xref: /linux/include/net/pkt_sched.h (revision 776cfebb430c7b22c208b1b17add97f354d97cab)
1 #ifndef __NET_PKT_SCHED_H
2 #define __NET_PKT_SCHED_H
3 
4 #include <net/sch_generic.h>
5 
6 struct qdisc_walker
7 {
8 	int	stop;
9 	int	skip;
10 	int	count;
11 	int	(*fn)(struct Qdisc *, unsigned long cl, struct qdisc_walker *);
12 };
13 
14 extern rwlock_t qdisc_tree_lock;
15 
16 #define	QDISC_ALIGN		32
17 #define	QDISC_ALIGN_CONST	(QDISC_ALIGN - 1)
18 
19 static inline void *qdisc_priv(struct Qdisc *q)
20 {
21 	return (char *)q + ((sizeof(struct Qdisc) + QDISC_ALIGN_CONST)
22 			      & ~QDISC_ALIGN_CONST);
23 }
24 
25 /*
26    Timer resolution MUST BE < 10% of min_schedulable_packet_size/bandwidth
27 
28    Normal IP packet size ~ 512byte, hence:
29 
30    0.5Kbyte/1Mbyte/sec = 0.5msec, so that we need 50usec timer for
31    10Mbit ethernet.
32 
33    10msec resolution -> <50Kbit/sec.
34 
35    The result: [34]86 is not good choice for QoS router :-(
36 
37    The things are not so bad, because we may use artifical
38    clock evaluated by integration of network data flow
39    in the most critical places.
40 
41    Note: we do not use fastgettimeofday.
42    The reason is that, when it is not the same thing as
43    gettimeofday, it returns invalid timestamp, which is
44    not updated, when net_bh is active.
45  */
46 
47 /* General note about internal clock.
48 
49    Any clock source returns time intervals, measured in units
50    close to 1usec. With source CONFIG_NET_SCH_CLK_GETTIMEOFDAY it is precisely
51    microseconds, otherwise something close but different chosen to minimize
52    arithmetic cost. Ratio usec/internal untis in form nominator/denominator
53    may be read from /proc/net/psched.
54  */
55 
56 
57 #ifdef CONFIG_NET_SCH_CLK_GETTIMEOFDAY
58 
59 typedef struct timeval	psched_time_t;
60 typedef long		psched_tdiff_t;
61 
62 #define PSCHED_GET_TIME(stamp) do_gettimeofday(&(stamp))
63 #define PSCHED_US2JIFFIE(usecs) (((usecs)+(1000000/HZ-1))/(1000000/HZ))
64 #define PSCHED_JIFFIE2US(delay) ((delay)*(1000000/HZ))
65 
66 #else /* !CONFIG_NET_SCH_CLK_GETTIMEOFDAY */
67 
68 typedef u64	psched_time_t;
69 typedef long	psched_tdiff_t;
70 
71 #ifdef CONFIG_NET_SCH_CLK_JIFFIES
72 
73 #if HZ < 96
74 #define PSCHED_JSCALE 14
75 #elif HZ >= 96 && HZ < 192
76 #define PSCHED_JSCALE 13
77 #elif HZ >= 192 && HZ < 384
78 #define PSCHED_JSCALE 12
79 #elif HZ >= 384 && HZ < 768
80 #define PSCHED_JSCALE 11
81 #elif HZ >= 768
82 #define PSCHED_JSCALE 10
83 #endif
84 
85 #define PSCHED_GET_TIME(stamp) ((stamp) = (get_jiffies_64()<<PSCHED_JSCALE))
86 #define PSCHED_US2JIFFIE(delay) (((delay)+(1<<PSCHED_JSCALE)-1)>>PSCHED_JSCALE)
87 #define PSCHED_JIFFIE2US(delay) ((delay)<<PSCHED_JSCALE)
88 
89 #endif /* CONFIG_NET_SCH_CLK_JIFFIES */
90 #ifdef CONFIG_NET_SCH_CLK_CPU
91 #include <asm/timex.h>
92 
93 extern psched_tdiff_t psched_clock_per_hz;
94 extern int psched_clock_scale;
95 extern psched_time_t psched_time_base;
96 extern cycles_t psched_time_mark;
97 
98 #define PSCHED_GET_TIME(stamp)						\
99 do {									\
100 	cycles_t cur = get_cycles();					\
101 	if (sizeof(cycles_t) == sizeof(u32)) {				\
102 		if (cur <= psched_time_mark)				\
103 			psched_time_base += 0x100000000ULL;		\
104 		psched_time_mark = cur;					\
105 		(stamp) = (psched_time_base + cur)>>psched_clock_scale;	\
106 	} else {							\
107 		(stamp) = cur>>psched_clock_scale;			\
108 	}								\
109 } while (0)
110 #define PSCHED_US2JIFFIE(delay) (((delay)+psched_clock_per_hz-1)/psched_clock_per_hz)
111 #define PSCHED_JIFFIE2US(delay) ((delay)*psched_clock_per_hz)
112 
113 #endif /* CONFIG_NET_SCH_CLK_CPU */
114 
115 #endif /* !CONFIG_NET_SCH_CLK_GETTIMEOFDAY */
116 
117 #ifdef CONFIG_NET_SCH_CLK_GETTIMEOFDAY
118 #define PSCHED_TDIFF(tv1, tv2) \
119 ({ \
120 	   int __delta_sec = (tv1).tv_sec - (tv2).tv_sec; \
121 	   int __delta = (tv1).tv_usec - (tv2).tv_usec; \
122 	   if (__delta_sec) { \
123 	           switch (__delta_sec) { \
124 		   default: \
125 			   __delta = 0; \
126 		   case 2: \
127 			   __delta += 1000000; \
128 		   case 1: \
129 			   __delta += 1000000; \
130 	           } \
131 	   } \
132 	   __delta; \
133 })
134 
135 static inline int
136 psched_tod_diff(int delta_sec, int bound)
137 {
138 	int delta;
139 
140 	if (bound <= 1000000 || delta_sec > (0x7FFFFFFF/1000000)-1)
141 		return bound;
142 	delta = delta_sec * 1000000;
143 	if (delta > bound || delta < 0)
144 		delta = bound;
145 	return delta;
146 }
147 
148 #define PSCHED_TDIFF_SAFE(tv1, tv2, bound) \
149 ({ \
150 	   int __delta_sec = (tv1).tv_sec - (tv2).tv_sec; \
151 	   int __delta = (tv1).tv_usec - (tv2).tv_usec; \
152 	   switch (__delta_sec) { \
153 	   default: \
154 		   __delta = psched_tod_diff(__delta_sec, bound);  break; \
155 	   case 2: \
156 		   __delta += 1000000; \
157 	   case 1: \
158 		   __delta += 1000000; \
159 	   case 0: \
160  		   if (__delta > bound || __delta < 0) \
161  			__delta = bound; \
162 	   } \
163 	   __delta; \
164 })
165 
166 #define PSCHED_TLESS(tv1, tv2) (((tv1).tv_usec < (tv2).tv_usec && \
167 				(tv1).tv_sec <= (tv2).tv_sec) || \
168 				 (tv1).tv_sec < (tv2).tv_sec)
169 
170 #define PSCHED_TADD2(tv, delta, tv_res) \
171 ({ \
172 	   int __delta = (tv).tv_usec + (delta); \
173 	   (tv_res).tv_sec = (tv).tv_sec; \
174 	   if (__delta > 1000000) { (tv_res).tv_sec++; __delta -= 1000000; } \
175 	   (tv_res).tv_usec = __delta; \
176 })
177 
178 #define PSCHED_TADD(tv, delta) \
179 ({ \
180 	   (tv).tv_usec += (delta); \
181 	   if ((tv).tv_usec > 1000000) { (tv).tv_sec++; \
182 		 (tv).tv_usec -= 1000000; } \
183 })
184 
185 /* Set/check that time is in the "past perfect";
186    it depends on concrete representation of system time
187  */
188 
189 #define PSCHED_SET_PASTPERFECT(t)	((t).tv_sec = 0)
190 #define PSCHED_IS_PASTPERFECT(t)	((t).tv_sec == 0)
191 
192 #define	PSCHED_AUDIT_TDIFF(t) ({ if ((t) > 2000000) (t) = 2000000; })
193 
194 #else /* !CONFIG_NET_SCH_CLK_GETTIMEOFDAY */
195 
196 #define PSCHED_TDIFF(tv1, tv2) (long)((tv1) - (tv2))
197 #define PSCHED_TDIFF_SAFE(tv1, tv2, bound) \
198 	min_t(long long, (tv1) - (tv2), bound)
199 
200 
201 #define PSCHED_TLESS(tv1, tv2) ((tv1) < (tv2))
202 #define PSCHED_TADD2(tv, delta, tv_res) ((tv_res) = (tv) + (delta))
203 #define PSCHED_TADD(tv, delta) ((tv) += (delta))
204 #define PSCHED_SET_PASTPERFECT(t)	((t) = 0)
205 #define PSCHED_IS_PASTPERFECT(t)	((t) == 0)
206 #define	PSCHED_AUDIT_TDIFF(t)
207 
208 #endif /* !CONFIG_NET_SCH_CLK_GETTIMEOFDAY */
209 
210 extern struct Qdisc noop_qdisc;
211 extern struct Qdisc_ops noop_qdisc_ops;
212 extern struct Qdisc_ops pfifo_qdisc_ops;
213 extern struct Qdisc_ops bfifo_qdisc_ops;
214 
215 extern int register_qdisc(struct Qdisc_ops *qops);
216 extern int unregister_qdisc(struct Qdisc_ops *qops);
217 extern struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle);
218 extern struct Qdisc *qdisc_lookup_class(struct net_device *dev, u32 handle);
219 extern void dev_init_scheduler(struct net_device *dev);
220 extern void dev_shutdown(struct net_device *dev);
221 extern void dev_activate(struct net_device *dev);
222 extern void dev_deactivate(struct net_device *dev);
223 extern void qdisc_reset(struct Qdisc *qdisc);
224 extern void qdisc_destroy(struct Qdisc *qdisc);
225 extern struct Qdisc * qdisc_create_dflt(struct net_device *dev,
226 	struct Qdisc_ops *ops);
227 extern struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
228 		struct rtattr *tab);
229 extern void qdisc_put_rtab(struct qdisc_rate_table *tab);
230 
231 extern int qdisc_restart(struct net_device *dev);
232 
233 static inline void qdisc_run(struct net_device *dev)
234 {
235 	while (!netif_queue_stopped(dev) && qdisc_restart(dev) < 0)
236 		/* NOTHING */;
237 }
238 
239 extern int tc_classify(struct sk_buff *skb, struct tcf_proto *tp,
240 	struct tcf_result *res);
241 
242 /* Calculate maximal size of packet seen by hard_start_xmit
243    routine of this device.
244  */
245 static inline unsigned psched_mtu(struct net_device *dev)
246 {
247 	unsigned mtu = dev->mtu;
248 	return dev->hard_header ? mtu + dev->hard_header_len : mtu;
249 }
250 
251 #endif
252