* [PATCH v4 1/3] virtio-balloon: tweak config_changed implementation [not found] <1546923005-40517-1-git-send-email-wei.w.wang@intel.com> @ 2019-01-08 4:50 ` Wei Wang 2019-01-08 4:50 ` [PATCH v4 2/3] virtio-balloon: improve update_balloon_size_func Wei Wang ` (4 subsequent siblings) 5 siblings, 0 replies; 6+ messages in thread From: Wei Wang @ 2019-01-08 4:50 UTC (permalink / raw) To: virtio-dev, linux-kernel, stable, virtualization, kvm, mst, cohuck Cc: pasic, dgilbert, pbonzini virtio-ccw has deadlock issues with reading the config space inside the interrupt context, so we tweak the virtballoon_changed implementation by moving the config read operations into the related workqueue contexts. The config_read_bitmap is used as a flag to the workqueue callbacks about the related config fields that need to be read. The cmd_id_received is also renamed to cmd_id_received_cache, and the value should be obtained via virtio_balloon_cmd_id_received. Fixes: 86a559787e6f ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT") Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Wei Wang <wei.w.wang@intel.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Halil Pasic <pasic@linux.ibm.com> Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> --- drivers/virtio/virtio_balloon.c | 98 +++++++++++++++++++++++++++-------------- 1 file changed, 65 insertions(+), 33 deletions(-) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 728ecd1..45d32f5 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -61,6 +61,10 @@ enum virtio_balloon_vq { VIRTIO_BALLOON_VQ_MAX }; +enum virtio_balloon_config_read { + VIRTIO_BALLOON_CONFIG_READ_CMD_ID = 0, +}; + struct virtio_balloon { struct virtio_device *vdev; struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq; @@ -77,14 +81,20 @@ struct virtio_balloon { /* Prevent updating balloon when it is being canceled. */ spinlock_t stop_update_lock; bool stop_update; + /* Bitmap to indicate if reading the related config fields are needed */ + unsigned long config_read_bitmap; /* The list of allocated free pages, waiting to be given back to mm */ struct list_head free_page_list; spinlock_t free_page_list_lock; /* The number of free page blocks on the above list */ unsigned long num_free_page_blocks; - /* The cmd id received from host */ - u32 cmd_id_received; + /* + * The cmd id received from host. + * Read it via virtio_balloon_cmd_id_received to get the latest value + * sent from host. + */ + u32 cmd_id_received_cache; /* The cmd id that is actively in use */ __virtio32 cmd_id_active; /* Buffer to store the stop sign */ @@ -390,37 +400,31 @@ static unsigned long return_free_pages_to_mm(struct virtio_balloon *vb, return num_returned; } +static void virtio_balloon_queue_free_page_work(struct virtio_balloon *vb) +{ + if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) + return; + + /* No need to queue the work if the bit was already set. */ + if (test_and_set_bit(VIRTIO_BALLOON_CONFIG_READ_CMD_ID, + &vb->config_read_bitmap)) + return; + + queue_work(vb->balloon_wq, &vb->report_free_page_work); +} + static void virtballoon_changed(struct virtio_device *vdev) { struct virtio_balloon *vb = vdev->priv; unsigned long flags; - s64 diff = towards_target(vb); - - if (diff) { - spin_lock_irqsave(&vb->stop_update_lock, flags); - if (!vb->stop_update) - queue_work(system_freezable_wq, - &vb->update_balloon_size_work); - spin_unlock_irqrestore(&vb->stop_update_lock, flags); - } - if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { - virtio_cread(vdev, struct virtio_balloon_config, - free_page_report_cmd_id, &vb->cmd_id_received); - if (vb->cmd_id_received == VIRTIO_BALLOON_CMD_ID_DONE) { - /* Pass ULONG_MAX to give back all the free pages */ - return_free_pages_to_mm(vb, ULONG_MAX); - } else if (vb->cmd_id_received != VIRTIO_BALLOON_CMD_ID_STOP && - vb->cmd_id_received != - virtio32_to_cpu(vdev, vb->cmd_id_active)) { - spin_lock_irqsave(&vb->stop_update_lock, flags); - if (!vb->stop_update) { - queue_work(vb->balloon_wq, - &vb->report_free_page_work); - } - spin_unlock_irqrestore(&vb->stop_update_lock, flags); - } + spin_lock_irqsave(&vb->stop_update_lock, flags); + if (!vb->stop_update) { + queue_work(system_freezable_wq, + &vb->update_balloon_size_work); + virtio_balloon_queue_free_page_work(vb); } + spin_unlock_irqrestore(&vb->stop_update_lock, flags); } static void update_balloon_size(struct virtio_balloon *vb) @@ -527,6 +531,17 @@ static int init_vqs(struct virtio_balloon *vb) return 0; } +static u32 virtio_balloon_cmd_id_received(struct virtio_balloon *vb) +{ + if (test_and_clear_bit(VIRTIO_BALLOON_CONFIG_READ_CMD_ID, + &vb->config_read_bitmap)) + virtio_cread(vb->vdev, struct virtio_balloon_config, + free_page_report_cmd_id, + &vb->cmd_id_received_cache); + + return vb->cmd_id_received_cache; +} + static int send_cmd_id_start(struct virtio_balloon *vb) { struct scatterlist sg; @@ -537,7 +552,8 @@ static int send_cmd_id_start(struct virtio_balloon *vb) while (virtqueue_get_buf(vq, &unused)) ; - vb->cmd_id_active = cpu_to_virtio32(vb->vdev, vb->cmd_id_received); + vb->cmd_id_active = cpu_to_virtio32(vb->vdev, + virtio_balloon_cmd_id_received(vb)); sg_init_one(&sg, &vb->cmd_id_active, sizeof(vb->cmd_id_active)); err = virtqueue_add_outbuf(vq, &sg, 1, &vb->cmd_id_active, GFP_KERNEL); if (!err) @@ -620,7 +636,8 @@ static int send_free_pages(struct virtio_balloon *vb) * stop the reporting. */ cmd_id_active = virtio32_to_cpu(vb->vdev, vb->cmd_id_active); - if (cmd_id_active != vb->cmd_id_received) + if (unlikely(cmd_id_active != + virtio_balloon_cmd_id_received(vb))) break; /* @@ -637,11 +654,9 @@ static int send_free_pages(struct virtio_balloon *vb) return 0; } -static void report_free_page_func(struct work_struct *work) +static void virtio_balloon_report_free_page(struct virtio_balloon *vb) { int err; - struct virtio_balloon *vb = container_of(work, struct virtio_balloon, - report_free_page_work); struct device *dev = &vb->vdev->dev; /* Start by sending the received cmd id to host with an outbuf. */ @@ -659,6 +674,23 @@ static void report_free_page_func(struct work_struct *work) dev_err(dev, "Failed to send a stop id, err = %d\n", err); } +static void report_free_page_func(struct work_struct *work) +{ + struct virtio_balloon *vb = container_of(work, struct virtio_balloon, + report_free_page_work); + u32 cmd_id_received; + + cmd_id_received = virtio_balloon_cmd_id_received(vb); + if (cmd_id_received == VIRTIO_BALLOON_CMD_ID_DONE) { + /* Pass ULONG_MAX to give back all the free pages */ + return_free_pages_to_mm(vb, ULONG_MAX); + } else if (cmd_id_received != VIRTIO_BALLOON_CMD_ID_STOP && + cmd_id_received != + virtio32_to_cpu(vb->vdev, vb->cmd_id_active)) { + virtio_balloon_report_free_page(vb); + } +} + #ifdef CONFIG_BALLOON_COMPACTION /* * virtballoon_migratepage - perform the balloon page migration on behalf of @@ -885,7 +917,7 @@ static int virtballoon_probe(struct virtio_device *vdev) goto out_del_vqs; } INIT_WORK(&vb->report_free_page_work, report_free_page_func); - vb->cmd_id_received = VIRTIO_BALLOON_CMD_ID_STOP; + vb->cmd_id_received_cache = VIRTIO_BALLOON_CMD_ID_STOP; vb->cmd_id_active = cpu_to_virtio32(vb->vdev, VIRTIO_BALLOON_CMD_ID_STOP); vb->cmd_id_stop = cpu_to_virtio32(vb->vdev, -- 2.7.4 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v4 2/3] virtio-balloon: improve update_balloon_size_func [not found] <1546923005-40517-1-git-send-email-wei.w.wang@intel.com> 2019-01-08 4:50 ` [PATCH v4 1/3] virtio-balloon: tweak config_changed implementation Wei Wang @ 2019-01-08 4:50 ` Wei Wang 2019-01-08 4:50 ` [PATCH v4 3/3] virtio_balloon: remove the unnecessary 0-initialization Wei Wang ` (3 subsequent siblings) 5 siblings, 0 replies; 6+ messages in thread From: Wei Wang @ 2019-01-08 4:50 UTC (permalink / raw) To: virtio-dev, linux-kernel, stable, virtualization, kvm, mst, cohuck Cc: pasic, dgilbert, pbonzini There is no need to update the balloon actual register when there is no ballooning request. This patch avoids update_balloon_size when diff is 0. Signed-off-by: Wei Wang <wei.w.wang@intel.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Halil Pasic <pasic@linux.ibm.com> Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> --- drivers/virtio/virtio_balloon.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 45d32f5..d48c12c 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -457,9 +457,12 @@ static void update_balloon_size_func(struct work_struct *work) update_balloon_size_work); diff = towards_target(vb); + if (!diff) + return; + if (diff > 0) diff -= fill_balloon(vb, diff); - else if (diff < 0) + else diff += leak_balloon(vb, -diff); update_balloon_size(vb); -- 2.7.4 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v4 3/3] virtio_balloon: remove the unnecessary 0-initialization [not found] <1546923005-40517-1-git-send-email-wei.w.wang@intel.com> 2019-01-08 4:50 ` [PATCH v4 1/3] virtio-balloon: tweak config_changed implementation Wei Wang 2019-01-08 4:50 ` [PATCH v4 2/3] virtio-balloon: improve update_balloon_size_func Wei Wang @ 2019-01-08 4:50 ` Wei Wang [not found] ` <1546923005-40517-2-git-send-email-wei.w.wang@intel.com> ` (2 subsequent siblings) 5 siblings, 0 replies; 6+ messages in thread From: Wei Wang @ 2019-01-08 4:50 UTC (permalink / raw) To: virtio-dev, linux-kernel, stable, virtualization, kvm, mst, cohuck Cc: pasic, dgilbert, pbonzini We've changed to kzalloc the vb struct, so no need to 0-initialize this field one more time. Signed-off-by: Wei Wang <wei.w.wang@intel.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> --- drivers/virtio/virtio_balloon.c | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index d48c12c..048959a 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -925,7 +925,6 @@ static int virtballoon_probe(struct virtio_device *vdev) VIRTIO_BALLOON_CMD_ID_STOP); vb->cmd_id_stop = cpu_to_virtio32(vb->vdev, VIRTIO_BALLOON_CMD_ID_STOP); - vb->num_free_page_blocks = 0; spin_lock_init(&vb->free_page_list_lock); INIT_LIST_HEAD(&vb->free_page_list); if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON)) { -- 2.7.4 ^ permalink raw reply related [flat|nested] 6+ messages in thread
[parent not found: <1546923005-40517-2-git-send-email-wei.w.wang@intel.com>]
* Re: [PATCH v4 1/3] virtio-balloon: tweak config_changed implementation [not found] ` <1546923005-40517-2-git-send-email-wei.w.wang@intel.com> @ 2019-01-08 7:10 ` Greg KH 0 siblings, 0 replies; 6+ messages in thread From: Greg KH @ 2019-01-08 7:10 UTC (permalink / raw) To: Wei Wang Cc: virtio-dev, kvm, mst, cohuck, linux-kernel, stable, virtualization, pasic, pbonzini, dgilbert On Tue, Jan 08, 2019 at 12:50:03PM +0800, Wei Wang wrote: > virtio-ccw has deadlock issues with reading the config space inside the > interrupt context, so we tweak the virtballoon_changed implementation > by moving the config read operations into the related workqueue contexts. > The config_read_bitmap is used as a flag to the workqueue callbacks > about the related config fields that need to be read. > > The cmd_id_received is also renamed to cmd_id_received_cache, and > the value should be obtained via virtio_balloon_cmd_id_received. > > Fixes: 86a559787e6f ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT") > Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> > Signed-off-by: Wei Wang <wei.w.wang@intel.com> > Reviewed-by: Cornelia Huck <cohuck@redhat.com> > Reviewed-by: Halil Pasic <pasic@linux.ibm.com> > Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> > --- > drivers/virtio/virtio_balloon.c | 98 +++++++++++++++++++++++++++-------------- > 1 file changed, 65 insertions(+), 33 deletions(-) > <formletter> This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly. </formletter> ^ permalink raw reply [flat|nested] 6+ messages in thread
[parent not found: <1546923005-40517-3-git-send-email-wei.w.wang@intel.com>]
* Re: [PATCH v4 2/3] virtio-balloon: improve update_balloon_size_func [not found] ` <1546923005-40517-3-git-send-email-wei.w.wang@intel.com> @ 2019-01-08 7:10 ` Greg KH 0 siblings, 0 replies; 6+ messages in thread From: Greg KH @ 2019-01-08 7:10 UTC (permalink / raw) To: Wei Wang Cc: virtio-dev, kvm, mst, cohuck, linux-kernel, stable, virtualization, pasic, pbonzini, dgilbert On Tue, Jan 08, 2019 at 12:50:04PM +0800, Wei Wang wrote: > There is no need to update the balloon actual register when there is no > ballooning request. This patch avoids update_balloon_size when diff is 0. > > Signed-off-by: Wei Wang <wei.w.wang@intel.com> > Reviewed-by: Cornelia Huck <cohuck@redhat.com> > Reviewed-by: Halil Pasic <pasic@linux.ibm.com> > Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> > --- > drivers/virtio/virtio_balloon.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index 45d32f5..d48c12c 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -457,9 +457,12 @@ static void update_balloon_size_func(struct work_struct *work) > update_balloon_size_work); > diff = towards_target(vb); > > + if (!diff) > + return; > + > if (diff > 0) > diff -= fill_balloon(vb, diff); > - else if (diff < 0) > + else > diff += leak_balloon(vb, -diff); > update_balloon_size(vb); > > -- > 2.7.4 > <formletter> This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly. </formletter> ^ permalink raw reply [flat|nested] 6+ messages in thread
[parent not found: <1546923005-40517-4-git-send-email-wei.w.wang@intel.com>]
* Re: [PATCH v4 3/3] virtio_balloon: remove the unnecessary 0-initialization [not found] ` <1546923005-40517-4-git-send-email-wei.w.wang@intel.com> @ 2019-01-08 7:10 ` Greg KH 0 siblings, 0 replies; 6+ messages in thread From: Greg KH @ 2019-01-08 7:10 UTC (permalink / raw) To: Wei Wang Cc: virtio-dev, kvm, mst, cohuck, linux-kernel, stable, virtualization, pasic, pbonzini, dgilbert On Tue, Jan 08, 2019 at 12:50:05PM +0800, Wei Wang wrote: > We've changed to kzalloc the vb struct, so no need to 0-initialize > this field one more time. > > Signed-off-by: Wei Wang <wei.w.wang@intel.com> > Reviewed-by: Cornelia Huck <cohuck@redhat.com> > --- > drivers/virtio/virtio_balloon.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index d48c12c..048959a 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -925,7 +925,6 @@ static int virtballoon_probe(struct virtio_device *vdev) > VIRTIO_BALLOON_CMD_ID_STOP); > vb->cmd_id_stop = cpu_to_virtio32(vb->vdev, > VIRTIO_BALLOON_CMD_ID_STOP); > - vb->num_free_page_blocks = 0; > spin_lock_init(&vb->free_page_list_lock); > INIT_LIST_HEAD(&vb->free_page_list); > if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON)) { > -- > 2.7.4 > <formletter> This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly. </formletter> ^ permalink raw reply [flat|nested] 6+ messages in thread
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[not found] <1546923005-40517-1-git-send-email-wei.w.wang@intel.com>
2019-01-08 4:50 ` [PATCH v4 1/3] virtio-balloon: tweak config_changed implementation Wei Wang
2019-01-08 4:50 ` [PATCH v4 2/3] virtio-balloon: improve update_balloon_size_func Wei Wang
2019-01-08 4:50 ` [PATCH v4 3/3] virtio_balloon: remove the unnecessary 0-initialization Wei Wang
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2019-01-08 7:10 ` [PATCH v4 1/3] virtio-balloon: tweak config_changed implementation Greg KH
[not found] ` <1546923005-40517-3-git-send-email-wei.w.wang@intel.com>
2019-01-08 7:10 ` [PATCH v4 2/3] virtio-balloon: improve update_balloon_size_func Greg KH
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2019-01-08 7:10 ` [PATCH v4 3/3] virtio_balloon: remove the unnecessary 0-initialization Greg KH
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