Commit a9a2c44f authored by Corey Minyard's avatar Corey Minyard Committed by Linus Torvalds
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[PATCH] ipmi: add timer thread



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: default avatarMatt Domsch <Matt_Domsch@dell.com>
Signed-off-by: default avatarCorey Minyard <minyard@acm.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent c3e7e791
......@@ -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 *send_info, int i_run_to_completion)
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 data)
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 irq, void *data, struct pt_regs *regs)
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(struct smi_info *smi_info)
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, struct smi_info **smi)
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, struct smi_info **smi)
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, struct smi_info **smi)
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 smi_info *to_clean)
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 smi_info *to_clean)
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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