Revision bfeda41d06d85ad9d52f2413cfc2b77be5022f75 authored by Omar Sandoval on 07 February 2017, 23:33:20 UTC, committed by Ingo Molnar on 08 February 2017, 07:21:31 UTC
Since KERN_CONT became meaningful again, lockdep stack traces have had annoying extra newlines, like this: [ 5.561122] -> #1 (B){+.+...}: [ 5.561528] [ 5.561532] [<ffffffff810d8873>] lock_acquire+0xc3/0x210 [ 5.562178] [ 5.562181] [<ffffffff816f6414>] mutex_lock_nested+0x74/0x6d0 [ 5.562861] [ 5.562880] [<ffffffffa01aa3c3>] init_btrfs_fs+0x21/0x196 [btrfs] [ 5.563717] [ 5.563721] [<ffffffff81000472>] do_one_initcall+0x52/0x1b0 [ 5.564554] [ 5.564559] [<ffffffff811a3af6>] do_init_module+0x5f/0x209 [ 5.565357] [ 5.565361] [<ffffffff81122f4d>] load_module+0x218d/0x2b80 [ 5.566020] [ 5.566021] [<ffffffff81123beb>] SyS_finit_module+0xeb/0x120 [ 5.566694] [ 5.566696] [<ffffffff816fd241>] entry_SYSCALL_64_fastpath+0x1f/0xc2 That's happening because each printk() call now gets printed on its own line, and we do a separate call to print the spaces before the symbol. Fix it by doing the printk() directly instead of using the print_ip_sym() helper. Additionally, the symbol address isn't very helpful, so let's get rid of that, too. The final result looks like this: [ 5.194518] -> #1 (B){+.+...}: [ 5.195002] lock_acquire+0xc3/0x210 [ 5.195439] mutex_lock_nested+0x74/0x6d0 [ 5.196491] do_one_initcall+0x52/0x1b0 [ 5.196939] do_init_module+0x5f/0x209 [ 5.197355] load_module+0x218d/0x2b80 [ 5.197792] SyS_finit_module+0xeb/0x120 [ 5.198251] entry_SYSCALL_64_fastpath+0x1f/0xc2 Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Omar Sandoval <osandov@fb.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kernel-team@fb.com Fixes: 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing continuation lines") Link: http://lkml.kernel.org/r/43b4e114724b2bdb0308fa86cb33aa07d3d67fad.1486510315.git.osandov@fb.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
1 parent 926af62
driver.c
/*
* driver.c - driver support
*
* (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
* Shaohua Li <shaohua.li@intel.com>
* Adam Belay <abelay@novell.com>
*
* This code is licenced under the GPL.
*/
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/cpuidle.h>
#include <linux/cpumask.h>
#include <linux/tick.h>
#include <linux/cpu.h>
#include "cpuidle.h"
DEFINE_SPINLOCK(cpuidle_driver_lock);
#ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS
static DEFINE_PER_CPU(struct cpuidle_driver *, cpuidle_drivers);
/**
* __cpuidle_get_cpu_driver - return the cpuidle driver tied to a CPU.
* @cpu: the CPU handled by the driver
*
* Returns a pointer to struct cpuidle_driver or NULL if no driver has been
* registered for @cpu.
*/
static struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu)
{
return per_cpu(cpuidle_drivers, cpu);
}
/**
* __cpuidle_unset_driver - unset per CPU driver variables.
* @drv: a valid pointer to a struct cpuidle_driver
*
* For each CPU in the driver's CPU mask, unset the registered driver per CPU
* variable. If @drv is different from the registered driver, the corresponding
* variable is not cleared.
*/
static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv)
{
int cpu;
for_each_cpu(cpu, drv->cpumask) {
if (drv != __cpuidle_get_cpu_driver(cpu))
continue;
per_cpu(cpuidle_drivers, cpu) = NULL;
}
}
/**
* __cpuidle_set_driver - set per CPU driver variables for the given driver.
* @drv: a valid pointer to a struct cpuidle_driver
*
* For each CPU in the driver's cpumask, unset the registered driver per CPU
* to @drv.
*
* Returns 0 on success, -EBUSY if the CPUs have driver(s) already.
*/
static inline int __cpuidle_set_driver(struct cpuidle_driver *drv)
{
int cpu;
for_each_cpu(cpu, drv->cpumask) {
if (__cpuidle_get_cpu_driver(cpu)) {
__cpuidle_unset_driver(drv);
return -EBUSY;
}
per_cpu(cpuidle_drivers, cpu) = drv;
}
return 0;
}
#else
static struct cpuidle_driver *cpuidle_curr_driver;
/**
* __cpuidle_get_cpu_driver - return the global cpuidle driver pointer.
* @cpu: ignored without the multiple driver support
*
* Return a pointer to a struct cpuidle_driver object or NULL if no driver was
* previously registered.
*/
static inline struct cpuidle_driver *__cpuidle_get_cpu_driver(int cpu)
{
return cpuidle_curr_driver;
}
/**
* __cpuidle_set_driver - assign the global cpuidle driver variable.
* @drv: pointer to a struct cpuidle_driver object
*
* Returns 0 on success, -EBUSY if the driver is already registered.
*/
static inline int __cpuidle_set_driver(struct cpuidle_driver *drv)
{
if (cpuidle_curr_driver)
return -EBUSY;
cpuidle_curr_driver = drv;
return 0;
}
/**
* __cpuidle_unset_driver - unset the global cpuidle driver variable.
* @drv: a pointer to a struct cpuidle_driver
*
* Reset the global cpuidle variable to NULL. If @drv does not match the
* registered driver, do nothing.
*/
static inline void __cpuidle_unset_driver(struct cpuidle_driver *drv)
{
if (drv == cpuidle_curr_driver)
cpuidle_curr_driver = NULL;
}
#endif
/**
* cpuidle_setup_broadcast_timer - enable/disable the broadcast timer on a cpu
* @arg: a void pointer used to match the SMP cross call API
*
* If @arg is NULL broadcast is disabled otherwise enabled
*
* This function is executed per CPU by an SMP cross call. It's not
* supposed to be called directly.
*/
static void cpuidle_setup_broadcast_timer(void *arg)
{
if (arg)
tick_broadcast_enable();
else
tick_broadcast_disable();
}
/**
* __cpuidle_driver_init - initialize the driver's internal data
* @drv: a valid pointer to a struct cpuidle_driver
*/
static void __cpuidle_driver_init(struct cpuidle_driver *drv)
{
int i;
drv->refcnt = 0;
/*
* Use all possible CPUs as the default, because if the kernel boots
* with some CPUs offline and then we online one of them, the CPU
* notifier has to know which driver to assign.
*/
if (!drv->cpumask)
drv->cpumask = (struct cpumask *)cpu_possible_mask;
/*
* Look for the timer stop flag in the different states, so that we know
* if the broadcast timer has to be set up. The loop is in the reverse
* order, because usually one of the deeper states have this flag set.
*/
for (i = drv->state_count - 1; i >= 0 ; i--) {
if (drv->states[i].flags & CPUIDLE_FLAG_TIMER_STOP) {
drv->bctimer = 1;
break;
}
}
}
#ifdef CONFIG_ARCH_HAS_CPU_RELAX
static int __cpuidle poll_idle(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index)
{
local_irq_enable();
if (!current_set_polling_and_test()) {
while (!need_resched())
cpu_relax();
}
current_clr_polling();
return index;
}
static void poll_idle_init(struct cpuidle_driver *drv)
{
struct cpuidle_state *state = &drv->states[0];
snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
state->exit_latency = 0;
state->target_residency = 0;
state->power_usage = -1;
state->enter = poll_idle;
state->disabled = false;
}
#else
static void poll_idle_init(struct cpuidle_driver *drv) {}
#endif /* !CONFIG_ARCH_HAS_CPU_RELAX */
/**
* __cpuidle_register_driver: register the driver
* @drv: a valid pointer to a struct cpuidle_driver
*
* Do some sanity checks, initialize the driver, assign the driver to the
* global cpuidle driver variable(s) and set up the broadcast timer if the
* cpuidle driver has some states that shut down the local timer.
*
* Returns 0 on success, a negative error code otherwise:
* * -EINVAL if the driver pointer is NULL or no idle states are available
* * -ENODEV if the cpuidle framework is disabled
* * -EBUSY if the driver is already assigned to the global variable(s)
*/
static int __cpuidle_register_driver(struct cpuidle_driver *drv)
{
int ret;
if (!drv || !drv->state_count)
return -EINVAL;
ret = cpuidle_coupled_state_verify(drv);
if (ret)
return ret;
if (cpuidle_disabled())
return -ENODEV;
__cpuidle_driver_init(drv);
ret = __cpuidle_set_driver(drv);
if (ret)
return ret;
if (drv->bctimer)
on_each_cpu_mask(drv->cpumask, cpuidle_setup_broadcast_timer,
(void *)1, 1);
poll_idle_init(drv);
return 0;
}
/**
* __cpuidle_unregister_driver - unregister the driver
* @drv: a valid pointer to a struct cpuidle_driver
*
* Check if the driver is no longer in use, reset the global cpuidle driver
* variable(s) and disable the timer broadcast notification mechanism if it was
* in use.
*
*/
static void __cpuidle_unregister_driver(struct cpuidle_driver *drv)
{
if (WARN_ON(drv->refcnt > 0))
return;
if (drv->bctimer) {
drv->bctimer = 0;
on_each_cpu_mask(drv->cpumask, cpuidle_setup_broadcast_timer,
NULL, 1);
}
__cpuidle_unset_driver(drv);
}
/**
* cpuidle_register_driver - registers a driver
* @drv: a pointer to a valid struct cpuidle_driver
*
* Register the driver under a lock to prevent concurrent attempts to
* [un]register the driver from occuring at the same time.
*
* Returns 0 on success, a negative error code (returned by
* __cpuidle_register_driver()) otherwise.
*/
int cpuidle_register_driver(struct cpuidle_driver *drv)
{
int ret;
spin_lock(&cpuidle_driver_lock);
ret = __cpuidle_register_driver(drv);
spin_unlock(&cpuidle_driver_lock);
return ret;
}
EXPORT_SYMBOL_GPL(cpuidle_register_driver);
/**
* cpuidle_unregister_driver - unregisters a driver
* @drv: a pointer to a valid struct cpuidle_driver
*
* Unregisters the cpuidle driver under a lock to prevent concurrent attempts
* to [un]register the driver from occuring at the same time. @drv has to
* match the currently registered driver.
*/
void cpuidle_unregister_driver(struct cpuidle_driver *drv)
{
spin_lock(&cpuidle_driver_lock);
__cpuidle_unregister_driver(drv);
spin_unlock(&cpuidle_driver_lock);
}
EXPORT_SYMBOL_GPL(cpuidle_unregister_driver);
/**
* cpuidle_get_driver - return the driver tied to the current CPU.
*
* Returns a struct cpuidle_driver pointer, or NULL if no driver is registered.
*/
struct cpuidle_driver *cpuidle_get_driver(void)
{
struct cpuidle_driver *drv;
int cpu;
cpu = get_cpu();
drv = __cpuidle_get_cpu_driver(cpu);
put_cpu();
return drv;
}
EXPORT_SYMBOL_GPL(cpuidle_get_driver);
/**
* cpuidle_get_cpu_driver - return the driver registered for a CPU.
* @dev: a valid pointer to a struct cpuidle_device
*
* Returns a struct cpuidle_driver pointer, or NULL if no driver is registered
* for the CPU associated with @dev.
*/
struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev)
{
if (!dev)
return NULL;
return __cpuidle_get_cpu_driver(dev->cpu);
}
EXPORT_SYMBOL_GPL(cpuidle_get_cpu_driver);
/**
* cpuidle_driver_ref - get a reference to the driver.
*
* Increment the reference counter of the cpuidle driver associated with
* the current CPU.
*
* Returns a pointer to the driver, or NULL if the current CPU has no driver.
*/
struct cpuidle_driver *cpuidle_driver_ref(void)
{
struct cpuidle_driver *drv;
spin_lock(&cpuidle_driver_lock);
drv = cpuidle_get_driver();
if (drv)
drv->refcnt++;
spin_unlock(&cpuidle_driver_lock);
return drv;
}
/**
* cpuidle_driver_unref - puts down the refcount for the driver
*
* Decrement the reference counter of the cpuidle driver associated with
* the current CPU.
*/
void cpuidle_driver_unref(void)
{
struct cpuidle_driver *drv;
spin_lock(&cpuidle_driver_lock);
drv = cpuidle_get_driver();
if (drv && !WARN_ON(drv->refcnt <= 0))
drv->refcnt--;
spin_unlock(&cpuidle_driver_lock);
}
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