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Optimise use of Giant in the LinuxKPI.

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- Make sure Giant is locked when calling PCI device methods.
Newbus currently requires this.

- Avoid unlocking Giant right before aquiring the sleepqueue lock.
This can save a task switch.

MFC after:	1 week
Sponsored by:	Mellanox Technologies
This commit is contained in:
hselasky 2018-03-30 20:11:12 +00:00
parent 7cf4e46e9b
commit bf24bc5621
5 changed files with 20 additions and 37 deletions
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2
sys/compat/linuxkpi/common/include/linux/module.h
View File

@ -78,9 +78,7 @@ _module_run(void *arg)
printf("Running %s (%p)\n", name, pc);
#endif
fn = arg;
DROP_GIANT();
fn();
PICKUP_GIANT();
}
#define module_init(fn) \

19
sys/compat/linuxkpi/common/src/linux_compat.c
View File

@ -1804,8 +1804,6 @@ linux_wait_for_common(struct completion *c, int flags)
if (SCHEDULER_STOPPED())
return (0);
DROP_GIANT();
task = current;
if (flags != 0)
@ -1819,22 +1817,25 @@ linux_wait_for_common(struct completion *c, int flags)
break;
sleepq_add(c, NULL, "completion", flags, 0);
if (flags & SLEEPQ_INTERRUPTIBLE) {
DROP_GIANT();
error = -sleepq_wait_sig(c, 0);
PICKUP_GIANT();
if (error != 0) {
linux_schedule_save_interrupt_value(task, error);
error = -ERESTARTSYS;
goto intr;
}
} else
} else {
DROP_GIANT();
sleepq_wait(c, 0);
PICKUP_GIANT();
}
}
if (c->done != UINT_MAX)
c->done--;
sleepq_release(c);
intr:
PICKUP_GIANT();
return (error);
}
@ -1851,8 +1852,6 @@ linux_wait_for_timeout_common(struct completion *c, int timeout, int flags)
if (SCHEDULER_STOPPED())
return (0);
DROP_GIANT();
task = current;
if (flags != 0)
@ -1866,10 +1865,14 @@ linux_wait_for_timeout_common(struct completion *c, int timeout, int flags)
break;
sleepq_add(c, NULL, "completion", flags, 0);
sleepq_set_timeout(c, linux_timer_jiffies_until(end));
DROP_GIANT();
if (flags & SLEEPQ_INTERRUPTIBLE)
error = -sleepq_timedwait_sig(c, 0);
else
error = -sleepq_timedwait(c, 0);
PICKUP_GIANT();
if (error != 0) {
/* check for timeout */
if (error == -EWOULDBLOCK) {
@ -1889,8 +1892,6 @@ linux_wait_for_timeout_common(struct completion *c, int timeout, int flags)
/* return how many jiffies are left */
error = linux_timer_jiffies_until(end);
done:
PICKUP_GIANT();
return (error);
}

12
sys/compat/linuxkpi/common/src/linux_pci.c
View File

@ -171,12 +171,11 @@ linux_pci_attach(device_t dev)
pdev->bus = pbus;
}
DROP_GIANT();
spin_lock(&pci_lock);
list_add(&pdev->links, &pci_devices);
spin_unlock(&pci_lock);
error = pdrv->probe(pdev, id);
PICKUP_GIANT();
if (error) {
spin_lock(&pci_lock);
list_del(&pdev->links);
@ -194,9 +193,9 @@ linux_pci_detach(device_t dev)
linux_set_current(curthread);
pdev = device_get_softc(dev);
DROP_GIANT();
pdev->pdrv->remove(pdev);
PICKUP_GIANT();
spin_lock(&pci_lock);
list_del(&pdev->links);
spin_unlock(&pci_lock);
@ -258,11 +257,8 @@ linux_pci_shutdown(device_t dev)
linux_set_current(curthread);
pdev = device_get_softc(dev);
if (pdev->pdrv->shutdown != NULL) {
DROP_GIANT();
if (pdev->pdrv->shutdown != NULL)
pdev->pdrv->shutdown(pdev);
PICKUP_GIANT();
}
return (0);
}

4
sys/compat/linuxkpi/common/src/linux_rcu.c
View File

@ -297,14 +297,14 @@ linux_synchronize_rcu(void)
td = curthread;
DROP_GIANT();
/*
* Synchronizing RCU might change the CPU core this function
* is running on. Save current values:
*/
thread_lock(td);
DROP_GIANT();
old_cpu = PCPU_GET(cpuid);
old_pinned = td->td_pinned;
old_prio = td->td_priority;

20
sys/compat/linuxkpi/common/src/linux_schedule.c
View File

@ -55,6 +55,8 @@ linux_add_to_sleepqueue(void *wchan, struct task_struct *task,
sleepq_add(wchan, NULL, wmesg, flags, 0);
if (timeout != 0)
sleepq_set_timeout(wchan, timeout);
DROP_GIANT();
if ((state & TASK_INTERRUPTIBLE) != 0) {
if (timeout == 0)
ret = -sleepq_wait_sig(wchan, 0);
@ -67,6 +69,8 @@ linux_add_to_sleepqueue(void *wchan, struct task_struct *task,
} else
ret = -sleepq_timedwait(wchan, 0);
}
PICKUP_GIANT();
/* filter return value */
if (ret != 0 && ret != -EWOULDBLOCK) {
linux_schedule_save_interrupt_value(task, ret);
@ -248,8 +252,6 @@ linux_wait_event_common(wait_queue_head_t *wqh, wait_queue_t *wq, int timeout,
if (lock != NULL)
spin_unlock_irq(lock);
DROP_GIANT();
/* range check timeout */
if (timeout < 1)
timeout = 1;
@ -272,8 +274,6 @@ linux_wait_event_common(wait_queue_head_t *wqh, wait_queue_t *wq, int timeout,
}
PRELE(task->task_thread->td_proc);
PICKUP_GIANT();
if (lock != NULL)
spin_lock_irq(lock);
return (ret);
@ -297,8 +297,6 @@ linux_schedule_timeout(int timeout)
remainder = ticks + timeout;
DROP_GIANT();
sleepq_lock(task);
state = atomic_read(&task->state);
if (state != TASK_WAKING) {
@ -309,8 +307,6 @@ linux_schedule_timeout(int timeout)
}
set_task_state(task, TASK_RUNNING);
PICKUP_GIANT();
if (timeout == 0)
return (MAX_SCHEDULE_TIMEOUT);
@ -356,8 +352,6 @@ linux_wait_on_bit_timeout(unsigned long *word, int bit, unsigned int state,
void *wchan;
int ret;
DROP_GIANT();
/* range check timeout */
if (timeout < 1)
timeout = 1;
@ -380,8 +374,6 @@ linux_wait_on_bit_timeout(unsigned long *word, int bit, unsigned int state,
}
set_task_state(task, TASK_RUNNING);
PICKUP_GIANT();
return (ret);
}
@ -399,8 +391,6 @@ linux_wait_on_atomic_t(atomic_t *a, unsigned int state)
void *wchan;
int ret;
DROP_GIANT();
task = current;
wchan = a;
for (;;) {
@ -417,8 +407,6 @@ linux_wait_on_atomic_t(atomic_t *a, unsigned int state)
}
set_task_state(task, TASK_RUNNING);
PICKUP_GIANT();
return (ret);
}