Jason Wang
2022-Jun-28 06:03 UTC
[PATCH v3 1/2] vhost: Add rbtree vdpa_mem_tree to saved the counted mem
On Tue, Jun 28, 2022 at 1:58 PM Michael S. Tsirkin <mst at redhat.com> wrote:> > On Tue, Jun 28, 2022 at 11:54:27AM +0800, Jason Wang wrote: > > On Mon, Jun 27, 2022 at 6:01 PM Michael S. Tsirkin <mst at redhat.com> wrote: > > > > > > On Mon, Jun 27, 2022 at 04:12:57PM +0800, Cindy Lu wrote: > > > > On Sun, Jun 26, 2022 at 6:01 PM Michael S. Tsirkin <mst at redhat.com> wrote: > > > > > > > > > > On Sun, Jun 26, 2022 at 05:04:08PM +0800, Cindy Lu wrote: > > > > > > We count pinned_vm as follow in vhost-vDPA > > > > > > > > > > > > lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; > > > > > > if (npages + atomic64_read(&dev->mm->pinned_vm) > lock_limit) { > > > > > > ret = -ENOMEM; > > > > > > goto unlock; > > > > > > } > > > > > > This means if we have two vDPA devices for the same VM the pages > > > > > > would be counted twice. So we add a tree to save the page that > > > > > > counted and we will not count it again. > > > > > > > > > > > > Add vdpa_mem_tree to saved the mem that already counted. > > > > > > use a hlist to saved the root for vdpa_mem_tree. > > > > > > > > > > > > Signed-off-by: Cindy Lu <lulu at redhat.com> > > > > > > --- > > > > > > drivers/vhost/vhost.c | 63 +++++++++++++++++++++++++++++++++++++++++++ > > > > > > drivers/vhost/vhost.h | 1 + > > > > > > 2 files changed, 64 insertions(+) > > > > > > > > > > > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > > > > > > index 40097826cff0..4ca8b1ed944b 100644 > > > > > > --- a/drivers/vhost/vhost.c > > > > > > +++ b/drivers/vhost/vhost.c > > > > > > @@ -32,6 +32,8 @@ > > > > > > #include <linux/kcov.h> > > > > > > > > > > > > #include "vhost.h" > > > > > > +#include <linux/hashtable.h> > > > > > > +#include <linux/jhash.h> > > > > > > > > > > > > static ushort max_mem_regions = 64; > > > > > > module_param(max_mem_regions, ushort, 0444); > > > > > > @@ -49,6 +51,14 @@ enum { > > > > > > #define vhost_used_event(vq) ((__virtio16 __user *)&vq->avail->ring[vq->num]) > > > > > > #define vhost_avail_event(vq) ((__virtio16 __user *)&vq->used->ring[vq->num]) > > > > > > > > > > > > +struct vhost_vdpa_rbtree_node { > > > > > > + struct hlist_node node; > > > > > > + struct rb_root_cached vdpa_mem_tree; > > > > > > + struct mm_struct *mm_using; > > > > > > +}; > > > > > > +static DECLARE_HASHTABLE(vhost_vdpa_rbtree_hlist, 8); > > > > > > +int vhost_vdpa_rbtree_hlist_status; > > > > > > + > > > > > > #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY > > > > > > static void vhost_disable_cross_endian(struct vhost_virtqueue *vq) > > > > > > { > > > > > > > > > > Are you trying to save some per-mm information here? > > > > > Can't we just add it to mm_struct? > > > > > > > > > yes, this is a per-mm information, but I have checked with jason before, > > > > seems it maybe difficult to change the mm_struct in upstream > > > > so I add an to add a hlist instead > > > > Thanks > > > > Cindy > > > > > > Difficult how? > > > > It is only useful for vDPA probably. Though it could be used by VFIO > > as well, VFIO does pinning/accounting at the container level and it > > has been there for years. > > Yes it's been there, I'm not sure this means it's perfect. > Also, rdma guys might be interested too I guess?It looks to me they plan to go to iommufd as well.> > > vDPA have an implicit "container" the > > mm_struct, but the accounting is done per device right now. > > > > In the future, when vDPA switches to iommufd, it can be then solved at > > iommufd level. > > So is it even worth fixing now?Not sure, but I guess it's better. (Or we need to teach the libvirt to have special care on this).> > > And if we do this in mm, it will bring extra overheads. > > > > Thanks > > Pointer per mm, not too bad ...Unless we enable it unconditionally, it requires a lot of tree operations at least. Thanks> > > > You get more scrutiny if you try, for sure, > > > and you need to need to generalize it enough that it looks > > > useful outside the driver. But I guess that's good? > > > > > > > > > > > > > > > > > > > @@ -571,6 +581,51 @@ static void vhost_detach_mm(struct vhost_dev *dev) > > > > > > dev->mm = NULL; > > > > > > } > > > > > > > > > > > > +struct rb_root_cached *vhost_vdpa_get_mem_tree(struct mm_struct *mm) > > > > > > +{ > > > > > > + struct vhost_vdpa_rbtree_node *rbtree_root = NULL; > > > > > > + struct rb_root_cached *vdpa_tree; > > > > > > + u32 key; > > > > > > + > > > > > > + /* No hased table, init one */ > > > > > > + if (vhost_vdpa_rbtree_hlist_status == 0) { > > > > > > + hash_init(vhost_vdpa_rbtree_hlist); > > > > > > + vhost_vdpa_rbtree_hlist_status = 1; > > > > > > + } > > > > > > + > > > > > > + key = jhash_1word((u64)mm, JHASH_INITVAL); > > > > > > + hash_for_each_possible(vhost_vdpa_rbtree_hlist, rbtree_root, node, > > > > > > + key) { > > > > > > + if (rbtree_root->mm_using == mm) > > > > > > + return &(rbtree_root->vdpa_mem_tree); > > > > > > + } > > > > > > + rbtree_root = kmalloc(sizeof(*rbtree_root), GFP_KERNEL); > > > > > > + if (!rbtree_root) > > > > > > + return NULL; > > > > > > + rbtree_root->mm_using = mm; > > > > > > + rbtree_root->vdpa_mem_tree = RB_ROOT_CACHED; > > > > > > + hash_add(vhost_vdpa_rbtree_hlist, &rbtree_root->node, key); > > > > > > + vdpa_tree = &(rbtree_root->vdpa_mem_tree); > > > > > > + return vdpa_tree; > > > > > > +} > > > > > > + > > > > > > +void vhost_vdpa_relase_mem_tree(struct mm_struct *mm) > > > > > > +{ > > > > > > + struct vhost_vdpa_rbtree_node *rbtree_root = NULL; > > > > > > + u32 key; > > > > > > + > > > > > > + key = jhash_1word((u64)mm, JHASH_INITVAL); > > > > > > + > > > > > > + /* No hased table, init one */ > > > > > > + hash_for_each_possible(vhost_vdpa_rbtree_hlist, rbtree_root, node, > > > > > > + key) { > > > > > > + if (rbtree_root->mm_using == mm) { > > > > > > + hash_del(&rbtree_root->node); > > > > > > + kfree(rbtree_root); > > > > > > + } > > > > > > + } > > > > > > +} > > > > > > + > > > > > > /* Caller should have device mutex */ > > > > > > long vhost_dev_set_owner(struct vhost_dev *dev) > > > > > > { > > > > > > @@ -605,6 +660,11 @@ long vhost_dev_set_owner(struct vhost_dev *dev) > > > > > > err = vhost_dev_alloc_iovecs(dev); > > > > > > if (err) > > > > > > goto err_cgroup; > > > > > > + dev->vdpa_mem_tree = vhost_vdpa_get_mem_tree(dev->mm); > > > > > > + if (dev->vdpa_mem_tree == NULL) { > > > > > > + err = -ENOMEM; > > > > > > + goto err_cgroup; > > > > > > + } > > > > > > > > > > > > return 0; > > > > > > err_cgroup: > > > > > > @@ -613,6 +673,7 @@ long vhost_dev_set_owner(struct vhost_dev *dev) > > > > > > dev->worker = NULL; > > > > > > } > > > > > > err_worker: > > > > > > + vhost_vdpa_relase_mem_tree(dev->mm); > > > > > > vhost_detach_mm(dev); > > > > > > dev->kcov_handle = 0; > > > > > > err_mm: > > > > > > @@ -710,6 +771,8 @@ void vhost_dev_cleanup(struct vhost_dev *dev) > > > > > > dev->worker = NULL; > > > > > > dev->kcov_handle = 0; > > > > > > } > > > > > > + > > > > > > + vhost_vdpa_relase_mem_tree(dev->mm); > > > > > > vhost_detach_mm(dev); > > > > > > } > > > > > > EXPORT_SYMBOL_GPL(vhost_dev_cleanup); > > > > > > diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h > > > > > > index d9109107af08..84de33de3abf 100644 > > > > > > --- a/drivers/vhost/vhost.h > > > > > > +++ b/drivers/vhost/vhost.h > > > > > > @@ -160,6 +160,7 @@ struct vhost_dev { > > > > > > int byte_weight; > > > > > > u64 kcov_handle; > > > > > > bool use_worker; > > > > > > + struct rb_root_cached *vdpa_mem_tree; > > > > > > int (*msg_handler)(struct vhost_dev *dev, u32 asid, > > > > > > struct vhost_iotlb_msg *msg); > > > > > > }; > > > > > > -- > > > > > > 2.34.3 > > > > > > > > >
Michael S. Tsirkin
2022-Jun-28 06:07 UTC
[PATCH v3 1/2] vhost: Add rbtree vdpa_mem_tree to saved the counted mem
On Tue, Jun 28, 2022 at 02:03:38PM +0800, Jason Wang wrote:> On Tue, Jun 28, 2022 at 1:58 PM Michael S. Tsirkin <mst at redhat.com> wrote: > > > > On Tue, Jun 28, 2022 at 11:54:27AM +0800, Jason Wang wrote: > > > On Mon, Jun 27, 2022 at 6:01 PM Michael S. Tsirkin <mst at redhat.com> wrote: > > > > > > > > On Mon, Jun 27, 2022 at 04:12:57PM +0800, Cindy Lu wrote: > > > > > On Sun, Jun 26, 2022 at 6:01 PM Michael S. Tsirkin <mst at redhat.com> wrote: > > > > > > > > > > > > On Sun, Jun 26, 2022 at 05:04:08PM +0800, Cindy Lu wrote: > > > > > > > We count pinned_vm as follow in vhost-vDPA > > > > > > > > > > > > > > lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; > > > > > > > if (npages + atomic64_read(&dev->mm->pinned_vm) > lock_limit) { > > > > > > > ret = -ENOMEM; > > > > > > > goto unlock; > > > > > > > } > > > > > > > This means if we have two vDPA devices for the same VM the pages > > > > > > > would be counted twice. So we add a tree to save the page that > > > > > > > counted and we will not count it again. > > > > > > > > > > > > > > Add vdpa_mem_tree to saved the mem that already counted. > > > > > > > use a hlist to saved the root for vdpa_mem_tree. > > > > > > > > > > > > > > Signed-off-by: Cindy Lu <lulu at redhat.com> > > > > > > > --- > > > > > > > drivers/vhost/vhost.c | 63 +++++++++++++++++++++++++++++++++++++++++++ > > > > > > > drivers/vhost/vhost.h | 1 + > > > > > > > 2 files changed, 64 insertions(+) > > > > > > > > > > > > > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > > > > > > > index 40097826cff0..4ca8b1ed944b 100644 > > > > > > > --- a/drivers/vhost/vhost.c > > > > > > > +++ b/drivers/vhost/vhost.c > > > > > > > @@ -32,6 +32,8 @@ > > > > > > > #include <linux/kcov.h> > > > > > > > > > > > > > > #include "vhost.h" > > > > > > > +#include <linux/hashtable.h> > > > > > > > +#include <linux/jhash.h> > > > > > > > > > > > > > > static ushort max_mem_regions = 64; > > > > > > > module_param(max_mem_regions, ushort, 0444); > > > > > > > @@ -49,6 +51,14 @@ enum { > > > > > > > #define vhost_used_event(vq) ((__virtio16 __user *)&vq->avail->ring[vq->num]) > > > > > > > #define vhost_avail_event(vq) ((__virtio16 __user *)&vq->used->ring[vq->num]) > > > > > > > > > > > > > > +struct vhost_vdpa_rbtree_node { > > > > > > > + struct hlist_node node; > > > > > > > + struct rb_root_cached vdpa_mem_tree; > > > > > > > + struct mm_struct *mm_using; > > > > > > > +}; > > > > > > > +static DECLARE_HASHTABLE(vhost_vdpa_rbtree_hlist, 8); > > > > > > > +int vhost_vdpa_rbtree_hlist_status; > > > > > > > + > > > > > > > #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY > > > > > > > static void vhost_disable_cross_endian(struct vhost_virtqueue *vq) > > > > > > > { > > > > > > > > > > > > Are you trying to save some per-mm information here? > > > > > > Can't we just add it to mm_struct? > > > > > > > > > > > yes, this is a per-mm information, but I have checked with jason before, > > > > > seems it maybe difficult to change the mm_struct in upstream > > > > > so I add an to add a hlist instead > > > > > Thanks > > > > > Cindy > > > > > > > > Difficult how? > > > > > > It is only useful for vDPA probably. Though it could be used by VFIO > > > as well, VFIO does pinning/accounting at the container level and it > > > has been there for years. > > > > Yes it's been there, I'm not sure this means it's perfect. > > Also, rdma guys might be interested too I guess? > > It looks to me they plan to go to iommufd as well. > > > > > > vDPA have an implicit "container" the > > > mm_struct, but the accounting is done per device right now. > > > > > > In the future, when vDPA switches to iommufd, it can be then solved at > > > iommufd level. > > > > So is it even worth fixing now? > > Not sure, but I guess it's better. (Or we need to teach the libvirt to > have special care on this).It already has to for existing kernels. Let's just move to iommufd faster then?> > > > > And if we do this in mm, it will bring extra overheads. > > > > > > Thanks > > > > Pointer per mm, not too bad ... > > Unless we enable it unconditionally, it requires a lot of tree > operations at least. > > ThanksNot sure I understand.> > > > > > You get more scrutiny if you try, for sure, > > > > and you need to need to generalize it enough that it looks > > > > useful outside the driver. But I guess that's good? > > > > > > > > > > > > > > > > > > > > > > > @@ -571,6 +581,51 @@ static void vhost_detach_mm(struct vhost_dev *dev) > > > > > > > dev->mm = NULL; > > > > > > > } > > > > > > > > > > > > > > +struct rb_root_cached *vhost_vdpa_get_mem_tree(struct mm_struct *mm) > > > > > > > +{ > > > > > > > + struct vhost_vdpa_rbtree_node *rbtree_root = NULL; > > > > > > > + struct rb_root_cached *vdpa_tree; > > > > > > > + u32 key; > > > > > > > + > > > > > > > + /* No hased table, init one */ > > > > > > > + if (vhost_vdpa_rbtree_hlist_status == 0) { > > > > > > > + hash_init(vhost_vdpa_rbtree_hlist); > > > > > > > + vhost_vdpa_rbtree_hlist_status = 1; > > > > > > > + } > > > > > > > + > > > > > > > + key = jhash_1word((u64)mm, JHASH_INITVAL); > > > > > > > + hash_for_each_possible(vhost_vdpa_rbtree_hlist, rbtree_root, node, > > > > > > > + key) { > > > > > > > + if (rbtree_root->mm_using == mm) > > > > > > > + return &(rbtree_root->vdpa_mem_tree); > > > > > > > + } > > > > > > > + rbtree_root = kmalloc(sizeof(*rbtree_root), GFP_KERNEL); > > > > > > > + if (!rbtree_root) > > > > > > > + return NULL; > > > > > > > + rbtree_root->mm_using = mm; > > > > > > > + rbtree_root->vdpa_mem_tree = RB_ROOT_CACHED; > > > > > > > + hash_add(vhost_vdpa_rbtree_hlist, &rbtree_root->node, key); > > > > > > > + vdpa_tree = &(rbtree_root->vdpa_mem_tree); > > > > > > > + return vdpa_tree; > > > > > > > +} > > > > > > > + > > > > > > > +void vhost_vdpa_relase_mem_tree(struct mm_struct *mm) > > > > > > > +{ > > > > > > > + struct vhost_vdpa_rbtree_node *rbtree_root = NULL; > > > > > > > + u32 key; > > > > > > > + > > > > > > > + key = jhash_1word((u64)mm, JHASH_INITVAL); > > > > > > > + > > > > > > > + /* No hased table, init one */ > > > > > > > + hash_for_each_possible(vhost_vdpa_rbtree_hlist, rbtree_root, node, > > > > > > > + key) { > > > > > > > + if (rbtree_root->mm_using == mm) { > > > > > > > + hash_del(&rbtree_root->node); > > > > > > > + kfree(rbtree_root); > > > > > > > + } > > > > > > > + } > > > > > > > +} > > > > > > > + > > > > > > > /* Caller should have device mutex */ > > > > > > > long vhost_dev_set_owner(struct vhost_dev *dev) > > > > > > > { > > > > > > > @@ -605,6 +660,11 @@ long vhost_dev_set_owner(struct vhost_dev *dev) > > > > > > > err = vhost_dev_alloc_iovecs(dev); > > > > > > > if (err) > > > > > > > goto err_cgroup; > > > > > > > + dev->vdpa_mem_tree = vhost_vdpa_get_mem_tree(dev->mm); > > > > > > > + if (dev->vdpa_mem_tree == NULL) { > > > > > > > + err = -ENOMEM; > > > > > > > + goto err_cgroup; > > > > > > > + } > > > > > > > > > > > > > > return 0; > > > > > > > err_cgroup: > > > > > > > @@ -613,6 +673,7 @@ long vhost_dev_set_owner(struct vhost_dev *dev) > > > > > > > dev->worker = NULL; > > > > > > > } > > > > > > > err_worker: > > > > > > > + vhost_vdpa_relase_mem_tree(dev->mm); > > > > > > > vhost_detach_mm(dev); > > > > > > > dev->kcov_handle = 0; > > > > > > > err_mm: > > > > > > > @@ -710,6 +771,8 @@ void vhost_dev_cleanup(struct vhost_dev *dev) > > > > > > > dev->worker = NULL; > > > > > > > dev->kcov_handle = 0; > > > > > > > } > > > > > > > + > > > > > > > + vhost_vdpa_relase_mem_tree(dev->mm); > > > > > > > vhost_detach_mm(dev); > > > > > > > } > > > > > > > EXPORT_SYMBOL_GPL(vhost_dev_cleanup); > > > > > > > diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h > > > > > > > index d9109107af08..84de33de3abf 100644 > > > > > > > --- a/drivers/vhost/vhost.h > > > > > > > +++ b/drivers/vhost/vhost.h > > > > > > > @@ -160,6 +160,7 @@ struct vhost_dev { > > > > > > > int byte_weight; > > > > > > > u64 kcov_handle; > > > > > > > bool use_worker; > > > > > > > + struct rb_root_cached *vdpa_mem_tree; > > > > > > > int (*msg_handler)(struct vhost_dev *dev, u32 asid, > > > > > > > struct vhost_iotlb_msg *msg); > > > > > > > }; > > > > > > > -- > > > > > > > 2.34.3 > > > > > > > > > > > >