~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/kernel/sched/cpudeadline.c

Version: ~ [ linux-5.4-rc3 ] ~ [ linux-5.3.6 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.79 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.149 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.196 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.196 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.75 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  *  kernel/sched/cpudl.c
  3  *
  4  *  Global CPU deadline management
  5  *
  6  *  Author: Juri Lelli <j.lelli@sssup.it>
  7  *
  8  *  This program is free software; you can redistribute it and/or
  9  *  modify it under the terms of the GNU General Public License
 10  *  as published by the Free Software Foundation; version 2
 11  *  of the License.
 12  */
 13 
 14 #include <linux/gfp.h>
 15 #include <linux/kernel.h>
 16 #include <linux/slab.h>
 17 #include "cpudeadline.h"
 18 
 19 static inline int parent(int i)
 20 {
 21         return (i - 1) >> 1;
 22 }
 23 
 24 static inline int left_child(int i)
 25 {
 26         return (i << 1) + 1;
 27 }
 28 
 29 static inline int right_child(int i)
 30 {
 31         return (i << 1) + 2;
 32 }
 33 
 34 static inline int dl_time_before(u64 a, u64 b)
 35 {
 36         return (s64)(a - b) < 0;
 37 }
 38 
 39 static void cpudl_exchange(struct cpudl *cp, int a, int b)
 40 {
 41         int cpu_a = cp->elements[a].cpu, cpu_b = cp->elements[b].cpu;
 42 
 43         swap(cp->elements[a].cpu, cp->elements[b].cpu);
 44         swap(cp->elements[a].dl , cp->elements[b].dl );
 45 
 46         swap(cp->elements[cpu_a].idx, cp->elements[cpu_b].idx);
 47 }
 48 
 49 static void cpudl_heapify(struct cpudl *cp, int idx)
 50 {
 51         int l, r, largest;
 52 
 53         /* adapted from lib/prio_heap.c */
 54         while(1) {
 55                 l = left_child(idx);
 56                 r = right_child(idx);
 57                 largest = idx;
 58 
 59                 if ((l < cp->size) && dl_time_before(cp->elements[idx].dl,
 60                                                         cp->elements[l].dl))
 61                         largest = l;
 62                 if ((r < cp->size) && dl_time_before(cp->elements[largest].dl,
 63                                                         cp->elements[r].dl))
 64                         largest = r;
 65                 if (largest == idx)
 66                         break;
 67 
 68                 /* Push idx down the heap one level and bump one up */
 69                 cpudl_exchange(cp, largest, idx);
 70                 idx = largest;
 71         }
 72 }
 73 
 74 static void cpudl_change_key(struct cpudl *cp, int idx, u64 new_dl)
 75 {
 76         WARN_ON(idx == IDX_INVALID || !cpu_present(idx));
 77 
 78         if (dl_time_before(new_dl, cp->elements[idx].dl)) {
 79                 cp->elements[idx].dl = new_dl;
 80                 cpudl_heapify(cp, idx);
 81         } else {
 82                 cp->elements[idx].dl = new_dl;
 83                 while (idx > 0 && dl_time_before(cp->elements[parent(idx)].dl,
 84                                         cp->elements[idx].dl)) {
 85                         cpudl_exchange(cp, idx, parent(idx));
 86                         idx = parent(idx);
 87                 }
 88         }
 89 }
 90 
 91 static inline int cpudl_maximum(struct cpudl *cp)
 92 {
 93         return cp->elements[0].cpu;
 94 }
 95 
 96 /*
 97  * cpudl_find - find the best (later-dl) CPU in the system
 98  * @cp: the cpudl max-heap context
 99  * @p: the task
100  * @later_mask: a mask to fill in with the selected CPUs (or NULL)
101  *
102  * Returns: int - best CPU (heap maximum if suitable)
103  */
104 int cpudl_find(struct cpudl *cp, struct task_struct *p,
105                struct cpumask *later_mask)
106 {
107         int best_cpu = -1;
108         const struct sched_dl_entity *dl_se = &p->dl;
109 
110         if (later_mask &&
111             cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) {
112                 best_cpu = cpumask_any(later_mask);
113                 goto out;
114         } else if (cpumask_test_cpu(cpudl_maximum(cp), &p->cpus_allowed) &&
115                         dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
116                 best_cpu = cpudl_maximum(cp);
117                 if (later_mask)
118                         cpumask_set_cpu(best_cpu, later_mask);
119         }
120 
121 out:
122         WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
123 
124         return best_cpu;
125 }
126 
127 /*
128  * cpudl_set - update the cpudl max-heap
129  * @cp: the cpudl max-heap context
130  * @cpu: the target cpu
131  * @dl: the new earliest deadline for this cpu
132  *
133  * Notes: assumes cpu_rq(cpu)->lock is locked
134  *
135  * Returns: (void)
136  */
137 void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid)
138 {
139         int old_idx, new_cpu;
140         unsigned long flags;
141 
142         WARN_ON(!cpu_present(cpu));
143 
144         raw_spin_lock_irqsave(&cp->lock, flags);
145         old_idx = cp->elements[cpu].idx;
146         if (!is_valid) {
147                 /* remove item */
148                 if (old_idx == IDX_INVALID) {
149                         /*
150                          * Nothing to remove if old_idx was invalid.
151                          * This could happen if a rq_offline_dl is
152                          * called for a CPU without -dl tasks running.
153                          */
154                         goto out;
155                 }
156                 new_cpu = cp->elements[cp->size - 1].cpu;
157                 cp->elements[old_idx].dl = cp->elements[cp->size - 1].dl;
158                 cp->elements[old_idx].cpu = new_cpu;
159                 cp->size--;
160                 cp->elements[new_cpu].idx = old_idx;
161                 cp->elements[cpu].idx = IDX_INVALID;
162                 while (old_idx > 0 && dl_time_before(
163                                 cp->elements[parent(old_idx)].dl,
164                                 cp->elements[old_idx].dl)) {
165                         cpudl_exchange(cp, old_idx, parent(old_idx));
166                         old_idx = parent(old_idx);
167                 }
168                 cpumask_set_cpu(cpu, cp->free_cpus);
169                 cpudl_heapify(cp, old_idx);
170 
171                 goto out;
172         }
173 
174         if (old_idx == IDX_INVALID) {
175                 cp->size++;
176                 cp->elements[cp->size - 1].dl = 0;
177                 cp->elements[cp->size - 1].cpu = cpu;
178                 cp->elements[cpu].idx = cp->size - 1;
179                 cpudl_change_key(cp, cp->size - 1, dl);
180                 cpumask_clear_cpu(cpu, cp->free_cpus);
181         } else {
182                 cpudl_change_key(cp, old_idx, dl);
183         }
184 
185 out:
186         raw_spin_unlock_irqrestore(&cp->lock, flags);
187 }
188 
189 /*
190  * cpudl_set_freecpu - Set the cpudl.free_cpus
191  * @cp: the cpudl max-heap context
192  * @cpu: rd attached cpu
193  */
194 void cpudl_set_freecpu(struct cpudl *cp, int cpu)
195 {
196         cpumask_set_cpu(cpu, cp->free_cpus);
197 }
198 
199 /*
200  * cpudl_clear_freecpu - Clear the cpudl.free_cpus
201  * @cp: the cpudl max-heap context
202  * @cpu: rd attached cpu
203  */
204 void cpudl_clear_freecpu(struct cpudl *cp, int cpu)
205 {
206         cpumask_clear_cpu(cpu, cp->free_cpus);
207 }
208 
209 /*
210  * cpudl_init - initialize the cpudl structure
211  * @cp: the cpudl max-heap context
212  */
213 int cpudl_init(struct cpudl *cp)
214 {
215         int i;
216 
217         memset(cp, 0, sizeof(*cp));
218         raw_spin_lock_init(&cp->lock);
219         cp->size = 0;
220 
221         cp->elements = kcalloc(nr_cpu_ids,
222                                sizeof(struct cpudl_item),
223                                GFP_KERNEL);
224         if (!cp->elements)
225                 return -ENOMEM;
226 
227         if (!zalloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) {
228                 kfree(cp->elements);
229                 return -ENOMEM;
230         }
231 
232         for_each_possible_cpu(i)
233                 cp->elements[i].idx = IDX_INVALID;
234 
235         return 0;
236 }
237 
238 /*
239  * cpudl_cleanup - clean up the cpudl structure
240  * @cp: the cpudl max-heap context
241  */
242 void cpudl_cleanup(struct cpudl *cp)
243 {
244         free_cpumask_var(cp->free_cpus);
245         kfree(cp->elements);
246 }
247 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp