Author: hselasky
Date: Fri Mar 30 20:11:12 2018
New Revision: 331828
URL: https://svnweb.freebsd.org/changeset/base/331828
Log:
Optimise use of Giant in the LinuxKPI.
- 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
Modified:
head/sys/compat/linuxkpi/common/include/linux/module.h
head/sys/compat/linuxkpi/common/src/linux_compat.c
head/sys/compat/linuxkpi/common/src/linux_pci.c
head/sys/compat/linuxkpi/common/src/linux_rcu.c
head/sys/compat/linuxkpi/common/src/linux_schedule.c
Modified: head/sys/compat/linuxkpi/common/include/linux/module.h
==============================================================================
--- head/sys/compat/linuxkpi/common/include/linux/module.h Fri Mar 30
19:58:58 2018 (r331827)
+++ head/sys/compat/linuxkpi/common/include/linux/module.h Fri Mar 30
20:11:12 2018 (r331828)
@@ -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)
\
Modified: head/sys/compat/linuxkpi/common/src/linux_compat.c
==============================================================================
--- head/sys/compat/linuxkpi/common/src/linux_compat.c Fri Mar 30 19:58:58
2018 (r331827)
+++ head/sys/compat/linuxkpi/common/src/linux_compat.c Fri Mar 30 20:11:12
2018 (r331828)
@@ -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, in
if (SCHEDULER_STOPPED())
return (0);
- DROP_GIANT();
-
task = current;
if (flags != 0)
@@ -1866,10 +1865,14 @@ linux_wait_for_timeout_common(struct completion *c, in
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, in
/* return how many jiffies are left */
error = linux_timer_jiffies_until(end);
done:
- PICKUP_GIANT();
-
return (error);
}
Modified: head/sys/compat/linuxkpi/common/src/linux_pci.c
==============================================================================
--- head/sys/compat/linuxkpi/common/src/linux_pci.c Fri Mar 30 19:58:58
2018 (r331827)
+++ head/sys/compat/linuxkpi/common/src/linux_pci.c Fri Mar 30 20:11:12
2018 (r331828)
@@ -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);
}
Modified: head/sys/compat/linuxkpi/common/src/linux_rcu.c
==============================================================================
--- head/sys/compat/linuxkpi/common/src/linux_rcu.c Fri Mar 30 19:58:58
2018 (r331827)
+++ head/sys/compat/linuxkpi/common/src/linux_rcu.c Fri Mar 30 20:11:12
2018 (r331828)
@@ -297,13 +297,13 @@ 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;
Modified: head/sys/compat/linuxkpi/common/src/linux_schedule.c
==============================================================================
--- head/sys/compat/linuxkpi/common/src/linux_schedule.c Fri Mar 30
19:58:58 2018 (r331827)
+++ head/sys/compat/linuxkpi/common/src/linux_schedule.c Fri Mar 30
20:11:12 2018 (r331828)
@@ -55,6 +55,8 @@ linux_add_to_sleepqueue(void *wchan, struct task_struc
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_struc
} 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_q
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_q
}
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
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
}
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 (;;) {
@@ -416,8 +406,6 @@ linux_wait_on_atomic_t(atomic_t *a, unsigned int state
break;
}
set_task_state(task, TASK_RUNNING);
-
- PICKUP_GIANT();
return (ret);
}
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