We must poll for responses to commands when interrupts aren't in use.
The default poll interval is based on using a kernel timer, which
varies with HZ. For character-based interfaces like KCS and SMIC
though, that can be way too slow (>15 minutes to flash a new firmware
with KCS, >20 seconds to retrieve the sensor list).
This creates a low-priority kernel thread to poll more often. If the
state machine is idle, so is the kernel thread. But if there's an
active command, it polls quite rapidly. This decrease a firmware
flash time from 15 minutes to 1.5 minutes, and the sensor list time to
4.5 seconds, on a Dell PowerEdge x8x system.
The timer-based polling remains, to ensure some amount of
responsiveness even under high user process CPU load.
Checking for a stopped timer at rmmod now uses atomics and
del_timer_sync() to ensure safe stoppage.
Signed-off-by: Matt Domsch <[email protected]>
Signed-off-by: Corey Minyard <[email protected]>
Index: linux-2.6.14-rc4/drivers/char/ipmi/ipmi_si_intf.c
===================================================================
--- linux-2.6.14-rc4.orig/drivers/char/ipmi/ipmi_si_intf.c
+++ linux-2.6.14-rc4/drivers/char/ipmi/ipmi_si_intf.c
@@ -126,6 +126,7 @@ struct ipmi_device_id {
struct smi_info
{
+ int intf_num;
ipmi_smi_t intf;
struct si_sm_data *si_sm;
struct si_sm_handlers *handlers;
@@ -193,8 +194,7 @@ struct smi_info
unsigned long last_timeout_jiffies;
/* Used to gracefully stop the timer without race conditions. */
- volatile int stop_operation;
- volatile int timer_stopped;
+ atomic_t stop_operation;
/* The driver will disable interrupts when it gets into a
situation where it cannot handle messages due to lack of
@@ -221,6 +221,9 @@ struct smi_info
unsigned long events;
unsigned long watchdog_pretimeouts;
unsigned long incoming_messages;
+
+ struct completion exiting;
+ long thread_pid;
};
static struct notifier_block *xaction_notifier_list;
@@ -779,6 +782,38 @@ static void set_run_to_completion(void *
spin_unlock_irqrestore(&(smi_info->si_lock), flags);
}
+static int ipmi_thread(void *data)
+{
+ struct smi_info *smi_info = data;
+ unsigned long flags, last=1;
+ enum si_sm_result smi_result;
+
+ daemonize("kipmi%d", smi_info->intf_num);
+ allow_signal(SIGKILL);
+ set_user_nice(current, 19);
+ while (!atomic_read(&smi_info->stop_operation)) {
+ schedule_timeout(last);
+ spin_lock_irqsave(&(smi_info->si_lock), flags);
+ smi_result=smi_event_handler(smi_info, 0);
+ spin_unlock_irqrestore(&(smi_info->si_lock), flags);
+ if (smi_result == SI_SM_CALL_WITHOUT_DELAY)
+ last = 0;
+ else if (smi_result == SI_SM_CALL_WITH_DELAY) {
+ udelay(1);
+ last = 0;
+ }
+ else {
+ /* System is idle; go to sleep */
+ last = 1;
+ current->state = TASK_INTERRUPTIBLE;
+ }
+ }
+ smi_info->thread_pid = 0;
+ complete_and_exit(&(smi_info->exiting), 0);
+ return 0;
+}
+
+
static void poll(void *send_info)
{
struct smi_info *smi_info = send_info;
@@ -837,10 +872,8 @@ static void smi_timeout(unsigned long da
struct timeval t;
#endif
- if (smi_info->stop_operation) {
- smi_info->timer_stopped = 1;
+ if (atomic_read(&smi_info->stop_operation))
return;
- }
spin_lock_irqsave(&(smi_info->si_lock), flags);
#ifdef DEBUG_TIMING
@@ -913,7 +946,7 @@ static irqreturn_t si_irq_handler(int ir
smi_info->interrupts++;
spin_unlock(&smi_info->count_lock);
- if (smi_info->stop_operation)
+ if (atomic_read(&smi_info->stop_operation))
goto out;
#ifdef DEBUG_TIMING
@@ -1432,7 +1465,7 @@ static u32 ipmi_acpi_gpe(void *context)
smi_info->interrupts++;
spin_unlock(&smi_info->count_lock);
- if (smi_info->stop_operation)
+ if (atomic_read(&smi_info->stop_operation))
goto out;
#ifdef DEBUG_TIMING
@@ -2177,6 +2210,16 @@ static void setup_xaction_handlers(struc
setup_dell_poweredge_bt_xaction_handler(smi_info);
}
+static inline void wait_for_timer_and_thread(struct smi_info *smi_info)
+{
+ if (smi_info->thread_pid > 0) {
+ /* wake the potentially sleeping thread */
+ kill_proc(smi_info->thread_pid, SIGKILL, 0);
+ wait_for_completion(&(smi_info->exiting));
+ }
+ del_timer_sync(&smi_info->si_timer);
+}
+
/* Returns 0 if initialized, or negative on an error. */
static int init_one_smi(int intf_num, struct smi_info **smi)
{
@@ -2284,8 +2327,8 @@ static int init_one_smi(int intf_num, st
new_smi->run_to_completion = 0;
new_smi->interrupt_disabled = 0;
- new_smi->timer_stopped = 0;
- new_smi->stop_operation = 0;
+ atomic_set(&new_smi->stop_operation, 0);
+ new_smi->intf_num = intf_num;
/* Start clearing the flags before we enable interrupts or the
timer to avoid racing with the timer. */
@@ -2303,7 +2346,14 @@ static int init_one_smi(int intf_num, st
new_smi->si_timer.function = smi_timeout;
new_smi->last_timeout_jiffies = jiffies;
new_smi->si_timer.expires = jiffies + SI_TIMEOUT_JIFFIES;
+
add_timer(&(new_smi->si_timer));
+ if (new_smi->si_type != SI_BT) {
+ init_completion(&(new_smi->exiting));
+ new_smi->thread_pid = kernel_thread(ipmi_thread, new_smi,
+ CLONE_FS|CLONE_FILES|
+ CLONE_SIGHAND);
+ }
rv = ipmi_register_smi(&handlers,
new_smi,
@@ -2345,12 +2395,8 @@ static int init_one_smi(int intf_num, st
return 0;
out_err_stop_timer:
- new_smi->stop_operation = 1;
-
- /* Wait for the timer to stop. This avoids problems with race
- conditions removing the timer here. */
- while (!new_smi->timer_stopped)
- schedule_timeout_uninterruptible(1);
+ atomic_inc(&new_smi->stop_operation);
+ wait_for_timer_and_thread(new_smi);
out_err:
if (new_smi->intf)
@@ -2456,8 +2502,7 @@ static void __exit cleanup_one_si(struct
spin_lock_irqsave(&(to_clean->si_lock), flags);
spin_lock(&(to_clean->msg_lock));
- to_clean->stop_operation = 1;
-
+ atomic_inc(&to_clean->stop_operation);
to_clean->irq_cleanup(to_clean);
spin_unlock(&(to_clean->msg_lock));
@@ -2468,10 +2513,7 @@ static void __exit cleanup_one_si(struct
interrupt. */
synchronize_sched();
- /* Wait for the timer to stop. This avoids problems with race
- conditions removing the timer here. */
- while (!to_clean->timer_stopped)
- schedule_timeout_uninterruptible(1);
+ wait_for_timer_and_thread(to_clean);
/* Interrupts and timeouts are stopped, now make sure the
interface is in a clean state. */
-
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