[deliverable/linux.git] / drivers / staging / lustre / lustre / ptlrpc / nrs_fifo.c

/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License version 2 for more details.  A copy is
 * included in the COPYING file that accompanied this code.

 * GPL HEADER END
 */
/*
 * Copyright (c) 2011 Intel Corporation
 *
 * Copyright 2012 Xyratex Technology Limited
 */
/*
 * lustre/ptlrpc/nrs_fifo.c
 *
 * Network Request Scheduler (NRS) FIFO policy
 *
 * Handles RPCs in a FIFO manner, as received from the network. This policy is
 * a logical wrapper around previous, non-NRS functionality. It is used as the
 * default and fallback policy for all types of RPCs on all PTLRPC service
 * partitions, for both regular and high-priority NRS heads. Default here means
 * the policy is the one enabled at PTLRPC service partition startup time, and
 * fallback means the policy is used to handle RPCs that are not handled
 * successfully or are not handled at all by any primary policy that may be
 * enabled on a given NRS head.
 *
 * Author: Liang Zhen <liang@whamcloud.com>
 * Author: Nikitas Angelinas <nikitas_angelinas@xyratex.com>
 */
/**
 * \addtogoup nrs
 * @{
 */

#define DEBUG_SUBSYSTEM S_RPC
#include "../include/obd_support.h"
#include "../include/obd_class.h"
#include "../../include/linux/libcfs/libcfs.h"
#include "ptlrpc_internal.h"

/**
 * \name fifo
 *
 * The FIFO policy is a logical wrapper around previous, non-NRS functionality.
 * It schedules RPCs in the same order as they are queued from LNet.
 *
 * @{
 */

#define NRS_POL_NAME_FIFO	"fifo"

/**
 * Is called before the policy transitions into
 * ptlrpc_nrs_pol_state::NRS_POL_STATE_STARTED; allocates and initializes a
 * policy-specific private data structure.
 *
 * \param[in] policy The policy to start
 *
 * \retval -ENOMEM OOM error
 * \retval  0	   success
 *
 * \see nrs_policy_register()
 * \see nrs_policy_ctl()
 */
static int nrs_fifo_start(struct ptlrpc_nrs_policy *policy)
{
	struct nrs_fifo_head *head;

	head = kzalloc_node(sizeof(*head), GFP_NOFS,
			    cfs_cpt_spread_node(nrs_pol2cptab(policy),
						nrs_pol2cptid(policy)));
	if (!head)
		return -ENOMEM;

	INIT_LIST_HEAD(&head->fh_list);
	policy->pol_private = head;
	return 0;
}

/**
 * Is called before the policy transitions into
 * ptlrpc_nrs_pol_state::NRS_POL_STATE_STOPPED; deallocates the policy-specific
 * private data structure.
 *
 * \param[in] policy The policy to stop
 *
 * \see nrs_policy_stop0()
 */
static void nrs_fifo_stop(struct ptlrpc_nrs_policy *policy)
{
	struct nrs_fifo_head *head = policy->pol_private;

	LASSERT(head);
	LASSERT(list_empty(&head->fh_list));

	kfree(head);
}

/**
 * Is called for obtaining a FIFO policy resource.
 *
 * \param[in]  policy	  The policy on which the request is being asked for
 * \param[in]  nrq	  The request for which resources are being taken
 * \param[in]  parent	  Parent resource, unused in this policy
 * \param[out] resp	  Resources references are placed in this array
 * \param[in]  moving_req Signifies limited caller context; unused in this
 *			  policy
 *
 * \retval 1 The FIFO policy only has a one-level resource hierarchy, as since
 *	     it implements a simple scheduling algorithm in which request
 *	     priority is determined on the request arrival order, it does not
 *	     need to maintain a set of resources that would otherwise be used
 *	     to calculate a request's priority.
 *
 * \see nrs_resource_get_safe()
 */
static int nrs_fifo_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)
{
	/**
	 * Just return the resource embedded inside nrs_fifo_head, and end this
	 * resource hierarchy reference request.
	 */
	*resp = &((struct nrs_fifo_head *)policy->pol_private)->fh_res;
	return 1;
}

/**
 * Called when getting a request from the FIFO policy for handling, or just
 * peeking; removes the request from the policy when it is to be handled.
 *
 * \param[in] policy The policy
 * \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  Force the policy to return a request; unused in this
 *		     policy
 *
 * \retval The request to be handled; this is the next request in the FIFO
 *	   queue
 *
 * \see ptlrpc_nrs_req_get_nolock()
 * \see nrs_request_get()
 */
static
struct ptlrpc_nrs_request *nrs_fifo_req_get(struct ptlrpc_nrs_policy *policy,
					    bool peek, bool force)
{
	struct nrs_fifo_head *head = policy->pol_private;
	struct ptlrpc_nrs_request *nrq;

	nrq = unlikely(list_empty(&head->fh_list)) ? NULL :
	      list_entry(head->fh_list.next, struct ptlrpc_nrs_request,
			     nr_u.fifo.fr_list);

	if (likely(!peek && nrq)) {
		struct ptlrpc_request *req = container_of(nrq,
							  struct ptlrpc_request,
							  rq_nrq);

		list_del_init(&nrq->nr_u.fifo.fr_list);

		CDEBUG(D_RPCTRACE, "NRS start %s request from %s, seq: %llu\n",
		       policy->pol_desc->pd_name, libcfs_id2str(req->rq_peer),
		       nrq->nr_u.fifo.fr_sequence);
	}

	return nrq;
}

/**
 * Adds request \a nrq to \a policy's list of queued requests
 *
 * \param[in] policy The policy
 * \param[in] nrq    The request to add
 *
 * \retval 0 success; nrs_request_enqueue() assumes this function will always
 *		      succeed
 */
static int nrs_fifo_req_add(struct ptlrpc_nrs_policy *policy,
			    struct ptlrpc_nrs_request *nrq)
{
	struct nrs_fifo_head *head;

	head = container_of(nrs_request_resource(nrq), struct nrs_fifo_head,
			    fh_res);
	/**
	 * Only used for debugging
	 */
	nrq->nr_u.fifo.fr_sequence = head->fh_sequence++;
	list_add_tail(&nrq->nr_u.fifo.fr_list, &head->fh_list);

	return 0;
}

/**
 * Removes request \a nrq from \a policy's list of queued requests.
 *
 * \param[in] policy The policy
 * \param[in] nrq    The request to remove
 */
static void nrs_fifo_req_del(struct ptlrpc_nrs_policy *policy,
			     struct ptlrpc_nrs_request *nrq)
{
	LASSERT(!list_empty(&nrq->nr_u.fifo.fr_list));
	list_del_init(&nrq->nr_u.fifo.fr_list);
}

/**
 * Prints a debug statement right before the request \a nrq stops being
 * handled.
 *
 * \param[in] policy The policy handling the request
 * \param[in] nrq    The request being handled
 *
 * \see ptlrpc_server_finish_request()
 * \see ptlrpc_nrs_req_stop_nolock()
 */
static void nrs_fifo_req_stop(struct ptlrpc_nrs_policy *policy,
			      struct ptlrpc_nrs_request *nrq)
{
	struct ptlrpc_request *req = container_of(nrq, struct ptlrpc_request,
						  rq_nrq);

	CDEBUG(D_RPCTRACE, "NRS stop %s request from %s, seq: %llu\n",
	       policy->pol_desc->pd_name, libcfs_id2str(req->rq_peer),
	       nrq->nr_u.fifo.fr_sequence);
}

/**
 * FIFO policy operations
 */
static const struct ptlrpc_nrs_pol_ops nrs_fifo_ops = {
	.op_policy_start	= nrs_fifo_start,
	.op_policy_stop		= nrs_fifo_stop,
	.op_res_get		= nrs_fifo_res_get,
	.op_req_get		= nrs_fifo_req_get,
	.op_req_enqueue		= nrs_fifo_req_add,
	.op_req_dequeue		= nrs_fifo_req_del,
	.op_req_stop		= nrs_fifo_req_stop,
};

/**
 * FIFO policy configuration
 */
struct ptlrpc_nrs_pol_conf nrs_conf_fifo = {
	.nc_name		= NRS_POL_NAME_FIFO,
	.nc_ops			= &nrs_fifo_ops,
	.nc_compat		= nrs_policy_compat_all,
	.nc_flags		= PTLRPC_NRS_FL_FALLBACK |
				  PTLRPC_NRS_FL_REG_START
};

/** @} fifo */

/** @} nrs */
Commit	Line	Data
d7e09d03 PT	1	/*
	2	* GPL HEADER START
	3	*
	4	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 only,
	8	* as published by the Free Software Foundation.
	9
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License version 2 for more details. A copy is
	14	* included in the COPYING file that accompanied this code.
	15
d7e09d03 PT	16	* GPL HEADER END
	17	*/
	18	/*
	19	* Copyright (c) 2011 Intel Corporation
	20	*
	21	* Copyright 2012 Xyratex Technology Limited
	22	*/
	23	/*
	24	* lustre/ptlrpc/nrs_fifo.c
	25	*
	26	* Network Request Scheduler (NRS) FIFO policy
	27	*
	28	* Handles RPCs in a FIFO manner, as received from the network. This policy is
	29	* a logical wrapper around previous, non-NRS functionality. It is used as the
	30	* default and fallback policy for all types of RPCs on all PTLRPC service
	31	* partitions, for both regular and high-priority NRS heads. Default here means
	32	* the policy is the one enabled at PTLRPC service partition startup time, and
	33	* fallback means the policy is used to handle RPCs that are not handled
	34	* successfully or are not handled at all by any primary policy that may be
	35	* enabled on a given NRS head.
	36	*
	37	* Author: Liang Zhen <liang@whamcloud.com>
	38	* Author: Nikitas Angelinas <nikitas_angelinas@xyratex.com>
	39	*/
	40	/**
	41	* \addtogoup nrs
	42	* @{
	43	*/
	44
	45	#define DEBUG_SUBSYSTEM S_RPC
e27db149 GKH	46	#include "../include/obd_support.h"
e27db149 GKH	47	#include "../include/obd_class.h"
9fdaf8c0	48	#include "../../include/linux/libcfs/libcfs.h"
d7e09d03 PT	49	#include "ptlrpc_internal.h"
	50
	51	/**
	52	* \name fifo
	53	*
	54	* The FIFO policy is a logical wrapper around previous, non-NRS functionality.
	55	* It schedules RPCs in the same order as they are queued from LNet.
	56	*
	57	* @{
	58	*/
	59
	60	#define NRS_POL_NAME_FIFO "fifo"
	61
	62	/**
	63	* Is called before the policy transitions into
	64	* ptlrpc_nrs_pol_state::NRS_POL_STATE_STARTED; allocates and initializes a
	65	* policy-specific private data structure.
	66	*
	67	* \param[in] policy The policy to start
	68	*
	69	* \retval -ENOMEM OOM error
	70	* \retval 0 success
	71	*
	72	* \see nrs_policy_register()
	73	* \see nrs_policy_ctl()
	74	*/
	75	static int nrs_fifo_start(struct ptlrpc_nrs_policy *policy)
	76	{
	77	struct nrs_fifo_head *head;
	78
b18d1100 JL	79	head = kzalloc_node(sizeof(*head), GFP_NOFS,
	80	cfs_cpt_spread_node(nrs_pol2cptab(policy),
	81	nrs_pol2cptid(policy)));
8b382089	82	if (!head)
d7e09d03 PT	83	return -ENOMEM;
	84
	85	INIT_LIST_HEAD(&head->fh_list);
	86	policy->pol_private = head;
	87	return 0;
	88	}
	89
	90	/**
	91	* Is called before the policy transitions into
	92	* ptlrpc_nrs_pol_state::NRS_POL_STATE_STOPPED; deallocates the policy-specific
	93	* private data structure.
	94	*
	95	* \param[in] policy The policy to stop
	96	*
	97	* \see nrs_policy_stop0()
	98	*/
	99	static void nrs_fifo_stop(struct ptlrpc_nrs_policy *policy)
	100	{
	101	struct nrs_fifo_head *head = policy->pol_private;
	102
8b382089	103	LASSERT(head);
d7e09d03 PT	104	LASSERT(list_empty(&head->fh_list));
d7e09d03 PT	105
9ae10597	106	kfree(head);
d7e09d03 PT	107	}
	108
	109	/**
	110	* Is called for obtaining a FIFO policy resource.
	111	*
	112	* \param[in] policy The policy on which the request is being asked for
	113	* \param[in] nrq The request for which resources are being taken
	114	* \param[in] parent Parent resource, unused in this policy
	115	* \param[out] resp Resources references are placed in this array
	116	* \param[in] moving_req Signifies limited caller context; unused in this
	117	* policy
	118	*
	119	* \retval 1 The FIFO policy only has a one-level resource hierarchy, as since
	120	* it implements a simple scheduling algorithm in which request
	121	* priority is determined on the request arrival order, it does not
	122	* need to maintain a set of resources that would otherwise be used
	123	* to calculate a request's priority.
	124	*
	125	* \see nrs_resource_get_safe()
	126	*/
	127	static int nrs_fifo_res_get(struct ptlrpc_nrs_policy *policy,
	128	struct ptlrpc_nrs_request *nrq,
	129	const struct ptlrpc_nrs_resource *parent,
	130	struct ptlrpc_nrs_resource **resp, bool moving_req)
	131	{
	132	/**
	133	* Just return the resource embedded inside nrs_fifo_head, and end this
	134	* resource hierarchy reference request.
	135	*/
	136	resp = &((struct nrs_fifo_head )policy->pol_private)->fh_res;
	137	return 1;
	138	}
	139
	140	/**
	141	* Called when getting a request from the FIFO policy for handling, or just
	142	* peeking; removes the request from the policy when it is to be handled.
	143	*
	144	* \param[in] policy The policy
	145	* \param[in] peek When set, signifies that we just want to examine the
	146	* request, and not handle it, so the request is not removed
	147	* from the policy.
	148	* \param[in] force Force the policy to return a request; unused in this
	149	* policy
	150	*
	151	* \retval The request to be handled; this is the next request in the FIFO
	152	* queue
	153	*
	154	* \see ptlrpc_nrs_req_get_nolock()
	155	* \see nrs_request_get()
	156	*/
	157	static
aff9d8e8	158	struct ptlrpc_nrs_request nrs_fifo_req_get(struct ptlrpc_nrs_policy policy,
d0bfef31	159	bool peek, bool force)
d7e09d03	160	{
d0bfef31	161	struct nrs_fifo_head *head = policy->pol_private;
d7e09d03 PT	162	struct ptlrpc_nrs_request *nrq;
	163
	164	nrq = unlikely(list_empty(&head->fh_list)) ? NULL :
	165	list_entry(head->fh_list.next, struct ptlrpc_nrs_request,
	166	nr_u.fifo.fr_list);
	167
8b382089	168	if (likely(!peek && nrq)) {
d7e09d03 PT	169	struct ptlrpc_request *req = container_of(nrq,
	170	struct ptlrpc_request,
	171	rq_nrq);
	172
	173	list_del_init(&nrq->nr_u.fifo.fr_list);
	174
b0f5aad5 GKH	175	CDEBUG(D_RPCTRACE, "NRS start %s request from %s, seq: %llu\n",
	176	policy->pol_desc->pd_name, libcfs_id2str(req->rq_peer),
	177	nrq->nr_u.fifo.fr_sequence);
d7e09d03 PT	178	}
	179
	180	return nrq;
	181	}
	182
	183	/**
	184	* Adds request \a nrq to \a policy's list of queued requests
	185	*
	186	* \param[in] policy The policy
	187	* \param[in] nrq The request to add
	188	*
	189	* \retval 0 success; nrs_request_enqueue() assumes this function will always
	190	* succeed
	191	*/
	192	static int nrs_fifo_req_add(struct ptlrpc_nrs_policy *policy,
	193	struct ptlrpc_nrs_request *nrq)
	194	{
	195	struct nrs_fifo_head *head;
	196
	197	head = container_of(nrs_request_resource(nrq), struct nrs_fifo_head,
	198	fh_res);
	199	/**
	200	* Only used for debugging
	201	*/
	202	nrq->nr_u.fifo.fr_sequence = head->fh_sequence++;
	203	list_add_tail(&nrq->nr_u.fifo.fr_list, &head->fh_list);
	204
	205	return 0;
	206	}
	207
	208	/**
	209	* Removes request \a nrq from \a policy's list of queued requests.
	210	*
	211	* \param[in] policy The policy
	212	* \param[in] nrq The request to remove
	213	*/
	214	static void nrs_fifo_req_del(struct ptlrpc_nrs_policy *policy,
	215	struct ptlrpc_nrs_request *nrq)
	216	{
	217	LASSERT(!list_empty(&nrq->nr_u.fifo.fr_list));
	218	list_del_init(&nrq->nr_u.fifo.fr_list);
	219	}
	220
	221	/**
	222	* Prints a debug statement right before the request \a nrq stops being
	223	* handled.
	224	*
	225	* \param[in] policy The policy handling the request
	226	* \param[in] nrq The request being handled
	227	*
	228	* \see ptlrpc_server_finish_request()
	229	* \see ptlrpc_nrs_req_stop_nolock()
	230	*/
	231	static void nrs_fifo_req_stop(struct ptlrpc_nrs_policy *policy,
	232	struct ptlrpc_nrs_request *nrq)
	233	{
	234	struct ptlrpc_request *req = container_of(nrq, struct ptlrpc_request,
	235	rq_nrq);
	236
b0f5aad5	237	CDEBUG(D_RPCTRACE, "NRS stop %s request from %s, seq: %llu\n",
d7e09d03 PT	238	policy->pol_desc->pd_name, libcfs_id2str(req->rq_peer),
	239	nrq->nr_u.fifo.fr_sequence);
	240	}
	241
	242	/**
	243	* FIFO policy operations
	244	*/
	245	static const struct ptlrpc_nrs_pol_ops nrs_fifo_ops = {
	246	.op_policy_start = nrs_fifo_start,
	247	.op_policy_stop = nrs_fifo_stop,
	248	.op_res_get = nrs_fifo_res_get,
	249	.op_req_get = nrs_fifo_req_get,
	250	.op_req_enqueue = nrs_fifo_req_add,
	251	.op_req_dequeue = nrs_fifo_req_del,
	252	.op_req_stop = nrs_fifo_req_stop,
	253	};
	254
	255	/**
	256	* FIFO policy configuration
	257	*/
	258	struct ptlrpc_nrs_pol_conf nrs_conf_fifo = {
	259	.nc_name = NRS_POL_NAME_FIFO,
	260	.nc_ops = &nrs_fifo_ops,
	261	.nc_compat = nrs_policy_compat_all,
	262	.nc_flags = PTLRPC_NRS_FL_FALLBACK \|
	263	PTLRPC_NRS_FL_REG_START
	264	};
	265
	266	/** @} fifo */
	267
	268	/** @} nrs */