This add new core infiniband structure and helper to implement ODP (on demand paging) on top of HMM. We need to retain the tree of ib_umem as some hardware associate unique identifiant with each umem (or mr) and only allow hardware page table to be updated using this unique id.
Changed since v1: - Adapt to new hmm_mirror lifetime rules. - Fix scan of existing mirror in ib_umem_odp_get(). Signed-off-by: Jérôme Glisse <[email protected]> Signed-off-by: John Hubbard <[email protected]> Signed-off-by: Haggai Eran <[email protected]> --- drivers/infiniband/core/umem_odp.c | 150 +++++++++++++++++++++++++++++++++- drivers/infiniband/core/uverbs_cmd.c | 6 +- drivers/infiniband/core/uverbs_main.c | 6 ++ include/rdma/ib_umem_odp.h | 28 ++++++- include/rdma/ib_verbs.h | 17 +++- 5 files changed, 201 insertions(+), 6 deletions(-) diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c index 7f16120..ac87ac6 100644 --- a/drivers/infiniband/core/umem_odp.c +++ b/drivers/infiniband/core/umem_odp.c @@ -41,9 +41,157 @@ #include <rdma/ib_umem.h> #include <rdma/ib_umem_odp.h> + #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM -#error "CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM not supported at this stage !" + + +static void ib_mirror_destroy(struct kref *kref) +{ + struct ib_mirror *ib_mirror; + struct ib_device *ib_device; + + ib_mirror = container_of(kref, struct ib_mirror, kref); + + ib_device = ib_mirror->ib_device; + mutex_lock(&ib_device->hmm_mutex); + list_del_init(&ib_mirror->list); + mutex_unlock(&ib_device->hmm_mutex); + + /* hmm_mirror_unregister() will free the structure. */ + hmm_mirror_unregister(&ib_mirror->base); +} + +void ib_mirror_unref(struct ib_mirror *ib_mirror) +{ + if (ib_mirror == NULL) + return; + + kref_put(&ib_mirror->kref, ib_mirror_destroy); +} +EXPORT_SYMBOL(ib_mirror_unref); + +static inline struct ib_mirror *ib_mirror_ref(struct ib_mirror *ib_mirror) +{ + if (!ib_mirror || !kref_get_unless_zero(&ib_mirror->kref)) + return NULL; + return ib_mirror; +} + +int ib_umem_odp_get(struct ib_ucontext *context, struct ib_umem *umem) +{ + struct mm_struct *mm = get_task_mm(current); + struct ib_device *ib_device = context->device; + struct ib_mirror *ib_mirror; + struct pid *our_pid; + int ret; + + if (!mm || !ib_device->hmm_ready) + return -EINVAL; + + /* FIXME can this really happen ? */ + if (unlikely(ib_umem_start(umem) == ib_umem_end(umem))) + return -EINVAL; + + /* Prevent creating ODP MRs in child processes */ + rcu_read_lock(); + our_pid = get_task_pid(current->group_leader, PIDTYPE_PID); + rcu_read_unlock(); + put_pid(our_pid); + if (context->tgid != our_pid) { + mmput(mm); + return -EINVAL; + } + + umem->hugetlb = 0; + umem->odp_data = kmalloc(sizeof(*umem->odp_data), GFP_KERNEL); + if (umem->odp_data == NULL) { + mmput(mm); + return -ENOMEM; + } + umem->odp_data->private = NULL; + umem->odp_data->umem = umem; + + mutex_lock(&ib_device->hmm_mutex); + /* Is there an existing mirror for this process mm ? */ + ib_mirror = ib_mirror_ref(context->ib_mirror); + if (!ib_mirror) { + struct ib_mirror *tmp; + + list_for_each_entry(tmp, &ib_device->ib_mirrors, list) { + if (tmp->base.hmm->mm != mm) + continue; + ib_mirror = ib_mirror_ref(tmp); + break; + } + } + + if (!ib_mirror) { + /* We need to create a new mirror. */ + ib_mirror = kmalloc(sizeof(*ib_mirror), GFP_KERNEL); + if (!ib_mirror) { + mutex_unlock(&ib_device->hmm_mutex); + mmput(mm); + return -ENOMEM; + } + kref_init(&ib_mirror->kref); + init_rwsem(&ib_mirror->hmm_mr_rwsem); + ib_mirror->umem_tree = RB_ROOT; + ib_mirror->ib_device = ib_device; + + ib_mirror->base.device = &ib_device->hmm_dev; + ret = hmm_mirror_register(&ib_mirror->base); + if (ret) { + mutex_unlock(&ib_device->hmm_mutex); + kfree(ib_mirror); + mmput(mm); + return ret; + } + + list_add(&ib_mirror->list, &ib_device->ib_mirrors); + context->ib_mirror = ib_mirror_ref(ib_mirror); + } + mutex_unlock(&ib_device->hmm_mutex); + umem->odp_data.ib_mirror = ib_mirror; + + down_write(&ib_mirror->umem_rwsem); + rbt_ib_umem_insert(&umem->odp_data->interval_tree, &mirror->umem_tree); + up_write(&ib_mirror->umem_rwsem); + + mmput(mm); + return 0; +} + +void ib_umem_odp_release(struct ib_umem *umem) +{ + struct ib_mirror *ib_mirror = umem->odp_data; + + /* + * Ensure that no more pages are mapped in the umem. + * + * It is the driver's responsibility to ensure, before calling us, + * that the hardware will not attempt to access the MR any more. + */ + + /* One optimization to release resources early here would be to call : + * hmm_mirror_range_discard(&ib_mirror->base, + * ib_umem_start(umem), + * ib_umem_end(umem)); + * But we can have overlapping umem so we would need to only discard + * range covered by one and only one umem while holding the umem rwsem. + */ + down_write(&ib_mirror->umem_rwsem); + rbt_ib_umem_remove(&umem->odp_data->interval_tree, &mirror->umem_tree); + up_write(&ib_mirror->umem_rwsem); + + ib_mirror_unref(ib_mirror); + kfree(umem->odp_data); + kfree(umem); +} + + #else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM */ + + static void ib_umem_notifier_start_account(struct ib_umem *item) { mutex_lock(&item->odp_data->umem_mutex); diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c index 58f9a73..165c9cd 100644 --- a/drivers/infiniband/core/uverbs_cmd.c +++ b/drivers/infiniband/core/uverbs_cmd.c @@ -337,7 +337,9 @@ ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file, ucontext->closing = 0; #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING -#ifndef CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM +#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM + ucontext->ib_mirror = NULL; +#else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM */ ucontext->umem_tree = RB_ROOT; init_rwsem(&ucontext->umem_rwsem); ucontext->odp_mrs_count = 0; @@ -348,7 +350,7 @@ ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file, goto err_free; if (!(dev_attr.device_cap_flags & IB_DEVICE_ON_DEMAND_PAGING)) ucontext->invalidate_range = NULL; -#endif /* !CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM */ +#endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM */ #endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */ resp.num_comp_vectors = file->device->num_comp_vectors; diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c index f6eef2d..361f531 100644 --- a/drivers/infiniband/core/uverbs_main.c +++ b/drivers/infiniband/core/uverbs_main.c @@ -45,6 +45,7 @@ #include <linux/cdev.h> #include <linux/anon_inodes.h> #include <linux/slab.h> +#include <rdma/ib_umem_odp.h> #include <asm/uaccess.h> @@ -298,6 +299,11 @@ static int ib_uverbs_cleanup_ucontext(struct ib_uverbs_file *file, kfree(uobj); } +#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM + ib_mirror_unref(context->ib_mirror); + context->ib_mirror = NULL; +#endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM */ + put_pid(context->tgid); return context->device->dealloc_ucontext(context); diff --git a/include/rdma/ib_umem_odp.h b/include/rdma/ib_umem_odp.h index 765aeb3..c7c2670 100644 --- a/include/rdma/ib_umem_odp.h +++ b/include/rdma/ib_umem_odp.h @@ -37,6 +37,32 @@ #include <rdma/ib_verbs.h> #include <linux/interval_tree.h> +#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM +/* struct ib_mirror - per process mirror structure for infiniband driver. + * + * @ib_device: Infiniband device this mirror is associated with. + * @base: The hmm base mirror struct. + * @kref: Refcount for the structure. + * @list: For the list of ib_mirror of a given ib_device. + * @umem_tree: Red black tree of ib_umem ordered by virtual address. + * @umem_rwsem: Semaphore protecting the reb black tree. + * + * Because ib_ucontext struct is tie to file descriptor there can be several of + * them for a same process, which violate HMM requirement. Hence we create only + * one ib_mirror struct per process and have each ib_umem struct reference it. + */ +struct ib_mirror { + struct ib_device *ib_device; + struct hmm_mirror base; + struct kref kref; + struct list_head list; + struct rb_root umem_tree; + struct rw_semaphore umem_rwsem; +}; + +void ib_mirror_unref(struct ib_mirror *ib_mirror); +#endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM */ + struct umem_odp_node { u64 __subtree_last; struct rb_node rb; @@ -44,7 +70,7 @@ struct umem_odp_node { struct ib_umem_odp { #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM -#error "CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM not supported at this stage !" + struct ib_mirror *ib_mirror; #else /* * An array of the pages included in the on-demand paging umem. diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h index a66551b..fc063e7 100644 --- a/include/rdma/ib_verbs.h +++ b/include/rdma/ib_verbs.h @@ -49,6 +49,9 @@ #include <linux/scatterlist.h> #include <linux/workqueue.h> #include <uapi/linux/if_ether.h> +#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM +#include <linux/hmm.h> +#endif #include <linux/atomic.h> #include <linux/mmu_notifier.h> @@ -1216,7 +1219,9 @@ struct ib_ucontext { struct pid *tgid; #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING -#ifndef CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM +#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM + struct ib_mirror *ib_mirror; +#else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM */ struct rb_root umem_tree; /* * Protects .umem_rbroot and tree, as well as odp_mrs_count and @@ -1231,7 +1236,7 @@ struct ib_ucontext { /* A list of umems that don't have private mmu notifier counters yet. */ struct list_head no_private_counters; int odp_mrs_count; -#endif /* !CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM */ +#endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM */ #endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */ }; @@ -1729,6 +1734,14 @@ struct ib_device { struct ib_dma_mapping_ops *dma_ops; +#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING_HMM + /* For ODP using HMM. */ + struct hmm_device hmm_dev; + struct list_head ib_mirrors; + struct mutex hmm_mutex; + bool hmm_ready; +#endif + struct module *owner; struct device dev; struct kobject *ports_parent; -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
