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author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-03-19 00:52:46 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-03-19 00:52:46 +0100 |
commit | f82c37e7bb4c4d9b6a476c642d5c2d2efbd6f240 (patch) | |
tree | 09fc553c2fb6f527962048d139159dc139e04afc /kernel/trace/trace_event_perf.c | |
parent | Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jik... (diff) | |
parent | perf: Fix unexported generic perf_arch_fetch_caller_regs (diff) | |
download | linux-f82c37e7bb4c4d9b6a476c642d5c2d2efbd6f240.tar.xz linux-f82c37e7bb4c4d9b6a476c642d5c2d2efbd6f240.zip |
Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (35 commits)
perf: Fix unexported generic perf_arch_fetch_caller_regs
perf record: Don't try to find buildids in a zero sized file
perf: export perf_trace_regs and perf_arch_fetch_caller_regs
perf, x86: Fix hw_perf_enable() event assignment
perf, ppc: Fix compile error due to new cpu notifiers
perf: Make the install relative to DESTDIR if specified
kprobes: Calculate the index correctly when freeing the out-of-line execution slot
perf tools: Fix sparse CPU numbering related bugs
perf_event: Fix oops triggered by cpu offline/online
perf: Drop the obsolete profile naming for trace events
perf: Take a hot regs snapshot for trace events
perf: Introduce new perf_fetch_caller_regs() for hot regs snapshot
perf/x86-64: Use frame pointer to walk on irq and process stacks
lockdep: Move lock events under lockdep recursion protection
perf report: Print the map table just after samples for which no map was found
perf report: Add multiple event support
perf session: Change perf_session post processing functions to take histogram tree
perf session: Add storage for seperating event types in report
perf session: Change add_hist_entry to take the tree root instead of session
perf record: Add ID and to recorded event data when recording multiple events
...
Diffstat (limited to 'kernel/trace/trace_event_perf.c')
-rw-r--r-- | kernel/trace/trace_event_perf.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c new file mode 100644 index 000000000000..81f691eb3a30 --- /dev/null +++ b/kernel/trace/trace_event_perf.c @@ -0,0 +1,168 @@ +/* + * trace event based perf event profiling/tracing + * + * Copyright (C) 2009 Red Hat Inc, Peter Zijlstra <pzijlstr@redhat.com> + * Copyright (C) 2009-2010 Frederic Weisbecker <fweisbec@gmail.com> + */ + +#include <linux/module.h> +#include <linux/kprobes.h> +#include "trace.h" + +DEFINE_PER_CPU(struct pt_regs, perf_trace_regs); +EXPORT_PER_CPU_SYMBOL_GPL(perf_trace_regs); + +EXPORT_SYMBOL_GPL(perf_arch_fetch_caller_regs); + +static char *perf_trace_buf; +static char *perf_trace_buf_nmi; + +typedef typeof(char [PERF_MAX_TRACE_SIZE]) perf_trace_t ; + +/* Count the events in use (per event id, not per instance) */ +static int total_ref_count; + +static int perf_trace_event_enable(struct ftrace_event_call *event) +{ + char *buf; + int ret = -ENOMEM; + + if (event->perf_refcount++ > 0) + return 0; + + if (!total_ref_count) { + buf = (char *)alloc_percpu(perf_trace_t); + if (!buf) + goto fail_buf; + + rcu_assign_pointer(perf_trace_buf, buf); + + buf = (char *)alloc_percpu(perf_trace_t); + if (!buf) + goto fail_buf_nmi; + + rcu_assign_pointer(perf_trace_buf_nmi, buf); + } + + ret = event->perf_event_enable(event); + if (!ret) { + total_ref_count++; + return 0; + } + +fail_buf_nmi: + if (!total_ref_count) { + free_percpu(perf_trace_buf_nmi); + free_percpu(perf_trace_buf); + perf_trace_buf_nmi = NULL; + perf_trace_buf = NULL; + } +fail_buf: + event->perf_refcount--; + + return ret; +} + +int perf_trace_enable(int event_id) +{ + struct ftrace_event_call *event; + int ret = -EINVAL; + + mutex_lock(&event_mutex); + list_for_each_entry(event, &ftrace_events, list) { + if (event->id == event_id && event->perf_event_enable && + try_module_get(event->mod)) { + ret = perf_trace_event_enable(event); + break; + } + } + mutex_unlock(&event_mutex); + + return ret; +} + +static void perf_trace_event_disable(struct ftrace_event_call *event) +{ + char *buf, *nmi_buf; + + if (--event->perf_refcount > 0) + return; + + event->perf_event_disable(event); + + if (!--total_ref_count) { + buf = perf_trace_buf; + rcu_assign_pointer(perf_trace_buf, NULL); + + nmi_buf = perf_trace_buf_nmi; + rcu_assign_pointer(perf_trace_buf_nmi, NULL); + + /* + * Ensure every events in profiling have finished before + * releasing the buffers + */ + synchronize_sched(); + + free_percpu(buf); + free_percpu(nmi_buf); + } +} + +void perf_trace_disable(int event_id) +{ + struct ftrace_event_call *event; + + mutex_lock(&event_mutex); + list_for_each_entry(event, &ftrace_events, list) { + if (event->id == event_id) { + perf_trace_event_disable(event); + module_put(event->mod); + break; + } + } + mutex_unlock(&event_mutex); +} + +__kprobes void *perf_trace_buf_prepare(int size, unsigned short type, + int *rctxp, unsigned long *irq_flags) +{ + struct trace_entry *entry; + char *trace_buf, *raw_data; + int pc, cpu; + + pc = preempt_count(); + + /* Protect the per cpu buffer, begin the rcu read side */ + local_irq_save(*irq_flags); + + *rctxp = perf_swevent_get_recursion_context(); + if (*rctxp < 0) + goto err_recursion; + + cpu = smp_processor_id(); + + if (in_nmi()) + trace_buf = rcu_dereference_sched(perf_trace_buf_nmi); + else + trace_buf = rcu_dereference_sched(perf_trace_buf); + + if (!trace_buf) + goto err; + + raw_data = per_cpu_ptr(trace_buf, cpu); + + /* zero the dead bytes from align to not leak stack to user */ + *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL; + + entry = (struct trace_entry *)raw_data; + tracing_generic_entry_update(entry, *irq_flags, pc); + entry->type = type; + + return raw_data; +err: + perf_swevent_put_recursion_context(*rctxp); +err_recursion: + local_irq_restore(*irq_flags); + return NULL; +} +EXPORT_SYMBOL_GPL(perf_trace_buf_prepare); |