1/*-
2 * Copyright (c) 2001-2002 Luigi Rizzo
3 *
4 * Supported by: the Xorp Project (www.xorp.org)
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
| 1/*-
2 * Copyright (c) 2001-2002 Luigi Rizzo
3 *
4 * Supported by: the Xorp Project (www.xorp.org)
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
|
27 * $FreeBSD: head/sys/kern/kern_poll.c 102052 2002-08-18 07:05:00Z sobomax $
| 27 * $FreeBSD: head/sys/kern/kern_poll.c 111888 2003-03-04 23:19:55Z jlemon $
|
28 */
29
30#include <sys/param.h>
31#include <sys/systm.h>
32#include <sys/kernel.h>
33#include <sys/socket.h> /* needed by net/if.h */
34#include <sys/sysctl.h>
35
36#include <net/if.h> /* for IFF_* flags */
37#include <net/netisr.h> /* for NETISR_POLL */
38
39#include <sys/proc.h>
40#include <sys/resourcevar.h>
41#include <sys/kthread.h>
42
43#ifdef SMP
44#ifndef COMPILING_LINT
45#error DEVICE_POLLING is not compatible with SMP
46#endif
47#endif
48
49static void netisr_poll(void); /* the two netisr handlers */
| 28 */
29
30#include <sys/param.h>
31#include <sys/systm.h>
32#include <sys/kernel.h>
33#include <sys/socket.h> /* needed by net/if.h */
34#include <sys/sysctl.h>
35
36#include <net/if.h> /* for IFF_* flags */
37#include <net/netisr.h> /* for NETISR_POLL */
38
39#include <sys/proc.h>
40#include <sys/resourcevar.h>
41#include <sys/kthread.h>
42
43#ifdef SMP
44#ifndef COMPILING_LINT
45#error DEVICE_POLLING is not compatible with SMP
46#endif
47#endif
48
49static void netisr_poll(void); /* the two netisr handlers */
|
50void netisr_pollmore(void);
| 50static void netisr_pollmore(void);
|
51
| 51
|
52void init_device_poll(void); /* init routine */
| |
53void hardclock_device_poll(void); /* hook from hardclock */
54void ether_poll(int); /* polling while in trap */
55
56/*
57 * Polling support for [network] device drivers.
58 *
59 * Drivers which support this feature try to register with the
60 * polling code.
61 *
62 * If registration is successful, the driver must disable interrupts,
63 * and further I/O is performed through the handler, which is invoked
64 * (at least once per clock tick) with 3 arguments: the "arg" passed at
65 * register time (a struct ifnet pointer), a command, and a "count" limit.
66 *
67 * The command can be one of the following:
68 * POLL_ONLY: quick move of "count" packets from input/output queues.
69 * POLL_AND_CHECK_STATUS: as above, plus check status registers or do
70 * other more expensive operations. This command is issued periodically
71 * but less frequently than POLL_ONLY.
72 * POLL_DEREGISTER: deregister and return to interrupt mode.
73 *
74 * The first two commands are only issued if the interface is marked as
75 * 'IFF_UP and IFF_RUNNING', the last one only if IFF_RUNNING is set.
76 *
77 * The count limit specifies how much work the handler can do during the
78 * call -- typically this is the number of packets to be received, or
79 * transmitted, etc. (drivers are free to interpret this number, as long
80 * as the max time spent in the function grows roughly linearly with the
81 * count).
82 *
83 * Deregistration can be requested by the driver itself (typically in the
84 * *_stop() routine), or by the polling code, by invoking the handler.
85 *
86 * Polling can be globally enabled or disabled with the sysctl variable
87 * kern.polling.enable (default is 0, disabled)
88 *
89 * A second variable controls the sharing of CPU between polling/kernel
90 * network processing, and other activities (typically userlevel tasks):
91 * kern.polling.user_frac (between 0 and 100, default 50) sets the share
92 * of CPU allocated to user tasks. CPU is allocated proportionally to the
93 * shares, by dynamically adjusting the "count" (poll_burst).
94 *
95 * Other parameters can should be left to their default values.
96 * The following constraints hold
97 *
98 * 1 <= poll_each_burst <= poll_burst <= poll_burst_max
99 * 0 <= poll_in_trap <= poll_each_burst
100 * MIN_POLL_BURST_MAX <= poll_burst_max <= MAX_POLL_BURST_MAX
101 */
102
103#define MIN_POLL_BURST_MAX 10
104#define MAX_POLL_BURST_MAX 1000
105
106SYSCTL_NODE(_kern, OID_AUTO, polling, CTLFLAG_RW, 0,
107 "Device polling parameters");
108
109static u_int32_t poll_burst = 5;
110SYSCTL_UINT(_kern_polling, OID_AUTO, burst, CTLFLAG_RW,
111 &poll_burst, 0, "Current polling burst size");
112
113static u_int32_t poll_each_burst = 5;
114SYSCTL_UINT(_kern_polling, OID_AUTO, each_burst, CTLFLAG_RW,
115 &poll_each_burst, 0, "Max size of each burst");
116
117static u_int32_t poll_burst_max = 150; /* good for 100Mbit net and HZ=1000 */
118SYSCTL_UINT(_kern_polling, OID_AUTO, burst_max, CTLFLAG_RW,
119 &poll_burst_max, 0, "Max Polling burst size");
120
121static u_int32_t poll_in_idle_loop=0; /* do we poll in idle loop ? */
122SYSCTL_UINT(_kern_polling, OID_AUTO, idle_poll, CTLFLAG_RW,
123 &poll_in_idle_loop, 0, "Enable device polling in idle loop");
124
125u_int32_t poll_in_trap; /* used in trap.c */
126SYSCTL_UINT(_kern_polling, OID_AUTO, poll_in_trap, CTLFLAG_RW,
127 &poll_in_trap, 0, "Poll burst size during a trap");
128
129static u_int32_t user_frac = 50;
130SYSCTL_UINT(_kern_polling, OID_AUTO, user_frac, CTLFLAG_RW,
131 &user_frac, 0, "Desired user fraction of cpu time");
132
133static u_int32_t reg_frac = 20 ;
134SYSCTL_UINT(_kern_polling, OID_AUTO, reg_frac, CTLFLAG_RW,
135 ®_frac, 0, "Every this many cycles poll register");
136
137static u_int32_t short_ticks;
138SYSCTL_UINT(_kern_polling, OID_AUTO, short_ticks, CTLFLAG_RW,
139 &short_ticks, 0, "Hardclock ticks shorter than they should be");
140
141static u_int32_t lost_polls;
142SYSCTL_UINT(_kern_polling, OID_AUTO, lost_polls, CTLFLAG_RW,
143 &lost_polls, 0, "How many times we would have lost a poll tick");
144
145static u_int32_t pending_polls;
146SYSCTL_UINT(_kern_polling, OID_AUTO, pending_polls, CTLFLAG_RW,
147 &pending_polls, 0, "Do we need to poll again");
148
149static int residual_burst = 0;
150SYSCTL_INT(_kern_polling, OID_AUTO, residual_burst, CTLFLAG_RW,
151 &residual_burst, 0, "# of residual cycles in burst");
152
153static u_int32_t poll_handlers; /* next free entry in pr[]. */
154SYSCTL_UINT(_kern_polling, OID_AUTO, handlers, CTLFLAG_RD,
155 &poll_handlers, 0, "Number of registered poll handlers");
156
157static int polling = 0; /* global polling enable */
158SYSCTL_UINT(_kern_polling, OID_AUTO, enable, CTLFLAG_RW,
159 &polling, 0, "Polling enabled");
160
161static u_int32_t phase;
162SYSCTL_UINT(_kern_polling, OID_AUTO, phase, CTLFLAG_RW,
163 &phase, 0, "Polling phase");
164
165static u_int32_t suspect;
166SYSCTL_UINT(_kern_polling, OID_AUTO, suspect, CTLFLAG_RW,
167 &suspect, 0, "suspect event");
168
169static u_int32_t stalled;
170SYSCTL_UINT(_kern_polling, OID_AUTO, stalled, CTLFLAG_RW,
171 &stalled, 0, "potential stalls");
172
173static u_int32_t idlepoll_sleeping; /* idlepoll is sleeping */
174SYSCTL_UINT(_kern_polling, OID_AUTO, idlepoll_sleeping, CTLFLAG_RD,
175 &idlepoll_sleeping, 0, "idlepoll is sleeping");
176
177
178#define POLL_LIST_LEN 128
179struct pollrec {
180 poll_handler_t *handler;
181 struct ifnet *ifp;
182};
183
184static struct pollrec pr[POLL_LIST_LEN];
185
| 52void hardclock_device_poll(void); /* hook from hardclock */
53void ether_poll(int); /* polling while in trap */
54
55/*
56 * Polling support for [network] device drivers.
57 *
58 * Drivers which support this feature try to register with the
59 * polling code.
60 *
61 * If registration is successful, the driver must disable interrupts,
62 * and further I/O is performed through the handler, which is invoked
63 * (at least once per clock tick) with 3 arguments: the "arg" passed at
64 * register time (a struct ifnet pointer), a command, and a "count" limit.
65 *
66 * The command can be one of the following:
67 * POLL_ONLY: quick move of "count" packets from input/output queues.
68 * POLL_AND_CHECK_STATUS: as above, plus check status registers or do
69 * other more expensive operations. This command is issued periodically
70 * but less frequently than POLL_ONLY.
71 * POLL_DEREGISTER: deregister and return to interrupt mode.
72 *
73 * The first two commands are only issued if the interface is marked as
74 * 'IFF_UP and IFF_RUNNING', the last one only if IFF_RUNNING is set.
75 *
76 * The count limit specifies how much work the handler can do during the
77 * call -- typically this is the number of packets to be received, or
78 * transmitted, etc. (drivers are free to interpret this number, as long
79 * as the max time spent in the function grows roughly linearly with the
80 * count).
81 *
82 * Deregistration can be requested by the driver itself (typically in the
83 * *_stop() routine), or by the polling code, by invoking the handler.
84 *
85 * Polling can be globally enabled or disabled with the sysctl variable
86 * kern.polling.enable (default is 0, disabled)
87 *
88 * A second variable controls the sharing of CPU between polling/kernel
89 * network processing, and other activities (typically userlevel tasks):
90 * kern.polling.user_frac (between 0 and 100, default 50) sets the share
91 * of CPU allocated to user tasks. CPU is allocated proportionally to the
92 * shares, by dynamically adjusting the "count" (poll_burst).
93 *
94 * Other parameters can should be left to their default values.
95 * The following constraints hold
96 *
97 * 1 <= poll_each_burst <= poll_burst <= poll_burst_max
98 * 0 <= poll_in_trap <= poll_each_burst
99 * MIN_POLL_BURST_MAX <= poll_burst_max <= MAX_POLL_BURST_MAX
100 */
101
102#define MIN_POLL_BURST_MAX 10
103#define MAX_POLL_BURST_MAX 1000
104
105SYSCTL_NODE(_kern, OID_AUTO, polling, CTLFLAG_RW, 0,
106 "Device polling parameters");
107
108static u_int32_t poll_burst = 5;
109SYSCTL_UINT(_kern_polling, OID_AUTO, burst, CTLFLAG_RW,
110 &poll_burst, 0, "Current polling burst size");
111
112static u_int32_t poll_each_burst = 5;
113SYSCTL_UINT(_kern_polling, OID_AUTO, each_burst, CTLFLAG_RW,
114 &poll_each_burst, 0, "Max size of each burst");
115
116static u_int32_t poll_burst_max = 150; /* good for 100Mbit net and HZ=1000 */
117SYSCTL_UINT(_kern_polling, OID_AUTO, burst_max, CTLFLAG_RW,
118 &poll_burst_max, 0, "Max Polling burst size");
119
120static u_int32_t poll_in_idle_loop=0; /* do we poll in idle loop ? */
121SYSCTL_UINT(_kern_polling, OID_AUTO, idle_poll, CTLFLAG_RW,
122 &poll_in_idle_loop, 0, "Enable device polling in idle loop");
123
124u_int32_t poll_in_trap; /* used in trap.c */
125SYSCTL_UINT(_kern_polling, OID_AUTO, poll_in_trap, CTLFLAG_RW,
126 &poll_in_trap, 0, "Poll burst size during a trap");
127
128static u_int32_t user_frac = 50;
129SYSCTL_UINT(_kern_polling, OID_AUTO, user_frac, CTLFLAG_RW,
130 &user_frac, 0, "Desired user fraction of cpu time");
131
132static u_int32_t reg_frac = 20 ;
133SYSCTL_UINT(_kern_polling, OID_AUTO, reg_frac, CTLFLAG_RW,
134 ®_frac, 0, "Every this many cycles poll register");
135
136static u_int32_t short_ticks;
137SYSCTL_UINT(_kern_polling, OID_AUTO, short_ticks, CTLFLAG_RW,
138 &short_ticks, 0, "Hardclock ticks shorter than they should be");
139
140static u_int32_t lost_polls;
141SYSCTL_UINT(_kern_polling, OID_AUTO, lost_polls, CTLFLAG_RW,
142 &lost_polls, 0, "How many times we would have lost a poll tick");
143
144static u_int32_t pending_polls;
145SYSCTL_UINT(_kern_polling, OID_AUTO, pending_polls, CTLFLAG_RW,
146 &pending_polls, 0, "Do we need to poll again");
147
148static int residual_burst = 0;
149SYSCTL_INT(_kern_polling, OID_AUTO, residual_burst, CTLFLAG_RW,
150 &residual_burst, 0, "# of residual cycles in burst");
151
152static u_int32_t poll_handlers; /* next free entry in pr[]. */
153SYSCTL_UINT(_kern_polling, OID_AUTO, handlers, CTLFLAG_RD,
154 &poll_handlers, 0, "Number of registered poll handlers");
155
156static int polling = 0; /* global polling enable */
157SYSCTL_UINT(_kern_polling, OID_AUTO, enable, CTLFLAG_RW,
158 &polling, 0, "Polling enabled");
159
160static u_int32_t phase;
161SYSCTL_UINT(_kern_polling, OID_AUTO, phase, CTLFLAG_RW,
162 &phase, 0, "Polling phase");
163
164static u_int32_t suspect;
165SYSCTL_UINT(_kern_polling, OID_AUTO, suspect, CTLFLAG_RW,
166 &suspect, 0, "suspect event");
167
168static u_int32_t stalled;
169SYSCTL_UINT(_kern_polling, OID_AUTO, stalled, CTLFLAG_RW,
170 &stalled, 0, "potential stalls");
171
172static u_int32_t idlepoll_sleeping; /* idlepoll is sleeping */
173SYSCTL_UINT(_kern_polling, OID_AUTO, idlepoll_sleeping, CTLFLAG_RD,
174 &idlepoll_sleeping, 0, "idlepoll is sleeping");
175
176
177#define POLL_LIST_LEN 128
178struct pollrec {
179 poll_handler_t *handler;
180 struct ifnet *ifp;
181};
182
183static struct pollrec pr[POLL_LIST_LEN];
184
|
186/*
187 * register relevant netisr. Called from kern_clock.c:
188 */
189void
| 185static void
|
190init_device_poll(void)
191{
| 186init_device_poll(void)
187{
|
192 register_netisr(NETISR_POLL, netisr_poll);
| 188
189 netisr_register(NETISR_POLL, (netisr_t *)netisr_poll, NULL);
190 netisr_register(NETISR_POLLMORE, (netisr_t *)netisr_pollmore, NULL);
|
193}
| 191}
|
| 192SYSINIT(device_poll, SI_SUB_CLOCKS, SI_ORDER_MIDDLE, init_device_poll, NULL)
|
194
| 193
|
| 194
|
195/*
196 * Hook from hardclock. Tries to schedule a netisr, but keeps track
197 * of lost ticks due to the previous handler taking too long.
198 * Normally, this should not happen, because polling handler should
199 * run for a short time. However, in some cases (e.g. when there are
200 * changes in link status etc.) the drivers take a very long time
201 * (even in the order of milliseconds) to reset and reconfigure the
202 * device, causing apparent lost polls.
203 *
204 * The first part of the code is just for debugging purposes, and tries
205 * to count how often hardclock ticks are shorter than they should,
206 * meaning either stray interrupts or delayed events.
207 */
208void
209hardclock_device_poll(void)
210{
211 static struct timeval prev_t, t;
212 int delta;
213
214 if (poll_handlers == 0)
215 return;
216
217 microuptime(&t);
218 delta = (t.tv_usec - prev_t.tv_usec) +
219 (t.tv_sec - prev_t.tv_sec)*1000000;
220 if (delta * hz < 500000)
221 short_ticks++;
222 else
223 prev_t = t;
224
225 if (pending_polls > 100) {
226 /*
227 * Too much, assume it has stalled (not always true
228 * see comment above).
229 */
230 stalled++;
231 pending_polls = 0;
232 phase = 0;
233 }
234
235 if (phase <= 2) {
236 if (phase != 0)
237 suspect++;
238 phase = 1;
| 195/*
196 * Hook from hardclock. Tries to schedule a netisr, but keeps track
197 * of lost ticks due to the previous handler taking too long.
198 * Normally, this should not happen, because polling handler should
199 * run for a short time. However, in some cases (e.g. when there are
200 * changes in link status etc.) the drivers take a very long time
201 * (even in the order of milliseconds) to reset and reconfigure the
202 * device, causing apparent lost polls.
203 *
204 * The first part of the code is just for debugging purposes, and tries
205 * to count how often hardclock ticks are shorter than they should,
206 * meaning either stray interrupts or delayed events.
207 */
208void
209hardclock_device_poll(void)
210{
211 static struct timeval prev_t, t;
212 int delta;
213
214 if (poll_handlers == 0)
215 return;
216
217 microuptime(&t);
218 delta = (t.tv_usec - prev_t.tv_usec) +
219 (t.tv_sec - prev_t.tv_sec)*1000000;
220 if (delta * hz < 500000)
221 short_ticks++;
222 else
223 prev_t = t;
224
225 if (pending_polls > 100) {
226 /*
227 * Too much, assume it has stalled (not always true
228 * see comment above).
229 */
230 stalled++;
231 pending_polls = 0;
232 phase = 0;
233 }
234
235 if (phase <= 2) {
236 if (phase != 0)
237 suspect++;
238 phase = 1;
|
239 schednetisr(NETISR_POLL);
| 239 schednetisrbits(1 << NETISR_POLL | 1 << NETISR_POLLMORE);
|
240 phase = 2;
241 }
242 if (pending_polls++ > 0)
243 lost_polls++;
244}
245
246/*
247 * ether_poll is called from the idle loop or from the trap handler.
248 */
249void
250ether_poll(int count)
251{
252 int i;
253
254 mtx_lock(&Giant);
255
256 if (count > poll_each_burst)
257 count = poll_each_burst;
258 for (i = 0 ; i < poll_handlers ; i++)
259 if (pr[i].handler && (IFF_UP|IFF_RUNNING) ==
260 (pr[i].ifp->if_flags & (IFF_UP|IFF_RUNNING)) )
261 pr[i].handler(pr[i].ifp, 0, count); /* quick check */
262 mtx_unlock(&Giant);
263}
264
265/*
266 * netisr_pollmore is called after other netisr's, possibly scheduling
267 * another NETISR_POLL call, or adapting the burst size for the next cycle.
268 *
269 * It is very bad to fetch large bursts of packets from a single card at once,
270 * because the burst could take a long time to be completely processed, or
271 * could saturate the intermediate queue (ipintrq or similar) leading to
272 * losses or unfairness. To reduce the problem, and also to account better for
273 * time spent in network-related processing, we split the burst in smaller
274 * chunks of fixed size, giving control to the other netisr's between chunks.
275 * This helps in improving the fairness, reducing livelock (because we
276 * emulate more closely the "process to completion" that we have with
277 * fastforwarding) and accounting for the work performed in low level
278 * handling and forwarding.
279 */
280
281static struct timeval poll_start_t;
282
283void
284netisr_pollmore()
285{
286 struct timeval t;
287 int kern_load;
288 /* XXX run at splhigh() or equivalent */
289
290 phase = 5;
291 if (residual_burst > 0) {
| 240 phase = 2;
241 }
242 if (pending_polls++ > 0)
243 lost_polls++;
244}
245
246/*
247 * ether_poll is called from the idle loop or from the trap handler.
248 */
249void
250ether_poll(int count)
251{
252 int i;
253
254 mtx_lock(&Giant);
255
256 if (count > poll_each_burst)
257 count = poll_each_burst;
258 for (i = 0 ; i < poll_handlers ; i++)
259 if (pr[i].handler && (IFF_UP|IFF_RUNNING) ==
260 (pr[i].ifp->if_flags & (IFF_UP|IFF_RUNNING)) )
261 pr[i].handler(pr[i].ifp, 0, count); /* quick check */
262 mtx_unlock(&Giant);
263}
264
265/*
266 * netisr_pollmore is called after other netisr's, possibly scheduling
267 * another NETISR_POLL call, or adapting the burst size for the next cycle.
268 *
269 * It is very bad to fetch large bursts of packets from a single card at once,
270 * because the burst could take a long time to be completely processed, or
271 * could saturate the intermediate queue (ipintrq or similar) leading to
272 * losses or unfairness. To reduce the problem, and also to account better for
273 * time spent in network-related processing, we split the burst in smaller
274 * chunks of fixed size, giving control to the other netisr's between chunks.
275 * This helps in improving the fairness, reducing livelock (because we
276 * emulate more closely the "process to completion" that we have with
277 * fastforwarding) and accounting for the work performed in low level
278 * handling and forwarding.
279 */
280
281static struct timeval poll_start_t;
282
283void
284netisr_pollmore()
285{
286 struct timeval t;
287 int kern_load;
288 /* XXX run at splhigh() or equivalent */
289
290 phase = 5;
291 if (residual_burst > 0) {
|
292 schednetisr(NETISR_POLL);
| 292 schednetisrbits(1 << NETISR_POLL | 1 << NETISR_POLLMORE);
|
293 /* will run immediately on return, followed by netisrs */
| 293 /* will run immediately on return, followed by netisrs */
|
294 return ;
| 294 return;
|
295 }
296 /* here we can account time spent in netisr's in this tick */
297 microuptime(&t);
298 kern_load = (t.tv_usec - poll_start_t.tv_usec) +
299 (t.tv_sec - poll_start_t.tv_sec)*1000000; /* us */
300 kern_load = (kern_load * hz) / 10000; /* 0..100 */
301 if (kern_load > (100 - user_frac)) { /* try decrease ticks */
302 if (poll_burst > 1)
303 poll_burst--;
304 } else {
305 if (poll_burst < poll_burst_max)
306 poll_burst++;
307 }
308
309 pending_polls--;
310 if (pending_polls == 0) /* we are done */
311 phase = 0;
312 else {
313 /*
314 * Last cycle was long and caused us to miss one or more
315 * hardclock ticks. Restart processing again, but slightly
316 * reduce the burst size to prevent that this happens again.
317 */
318 poll_burst -= (poll_burst / 8);
319 if (poll_burst < 1)
320 poll_burst = 1;
| 295 }
296 /* here we can account time spent in netisr's in this tick */
297 microuptime(&t);
298 kern_load = (t.tv_usec - poll_start_t.tv_usec) +
299 (t.tv_sec - poll_start_t.tv_sec)*1000000; /* us */
300 kern_load = (kern_load * hz) / 10000; /* 0..100 */
301 if (kern_load > (100 - user_frac)) { /* try decrease ticks */
302 if (poll_burst > 1)
303 poll_burst--;
304 } else {
305 if (poll_burst < poll_burst_max)
306 poll_burst++;
307 }
308
309 pending_polls--;
310 if (pending_polls == 0) /* we are done */
311 phase = 0;
312 else {
313 /*
314 * Last cycle was long and caused us to miss one or more
315 * hardclock ticks. Restart processing again, but slightly
316 * reduce the burst size to prevent that this happens again.
317 */
318 poll_burst -= (poll_burst / 8);
319 if (poll_burst < 1)
320 poll_burst = 1;
|
321 schednetisr(NETISR_POLL);
| 321 schednetisrbits(1 << NETISR_POLL | 1 << NETISR_POLLMORE);
|
322 phase = 6;
323 }
324}
325
326/*
327 * netisr_poll is scheduled by schednetisr when appropriate, typically once
328 * per tick. It is called at splnet() so first thing to do is to upgrade to
329 * splimp(), and call all registered handlers.
330 */
331static void
332netisr_poll(void)
333{
334 static int reg_frac_count;
335 int i, cycles;
336 enum poll_cmd arg = POLL_ONLY;
337 mtx_lock(&Giant);
338
339 phase = 3;
340 if (residual_burst == 0) { /* first call in this tick */
341 microuptime(&poll_start_t);
342 /*
343 * Check that paremeters are consistent with runtime
344 * variables. Some of these tests could be done at sysctl
345 * time, but the savings would be very limited because we
346 * still have to check against reg_frac_count and
347 * poll_each_burst. So, instead of writing separate sysctl
348 * handlers, we do all here.
349 */
350
351 if (reg_frac > hz)
352 reg_frac = hz;
353 else if (reg_frac < 1)
354 reg_frac = 1;
355 if (reg_frac_count > reg_frac)
356 reg_frac_count = reg_frac - 1;
357 if (reg_frac_count-- == 0) {
358 arg = POLL_AND_CHECK_STATUS;
359 reg_frac_count = reg_frac - 1;
360 }
361 if (poll_burst_max < MIN_POLL_BURST_MAX)
362 poll_burst_max = MIN_POLL_BURST_MAX;
363 else if (poll_burst_max > MAX_POLL_BURST_MAX)
364 poll_burst_max = MAX_POLL_BURST_MAX;
365
366 if (poll_each_burst < 1)
367 poll_each_burst = 1;
368 else if (poll_each_burst > poll_burst_max)
369 poll_each_burst = poll_burst_max;
370
371 residual_burst = poll_burst;
372 }
373 cycles = (residual_burst < poll_each_burst) ?
374 residual_burst : poll_each_burst;
375 residual_burst -= cycles;
376
377 if (polling) {
378 for (i = 0 ; i < poll_handlers ; i++)
379 if (pr[i].handler && (IFF_UP|IFF_RUNNING) ==
380 (pr[i].ifp->if_flags & (IFF_UP|IFF_RUNNING)) )
381 pr[i].handler(pr[i].ifp, arg, cycles);
382 } else { /* unregister */
383 for (i = 0 ; i < poll_handlers ; i++) {
384 if (pr[i].handler &&
385 pr[i].ifp->if_flags & IFF_RUNNING) {
386 pr[i].ifp->if_flags &= ~IFF_POLLING;
387 pr[i].handler(pr[i].ifp, POLL_DEREGISTER, 1);
388 }
389 pr[i].handler=NULL;
390 }
391 residual_burst = 0;
392 poll_handlers = 0;
393 }
394 /* on -stable, schednetisr(NETISR_POLLMORE); */
395 phase = 4;
396 mtx_unlock(&Giant);
397}
398
399/*
400 * Try to register routine for polling. Returns 1 if successful
401 * (and polling should be enabled), 0 otherwise.
402 * A device is not supposed to register itself multiple times.
403 *
404 * This is called from within the *_intr() functions, so we do not need
405 * further locking.
406 */
407int
408ether_poll_register(poll_handler_t *h, struct ifnet *ifp)
409{
410 int s;
411
412 if (polling == 0) /* polling disabled, cannot register */
413 return 0;
414 if (h == NULL || ifp == NULL) /* bad arguments */
415 return 0;
416 if ( !(ifp->if_flags & IFF_UP) ) /* must be up */
417 return 0;
418 if (ifp->if_flags & IFF_POLLING) /* already polling */
419 return 0;
420
421 s = splhigh();
422 if (poll_handlers >= POLL_LIST_LEN) {
423 /*
424 * List full, cannot register more entries.
425 * This should never happen; if it does, it is probably a
426 * broken driver trying to register multiple times. Checking
427 * this at runtime is expensive, and won't solve the problem
428 * anyways, so just report a few times and then give up.
429 */
430 static int verbose = 10 ;
431 splx(s);
432 if (verbose >0) {
433 printf("poll handlers list full, "
434 "maybe a broken driver ?\n");
435 verbose--;
436 }
437 return 0; /* no polling for you */
438 }
439
440 pr[poll_handlers].handler = h;
441 pr[poll_handlers].ifp = ifp;
442 poll_handlers++;
443 ifp->if_flags |= IFF_POLLING;
444 splx(s);
445 if (idlepoll_sleeping)
446 wakeup(&idlepoll_sleeping);
447 return 1; /* polling enabled in next call */
448}
449
450/*
451 * Remove interface from the polling list. Normally called by *_stop().
452 * It is not an error to call it with IFF_POLLING clear, the call is
453 * sufficiently rare to be preferable to save the space for the extra
454 * test in each driver in exchange of one additional function call.
455 */
456int
457ether_poll_deregister(struct ifnet *ifp)
458{
459 int i;
460
461 mtx_lock(&Giant);
462 if ( !ifp || !(ifp->if_flags & IFF_POLLING) ) {
463 mtx_unlock(&Giant);
464 return 0;
465 }
466 for (i = 0 ; i < poll_handlers ; i++)
467 if (pr[i].ifp == ifp) /* found it */
468 break;
469 ifp->if_flags &= ~IFF_POLLING; /* found or not... */
470 if (i == poll_handlers) {
471 mtx_unlock(&Giant);
472 printf("ether_poll_deregister: ifp not found!!!\n");
473 return 0;
474 }
475 poll_handlers--;
476 if (i < poll_handlers) { /* Last entry replaces this one. */
477 pr[i].handler = pr[poll_handlers].handler;
478 pr[i].ifp = pr[poll_handlers].ifp;
479 }
480 mtx_unlock(&Giant);
481 return 1;
482}
483
484static void
485poll_idle(void)
486{
487 struct thread *td = curthread;
488 struct rtprio rtp;
489 int pri;
490
491 rtp.prio = RTP_PRIO_MAX; /* lowest priority */
492 rtp.type = RTP_PRIO_IDLE;
493 mtx_lock_spin(&sched_lock);
494 rtp_to_pri(&rtp, td->td_ksegrp);
495 pri = td->td_priority;
496 mtx_unlock_spin(&sched_lock);
497
498 for (;;) {
499 if (poll_in_idle_loop && poll_handlers > 0) {
500 idlepoll_sleeping = 0;
501 mtx_lock(&Giant);
502 ether_poll(poll_each_burst);
503 mtx_unlock(&Giant);
504 mtx_assert(&Giant, MA_NOTOWNED);
505 mtx_lock_spin(&sched_lock);
506 td->td_proc->p_stats->p_ru.ru_nvcsw++;
507 mi_switch();
508 mtx_unlock_spin(&sched_lock);
509 } else {
510 idlepoll_sleeping = 1;
511 tsleep(&idlepoll_sleeping, pri, "pollid", hz * 3);
512 }
513 }
514}
515
516static struct proc *idlepoll;
517static struct kproc_desc idlepoll_kp = {
518 "idlepoll",
519 poll_idle,
520 &idlepoll
521};
522SYSINIT(idlepoll, SI_SUB_KTHREAD_VM, SI_ORDER_ANY, kproc_start, &idlepoll_kp)
| 322 phase = 6;
323 }
324}
325
326/*
327 * netisr_poll is scheduled by schednetisr when appropriate, typically once
328 * per tick. It is called at splnet() so first thing to do is to upgrade to
329 * splimp(), and call all registered handlers.
330 */
331static void
332netisr_poll(void)
333{
334 static int reg_frac_count;
335 int i, cycles;
336 enum poll_cmd arg = POLL_ONLY;
337 mtx_lock(&Giant);
338
339 phase = 3;
340 if (residual_burst == 0) { /* first call in this tick */
341 microuptime(&poll_start_t);
342 /*
343 * Check that paremeters are consistent with runtime
344 * variables. Some of these tests could be done at sysctl
345 * time, but the savings would be very limited because we
346 * still have to check against reg_frac_count and
347 * poll_each_burst. So, instead of writing separate sysctl
348 * handlers, we do all here.
349 */
350
351 if (reg_frac > hz)
352 reg_frac = hz;
353 else if (reg_frac < 1)
354 reg_frac = 1;
355 if (reg_frac_count > reg_frac)
356 reg_frac_count = reg_frac - 1;
357 if (reg_frac_count-- == 0) {
358 arg = POLL_AND_CHECK_STATUS;
359 reg_frac_count = reg_frac - 1;
360 }
361 if (poll_burst_max < MIN_POLL_BURST_MAX)
362 poll_burst_max = MIN_POLL_BURST_MAX;
363 else if (poll_burst_max > MAX_POLL_BURST_MAX)
364 poll_burst_max = MAX_POLL_BURST_MAX;
365
366 if (poll_each_burst < 1)
367 poll_each_burst = 1;
368 else if (poll_each_burst > poll_burst_max)
369 poll_each_burst = poll_burst_max;
370
371 residual_burst = poll_burst;
372 }
373 cycles = (residual_burst < poll_each_burst) ?
374 residual_burst : poll_each_burst;
375 residual_burst -= cycles;
376
377 if (polling) {
378 for (i = 0 ; i < poll_handlers ; i++)
379 if (pr[i].handler && (IFF_UP|IFF_RUNNING) ==
380 (pr[i].ifp->if_flags & (IFF_UP|IFF_RUNNING)) )
381 pr[i].handler(pr[i].ifp, arg, cycles);
382 } else { /* unregister */
383 for (i = 0 ; i < poll_handlers ; i++) {
384 if (pr[i].handler &&
385 pr[i].ifp->if_flags & IFF_RUNNING) {
386 pr[i].ifp->if_flags &= ~IFF_POLLING;
387 pr[i].handler(pr[i].ifp, POLL_DEREGISTER, 1);
388 }
389 pr[i].handler=NULL;
390 }
391 residual_burst = 0;
392 poll_handlers = 0;
393 }
394 /* on -stable, schednetisr(NETISR_POLLMORE); */
395 phase = 4;
396 mtx_unlock(&Giant);
397}
398
399/*
400 * Try to register routine for polling. Returns 1 if successful
401 * (and polling should be enabled), 0 otherwise.
402 * A device is not supposed to register itself multiple times.
403 *
404 * This is called from within the *_intr() functions, so we do not need
405 * further locking.
406 */
407int
408ether_poll_register(poll_handler_t *h, struct ifnet *ifp)
409{
410 int s;
411
412 if (polling == 0) /* polling disabled, cannot register */
413 return 0;
414 if (h == NULL || ifp == NULL) /* bad arguments */
415 return 0;
416 if ( !(ifp->if_flags & IFF_UP) ) /* must be up */
417 return 0;
418 if (ifp->if_flags & IFF_POLLING) /* already polling */
419 return 0;
420
421 s = splhigh();
422 if (poll_handlers >= POLL_LIST_LEN) {
423 /*
424 * List full, cannot register more entries.
425 * This should never happen; if it does, it is probably a
426 * broken driver trying to register multiple times. Checking
427 * this at runtime is expensive, and won't solve the problem
428 * anyways, so just report a few times and then give up.
429 */
430 static int verbose = 10 ;
431 splx(s);
432 if (verbose >0) {
433 printf("poll handlers list full, "
434 "maybe a broken driver ?\n");
435 verbose--;
436 }
437 return 0; /* no polling for you */
438 }
439
440 pr[poll_handlers].handler = h;
441 pr[poll_handlers].ifp = ifp;
442 poll_handlers++;
443 ifp->if_flags |= IFF_POLLING;
444 splx(s);
445 if (idlepoll_sleeping)
446 wakeup(&idlepoll_sleeping);
447 return 1; /* polling enabled in next call */
448}
449
450/*
451 * Remove interface from the polling list. Normally called by *_stop().
452 * It is not an error to call it with IFF_POLLING clear, the call is
453 * sufficiently rare to be preferable to save the space for the extra
454 * test in each driver in exchange of one additional function call.
455 */
456int
457ether_poll_deregister(struct ifnet *ifp)
458{
459 int i;
460
461 mtx_lock(&Giant);
462 if ( !ifp || !(ifp->if_flags & IFF_POLLING) ) {
463 mtx_unlock(&Giant);
464 return 0;
465 }
466 for (i = 0 ; i < poll_handlers ; i++)
467 if (pr[i].ifp == ifp) /* found it */
468 break;
469 ifp->if_flags &= ~IFF_POLLING; /* found or not... */
470 if (i == poll_handlers) {
471 mtx_unlock(&Giant);
472 printf("ether_poll_deregister: ifp not found!!!\n");
473 return 0;
474 }
475 poll_handlers--;
476 if (i < poll_handlers) { /* Last entry replaces this one. */
477 pr[i].handler = pr[poll_handlers].handler;
478 pr[i].ifp = pr[poll_handlers].ifp;
479 }
480 mtx_unlock(&Giant);
481 return 1;
482}
483
484static void
485poll_idle(void)
486{
487 struct thread *td = curthread;
488 struct rtprio rtp;
489 int pri;
490
491 rtp.prio = RTP_PRIO_MAX; /* lowest priority */
492 rtp.type = RTP_PRIO_IDLE;
493 mtx_lock_spin(&sched_lock);
494 rtp_to_pri(&rtp, td->td_ksegrp);
495 pri = td->td_priority;
496 mtx_unlock_spin(&sched_lock);
497
498 for (;;) {
499 if (poll_in_idle_loop && poll_handlers > 0) {
500 idlepoll_sleeping = 0;
501 mtx_lock(&Giant);
502 ether_poll(poll_each_burst);
503 mtx_unlock(&Giant);
504 mtx_assert(&Giant, MA_NOTOWNED);
505 mtx_lock_spin(&sched_lock);
506 td->td_proc->p_stats->p_ru.ru_nvcsw++;
507 mi_switch();
508 mtx_unlock_spin(&sched_lock);
509 } else {
510 idlepoll_sleeping = 1;
511 tsleep(&idlepoll_sleeping, pri, "pollid", hz * 3);
512 }
513 }
514}
515
516static struct proc *idlepoll;
517static struct kproc_desc idlepoll_kp = {
518 "idlepoll",
519 poll_idle,
520 &idlepoll
521};
522SYSINIT(idlepoll, SI_SUB_KTHREAD_VM, SI_ORDER_ANY, kproc_start, &idlepoll_kp)
|