Michael S. Tsirkin
2022-Jun-26 10:01 UTC
[PATCH v3 1/2] vhost: Add rbtree vdpa_mem_tree to saved the counted mem
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?> @@ -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