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Commit | Line | Data |
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1da177e4 | 1 | /* |
1da177e4 LT |
2 | * Virtual cpu timer based timer functions. |
3 | * | |
27f6b416 | 4 | * Copyright IBM Corp. 2004, 2012 |
1da177e4 LT |
5 | * Author(s): Jan Glauber <jan.glauber@de.ibm.com> |
6 | */ | |
7 | ||
27f6b416 | 8 | #include <linux/kernel_stat.h> |
27f6b416 | 9 | #include <linux/export.h> |
1da177e4 | 10 | #include <linux/kernel.h> |
1da177e4 | 11 | #include <linux/timex.h> |
27f6b416 MS |
12 | #include <linux/types.h> |
13 | #include <linux/time.h> | |
1da177e4 | 14 | |
76d4e00a | 15 | #include <asm/cputime.h> |
27f6b416 | 16 | #include <asm/vtimer.h> |
a5725ac2 | 17 | #include <asm/vtime.h> |
10ad34bc MS |
18 | #include <asm/cpu_mf.h> |
19 | #include <asm/smp.h> | |
1da177e4 | 20 | |
521b00cd HC |
21 | #include "entry.h" |
22 | ||
27f6b416 | 23 | static void virt_timer_expire(void); |
1da177e4 | 24 | |
27f6b416 MS |
25 | static LIST_HEAD(virt_timer_list); |
26 | static DEFINE_SPINLOCK(virt_timer_lock); | |
27 | static atomic64_t virt_timer_current; | |
28 | static atomic64_t virt_timer_elapsed; | |
29 | ||
72d38b19 | 30 | DEFINE_PER_CPU(u64, mt_cycles[8]); |
10ad34bc MS |
31 | static DEFINE_PER_CPU(u64, mt_scaling_mult) = { 1 }; |
32 | static DEFINE_PER_CPU(u64, mt_scaling_div) = { 1 }; | |
f341b8df | 33 | static DEFINE_PER_CPU(u64, mt_scaling_jiffies); |
10ad34bc | 34 | |
27f6b416 | 35 | static inline u64 get_vtimer(void) |
9cfb9b3c | 36 | { |
27f6b416 | 37 | u64 timer; |
9cfb9b3c | 38 | |
27f6b416 | 39 | asm volatile("stpt %0" : "=m" (timer)); |
9cfb9b3c MS |
40 | return timer; |
41 | } | |
42 | ||
27f6b416 | 43 | static inline void set_vtimer(u64 expires) |
9cfb9b3c | 44 | { |
27f6b416 | 45 | u64 timer; |
9cfb9b3c | 46 | |
27f6b416 MS |
47 | asm volatile( |
48 | " stpt %0\n" /* Store current cpu timer value */ | |
49 | " spt %1" /* Set new value imm. afterwards */ | |
50 | : "=m" (timer) : "m" (expires)); | |
9cfb9b3c MS |
51 | S390_lowcore.system_timer += S390_lowcore.last_update_timer - timer; |
52 | S390_lowcore.last_update_timer = expires; | |
53 | } | |
54 | ||
27f6b416 MS |
55 | static inline int virt_timer_forward(u64 elapsed) |
56 | { | |
57 | BUG_ON(!irqs_disabled()); | |
58 | ||
59 | if (list_empty(&virt_timer_list)) | |
60 | return 0; | |
61 | elapsed = atomic64_add_return(elapsed, &virt_timer_elapsed); | |
62 | return elapsed >= atomic64_read(&virt_timer_current); | |
63 | } | |
64 | ||
72d38b19 MS |
65 | static void update_mt_scaling(void) |
66 | { | |
67 | u64 cycles_new[8], *cycles_old; | |
68 | u64 delta, fac, mult, div; | |
69 | int i; | |
70 | ||
71 | stcctm5(smp_cpu_mtid + 1, cycles_new); | |
72 | cycles_old = this_cpu_ptr(mt_cycles); | |
73 | fac = 1; | |
74 | mult = div = 0; | |
75 | for (i = 0; i <= smp_cpu_mtid; i++) { | |
76 | delta = cycles_new[i] - cycles_old[i]; | |
77 | div += delta; | |
78 | mult *= i + 1; | |
79 | mult += delta * fac; | |
80 | fac *= i + 1; | |
81 | } | |
82 | div *= fac; | |
83 | if (div > 0) { | |
84 | /* Update scaling factor */ | |
85 | __this_cpu_write(mt_scaling_mult, mult); | |
86 | __this_cpu_write(mt_scaling_div, div); | |
87 | memcpy(cycles_old, cycles_new, | |
88 | sizeof(u64) * (smp_cpu_mtid + 1)); | |
89 | } | |
90 | __this_cpu_write(mt_scaling_jiffies, jiffies_64); | |
91 | } | |
92 | ||
1da177e4 LT |
93 | /* |
94 | * Update process times based on virtual cpu times stored by entry.S | |
95 | * to the lowcore fields user_timer, system_timer & steal_clock. | |
96 | */ | |
27f6b416 | 97 | static int do_account_vtime(struct task_struct *tsk, int hardirq_offset) |
1da177e4 | 98 | { |
aa5e97ce | 99 | struct thread_info *ti = task_thread_info(tsk); |
27f6b416 | 100 | u64 timer, clock, user, system, steal; |
10ad34bc | 101 | u64 user_scaled, system_scaled; |
1da177e4 LT |
102 | |
103 | timer = S390_lowcore.last_update_timer; | |
104 | clock = S390_lowcore.last_update_clock; | |
27f6b416 MS |
105 | asm volatile( |
106 | " stpt %0\n" /* Store current cpu timer value */ | |
1f759bb3 MS |
107 | #ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES |
108 | " stckf %1" /* Store current tod clock value */ | |
109 | #else | |
27f6b416 | 110 | " stck %1" /* Store current tod clock value */ |
1f759bb3 | 111 | #endif |
27f6b416 MS |
112 | : "=m" (S390_lowcore.last_update_timer), |
113 | "=m" (S390_lowcore.last_update_clock)); | |
1da177e4 | 114 | S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer; |
aa5e97ce | 115 | S390_lowcore.steal_timer += S390_lowcore.last_update_clock - clock; |
1da177e4 | 116 | |
72d38b19 | 117 | /* Update MT utilization calculation */ |
f341b8df | 118 | if (smp_cpu_mtid && |
72d38b19 MS |
119 | time_after64(jiffies_64, this_cpu_read(mt_scaling_jiffies))) |
120 | update_mt_scaling(); | |
10ad34bc | 121 | |
aa5e97ce MS |
122 | user = S390_lowcore.user_timer - ti->user_timer; |
123 | S390_lowcore.steal_timer -= user; | |
124 | ti->user_timer = S390_lowcore.user_timer; | |
1da177e4 | 125 | |
aa5e97ce MS |
126 | system = S390_lowcore.system_timer - ti->system_timer; |
127 | S390_lowcore.steal_timer -= system; | |
128 | ti->system_timer = S390_lowcore.system_timer; | |
10ad34bc MS |
129 | |
130 | user_scaled = user; | |
131 | system_scaled = system; | |
132 | /* Do MT utilization scaling */ | |
133 | if (smp_cpu_mtid) { | |
134 | u64 mult = __this_cpu_read(mt_scaling_mult); | |
135 | u64 div = __this_cpu_read(mt_scaling_div); | |
136 | ||
137 | user_scaled = (user_scaled * mult) / div; | |
138 | system_scaled = (system_scaled * mult) / div; | |
139 | } | |
140 | account_user_time(tsk, user, user_scaled); | |
141 | account_system_time(tsk, hardirq_offset, system, system_scaled); | |
1da177e4 | 142 | |
aa5e97ce MS |
143 | steal = S390_lowcore.steal_timer; |
144 | if ((s64) steal > 0) { | |
145 | S390_lowcore.steal_timer = 0; | |
9cfb9b3c | 146 | account_steal_time(steal); |
1da177e4 | 147 | } |
27f6b416 MS |
148 | |
149 | return virt_timer_forward(user + system); | |
1da177e4 LT |
150 | } |
151 | ||
bf9fae9f | 152 | void vtime_task_switch(struct task_struct *prev) |
1f1c12af | 153 | { |
aa5e97ce MS |
154 | struct thread_info *ti; |
155 | ||
156 | do_account_vtime(prev, 0); | |
157 | ti = task_thread_info(prev); | |
158 | ti->user_timer = S390_lowcore.user_timer; | |
159 | ti->system_timer = S390_lowcore.system_timer; | |
baa36046 | 160 | ti = task_thread_info(current); |
aa5e97ce MS |
161 | S390_lowcore.user_timer = ti->user_timer; |
162 | S390_lowcore.system_timer = ti->system_timer; | |
163 | } | |
1f1c12af | 164 | |
bcebdf84 FW |
165 | /* |
166 | * In s390, accounting pending user time also implies | |
167 | * accounting system time in order to correctly compute | |
168 | * the stolen time accounting. | |
169 | */ | |
170 | void vtime_account_user(struct task_struct *tsk) | |
aa5e97ce | 171 | { |
27f6b416 MS |
172 | if (do_account_vtime(tsk, HARDIRQ_OFFSET)) |
173 | virt_timer_expire(); | |
1f1c12af MS |
174 | } |
175 | ||
1da177e4 LT |
176 | /* |
177 | * Update process times based on virtual cpu times stored by entry.S | |
178 | * to the lowcore fields user_timer, system_timer & steal_clock. | |
179 | */ | |
6a61671b | 180 | void vtime_account_irq_enter(struct task_struct *tsk) |
1da177e4 | 181 | { |
aa5e97ce | 182 | struct thread_info *ti = task_thread_info(tsk); |
10ad34bc | 183 | u64 timer, system, system_scaled; |
1da177e4 LT |
184 | |
185 | timer = S390_lowcore.last_update_timer; | |
9cfb9b3c | 186 | S390_lowcore.last_update_timer = get_vtimer(); |
1da177e4 LT |
187 | S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer; |
188 | ||
72d38b19 MS |
189 | /* Update MT utilization calculation */ |
190 | if (smp_cpu_mtid && | |
191 | time_after64(jiffies_64, this_cpu_read(mt_scaling_jiffies))) | |
192 | update_mt_scaling(); | |
193 | ||
aa5e97ce MS |
194 | system = S390_lowcore.system_timer - ti->system_timer; |
195 | S390_lowcore.steal_timer -= system; | |
196 | ti->system_timer = S390_lowcore.system_timer; | |
10ad34bc MS |
197 | system_scaled = system; |
198 | /* Do MT utilization scaling */ | |
199 | if (smp_cpu_mtid) { | |
200 | u64 mult = __this_cpu_read(mt_scaling_mult); | |
201 | u64 div = __this_cpu_read(mt_scaling_div); | |
202 | ||
203 | system_scaled = (system_scaled * mult) / div; | |
204 | } | |
205 | account_system_time(tsk, 0, system, system_scaled); | |
27f6b416 MS |
206 | |
207 | virt_timer_forward(system); | |
1da177e4 | 208 | } |
6a61671b | 209 | EXPORT_SYMBOL_GPL(vtime_account_irq_enter); |
1da177e4 | 210 | |
fd25b4c2 | 211 | void vtime_account_system(struct task_struct *tsk) |
6a61671b | 212 | __attribute__((alias("vtime_account_irq_enter"))); |
fd25b4c2 | 213 | EXPORT_SYMBOL_GPL(vtime_account_system); |
11113334 | 214 | |
1da177e4 LT |
215 | /* |
216 | * Sorted add to a list. List is linear searched until first bigger | |
217 | * element is found. | |
218 | */ | |
219 | static void list_add_sorted(struct vtimer_list *timer, struct list_head *head) | |
220 | { | |
27f6b416 | 221 | struct vtimer_list *tmp; |
1da177e4 | 222 | |
27f6b416 MS |
223 | list_for_each_entry(tmp, head, entry) { |
224 | if (tmp->expires > timer->expires) { | |
225 | list_add_tail(&timer->entry, &tmp->entry); | |
1da177e4 LT |
226 | return; |
227 | } | |
228 | } | |
229 | list_add_tail(&timer->entry, head); | |
230 | } | |
231 | ||
232 | /* | |
27f6b416 | 233 | * Handler for expired virtual CPU timer. |
1da177e4 | 234 | */ |
27f6b416 | 235 | static void virt_timer_expire(void) |
1da177e4 | 236 | { |
27f6b416 MS |
237 | struct vtimer_list *timer, *tmp; |
238 | unsigned long elapsed; | |
239 | LIST_HEAD(cb_list); | |
240 | ||
241 | /* walk timer list, fire all expired timers */ | |
242 | spin_lock(&virt_timer_lock); | |
243 | elapsed = atomic64_read(&virt_timer_elapsed); | |
244 | list_for_each_entry_safe(timer, tmp, &virt_timer_list, entry) { | |
245 | if (timer->expires < elapsed) | |
9cfb9b3c | 246 | /* move expired timer to the callback queue */ |
27f6b416 | 247 | list_move_tail(&timer->entry, &cb_list); |
9cfb9b3c | 248 | else |
27f6b416 | 249 | timer->expires -= elapsed; |
1da177e4 | 250 | } |
27f6b416 MS |
251 | if (!list_empty(&virt_timer_list)) { |
252 | timer = list_first_entry(&virt_timer_list, | |
253 | struct vtimer_list, entry); | |
254 | atomic64_set(&virt_timer_current, timer->expires); | |
255 | } | |
256 | atomic64_sub(elapsed, &virt_timer_elapsed); | |
257 | spin_unlock(&virt_timer_lock); | |
258 | ||
259 | /* Do callbacks and recharge periodic timers */ | |
260 | list_for_each_entry_safe(timer, tmp, &cb_list, entry) { | |
261 | list_del_init(&timer->entry); | |
262 | timer->function(timer->data); | |
263 | if (timer->interval) { | |
264 | /* Recharge interval timer */ | |
265 | timer->expires = timer->interval + | |
266 | atomic64_read(&virt_timer_elapsed); | |
267 | spin_lock(&virt_timer_lock); | |
268 | list_add_sorted(timer, &virt_timer_list); | |
269 | spin_unlock(&virt_timer_lock); | |
270 | } | |
4c1051e3 | 271 | } |
1da177e4 LT |
272 | } |
273 | ||
274 | void init_virt_timer(struct vtimer_list *timer) | |
275 | { | |
1da177e4 LT |
276 | timer->function = NULL; |
277 | INIT_LIST_HEAD(&timer->entry); | |
1da177e4 LT |
278 | } |
279 | EXPORT_SYMBOL(init_virt_timer); | |
280 | ||
1da177e4 LT |
281 | static inline int vtimer_pending(struct vtimer_list *timer) |
282 | { | |
27f6b416 | 283 | return !list_empty(&timer->entry); |
1da177e4 LT |
284 | } |
285 | ||
1da177e4 LT |
286 | static void internal_add_vtimer(struct vtimer_list *timer) |
287 | { | |
27f6b416 MS |
288 | if (list_empty(&virt_timer_list)) { |
289 | /* First timer, just program it. */ | |
290 | atomic64_set(&virt_timer_current, timer->expires); | |
291 | atomic64_set(&virt_timer_elapsed, 0); | |
292 | list_add(&timer->entry, &virt_timer_list); | |
9cfb9b3c | 293 | } else { |
27f6b416 MS |
294 | /* Update timer against current base. */ |
295 | timer->expires += atomic64_read(&virt_timer_elapsed); | |
296 | if (likely((s64) timer->expires < | |
297 | (s64) atomic64_read(&virt_timer_current))) | |
9cfb9b3c | 298 | /* The new timer expires before the current timer. */ |
27f6b416 MS |
299 | atomic64_set(&virt_timer_current, timer->expires); |
300 | /* Insert new timer into the list. */ | |
301 | list_add_sorted(timer, &virt_timer_list); | |
1da177e4 | 302 | } |
1da177e4 LT |
303 | } |
304 | ||
27f6b416 | 305 | static void __add_vtimer(struct vtimer_list *timer, int periodic) |
1da177e4 | 306 | { |
27f6b416 MS |
307 | unsigned long flags; |
308 | ||
309 | timer->interval = periodic ? timer->expires : 0; | |
310 | spin_lock_irqsave(&virt_timer_lock, flags); | |
311 | internal_add_vtimer(timer); | |
312 | spin_unlock_irqrestore(&virt_timer_lock, flags); | |
1da177e4 LT |
313 | } |
314 | ||
315 | /* | |
316 | * add_virt_timer - add an oneshot virtual CPU timer | |
317 | */ | |
27f6b416 | 318 | void add_virt_timer(struct vtimer_list *timer) |
1da177e4 | 319 | { |
27f6b416 | 320 | __add_vtimer(timer, 0); |
1da177e4 LT |
321 | } |
322 | EXPORT_SYMBOL(add_virt_timer); | |
323 | ||
324 | /* | |
325 | * add_virt_timer_int - add an interval virtual CPU timer | |
326 | */ | |
27f6b416 | 327 | void add_virt_timer_periodic(struct vtimer_list *timer) |
1da177e4 | 328 | { |
27f6b416 | 329 | __add_vtimer(timer, 1); |
1da177e4 LT |
330 | } |
331 | EXPORT_SYMBOL(add_virt_timer_periodic); | |
332 | ||
27f6b416 | 333 | static int __mod_vtimer(struct vtimer_list *timer, u64 expires, int periodic) |
1da177e4 | 334 | { |
1da177e4 | 335 | unsigned long flags; |
27f6b416 | 336 | int rc; |
1da177e4 | 337 | |
ca366a32 | 338 | BUG_ON(!timer->function); |
1da177e4 | 339 | |
1da177e4 LT |
340 | if (timer->expires == expires && vtimer_pending(timer)) |
341 | return 1; | |
27f6b416 MS |
342 | spin_lock_irqsave(&virt_timer_lock, flags); |
343 | rc = vtimer_pending(timer); | |
344 | if (rc) | |
345 | list_del_init(&timer->entry); | |
346 | timer->interval = periodic ? expires : 0; | |
1da177e4 | 347 | timer->expires = expires; |
1da177e4 | 348 | internal_add_vtimer(timer); |
27f6b416 MS |
349 | spin_unlock_irqrestore(&virt_timer_lock, flags); |
350 | return rc; | |
1da177e4 | 351 | } |
b6ecfa92 JG |
352 | |
353 | /* | |
b6ecfa92 JG |
354 | * returns whether it has modified a pending timer (1) or not (0) |
355 | */ | |
27f6b416 | 356 | int mod_virt_timer(struct vtimer_list *timer, u64 expires) |
b6ecfa92 JG |
357 | { |
358 | return __mod_vtimer(timer, expires, 0); | |
359 | } | |
1da177e4 LT |
360 | EXPORT_SYMBOL(mod_virt_timer); |
361 | ||
b6ecfa92 | 362 | /* |
b6ecfa92 JG |
363 | * returns whether it has modified a pending timer (1) or not (0) |
364 | */ | |
27f6b416 | 365 | int mod_virt_timer_periodic(struct vtimer_list *timer, u64 expires) |
b6ecfa92 JG |
366 | { |
367 | return __mod_vtimer(timer, expires, 1); | |
368 | } | |
369 | EXPORT_SYMBOL(mod_virt_timer_periodic); | |
370 | ||
1da177e4 | 371 | /* |
27f6b416 | 372 | * Delete a virtual timer. |
1da177e4 LT |
373 | * |
374 | * returns whether the deleted timer was pending (1) or not (0) | |
375 | */ | |
376 | int del_virt_timer(struct vtimer_list *timer) | |
377 | { | |
378 | unsigned long flags; | |
1da177e4 | 379 | |
1da177e4 LT |
380 | if (!vtimer_pending(timer)) |
381 | return 0; | |
27f6b416 | 382 | spin_lock_irqsave(&virt_timer_lock, flags); |
1da177e4 | 383 | list_del_init(&timer->entry); |
27f6b416 | 384 | spin_unlock_irqrestore(&virt_timer_lock, flags); |
1da177e4 LT |
385 | return 1; |
386 | } | |
387 | EXPORT_SYMBOL(del_virt_timer); | |
388 | ||
389 | /* | |
390 | * Start the virtual CPU timer on the current CPU. | |
391 | */ | |
b5f87f15 | 392 | void vtime_init(void) |
1da177e4 | 393 | { |
8b646bd7 | 394 | /* set initial cpu timer */ |
27f6b416 | 395 | set_vtimer(VTIMER_MAX_SLICE); |
f341b8df MS |
396 | /* Setup initial MT scaling values */ |
397 | if (smp_cpu_mtid) { | |
398 | __this_cpu_write(mt_scaling_jiffies, jiffies); | |
399 | __this_cpu_write(mt_scaling_mult, 1); | |
400 | __this_cpu_write(mt_scaling_div, 1); | |
401 | stcctm5(smp_cpu_mtid + 1, this_cpu_ptr(mt_cycles)); | |
402 | } | |
1da177e4 | 403 | } |