From 3df5edad87a998273aa5a9a8c728c05d855ad00e Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 8 May 2009 18:52:22 +0200 Subject: [PATCH] perf_counter: rework ioctl()s Corey noticed that ioctl()s on grouped counters didn't work on the whole group. This extends the ioctl() interface to take a second argument that is interpreted as a flags field. We then provide PERF_IOC_FLAG_GROUP to toggle the behaviour. Having this flag gives the greatest flexibility, allowing you to individually enable/disable/reset counters in a group, or all together. [ Impact: fix group counter enable/disable semantics ] Reported-by: Corey Ashford Signed-off-by: Peter Zijlstra Cc: Paul Mackerras LKML-Reference: <20090508170028.837558214@chello.nl> Signed-off-by: Ingo Molnar --- include/linux/perf_counter.h | 10 +++- kernel/perf_counter.c | 104 +++++++++++++++++++---------------- 2 files changed, 65 insertions(+), 49 deletions(-) diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index 00081d84169f..88f863ec2748 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -157,10 +157,14 @@ struct perf_counter_hw_event { /* * Ioctls that can be done on a perf counter fd: */ -#define PERF_COUNTER_IOC_ENABLE _IO ('$', 0) -#define PERF_COUNTER_IOC_DISABLE _IO ('$', 1) +#define PERF_COUNTER_IOC_ENABLE _IOW('$', 0, u32) +#define PERF_COUNTER_IOC_DISABLE _IOW('$', 1, u32) #define PERF_COUNTER_IOC_REFRESH _IOW('$', 2, u32) -#define PERF_COUNTER_IOC_RESET _IO ('$', 3) +#define PERF_COUNTER_IOC_RESET _IOW('$', 3, u32) + +enum perf_counter_ioc_flags { + PERF_IOC_FLAG_GROUP = 1U << 0, +}; /* * Structure of the page that can be mapped via mmap diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index fdb0d2421276..f4883f1f47eb 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -82,7 +82,7 @@ list_add_counter(struct perf_counter *counter, struct perf_counter_context *ctx) * add it straight to the context's counter list, or to the group * leader's sibling list: */ - if (counter->group_leader == counter) + if (group_leader == counter) list_add_tail(&counter->list_entry, &ctx->counter_list); else { list_add_tail(&counter->list_entry, &group_leader->sibling_list); @@ -385,24 +385,6 @@ static void perf_counter_disable(struct perf_counter *counter) spin_unlock_irq(&ctx->lock); } -/* - * Disable a counter and all its children. - */ -static void perf_counter_disable_family(struct perf_counter *counter) -{ - struct perf_counter *child; - - perf_counter_disable(counter); - - /* - * Lock the mutex to protect the list of children - */ - mutex_lock(&counter->mutex); - list_for_each_entry(child, &counter->child_list, child_list) - perf_counter_disable(child); - mutex_unlock(&counter->mutex); -} - static int counter_sched_in(struct perf_counter *counter, struct perf_cpu_context *cpuctx, @@ -753,24 +735,6 @@ static int perf_counter_refresh(struct perf_counter *counter, int refresh) return 0; } -/* - * Enable a counter and all its children. - */ -static void perf_counter_enable_family(struct perf_counter *counter) -{ - struct perf_counter *child; - - perf_counter_enable(counter); - - /* - * Lock the mutex to protect the list of children - */ - mutex_lock(&counter->mutex); - list_for_each_entry(child, &counter->child_list, child_list) - perf_counter_enable(child); - mutex_unlock(&counter->mutex); -} - void __perf_counter_sched_out(struct perf_counter_context *ctx, struct perf_cpu_context *cpuctx) { @@ -1307,31 +1271,79 @@ static unsigned int perf_poll(struct file *file, poll_table *wait) static void perf_counter_reset(struct perf_counter *counter) { + (void)perf_counter_read(counter); atomic_set(&counter->count, 0); + perf_counter_update_userpage(counter); +} + +static void perf_counter_for_each_sibling(struct perf_counter *counter, + void (*func)(struct perf_counter *)) +{ + struct perf_counter_context *ctx = counter->ctx; + struct perf_counter *sibling; + + spin_lock_irq(&ctx->lock); + counter = counter->group_leader; + + func(counter); + list_for_each_entry(sibling, &counter->sibling_list, list_entry) + func(sibling); + spin_unlock_irq(&ctx->lock); +} + +static void perf_counter_for_each_child(struct perf_counter *counter, + void (*func)(struct perf_counter *)) +{ + struct perf_counter *child; + + mutex_lock(&counter->mutex); + func(counter); + list_for_each_entry(child, &counter->child_list, child_list) + func(child); + mutex_unlock(&counter->mutex); +} + +static void perf_counter_for_each(struct perf_counter *counter, + void (*func)(struct perf_counter *)) +{ + struct perf_counter *child; + + mutex_lock(&counter->mutex); + perf_counter_for_each_sibling(counter, func); + list_for_each_entry(child, &counter->child_list, child_list) + perf_counter_for_each_sibling(child, func); + mutex_unlock(&counter->mutex); } static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct perf_counter *counter = file->private_data; - int err = 0; + void (*func)(struct perf_counter *); + u32 flags = arg; switch (cmd) { case PERF_COUNTER_IOC_ENABLE: - perf_counter_enable_family(counter); + func = perf_counter_enable; break; case PERF_COUNTER_IOC_DISABLE: - perf_counter_disable_family(counter); - break; - case PERF_COUNTER_IOC_REFRESH: - err = perf_counter_refresh(counter, arg); + func = perf_counter_disable; break; case PERF_COUNTER_IOC_RESET: - perf_counter_reset(counter); + func = perf_counter_reset; break; + + case PERF_COUNTER_IOC_REFRESH: + return perf_counter_refresh(counter, arg); default: - err = -ENOTTY; + return -ENOTTY; } - return err; + + if (flags & PERF_IOC_FLAG_GROUP) + perf_counter_for_each(counter, func); + else + perf_counter_for_each_child(counter, func); + + return 0; } /* -- 2.20.1