From 48ead02030f849d011259244bb4ea9b985479006 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Thu, 12 Mar 2009 18:24:49 +0100 Subject: tracing/core: bring back raw trace_printk for dynamic formats strings Impact: fix callsites with dynamic format strings Since its new binary implementation, trace_printk() internally uses static containers for the format strings on each callsites. But the value is assigned once at build time, which means that it can't take dynamic formats. So this patch unearthes the raw trace_printk implementation for the callers that will need trace_printk to be able to carry these dynamic format strings. The trace_printk() macro will use the appropriate implementation for each callsite. Most of the time however, the binary implementation will still be used. The other impact of this patch is that mmiotrace_printk() will use the old implementation because it calls the low level trace_vprintk and we can't guess here whether the format passed in it is dynamic or not. Some parts of this patch have been written by Steven Rostedt (most notably the part that chooses the appropriate implementation for each callsites). Signed-off-by: Frederic Weisbecker Signed-off-by: Steven Rostedt --- include/linux/kernel.h | 40 +++++++++++++++++++++++++++------------- 1 file changed, 27 insertions(+), 13 deletions(-) (limited to 'include/linux') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 7742798c9208..1daca3b062bb 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -452,31 +452,45 @@ do { \ #define trace_printk(fmt, args...) \ do { \ - static const char *trace_printk_fmt \ - __attribute__((section("__trace_printk_fmt"))); \ - \ - if (!trace_printk_fmt) \ - trace_printk_fmt = fmt; \ - \ __trace_printk_check_format(fmt, ##args); \ - __trace_printk(_THIS_IP_, trace_printk_fmt, ##args); \ + if (__builtin_constant_p(fmt)) { \ + static const char *trace_printk_fmt \ + __attribute__((section("__trace_printk_fmt"))) = \ + __builtin_constant_p(fmt) ? fmt : NULL; \ + \ + __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \ + } else \ + __trace_printk(_THIS_IP_, fmt, ##args); \ } while (0) +extern int +__trace_bprintk(unsigned long ip, const char *fmt, ...) + __attribute__ ((format (printf, 2, 3))); + extern int __trace_printk(unsigned long ip, const char *fmt, ...) __attribute__ ((format (printf, 2, 3))); +/* + * The double __builtin_constant_p is because gcc will give us an error + * if we try to allocate the static variable to fmt if it is not a + * constant. Even with the outer if statement. + */ #define ftrace_vprintk(fmt, vargs) \ do { \ - static const char *trace_printk_fmt \ - __attribute__((section("__trace_printk_fmt"))); \ - \ - if (!trace_printk_fmt) \ - trace_printk_fmt = fmt; \ + if (__builtin_constant_p(fmt)) { \ + static const char *trace_printk_fmt \ + __attribute__((section("__trace_printk_fmt"))) = \ + __builtin_constant_p(fmt) ? fmt : NULL; \ \ - __ftrace_vprintk(_THIS_IP_, trace_printk_fmt, vargs); \ + __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \ + } else \ + __ftrace_vprintk(_THIS_IP_, fmt, vargs); \ } while (0) +extern int +__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap); + extern int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap); -- cgit v1.2.3 From 5d592b44b29a1d73e13d5c9e3426eed843bdc359 Mon Sep 17 00:00:00 2001 From: Jason Baron Date: Thu, 12 Mar 2009 14:33:36 -0400 Subject: tracing: tracepoints for softirq entry/exit - add softirq-to-name array Create a 'softirq_to_name' array, which is indexed by softirq #, so that we can easily convert between the softirq index # and its name, in order to get more meaningful output messages. LKML-Reference: <20090312183336.GB3352@redhat.com> Signed-off-by: Jason Baron Signed-off-by: Steven Rostedt --- include/linux/interrupt.h | 5 +++++ kernel/softirq.c | 9 ++++++++- 2 files changed, 13 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 472f11765f60..9b7e9d743476 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -258,6 +258,11 @@ enum NR_SOFTIRQS }; +/* map softirq index to softirq name. update 'softirq_to_name' in + * kernel/softirq.c when adding a new softirq. + */ +extern char *softirq_to_name[NR_SOFTIRQS]; + /* softirq mask and active fields moved to irq_cpustat_t in * asm/hardirq.h to get better cache usage. KAO */ diff --git a/kernel/softirq.c b/kernel/softirq.c index 7571bcb71be4..9f90fdc039f4 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -53,6 +53,12 @@ static struct softirq_action softirq_vec[NR_SOFTIRQS] __cacheline_aligned_in_smp static DEFINE_PER_CPU(struct task_struct *, ksoftirqd); +char *softirq_to_name[NR_SOFTIRQS] = { + "HI_SOFTIRQ", "TIMER_SOFTIRQ", "NET_TX_SOFTIRQ", "NET_RX_SOFTIRQ", + "BLOCK_SOFTIRQ", "TASKLET_SOFTIRQ", "SCHED_SOFTIRQ", "HRTIMER_SOFTIRQ", + "RCU_SOFTIRQ" +}; + /* * we cannot loop indefinitely here to avoid userspace starvation, * but we also don't want to introduce a worst case 1/HZ latency @@ -209,9 +215,10 @@ restart: h->action(h); if (unlikely(prev_count != preempt_count())) { - printk(KERN_ERR "huh, entered softirq %td %p" + printk(KERN_ERR "huh, entered softirq %td %s %p" "with preempt_count %08x," " exited with %08x?\n", h - softirq_vec, + softirq_to_name[h - softirq_vec], h->action, prev_count, preempt_count()); preempt_count() = prev_count; } -- cgit v1.2.3