+ /** Number of locks awaiting client ACK */
+ int rs_nlocks;
+ /** Handles of locks awaiting client reply ACK */
+ struct lustre_handle rs_locks[RS_MAX_LOCKS];
+ /** Lock modes of locks in \a rs_locks */
+ ldlm_mode_t rs_modes[RS_MAX_LOCKS];
+};
+
+struct ptlrpc_thread;
+
+/** RPC stages */
+enum rq_phase {
+ RQ_PHASE_NEW = 0xebc0de00,
+ RQ_PHASE_RPC = 0xebc0de01,
+ RQ_PHASE_BULK = 0xebc0de02,
+ RQ_PHASE_INTERPRET = 0xebc0de03,
+ RQ_PHASE_COMPLETE = 0xebc0de04,
+ RQ_PHASE_UNREGISTERING = 0xebc0de05,
+ RQ_PHASE_UNDEFINED = 0xebc0de06
+};
+
+/** Type of request interpreter call-back */
+typedef int (*ptlrpc_interpterer_t)(const struct lu_env *env,
+ struct ptlrpc_request *req,
+ void *arg, int rc);
+/** Type of request resend call-back */
+typedef void (*ptlrpc_resend_cb_t)(struct ptlrpc_request *req,
+ void *arg);
+
+/**
+ * Definition of request pool structure.
+ * The pool is used to store empty preallocated requests for the case
+ * when we would actually need to send something without performing
+ * any allocations (to avoid e.g. OOM).
+ */
+struct ptlrpc_request_pool {
+ /** Locks the list */
+ spinlock_t prp_lock;
+ /** list of ptlrpc_request structs */
+ struct list_head prp_req_list;
+ /** Maximum message size that would fit into a rquest from this pool */
+ int prp_rq_size;
+ /** Function to allocate more requests for this pool */
+ void (*prp_populate)(struct ptlrpc_request_pool *, int);
+};
+
+struct lu_context;
+struct lu_env;
+
+struct ldlm_lock;
+
+/**
+ * \defgroup nrs Network Request Scheduler
+ * @{
+ */
+struct ptlrpc_nrs_policy;
+struct ptlrpc_nrs_resource;
+struct ptlrpc_nrs_request;
+
+/**
+ * NRS control operations.
+ *
+ * These are common for all policies.
+ */
+enum ptlrpc_nrs_ctl {
+ /**
+ * Not a valid opcode.
+ */
+ PTLRPC_NRS_CTL_INVALID,
+ /**
+ * Activate the policy.
+ */
+ PTLRPC_NRS_CTL_START,
+ /**
+ * Reserved for multiple primary policies, which may be a possibility
+ * in the future.
+ */
+ PTLRPC_NRS_CTL_STOP,
+ /**
+ * Policies can start using opcodes from this value and onwards for
+ * their own purposes; the assigned value itself is arbitrary.
+ */
+ PTLRPC_NRS_CTL_1ST_POL_SPEC = 0x20,
+};
+
+/**
+ * ORR policy operations
+ */
+enum nrs_ctl_orr {
+ NRS_CTL_ORR_RD_QUANTUM = PTLRPC_NRS_CTL_1ST_POL_SPEC,
+ NRS_CTL_ORR_WR_QUANTUM,
+ NRS_CTL_ORR_RD_OFF_TYPE,
+ NRS_CTL_ORR_WR_OFF_TYPE,
+ NRS_CTL_ORR_RD_SUPP_REQ,
+ NRS_CTL_ORR_WR_SUPP_REQ,
+};
+
+/**
+ * NRS policy operations.
+ *
+ * These determine the behaviour of a policy, and are called in response to
+ * NRS core events.
+ */
+struct ptlrpc_nrs_pol_ops {
+ /**
+ * Called during policy registration; this operation is optional.
+ *
+ * \param[in,out] policy The policy being initialized
+ */
+ int (*op_policy_init) (struct ptlrpc_nrs_policy *policy);
+ /**
+ * Called during policy unregistration; this operation is optional.
+ *
+ * \param[in,out] policy The policy being unregistered/finalized
+ */
+ void (*op_policy_fini) (struct ptlrpc_nrs_policy *policy);
+ /**
+ * Called when activating a policy via lprocfs; policies allocate and
+ * initialize their resources here; this operation is optional.
+ *
+ * \param[in,out] policy The policy being started
+ * \param[in,out] arg A generic char buffer
+ *
+ * \see nrs_policy_start_locked()
+ */
+ int (*op_policy_start) (struct ptlrpc_nrs_policy *policy,
+ char *arg);
+ /**
+ * Called when deactivating a policy via lprocfs; policies deallocate
+ * their resources here; this operation is optional
+ *
+ * \param[in,out] policy The policy being stopped
+ *
+ * \see nrs_policy_stop0()
+ */
+ void (*op_policy_stop) (struct ptlrpc_nrs_policy *policy);
+ /**
+ * Used for policy-specific operations; i.e. not generic ones like
+ * \e PTLRPC_NRS_CTL_START and \e PTLRPC_NRS_CTL_GET_INFO; analogous
+ * to an ioctl; this operation is optional.
+ *
+ * \param[in,out] policy The policy carrying out operation \a opc
+ * \param[in] opc The command operation being carried out
+ * \param[in,out] arg An generic buffer for communication between the
+ * user and the control operation
+ *
+ * \retval -ve error
+ * \retval 0 success
+ *
+ * \see ptlrpc_nrs_policy_control()
+ */
+ int (*op_policy_ctl) (struct ptlrpc_nrs_policy *policy,
+ enum ptlrpc_nrs_ctl opc, void *arg);
+
+ /**
+ * Called when obtaining references to the resources of the resource
+ * hierarchy for a request that has arrived for handling at the PTLRPC
+ * service. Policies should return -ve for requests they do not wish
+ * to handle. This operation is mandatory.
+ *
+ * \param[in,out] policy The policy we're getting resources for.
+ * \param[in,out] nrq The request we are getting resources for.
+ * \param[in] parent The parent resource of the resource being
+ * requested; set to NULL if none.
+ * \param[out] resp The resource is to be returned here; the
+ * fallback policy in an NRS head should
+ * \e always return a non-NULL pointer value.
+ * \param[in] moving_req When set, signifies that this is an attempt
+ * to obtain resources for a request being moved
+ * to the high-priority NRS head by
+ * ldlm_lock_reorder_req().
+ * This implies two things:
+ * 1. We are under obd_export::exp_rpc_lock and
+ * so should not sleep.
+ * 2. We should not perform non-idempotent or can
+ * skip performing idempotent operations that
+ * were carried out when resources were first
+ * taken for the request when it was initialized
+ * in ptlrpc_nrs_req_initialize().
+ *
+ * \retval 0, +ve The level of the returned resource in the resource
+ * hierarchy; currently only 0 (for a non-leaf resource)
+ * and 1 (for a leaf resource) are supported by the
+ * framework.
+ * \retval -ve error
+ *
+ * \see ptlrpc_nrs_req_initialize()
+ * \see ptlrpc_nrs_hpreq_add_nolock()
+ * \see ptlrpc_nrs_req_hp_move()
+ */
+ int (*op_res_get) (struct ptlrpc_nrs_policy *policy,
+ struct ptlrpc_nrs_request *nrq,
+ const struct ptlrpc_nrs_resource *parent,
+ struct ptlrpc_nrs_resource **resp,
+ bool moving_req);
+ /**
+ * Called when releasing references taken for resources in the resource
+ * hierarchy for the request; this operation is optional.
+ *
+ * \param[in,out] policy The policy the resource belongs to
+ * \param[in] res The resource to be freed
+ *
+ * \see ptlrpc_nrs_req_finalize()
+ * \see ptlrpc_nrs_hpreq_add_nolock()
+ * \see ptlrpc_nrs_req_hp_move()
+ */
+ void (*op_res_put) (struct ptlrpc_nrs_policy *policy,
+ const struct ptlrpc_nrs_resource *res);
+
+ /**
+ * Obtains a request for handling from the policy, and optionally
+ * removes the request from the policy; this operation is mandatory.
+ *
+ * \param[in,out] policy The policy to poll
+ * \param[in] peek When set, signifies that we just want to
+ * examine the request, and not handle it, so the
+ * request is not removed from the policy.
+ * \param[in] force When set, it will force a policy to return a
+ * request if it has one queued.
+ *
+ * \retval NULL No request available for handling
+ * \retval valid-pointer The request polled for handling
+ *
+ * \see ptlrpc_nrs_req_get_nolock()
+ */
+ struct ptlrpc_nrs_request *
+ (*op_req_get) (struct ptlrpc_nrs_policy *policy, bool peek,
+ bool force);
+ /**
+ * Called when attempting to add a request to a policy for later
+ * handling; this operation is mandatory.
+ *
+ * \param[in,out] policy The policy on which to enqueue \a nrq
+ * \param[in,out] nrq The request to enqueue
+ *
+ * \retval 0 success
+ * \retval != 0 error
+ *
+ * \see ptlrpc_nrs_req_add_nolock()
+ */
+ int (*op_req_enqueue) (struct ptlrpc_nrs_policy *policy,
+ struct ptlrpc_nrs_request *nrq);
+ /**
+ * Removes a request from the policy's set of pending requests. Normally
+ * called after a request has been polled successfully from the policy
+ * for handling; this operation is mandatory.
+ *
+ * \param[in,out] policy The policy the request \a nrq belongs to
+ * \param[in,out] nrq The request to dequeue
+ *
+ * \see ptlrpc_nrs_req_del_nolock()
+ */
+ void (*op_req_dequeue) (struct ptlrpc_nrs_policy *policy,
+ struct ptlrpc_nrs_request *nrq);
+ /**
+ * Called after the request being carried out. Could be used for
+ * job/resource control; this operation is optional.
+ *
+ * \param[in,out] policy The policy which is stopping to handle request
+ * \a nrq
+ * \param[in,out] nrq The request
+ *
+ * \pre assert_spin_locked(&svcpt->scp_req_lock)
+ *
+ * \see ptlrpc_nrs_req_stop_nolock()
+ */
+ void (*op_req_stop) (struct ptlrpc_nrs_policy *policy,
+ struct ptlrpc_nrs_request *nrq);
+ /**
+ * Registers the policy's lprocfs interface with a PTLRPC service.
+ *
+ * \param[in] svc The service
+ *
+ * \retval 0 success
+ * \retval != 0 error
+ */
+ int (*op_lprocfs_init) (struct ptlrpc_service *svc);
+ /**
+ * Unegisters the policy's lprocfs interface with a PTLRPC service.
+ *
+ * In cases of failed policy registration in
+ * \e ptlrpc_nrs_policy_register(), this function may be called for a
+ * service which has not registered the policy successfully, so
+ * implementations of this method should make sure their operations are
+ * safe in such cases.
+ *
+ * \param[in] svc The service
+ */
+ void (*op_lprocfs_fini) (struct ptlrpc_service *svc);
+};
+
+/**
+ * Policy flags
+ */
+enum nrs_policy_flags {
+ /**
+ * Fallback policy, use this flag only on a single supported policy per
+ * service. The flag cannot be used on policies that use
+ * \e PTLRPC_NRS_FL_REG_EXTERN
+ */
+ PTLRPC_NRS_FL_FALLBACK = (1 << 0),
+ /**
+ * Start policy immediately after registering.
+ */
+ PTLRPC_NRS_FL_REG_START = (1 << 1),
+ /**
+ * This is a policy registering from a module different to the one NRS
+ * core ships in (currently ptlrpc).
+ */
+ PTLRPC_NRS_FL_REG_EXTERN = (1 << 2),
+};
+
+/**
+ * NRS queue type.
+ *
+ * Denotes whether an NRS instance is for handling normal or high-priority
+ * RPCs, or whether an operation pertains to one or both of the NRS instances
+ * in a service.
+ */
+enum ptlrpc_nrs_queue_type {
+ PTLRPC_NRS_QUEUE_REG = (1 << 0),
+ PTLRPC_NRS_QUEUE_HP = (1 << 1),
+ PTLRPC_NRS_QUEUE_BOTH = (PTLRPC_NRS_QUEUE_REG | PTLRPC_NRS_QUEUE_HP)
+};
+
+/**
+ * NRS head
+ *
+ * A PTLRPC service has at least one NRS head instance for handling normal
+ * priority RPCs, and may optionally have a second NRS head instance for
+ * handling high-priority RPCs. Each NRS head maintains a list of available
+ * policies, of which one and only one policy is acting as the fallback policy,
+ * and optionally a different policy may be acting as the primary policy. For
+ * all RPCs handled by this NRS head instance, NRS core will first attempt to
+ * enqueue the RPC using the primary policy (if any). The fallback policy is
+ * used in the following cases:
+ * - when there was no primary policy in the
+ * ptlrpc_nrs_pol_state::NRS_POL_STATE_STARTED state at the time the request
+ * was initialized.
+ * - when the primary policy that was at the
+ * ptlrpc_nrs_pol_state::PTLRPC_NRS_POL_STATE_STARTED state at the time the
+ * RPC was initialized, denoted it did not wish, or for some other reason was
+ * not able to handle the request, by returning a non-valid NRS resource
+ * reference.
+ * - when the primary policy that was at the
+ * ptlrpc_nrs_pol_state::PTLRPC_NRS_POL_STATE_STARTED state at the time the
+ * RPC was initialized, fails later during the request enqueueing stage.
+ *
+ * \see nrs_resource_get_safe()
+ * \see nrs_request_enqueue()
+ */
+struct ptlrpc_nrs {
+ spinlock_t nrs_lock;
+ /** XXX Possibly replace svcpt->scp_req_lock with another lock here. */
+ /**
+ * List of registered policies
+ */
+ struct list_head nrs_policy_list;
+ /**
+ * List of policies with queued requests. Policies that have any
+ * outstanding requests are queued here, and this list is queried
+ * in a round-robin manner from NRS core when obtaining a request
+ * for handling. This ensures that requests from policies that at some
+ * point transition away from the
+ * ptlrpc_nrs_pol_state::NRS_POL_STATE_STARTED state are drained.
+ */
+ struct list_head nrs_policy_queued;
+ /**
+ * Service partition for this NRS head
+ */
+ struct ptlrpc_service_part *nrs_svcpt;
+ /**
+ * Primary policy, which is the preferred policy for handling RPCs
+ */
+ struct ptlrpc_nrs_policy *nrs_policy_primary;
+ /**
+ * Fallback policy, which is the backup policy for handling RPCs
+ */
+ struct ptlrpc_nrs_policy *nrs_policy_fallback;
+ /**
+ * This NRS head handles either HP or regular requests
+ */
+ enum ptlrpc_nrs_queue_type nrs_queue_type;
+ /**
+ * # queued requests from all policies in this NRS head
+ */
+ unsigned long nrs_req_queued;
+ /**
+ * # scheduled requests from all policies in this NRS head
+ */
+ unsigned long nrs_req_started;
+ /**
+ * # policies on this NRS
+ */
+ unsigned nrs_num_pols;
+ /**
+ * This NRS head is in progress of starting a policy
+ */
+ unsigned nrs_policy_starting:1;
+ /**
+ * In progress of shutting down the whole NRS head; used during
+ * unregistration
+ */
+ unsigned nrs_stopping:1;
+ /**
+ * NRS policy is throttling reqeust
+ */
+ unsigned nrs_throttling:1;
+};
+
+#define NRS_POL_NAME_MAX 16
+
+struct ptlrpc_nrs_pol_desc;
+
+/**
+ * Service compatibility predicate; this determines whether a policy is adequate
+ * for handling RPCs of a particular PTLRPC service.
+ *
+ * XXX:This should give the same result during policy registration and
+ * unregistration, and for all partitions of a service; so the result should not
+ * depend on temporal service or other properties, that may influence the
+ * result.
+ */
+typedef bool (*nrs_pol_desc_compat_t) (const struct ptlrpc_service *svc,
+ const struct ptlrpc_nrs_pol_desc *desc);
+
+struct ptlrpc_nrs_pol_conf {
+ /**
+ * Human-readable policy name
+ */
+ char nc_name[NRS_POL_NAME_MAX];
+ /**
+ * NRS operations for this policy
+ */
+ const struct ptlrpc_nrs_pol_ops *nc_ops;
+ /**
+ * Service compatibility predicate
+ */
+ nrs_pol_desc_compat_t nc_compat;
+ /**
+ * Set for policies that support a single ptlrpc service, i.e. ones that
+ * have \a pd_compat set to nrs_policy_compat_one(). The variable value
+ * depicts the name of the single service that such policies are
+ * compatible with.
+ */
+ const char *nc_compat_svc_name;
+ /**
+ * Owner module for this policy descriptor; policies registering from a
+ * different module to the one the NRS framework is held within
+ * (currently ptlrpc), should set this field to THIS_MODULE.
+ */
+ struct module *nc_owner;
+ /**
+ * Policy registration flags; a bitmast of \e nrs_policy_flags
+ */
+ unsigned nc_flags;
+};
+
+/**
+ * NRS policy registering descriptor
+ *
+ * Is used to hold a description of a policy that can be passed to NRS core in
+ * order to register the policy with NRS heads in different PTLRPC services.
+ */
+struct ptlrpc_nrs_pol_desc {
+ /**
+ * Human-readable policy name
+ */
+ char pd_name[NRS_POL_NAME_MAX];
+ /**
+ * Link into nrs_core::nrs_policies
+ */
+ struct list_head pd_list;
+ /**
+ * NRS operations for this policy
+ */
+ const struct ptlrpc_nrs_pol_ops *pd_ops;
+ /**
+ * Service compatibility predicate
+ */
+ nrs_pol_desc_compat_t pd_compat;
+ /**
+ * Set for policies that are compatible with only one PTLRPC service.
+ *
+ * \see ptlrpc_nrs_pol_conf::nc_compat_svc_name
+ */
+ const char *pd_compat_svc_name;
+ /**
+ * Owner module for this policy descriptor.
+ *
+ * We need to hold a reference to the module whenever we might make use
+ * of any of the module's contents, i.e.
+ * - If one or more instances of the policy are at a state where they
+ * might be handling a request, i.e.
+ * ptlrpc_nrs_pol_state::NRS_POL_STATE_STARTED or
+ * ptlrpc_nrs_pol_state::NRS_POL_STATE_STOPPING as we will have to
+ * call into the policy's ptlrpc_nrs_pol_ops() handlers. A reference
+ * is taken on the module when
+ * \e ptlrpc_nrs_pol_desc::pd_refs becomes 1, and released when it
+ * becomes 0, so that we hold only one reference to the module maximum
+ * at any time.
+ *
+ * We do not need to hold a reference to the module, even though we
+ * might use code and data from the module, in the following cases:
+ * - During external policy registration, because this should happen in
+ * the module's init() function, in which case the module is safe from
+ * removal because a reference is being held on the module by the
+ * kernel, and iirc kmod (and I guess module-init-tools also) will
+ * serialize any racing processes properly anyway.
+ * - During external policy unregistration, because this should happen
+ * in a module's exit() function, and any attempts to start a policy
+ * instance would need to take a reference on the module, and this is
+ * not possible once we have reached the point where the exit()
+ * handler is called.
+ * - During service registration and unregistration, as service setup
+ * and cleanup, and policy registration, unregistration and policy
+ * instance starting, are serialized by \e nrs_core::nrs_mutex, so
+ * as long as users adhere to the convention of registering policies
+ * in init() and unregistering them in module exit() functions, there
+ * should not be a race between these operations.
+ * - During any policy-specific lprocfs operations, because a reference
+ * is held by the kernel on a proc entry that has been entered by a
+ * syscall, so as long as proc entries are removed during unregistration time,
+ * then unregistration and lprocfs operations will be properly
+ * serialized.
+ */
+ struct module *pd_owner;
+ /**
+ * Bitmask of \e nrs_policy_flags
+ */
+ unsigned pd_flags;
+ /**
+ * # of references on this descriptor
+ */
+ atomic_t pd_refs;
+};
+
+/**
+ * NRS policy state
+ *
+ * Policies transition from one state to the other during their lifetime
+ */
+enum ptlrpc_nrs_pol_state {
+ /**
+ * Not a valid policy state.
+ */
+ NRS_POL_STATE_INVALID,
+ /**
+ * Policies are at this state either at the start of their life, or
+ * transition here when the user selects a different policy to act
+ * as the primary one.
+ */
+ NRS_POL_STATE_STOPPED,
+ /**
+ * Policy is progress of stopping
+ */
+ NRS_POL_STATE_STOPPING,
+ /**
+ * Policy is in progress of starting
+ */
+ NRS_POL_STATE_STARTING,
+ /**
+ * A policy is in this state in two cases:
+ * - it is the fallback policy, which is always in this state.
+ * - it has been activated by the user; i.e. it is the primary policy,
+ */
+ NRS_POL_STATE_STARTED,
+};
+
+/**
+ * NRS policy information
+ *
+ * Used for obtaining information for the status of a policy via lprocfs
+ */
+struct ptlrpc_nrs_pol_info {
+ /**
+ * Policy name
+ */
+ char pi_name[NRS_POL_NAME_MAX];
+ /**
+ * Current policy state
+ */
+ enum ptlrpc_nrs_pol_state pi_state;
+ /**
+ * # RPCs enqueued for later dispatching by the policy
+ */
+ long pi_req_queued;
+ /**
+ * # RPCs started for dispatch by the policy
+ */
+ long pi_req_started;
+ /**
+ * Is this a fallback policy?
+ */
+ unsigned pi_fallback:1;
+};
+
+/**
+ * NRS policy
+ *
+ * There is one instance of this for each policy in each NRS head of each
+ * PTLRPC service partition.
+ */
+struct ptlrpc_nrs_policy {
+ /**
+ * Linkage into the NRS head's list of policies,
+ * ptlrpc_nrs:nrs_policy_list
+ */
+ struct list_head pol_list;
+ /**
+ * Linkage into the NRS head's list of policies with enqueued
+ * requests ptlrpc_nrs:nrs_policy_queued
+ */
+ struct list_head pol_list_queued;
+ /**
+ * Current state of this policy
+ */
+ enum ptlrpc_nrs_pol_state pol_state;
+ /**
+ * Bitmask of nrs_policy_flags
+ */
+ unsigned pol_flags;
+ /**
+ * # RPCs enqueued for later dispatching by the policy
+ */
+ long pol_req_queued;
+ /**
+ * # RPCs started for dispatch by the policy
+ */
+ long pol_req_started;
+ /**
+ * Usage Reference count taken on the policy instance
+ */
+ long pol_ref;
+ /**
+ * The NRS head this policy has been created at
+ */
+ struct ptlrpc_nrs *pol_nrs;
+ /**
+ * Private policy data; varies by policy type
+ */
+ void *pol_private;
+ /**
+ * Policy descriptor for this policy instance.
+ */
+ struct ptlrpc_nrs_pol_desc *pol_desc;
+};
+
+/**
+ * NRS resource
+ *
+ * Resources are embedded into two types of NRS entities:
+ * - Inside NRS policies, in the policy's private data in
+ * ptlrpc_nrs_policy::pol_private
+ * - In objects that act as prime-level scheduling entities in different NRS
+ * policies; e.g. on a policy that performs round robin or similar order
+ * scheduling across client NIDs, there would be one NRS resource per unique
+ * client NID. On a policy which performs round robin scheduling across
+ * backend filesystem objects, there would be one resource associated with
+ * each of the backend filesystem objects partaking in the scheduling
+ * performed by the policy.
+ *
+ * NRS resources share a parent-child relationship, in which resources embedded
+ * in policy instances are the parent entities, with all scheduling entities
+ * a policy schedules across being the children, thus forming a simple resource
+ * hierarchy. This hierarchy may be extended with one or more levels in the
+ * future if the ability to have more than one primary policy is added.
+ *
+ * Upon request initialization, references to the then active NRS policies are
+ * taken and used to later handle the dispatching of the request with one of
+ * these policies.
+ *
+ * \see nrs_resource_get_safe()
+ * \see ptlrpc_nrs_req_add()
+ */
+struct ptlrpc_nrs_resource {
+ /**
+ * This NRS resource's parent; is NULL for resources embedded in NRS
+ * policy instances; i.e. those are top-level ones.
+ */
+ struct ptlrpc_nrs_resource *res_parent;
+ /**
+ * The policy associated with this resource.
+ */
+ struct ptlrpc_nrs_policy *res_policy;
+};
+
+enum {
+ NRS_RES_FALLBACK,
+ NRS_RES_PRIMARY,
+ NRS_RES_MAX
+};
+
+/* \name fifo
+ *
+ * FIFO policy
+ *
+ * This policy is a logical wrapper around previous, non-NRS functionality.
+ * It dispatches RPCs in the same order as they arrive from the network. This
+ * policy is currently used as the fallback policy, and the only enabled policy
+ * on all NRS heads of all PTLRPC service partitions.
+ * @{
+ */
+
+/**
+ * Private data structure for the FIFO policy
+ */
+struct nrs_fifo_head {
+ /**
+ * Resource object for policy instance.
+ */
+ struct ptlrpc_nrs_resource fh_res;
+ /**
+ * List of queued requests.
+ */
+ struct list_head fh_list;
+ /**
+ * For debugging purposes.
+ */
+ __u64 fh_sequence;
+};
+
+struct nrs_fifo_req {
+ struct list_head fr_list;
+ __u64 fr_sequence;
+};
+
+/** @} fifo */
+
+/**
+ * \name CRR-N
+ *
+ * CRR-N, Client Round Robin over NIDs
+ * @{
+ */
+
+/**
+ * private data structure for CRR-N NRS
+ */
+struct nrs_crrn_net {
+ struct ptlrpc_nrs_resource cn_res;
+ cfs_binheap_t *cn_binheap;
+ cfs_hash_t *cn_cli_hash;
+ /**
+ * Used when a new scheduling round commences, in order to synchronize
+ * all clients with the new round number.
+ */
+ __u64 cn_round;
+ /**
+ * Determines the relevant ordering amongst request batches within a
+ * scheduling round.
+ */
+ __u64 cn_sequence;
+ /**
+ * Round Robin quantum; the maximum number of RPCs that each request
+ * batch for each client can have in a scheduling round.
+ */
+ __u16 cn_quantum;
+};
+
+/**
+ * Object representing a client in CRR-N, as identified by its NID
+ */
+struct nrs_crrn_client {
+ struct ptlrpc_nrs_resource cc_res;
+ struct hlist_node cc_hnode;
+ lnet_nid_t cc_nid;
+ /**
+ * The round number against which this client is currently scheduling
+ * requests.
+ */
+ __u64 cc_round;
+ /**
+ * The sequence number used for requests scheduled by this client during
+ * the current round number.
+ */
+ __u64 cc_sequence;
+ atomic_t cc_ref;
+ /**
+ * Round Robin quantum; the maximum number of RPCs the client is allowed
+ * to schedule in a single batch of each round.
+ */
+ __u16 cc_quantum;
+ /**
+ * # of pending requests for this client, on all existing rounds
+ */
+ __u16 cc_active;
+};
+
+/**
+ * CRR-N NRS request definition
+ */
+struct nrs_crrn_req {
+ /**
+ * Round number for this request; shared with all other requests in the
+ * same batch.
+ */
+ __u64 cr_round;
+ /**
+ * Sequence number for this request; shared with all other requests in
+ * the same batch.
+ */
+ __u64 cr_sequence;
+};
+
+/**
+ * CRR-N policy operations.
+ */
+enum nrs_ctl_crr {
+ /**
+ * Read the RR quantum size of a CRR-N policy.
+ */
+ NRS_CTL_CRRN_RD_QUANTUM = PTLRPC_NRS_CTL_1ST_POL_SPEC,
+ /**
+ * Write the RR quantum size of a CRR-N policy.
+ */
+ NRS_CTL_CRRN_WR_QUANTUM,
+};
+
+/** @} CRR-N */
+
+/**
+ * \name ORR/TRR
+ *
+ * ORR/TRR (Object-based Round Robin/Target-based Round Robin) NRS policies
+ * @{
+ */
+
+/**
+ * Lower and upper byte offsets of a brw RPC
+ */
+struct nrs_orr_req_range {
+ __u64 or_start;
+ __u64 or_end;
+};
+
+/**
+ * RPC types supported by the ORR/TRR policies
+ */
+enum nrs_orr_supp {
+ NOS_OST_READ = (1 << 0),
+ NOS_OST_WRITE = (1 << 1),
+ NOS_OST_RW = (NOS_OST_READ | NOS_OST_WRITE),
+ /**
+ * Default value for policies.
+ */
+ NOS_DFLT = NOS_OST_READ