From a9a2c44ff0a1350f8bfe3a162ecf71b1c9ce5cc2 Mon Sep 17 00:00:00 2001 From: Corey Minyard Date: Mon, 7 Nov 2005 01:00:03 -0800 Subject: [PATCH] [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: Matt Domsch Signed-off-by: Corey Minyard Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/char/ipmi/ipmi_si_intf.c | 84 ++++++++++++++++++++++++-------- 1 file changed, 63 insertions(+), 21 deletions(-) diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c index d514df7c7283..fa3be622ca97 100644 --- a/drivers/char/ipmi/ipmi_si_intf.c +++ b/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 *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. */