [Qemu-devel] " Peter Xu 2018-06-05 13:22 ` Wei Wang 2018-06-05 13:22 ` [virtio-dev] " Wei Wang 2018-06-06 5:42 ` [Qemu-devel] " Peter Xu 2018-06-06 10:04 ` Wei Wang 2018-06-06 10:04 ` [virtio-dev] " Wei Wang 2018-06-06 11:02 ` [Qemu-devel] " Peter Xu 2018-06-07 5:24 ` Wei Wang 2018-06-07 5:24 ` [virtio-dev] " Wei Wang 2018-06-07 6:32 ` [Qemu-devel] " Peter Xu 2018-06-07 11:59 ` Wei Wang 2018-06-07 11:59 ` [virtio-dev] " Wei Wang 2018-06-08 2:17 ` [Qemu-devel] " Peter Xu 2018-06-08 7:14 ` Wei Wang 2018-06-08 7:14 ` [virtio-dev] " Wei Wang 2018-06-08 7:31 ` [Qemu-devel] " Wei Wang 2018-06-08 7:31 ` [virtio-dev] " Wei Wang 2018-06-06 6:43 ` [Qemu-devel] " Peter Xu 2018-06-06 10:11 ` Wei Wang [this message] 2018-06-06 10:11 ` [virtio-dev] " Wei Wang 2018-06-07 3:17 ` Peter Xu 2018-06-07 5:29 ` Wei Wang 2018-06-07 5:29 ` [virtio-dev] " Wei Wang 2018-06-07 6:58 ` Peter Xu 2018-06-07 12:01 ` Wei Wang 2018-06-07 12:01 ` [virtio-dev] " Wei Wang 2018-06-08 1:37 ` Peter Xu 2018-06-08 1:58 ` Peter Xu 2018-06-08 1:58 ` Michael S. Tsirkin 2018-06-08 1:58 ` [virtio-dev] " Michael S. Tsirkin 2018-06-08 2:34 ` Peter Xu 2018-06-08 2:49 ` Michael S. Tsirkin 2018-06-08 2:49 ` [virtio-dev] " Michael S. Tsirkin 2018-06-08 3:34 ` Peter Xu 2018-04-24 6:13 ` [Qemu-devel] [PATCH v7 5/5] migration: use the free page hint feature from balloon Wei Wang 2018-04-24 6:13 ` [virtio-dev] " Wei Wang 2018-04-24 6:42 ` [Qemu-devel] [PATCH v7 0/5] virtio-balloon: free page hint reporting support Wei Wang 2018-04-24 6:42 ` [virtio-dev] " Wei Wang 2018-05-14 1:22 ` [Qemu-devel] " Wei Wang 2018-05-14 1:22 ` [virtio-dev] " Wei Wang 2018-05-29 15:00 ` [Qemu-devel] " Hailiang Zhang 2018-05-29 15:24 ` Michael S. Tsirkin 2018-05-29 15:24 ` [virtio-dev] " Michael S. Tsirkin 2018-06-01 4:58 ` Peter Xu 2018-06-01 5:07 ` Peter Xu 2018-06-01 7:29 ` Wei Wang 2018-06-01 7:29 ` [virtio-dev] " Wei Wang 2018-06-01 10:02 ` Peter Xu 2018-06-01 12:31 ` Wei Wang 2018-06-01 12:31 ` [virtio-dev] " Wei Wang 2018-06-01 7:21 ` Wei Wang 2018-06-01 7:21 ` [virtio-dev] " Wei Wang 2018-06-01 10:40 ` Peter Xu 2018-06-01 15:33 ` Dr. David Alan Gilbert 2018-06-05 6:42 ` Peter Xu 2018-06-05 14:40 ` Michael S. Tsirkin 2018-06-05 14:40 ` [virtio-dev] " Michael S. Tsirkin 2018-06-05 14:39 ` Michael S. Tsirkin 2018-06-05 14:39 ` [virtio-dev] " Michael S. Tsirkin
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