From 1427cdf0592368bdec57276edaf714040ee8744f Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Fri, 6 Mar 2009 17:21:47 +0100 Subject: tracing: infrastructure for supporting binary record Impact: save on memory for tracing Current tracers are typically using a struct(like struct ftrace_entry, struct ctx_switch_entry, struct special_entr etc...)to record a binary event. These structs can only record a their own kind of events. A new kind of tracer need a new struct and a lot of code too handle it. So we need a generic binary record for events. This infrastructure is for this purpose. [fweisbec@gmail.com: rebase against latest -tip, make it safe while sched tracing as reported by Steven Rostedt] Signed-off-by: Lai Jiangshan Signed-off-by: Frederic Weisbecker Acked-by: Steven Rostedt LKML-Reference: <1236356510-8381-3-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 4987694..1c9cdca 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -223,6 +223,9 @@ extern int ftrace_make_nop(struct module *mod, */ extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr); +#ifdef CONFIG_TRACE_BPRINTK +extern int trace_vbprintk(unsigned long ip, const char *fmt, va_list args); +#endif /* May be defined in arch */ extern int ftrace_arch_read_dyn_info(char *buf, int size); diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 058d949..ad8d361 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -97,6 +97,12 @@ config FUNCTION_GRAPH_TRACER This is done by setting the current return address on the current task structure into a stack of calls. +config TRACE_BPRINTK + bool "Binary printk for tracing" + default y + depends on TRACING + select BINARY_PRINTF + config IRQSOFF_TRACER bool "Interrupts-off Latency Tracer" default n diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index f44736c..46557ef 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -22,6 +22,7 @@ obj-$(CONFIG_TRACING) += trace.o obj-$(CONFIG_TRACING) += trace_clock.o obj-$(CONFIG_TRACING) += trace_output.o obj-$(CONFIG_TRACING) += trace_stat.o +obj-$(CONFIG_TRACE_BPRINTK) += trace_bprintk.o obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o obj-$(CONFIG_SYSPROF_TRACER) += trace_sysprof.o obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index e6144ac..ff53509 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3792,6 +3792,62 @@ int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap) } EXPORT_SYMBOL_GPL(__ftrace_vprintk); +/** + * trace_vbprintk - write binary msg to tracing buffer + * + * Caller must insure @fmt are valid when msg is in tracing buffer. + */ +int trace_vbprintk(unsigned long ip, const char *fmt, va_list args) +{ + static DEFINE_SPINLOCK(trace_buf_lock); + static u32 trace_buf[TRACE_BUF_SIZE]; + + struct ring_buffer_event *event; + struct trace_array *tr = &global_trace; + struct trace_array_cpu *data; + struct bprintk_entry *entry; + unsigned long flags; + int resched; + int cpu, len = 0, size, pc; + + if (tracing_disabled || !trace_bprintk_enable) + return 0; + + pc = preempt_count(); + resched = ftrace_preempt_disable(); + cpu = raw_smp_processor_id(); + data = tr->data[cpu]; + + if (unlikely(atomic_read(&data->disabled))) + goto out; + + spin_lock_irqsave(&trace_buf_lock, flags); + len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args); + + if (len > TRACE_BUF_SIZE || len < 0) + goto out_unlock; + + size = sizeof(*entry) + sizeof(u32) * len; + event = trace_buffer_lock_reserve(tr, TRACE_BPRINTK, size, flags, pc); + if (!event) + goto out_unlock; + entry = ring_buffer_event_data(event); + entry->ip = ip; + entry->fmt = fmt; + + memcpy(entry->buf, trace_buf, sizeof(u32) * len); + ring_buffer_unlock_commit(tr->buffer, event); + +out_unlock: + spin_unlock_irqrestore(&trace_buf_lock, flags); + +out: + ftrace_preempt_enable(resched); + + return len; +} +EXPORT_SYMBOL_GPL(trace_vbprintk); + static int trace_panic_handler(struct notifier_block *this, unsigned long event, void *unused) { diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 8beff03..0f5077f 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -20,6 +20,7 @@ enum trace_type { TRACE_WAKE, TRACE_STACK, TRACE_PRINT, + TRACE_BPRINTK, TRACE_SPECIAL, TRACE_MMIO_RW, TRACE_MMIO_MAP, @@ -124,6 +125,16 @@ struct print_entry { char buf[]; }; +struct bprintk_entry { + struct trace_entry ent; + unsigned long ip; + const char *fmt; + u32 buf[]; +}; +#ifdef CONFIG_TRACE_BPRINTK +extern int trace_bprintk_enable; +#endif + #define TRACE_OLD_SIZE 88 struct trace_field_cont { @@ -285,6 +296,7 @@ extern void __ftrace_bad_type(void); IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK); \ IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\ IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT); \ + IF_ASSIGN(var, ent, struct bprintk_entry, TRACE_BPRINTK);\ IF_ASSIGN(var, ent, struct special_entry, 0); \ IF_ASSIGN(var, ent, struct trace_mmiotrace_rw, \ TRACE_MMIO_RW); \ diff --git a/kernel/trace/trace_bprintk.c b/kernel/trace/trace_bprintk.c new file mode 100644 index 0000000..1f8e532 --- /dev/null +++ b/kernel/trace/trace_bprintk.c @@ -0,0 +1,87 @@ +/* + * trace binary printk + * + * Copyright (C) 2008 Lai Jiangshan + * + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "trace.h" + +/* binary printk basic */ +static DEFINE_MUTEX(btrace_mutex); +static int btrace_metadata_count; + +static inline void lock_btrace(void) +{ + mutex_lock(&btrace_mutex); +} + +static inline void unlock_btrace(void) +{ + mutex_unlock(&btrace_mutex); +} + +static void get_btrace_metadata(void) +{ + lock_btrace(); + btrace_metadata_count++; + unlock_btrace(); +} + +static void put_btrace_metadata(void) +{ + lock_btrace(); + btrace_metadata_count--; + unlock_btrace(); +} + +/* events tracer */ +int trace_bprintk_enable; + +static void start_bprintk_trace(struct trace_array *tr) +{ + get_btrace_metadata(); + tracing_reset_online_cpus(tr); + trace_bprintk_enable = 1; +} + +static void stop_bprintk_trace(struct trace_array *tr) +{ + trace_bprintk_enable = 0; + tracing_reset_online_cpus(tr); + put_btrace_metadata(); +} + +static int init_bprintk_trace(struct trace_array *tr) +{ + start_bprintk_trace(tr); + return 0; +} + +static struct tracer bprintk_trace __read_mostly = +{ + .name = "events", + .init = init_bprintk_trace, + .reset = stop_bprintk_trace, + .start = start_bprintk_trace, + .stop = stop_bprintk_trace, +}; + +static __init int init_bprintk(void) +{ + return register_tracer(&bprintk_trace); +} + +device_initcall(init_bprintk); diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 306fef8..4ab7120 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -53,6 +53,26 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...) return len; } +static int +trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) +{ + int len = (PAGE_SIZE - 1) - s->len; + int ret; + + if (!len) + return 0; + + ret = bstr_printf(s->buffer + s->len, len, fmt, binary); + + /* If we can't write it all, don't bother writing anything */ + if (ret >= len) + return 0; + + s->len += ret; + + return len; +} + /** * trace_seq_puts - trace sequence printing of simple string * @s: trace sequence descriptor @@ -855,6 +875,60 @@ static struct trace_event trace_print_event = { .raw = trace_print_raw, }; +/* TRACE_BPRINTK */ +static enum print_line_t +trace_bprintk_print(struct trace_iterator *iter, int flags) +{ + struct trace_entry *entry = iter->ent; + struct trace_seq *s = &iter->seq; + struct bprintk_entry *field; + + trace_assign_type(field, entry); + + if (!seq_print_ip_sym(s, field->ip, flags)) + goto partial; + + if (!trace_seq_puts(s, ": ")) + goto partial; + + if (!trace_seq_bprintf(s, field->fmt, field->buf)) + goto partial; + + return TRACE_TYPE_HANDLED; + + partial: + return TRACE_TYPE_PARTIAL_LINE; +} + +static enum print_line_t +trace_bprintk_raw(struct trace_iterator *iter, int flags) +{ + struct trace_entry *entry = iter->ent; + struct trace_seq *s = &iter->seq; + struct bprintk_entry *field; + + trace_assign_type(field, entry); + + if (!trace_seq_printf(s, ": %lx : ", field->ip)) + goto partial; + + if (!trace_seq_bprintf(s, field->fmt, field->buf)) + goto partial; + + return TRACE_TYPE_HANDLED; + + partial: + return TRACE_TYPE_PARTIAL_LINE; +} + +static struct trace_event trace_bprintk_event = { + .type = TRACE_BPRINTK, + .trace = trace_bprintk_print, + .raw = trace_bprintk_raw, + .hex = trace_nop_print, + .binary = trace_nop_print, +}; + static struct trace_event *events[] __initdata = { &trace_fn_event, &trace_ctx_event, @@ -863,6 +937,7 @@ static struct trace_event *events[] __initdata = { &trace_stack_event, &trace_user_stack_event, &trace_print_event, + &trace_bprintk_event, NULL }; 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