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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 | ||
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to the Free Software | |
18 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
19 | * | |
20 | * GPL HEADER END | |
21 | */ | |
22 | /* | |
23 | * Copyright (c) 2011 Intel Corporation | |
24 | * | |
25 | * Copyright 2012 Xyratex Technology Limited | |
26 | */ | |
27 | /* | |
28 | * lustre/ptlrpc/nrs_fifo.c | |
29 | * | |
30 | * Network Request Scheduler (NRS) FIFO policy | |
31 | * | |
32 | * Handles RPCs in a FIFO manner, as received from the network. This policy is | |
33 | * a logical wrapper around previous, non-NRS functionality. It is used as the | |
34 | * default and fallback policy for all types of RPCs on all PTLRPC service | |
35 | * partitions, for both regular and high-priority NRS heads. Default here means | |
36 | * the policy is the one enabled at PTLRPC service partition startup time, and | |
37 | * fallback means the policy is used to handle RPCs that are not handled | |
38 | * successfully or are not handled at all by any primary policy that may be | |
39 | * enabled on a given NRS head. | |
40 | * | |
41 | * Author: Liang Zhen <liang@whamcloud.com> | |
42 | * Author: Nikitas Angelinas <nikitas_angelinas@xyratex.com> | |
43 | */ | |
44 | /** | |
45 | * \addtogoup nrs | |
46 | * @{ | |
47 | */ | |
48 | ||
49 | #define DEBUG_SUBSYSTEM S_RPC | |
50 | #include <obd_support.h> | |
51 | #include <obd_class.h> | |
9fdaf8c0 | 52 | #include "../../include/linux/libcfs/libcfs.h" |
d7e09d03 PT |
53 | #include "ptlrpc_internal.h" |
54 | ||
55 | /** | |
56 | * \name fifo | |
57 | * | |
58 | * The FIFO policy is a logical wrapper around previous, non-NRS functionality. | |
59 | * It schedules RPCs in the same order as they are queued from LNet. | |
60 | * | |
61 | * @{ | |
62 | */ | |
63 | ||
64 | #define NRS_POL_NAME_FIFO "fifo" | |
65 | ||
66 | /** | |
67 | * Is called before the policy transitions into | |
68 | * ptlrpc_nrs_pol_state::NRS_POL_STATE_STARTED; allocates and initializes a | |
69 | * policy-specific private data structure. | |
70 | * | |
71 | * \param[in] policy The policy to start | |
72 | * | |
73 | * \retval -ENOMEM OOM error | |
74 | * \retval 0 success | |
75 | * | |
76 | * \see nrs_policy_register() | |
77 | * \see nrs_policy_ctl() | |
78 | */ | |
79 | static int nrs_fifo_start(struct ptlrpc_nrs_policy *policy) | |
80 | { | |
81 | struct nrs_fifo_head *head; | |
82 | ||
83 | OBD_CPT_ALLOC_PTR(head, nrs_pol2cptab(policy), nrs_pol2cptid(policy)); | |
84 | if (head == NULL) | |
85 | return -ENOMEM; | |
86 | ||
87 | INIT_LIST_HEAD(&head->fh_list); | |
88 | policy->pol_private = head; | |
89 | return 0; | |
90 | } | |
91 | ||
92 | /** | |
93 | * Is called before the policy transitions into | |
94 | * ptlrpc_nrs_pol_state::NRS_POL_STATE_STOPPED; deallocates the policy-specific | |
95 | * private data structure. | |
96 | * | |
97 | * \param[in] policy The policy to stop | |
98 | * | |
99 | * \see nrs_policy_stop0() | |
100 | */ | |
101 | static void nrs_fifo_stop(struct ptlrpc_nrs_policy *policy) | |
102 | { | |
103 | struct nrs_fifo_head *head = policy->pol_private; | |
104 | ||
105 | LASSERT(head != NULL); | |
106 | LASSERT(list_empty(&head->fh_list)); | |
107 | ||
108 | OBD_FREE_PTR(head); | |
109 | } | |
110 | ||
111 | /** | |
112 | * Is called for obtaining a FIFO policy resource. | |
113 | * | |
114 | * \param[in] policy The policy on which the request is being asked for | |
115 | * \param[in] nrq The request for which resources are being taken | |
116 | * \param[in] parent Parent resource, unused in this policy | |
117 | * \param[out] resp Resources references are placed in this array | |
118 | * \param[in] moving_req Signifies limited caller context; unused in this | |
119 | * policy | |
120 | * | |
121 | * \retval 1 The FIFO policy only has a one-level resource hierarchy, as since | |
122 | * it implements a simple scheduling algorithm in which request | |
123 | * priority is determined on the request arrival order, it does not | |
124 | * need to maintain a set of resources that would otherwise be used | |
125 | * to calculate a request's priority. | |
126 | * | |
127 | * \see nrs_resource_get_safe() | |
128 | */ | |
129 | static int nrs_fifo_res_get(struct ptlrpc_nrs_policy *policy, | |
130 | struct ptlrpc_nrs_request *nrq, | |
131 | const struct ptlrpc_nrs_resource *parent, | |
132 | struct ptlrpc_nrs_resource **resp, bool moving_req) | |
133 | { | |
134 | /** | |
135 | * Just return the resource embedded inside nrs_fifo_head, and end this | |
136 | * resource hierarchy reference request. | |
137 | */ | |
138 | *resp = &((struct nrs_fifo_head *)policy->pol_private)->fh_res; | |
139 | return 1; | |
140 | } | |
141 | ||
142 | /** | |
143 | * Called when getting a request from the FIFO policy for handling, or just | |
144 | * peeking; removes the request from the policy when it is to be handled. | |
145 | * | |
146 | * \param[in] policy The policy | |
147 | * \param[in] peek When set, signifies that we just want to examine the | |
148 | * request, and not handle it, so the request is not removed | |
149 | * from the policy. | |
150 | * \param[in] force Force the policy to return a request; unused in this | |
151 | * policy | |
152 | * | |
153 | * \retval The request to be handled; this is the next request in the FIFO | |
154 | * queue | |
155 | * | |
156 | * \see ptlrpc_nrs_req_get_nolock() | |
157 | * \see nrs_request_get() | |
158 | */ | |
159 | static | |
160 | struct ptlrpc_nrs_request * nrs_fifo_req_get(struct ptlrpc_nrs_policy *policy, | |
161 | bool peek, bool force) | |
162 | { | |
163 | struct nrs_fifo_head *head = policy->pol_private; | |
164 | struct ptlrpc_nrs_request *nrq; | |
165 | ||
166 | nrq = unlikely(list_empty(&head->fh_list)) ? NULL : | |
167 | list_entry(head->fh_list.next, struct ptlrpc_nrs_request, | |
168 | nr_u.fifo.fr_list); | |
169 | ||
170 | if (likely(!peek && nrq != NULL)) { | |
171 | struct ptlrpc_request *req = container_of(nrq, | |
172 | struct ptlrpc_request, | |
173 | rq_nrq); | |
174 | ||
175 | list_del_init(&nrq->nr_u.fifo.fr_list); | |
176 | ||
177 | CDEBUG(D_RPCTRACE, "NRS start %s request from %s, seq: "LPU64 | |
178 | "\n", policy->pol_desc->pd_name, | |
179 | libcfs_id2str(req->rq_peer), nrq->nr_u.fifo.fr_sequence); | |
180 | } | |
181 | ||
182 | return nrq; | |
183 | } | |
184 | ||
185 | /** | |
186 | * Adds request \a nrq to \a policy's list of queued requests | |
187 | * | |
188 | * \param[in] policy The policy | |
189 | * \param[in] nrq The request to add | |
190 | * | |
191 | * \retval 0 success; nrs_request_enqueue() assumes this function will always | |
192 | * succeed | |
193 | */ | |
194 | static int nrs_fifo_req_add(struct ptlrpc_nrs_policy *policy, | |
195 | struct ptlrpc_nrs_request *nrq) | |
196 | { | |
197 | struct nrs_fifo_head *head; | |
198 | ||
199 | head = container_of(nrs_request_resource(nrq), struct nrs_fifo_head, | |
200 | fh_res); | |
201 | /** | |
202 | * Only used for debugging | |
203 | */ | |
204 | nrq->nr_u.fifo.fr_sequence = head->fh_sequence++; | |
205 | list_add_tail(&nrq->nr_u.fifo.fr_list, &head->fh_list); | |
206 | ||
207 | return 0; | |
208 | } | |
209 | ||
210 | /** | |
211 | * Removes request \a nrq from \a policy's list of queued requests. | |
212 | * | |
213 | * \param[in] policy The policy | |
214 | * \param[in] nrq The request to remove | |
215 | */ | |
216 | static void nrs_fifo_req_del(struct ptlrpc_nrs_policy *policy, | |
217 | struct ptlrpc_nrs_request *nrq) | |
218 | { | |
219 | LASSERT(!list_empty(&nrq->nr_u.fifo.fr_list)); | |
220 | list_del_init(&nrq->nr_u.fifo.fr_list); | |
221 | } | |
222 | ||
223 | /** | |
224 | * Prints a debug statement right before the request \a nrq stops being | |
225 | * handled. | |
226 | * | |
227 | * \param[in] policy The policy handling the request | |
228 | * \param[in] nrq The request being handled | |
229 | * | |
230 | * \see ptlrpc_server_finish_request() | |
231 | * \see ptlrpc_nrs_req_stop_nolock() | |
232 | */ | |
233 | static void nrs_fifo_req_stop(struct ptlrpc_nrs_policy *policy, | |
234 | struct ptlrpc_nrs_request *nrq) | |
235 | { | |
236 | struct ptlrpc_request *req = container_of(nrq, struct ptlrpc_request, | |
237 | rq_nrq); | |
238 | ||
239 | CDEBUG(D_RPCTRACE, "NRS stop %s request from %s, seq: "LPU64"\n", | |
240 | policy->pol_desc->pd_name, libcfs_id2str(req->rq_peer), | |
241 | nrq->nr_u.fifo.fr_sequence); | |
242 | } | |
243 | ||
244 | /** | |
245 | * FIFO policy operations | |
246 | */ | |
247 | static const struct ptlrpc_nrs_pol_ops nrs_fifo_ops = { | |
248 | .op_policy_start = nrs_fifo_start, | |
249 | .op_policy_stop = nrs_fifo_stop, | |
250 | .op_res_get = nrs_fifo_res_get, | |
251 | .op_req_get = nrs_fifo_req_get, | |
252 | .op_req_enqueue = nrs_fifo_req_add, | |
253 | .op_req_dequeue = nrs_fifo_req_del, | |
254 | .op_req_stop = nrs_fifo_req_stop, | |
255 | }; | |
256 | ||
257 | /** | |
258 | * FIFO policy configuration | |
259 | */ | |
260 | struct ptlrpc_nrs_pol_conf nrs_conf_fifo = { | |
261 | .nc_name = NRS_POL_NAME_FIFO, | |
262 | .nc_ops = &nrs_fifo_ops, | |
263 | .nc_compat = nrs_policy_compat_all, | |
264 | .nc_flags = PTLRPC_NRS_FL_FALLBACK | | |
265 | PTLRPC_NRS_FL_REG_START | |
266 | }; | |
267 | ||
268 | /** @} fifo */ | |
269 | ||
270 | /** @} nrs */ |