diff options
author | Bjoern Brandenburg <bbb@mpi-sws.org> | 2016-02-14 08:56:40 -0500 |
---|---|---|
committer | Bjoern Brandenburg <bbb@mpi-sws.org> | 2016-03-08 10:12:49 -0500 |
commit | a83a958e62cb903e14bc458a5ace4b9f380fc802 (patch) | |
tree | a8a0a2cea9d0cfd31f5f989b92da7202048ad187 | |
parent | 5c3fc90c1f92c65f315166f8de9071615c08c088 (diff) |
LITMUS^RT core: add should_wait_for_stack() callback
Allow plugins to give up when waiting for a stack to become available.
-rw-r--r-- | include/litmus/sched_plugin.h | 7 | ||||
-rw-r--r-- | kernel/sched/litmus.c | 13 | ||||
-rw-r--r-- | litmus/sched_plugin.c | 6 |
3 files changed, 26 insertions, 0 deletions
diff --git a/include/litmus/sched_plugin.h b/include/litmus/sched_plugin.h index 0c2aabad40c9..1906a139e6e9 100644 --- a/include/litmus/sched_plugin.h +++ b/include/litmus/sched_plugin.h | |||
@@ -29,6 +29,12 @@ typedef struct task_struct* (*schedule_t)(struct task_struct * prev); | |||
29 | typedef void (*finish_switch_t)(struct task_struct *prev); | 29 | typedef void (*finish_switch_t)(struct task_struct *prev); |
30 | 30 | ||
31 | 31 | ||
32 | /* When waiting for the stack of the task selected by the plugin | ||
33 | * to become available, this callback is invoked to give the | ||
34 | * plugin a chance to cancel the wait. If the plugin returns false, | ||
35 | * the scheduler is invoked again. */ | ||
36 | typedef bool (*should_wait_for_stack_t)(struct task_struct *next); | ||
37 | |||
32 | /********************* task state changes ********************/ | 38 | /********************* task state changes ********************/ |
33 | 39 | ||
34 | /* Called to setup a new real-time task. | 40 | /* Called to setup a new real-time task. |
@@ -103,6 +109,7 @@ struct sched_plugin { | |||
103 | /* scheduler invocation */ | 109 | /* scheduler invocation */ |
104 | schedule_t schedule; | 110 | schedule_t schedule; |
105 | finish_switch_t finish_switch; | 111 | finish_switch_t finish_switch; |
112 | should_wait_for_stack_t should_wait_for_stack; | ||
106 | 113 | ||
107 | /* syscall backend */ | 114 | /* syscall backend */ |
108 | complete_job_t complete_job; | 115 | complete_job_t complete_job; |
diff --git a/kernel/sched/litmus.c b/kernel/sched/litmus.c index 2cdba907f0a8..4fa5a941a284 100644 --- a/kernel/sched/litmus.c +++ b/kernel/sched/litmus.c | |||
@@ -78,6 +78,19 @@ litmus_schedule(struct rq *rq, struct task_struct *prev) | |||
78 | if (next->rt_param.stack_in_use == NO_CPU) | 78 | if (next->rt_param.stack_in_use == NO_CPU) |
79 | TRACE_TASK(next,"descheduled. Proceeding.\n"); | 79 | TRACE_TASK(next,"descheduled. Proceeding.\n"); |
80 | 80 | ||
81 | if (!litmus->should_wait_for_stack(next)) { | ||
82 | /* plugin aborted the wait */ | ||
83 | TRACE_TASK(next, | ||
84 | "plugin gave up waiting for stack\n"); | ||
85 | next = NULL; | ||
86 | /* Make sure plugin is given a chance to | ||
87 | * reconsider. */ | ||
88 | litmus_reschedule_local(); | ||
89 | /* give up */ | ||
90 | raw_spin_lock(&rq->lock); | ||
91 | return next; | ||
92 | } | ||
93 | |||
81 | if (lt_before(_maybe_deadlock + 1000000000L, | 94 | if (lt_before(_maybe_deadlock + 1000000000L, |
82 | litmus_clock())) { | 95 | litmus_clock())) { |
83 | /* We've been spinning for 1s. | 96 | /* We've been spinning for 1s. |
diff --git a/litmus/sched_plugin.c b/litmus/sched_plugin.c index 6ab5b85082c9..4007e5129e80 100644 --- a/litmus/sched_plugin.c +++ b/litmus/sched_plugin.c | |||
@@ -70,6 +70,11 @@ static struct task_struct* litmus_dummy_schedule(struct task_struct * prev) | |||
70 | return NULL; | 70 | return NULL; |
71 | } | 71 | } |
72 | 72 | ||
73 | static bool litmus_dummy_should_wait_for_stack(struct task_struct *next) | ||
74 | { | ||
75 | return true; /* by default, wait indefinitely */ | ||
76 | } | ||
77 | |||
73 | static long litmus_dummy_admit_task(struct task_struct* tsk) | 78 | static long litmus_dummy_admit_task(struct task_struct* tsk) |
74 | { | 79 | { |
75 | printk(KERN_CRIT "LITMUS^RT: Linux plugin rejects %s/%d.\n", | 80 | printk(KERN_CRIT "LITMUS^RT: Linux plugin rejects %s/%d.\n", |
@@ -186,6 +191,7 @@ int register_sched_plugin(struct sched_plugin* plugin) | |||
186 | /* make sure we don't trip over null pointers later */ | 191 | /* make sure we don't trip over null pointers later */ |
187 | CHECK(finish_switch); | 192 | CHECK(finish_switch); |
188 | CHECK(schedule); | 193 | CHECK(schedule); |
194 | CHECK(should_wait_for_stack); | ||
189 | CHECK(task_wake_up); | 195 | CHECK(task_wake_up); |
190 | CHECK(task_exit); | 196 | CHECK(task_exit); |
191 | CHECK(task_cleanup); | 197 | CHECK(task_cleanup); |