The .alloc_pdata hook of the scheduler interface is
called, in schedule_cpu_switch(), unconditionally,
for all schedulers.
This forces even schedulers that do not require any
actual allocation of per-pCPU data to:
- contain an implementation of the hook;
- return some artificial non-NULL value to make
such a caller happy.
This changes allows schedulers that do not need per-pCPU
allocations to avoid implementing the hook. It also
kills such artificial implementation from the ARINC653
scheduler (and, while there, it nukes .free_pdata from
there too, which is equally useless).
Signed-off-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
---
Cc: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
Cc: Robert VanVossen <robert.vanvossen@xxxxxxxxxxxxxxx>
Cc: Josh Whitehead <josh.whitehead@xxxxxxxxxxxxxxx>
---
xen/common/sched_arinc653.c | 31 -------------------------------
xen/common/schedule.c | 6 +++---
2 files changed, 3 insertions(+), 34 deletions(-)
diff --git a/xen/common/sched_arinc653.c b/xen/common/sched_arinc653.c
index cff5da9..ef192c3 100644
--- a/xen/common/sched_arinc653.c
+++ b/xen/common/sched_arinc653.c
@@ -455,34 +455,6 @@ a653sched_free_vdata(const struct scheduler *ops, void
*priv)
}
/**
- * This function allocates scheduler-specific data for a physical CPU
- *
- * We do not actually make use of any per-CPU data but the hypervisor expects
- * a non-NULL return value
- *
- * @param ops Pointer to this instance of the scheduler structure
- *
- * @return Pointer to the allocated data
- */
-static void *
-a653sched_alloc_pdata(const struct scheduler *ops, int cpu)
-{
- /* return a non-NULL value to keep schedule.c happy */
- return SCHED_PRIV(ops);
-}
-
-/**
- * This function frees scheduler-specific data for a physical CPU
- *
- * @param ops Pointer to this instance of the scheduler structure
- */
-static void
-a653sched_free_pdata(const struct scheduler *ops, void *pcpu, int cpu)
-{
- /* nop */
-}
-
-/**
* This function allocates scheduler-specific data for a domain
*
* We do not actually make use of any per-domain data but the hypervisor
@@ -736,9 +708,6 @@ const struct scheduler sched_arinc653_def = {
.free_vdata = a653sched_free_vdata,
.alloc_vdata = a653sched_alloc_vdata,
- .free_pdata = a653sched_free_pdata,
- .alloc_pdata = a653sched_alloc_pdata,
-
.free_domdata = a653sched_free_domdata,
.alloc_domdata = a653sched_alloc_domdata,
diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index 83244d7..0e02af2 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -1493,7 +1493,7 @@ void __init scheduler_init(void)
int schedule_cpu_switch(unsigned int cpu, struct cpupool *c)
{
struct vcpu *idle;
- void *ppriv, *ppriv_old, *vpriv, *vpriv_old;
+ void *ppriv = NULL, *ppriv_old, *vpriv, *vpriv_old;
struct scheduler *old_ops = per_cpu(scheduler, cpu);
struct scheduler *new_ops = (c == NULL) ? &ops : c->sched;
@@ -1501,8 +1501,8 @@ int schedule_cpu_switch(unsigned int cpu, struct cpupool
*c)
return 0;
idle = idle_vcpu[cpu];
- ppriv = SCHED_OP(new_ops, alloc_pdata, cpu);
- if ( ppriv == NULL )
+ if ( (new_ops->alloc_pdata != NULL) &&
+ ((ppriv = new_ops->alloc_pdata(new_ops, cpu)) == NULL) )
return -ENOMEM;
vpriv = SCHED_OP(new_ops, alloc_vdata, idle, idle->domain->sched_priv);
if ( vpriv == NULL )
