diff options
| author | Bjoern B. Brandenburg <bbb@cs.unc.edu> | 2011-07-28 01:15:58 -0400 |
|---|---|---|
| committer | Bjoern B. Brandenburg <bbb@cs.unc.edu> | 2011-11-24 15:21:08 -0500 |
| commit | 5bd89a34d89f252619d83fef3c9325e24311389e (patch) | |
| tree | 0860be1b38ce94b09f8715e47a130f4da1827408 /litmus/sched_plugin.c | |
| parent | 81b8eb2ae452c241df9b3a1fb2116fa4d5adcb75 (diff) | |
Litmus core: simplify np-section protocolwip-2011.2-bbb
User a 32-bit word for all non-preemptive section flags.
Set the "please yield soon" flag atomically when
accessing it on remotely-scheduled tasks.
Diffstat (limited to 'litmus/sched_plugin.c')
| -rw-r--r-- | litmus/sched_plugin.c | 23 |
1 files changed, 6 insertions, 17 deletions
diff --git a/litmus/sched_plugin.c b/litmus/sched_plugin.c index d54886df1f57..00a1900d6457 100644 --- a/litmus/sched_plugin.c +++ b/litmus/sched_plugin.c | |||
| @@ -35,29 +35,18 @@ void preempt_if_preemptable(struct task_struct* t, int cpu) | |||
| 35 | /* local CPU case */ | 35 | /* local CPU case */ |
| 36 | /* check if we need to poke userspace */ | 36 | /* check if we need to poke userspace */ |
| 37 | if (is_user_np(t)) | 37 | if (is_user_np(t)) |
| 38 | /* yes, poke it */ | 38 | /* Yes, poke it. This doesn't have to be atomic since |
| 39 | * the task is definitely not executing. */ | ||
| 39 | request_exit_np(t); | 40 | request_exit_np(t); |
| 40 | else if (!is_kernel_np(t)) | 41 | else if (!is_kernel_np(t)) |
| 41 | /* only if we are allowed to preempt the | 42 | /* only if we are allowed to preempt the |
| 42 | * currently-executing task */ | 43 | * currently-executing task */ |
| 43 | reschedule = 1; | 44 | reschedule = 1; |
| 44 | } else { | 45 | } else { |
| 45 | /* remote CPU case */ | 46 | /* Remote CPU case. Only notify if it's not a kernel |
| 46 | if (is_user_np(t)) { | 47 | * NP section and if we didn't set the userspace |
| 47 | /* need to notify user space of delayed | 48 | * flag. */ |
| 48 | * preemption */ | 49 | reschedule = !(is_kernel_np(t) || request_exit_np_atomic(t)); |
| 49 | |||
| 50 | /* to avoid a race, set the flag, then test | ||
| 51 | * again */ | ||
| 52 | request_exit_np(t); | ||
| 53 | /* make sure it got written */ | ||
| 54 | mb(); | ||
| 55 | } | ||
| 56 | /* Only send an ipi if remote task might have raced our | ||
| 57 | * request, i.e., send an IPI to make sure in case it | ||
| 58 | * exited its critical section. | ||
| 59 | */ | ||
| 60 | reschedule = !is_np(t) && !is_kernel_np(t); | ||
| 61 | } | 50 | } |
| 62 | } | 51 | } |
| 63 | if (likely(reschedule)) | 52 | if (likely(reschedule)) |