From 29ad23b00474c34e3b5040dda508c78d33a1a3eb Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Mon, 14 Oct 2013 17:24:26 +0900 Subject: ftrace: Add set_graph_notrace filter The set_graph_notrace filter is analogous to set_ftrace_notrace and can be used for eliminating uninteresting part of function graph trace output. It also works with set_graph_function nicely. # cd /sys/kernel/debug/tracing/ # echo do_page_fault > set_graph_function # perf ftrace live true 2) | do_page_fault() { 2) | __do_page_fault() { 2) 0.381 us | down_read_trylock(); 2) 0.055 us | __might_sleep(); 2) 0.696 us | find_vma(); 2) | handle_mm_fault() { 2) | handle_pte_fault() { 2) | __do_fault() { 2) | filemap_fault() { 2) | find_get_page() { 2) 0.033 us | __rcu_read_lock(); 2) 0.035 us | __rcu_read_unlock(); 2) 1.696 us | } 2) 0.031 us | __might_sleep(); 2) 2.831 us | } 2) | _raw_spin_lock() { 2) 0.046 us | add_preempt_count(); 2) 0.841 us | } 2) 0.033 us | page_add_file_rmap(); 2) | _raw_spin_unlock() { 2) 0.057 us | sub_preempt_count(); 2) 0.568 us | } 2) | unlock_page() { 2) 0.084 us | page_waitqueue(); 2) 0.126 us | __wake_up_bit(); 2) 1.117 us | } 2) 7.729 us | } 2) 8.397 us | } 2) 8.956 us | } 2) 0.085 us | up_read(); 2) + 12.745 us | } 2) + 13.401 us | } ... # echo handle_mm_fault > set_graph_notrace # perf ftrace live true 1) | do_page_fault() { 1) | __do_page_fault() { 1) 0.205 us | down_read_trylock(); 1) 0.041 us | __might_sleep(); 1) 0.344 us | find_vma(); 1) 0.069 us | up_read(); 1) 4.692 us | } 1) 5.311 us | } ... Link: http://lkml.kernel.org/r/1381739066-7531-5-git-send-email-namhyung@kernel.org Signed-off-by: Namhyung Kim Signed-off-by: Steven Rostedt --- kernel/trace/trace_functions_graph.c | 56 ++++++++++++++++++++++++++++++++++-- 1 file changed, 53 insertions(+), 3 deletions(-) (limited to 'kernel/trace/trace_functions_graph.c') diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index b5c09242683d..e08c030b8f38 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -114,16 +114,37 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth, return -EBUSY; } + /* + * The curr_ret_stack is an index to ftrace return stack of + * current task. Its value should be in [0, FTRACE_RETFUNC_ + * DEPTH) when the function graph tracer is used. To support + * filtering out specific functions, it makes the index + * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH) + * so when it sees a negative index the ftrace will ignore + * the record. And the index gets recovered when returning + * from the filtered function by adding the FTRACE_NOTRACE_ + * DEPTH and then it'll continue to record functions normally. + * + * The curr_ret_stack is initialized to -1 and get increased + * in this function. So it can be less than -1 only if it was + * filtered out via ftrace_graph_notrace_addr() which can be + * set from set_graph_notrace file in debugfs by user. + */ + if (current->curr_ret_stack < -1) + return -EBUSY; + calltime = trace_clock_local(); index = ++current->curr_ret_stack; + if (ftrace_graph_notrace_addr(func)) + current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH; barrier(); current->ret_stack[index].ret = ret; current->ret_stack[index].func = func; current->ret_stack[index].calltime = calltime; current->ret_stack[index].subtime = 0; current->ret_stack[index].fp = frame_pointer; - *depth = index; + *depth = current->curr_ret_stack; return 0; } @@ -137,7 +158,17 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret, index = current->curr_ret_stack; - if (unlikely(index < 0)) { + /* + * A negative index here means that it's just returned from a + * notrace'd function. Recover index to get an original + * return address. See ftrace_push_return_trace(). + * + * TODO: Need to check whether the stack gets corrupted. + */ + if (index < 0) + index += FTRACE_NOTRACE_DEPTH; + + if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) { ftrace_graph_stop(); WARN_ON(1); /* Might as well panic, otherwise we have no where to go */ @@ -193,6 +224,15 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer) trace.rettime = trace_clock_local(); barrier(); current->curr_ret_stack--; + /* + * The curr_ret_stack can be less than -1 only if it was + * filtered out and it's about to return from the function. + * Recover the index and continue to trace normal functions. + */ + if (current->curr_ret_stack < -1) { + current->curr_ret_stack += FTRACE_NOTRACE_DEPTH; + return ret; + } /* * The trace should run after decrementing the ret counter @@ -259,10 +299,20 @@ int trace_graph_entry(struct ftrace_graph_ent *trace) /* trace it when it is-nested-in or is a function enabled. */ if ((!(trace->depth || ftrace_graph_addr(trace->func)) || - ftrace_graph_ignore_irqs()) || + ftrace_graph_ignore_irqs()) || (trace->depth < 0) || (max_depth && trace->depth >= max_depth)) return 0; + /* + * Do not trace a function if it's filtered by set_graph_notrace. + * Make the index of ret stack negative to indicate that it should + * ignore further functions. But it needs its own ret stack entry + * to recover the original index in order to continue tracing after + * returning from the function. + */ + if (ftrace_graph_notrace_addr(trace->func)) + return 1; + local_irq_save(flags); cpu = raw_smp_processor_id(); data = per_cpu_ptr(tr->trace_buffer.data, cpu); -- cgit v1.2.3 From f306cc82a93d6b19f01634b80c580b9755c8b7cc Mon Sep 17 00:00:00 2001 From: Tom Zanussi Date: Thu, 24 Oct 2013 08:34:17 -0500 Subject: tracing: Update event filters for multibuffer The trace event filters are still tied to event calls rather than event files, which means you don't get what you'd expect when using filters in the multibuffer case: Before: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 2048 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 Setting the filter in tracing/instances/test1/events shouldn't affect the same event in tracing/events as it does above. After: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 We'd like to just move the filter directly from ftrace_event_call to ftrace_event_file, but there are a couple cases that don't yet have multibuffer support and therefore have to continue using the current event_call-based filters. For those cases, a new USE_CALL_FILTER bit is added to the event_call flags, whose main purpose is to keep the old behavior for those cases until they can be updated with multibuffer support; at that point, the USE_CALL_FILTER flag (and the new associated call_filter_check_discard() function) can go away. The multibuffer support also made filter_current_check_discard() redundant, so this change removes that function as well and replaces it with filter_check_discard() (or call_filter_check_discard() as appropriate). Link: http://lkml.kernel.org/r/f16e9ce4270c62f46b2e966119225e1c3cca7e60.1382620672.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt --- kernel/trace/trace_functions_graph.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/trace/trace_functions_graph.c') diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index e08c030b8f38..80387d1d27e1 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -270,7 +270,7 @@ int __trace_graph_entry(struct trace_array *tr, return 0; entry = ring_buffer_event_data(event); entry->graph_ent = *trace; - if (!filter_current_check_discard(buffer, call, entry, event)) + if (!call_filter_check_discard(call, entry, buffer, event)) __buffer_unlock_commit(buffer, event); return 1; @@ -385,7 +385,7 @@ void __trace_graph_return(struct trace_array *tr, return; entry = ring_buffer_event_data(event); entry->ret = *trace; - if (!filter_current_check_discard(buffer, call, entry, event)) + if (!call_filter_check_discard(call, entry, buffer, event)) __buffer_unlock_commit(buffer, event); } -- cgit v1.2.3 From 6fc84ea70eae478099c866ace022ecfdef998032 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 6 Nov 2013 14:50:06 -0500 Subject: tracing: Do not use signed enums with unsigned long long in fgragh output The duration field of print_graph_duration() can also be used to do the space filling by passing an enum in it: DURATION_FILL_FULL DURATION_FILL_START DURATION_FILL_END The problem is that these are enums and defined as negative, but the duration field is unsigned long long. Most archs are fine with this but blackfin fails to compile because of it: kernel/built-in.o: In function `print_graph_duration': kernel/trace/trace_functions_graph.c:782: undefined reference to `__ucmpdi2' Overloading a unsigned long long with an signed enum is just bad in principle. We can accomplish the same thing by using part of the flags field instead. Cc: Mike Frysinger Cc: Frederic Weisbecker Signed-off-by: Steven Rostedt --- kernel/trace/trace_functions_graph.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) (limited to 'kernel/trace/trace_functions_graph.c') diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 80387d1d27e1..0b99120d395c 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -82,9 +82,9 @@ static struct trace_array *graph_array; * to fill in space into DURATION column. */ enum { - DURATION_FILL_FULL = -1, - DURATION_FILL_START = -2, - DURATION_FILL_END = -3, + FLAGS_FILL_FULL = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT, + FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT, + FLAGS_FILL_END = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT, }; static enum print_line_t @@ -702,7 +702,7 @@ print_graph_irq(struct trace_iterator *iter, unsigned long addr, } /* No overhead */ - ret = print_graph_duration(DURATION_FILL_START, s, flags); + ret = print_graph_duration(0, s, flags | FLAGS_FILL_START); if (ret != TRACE_TYPE_HANDLED) return ret; @@ -714,7 +714,7 @@ print_graph_irq(struct trace_iterator *iter, unsigned long addr, if (!ret) return TRACE_TYPE_PARTIAL_LINE; - ret = print_graph_duration(DURATION_FILL_END, s, flags); + ret = print_graph_duration(0, s, flags | FLAGS_FILL_END); if (ret != TRACE_TYPE_HANDLED) return ret; @@ -779,14 +779,14 @@ print_graph_duration(unsigned long long duration, struct trace_seq *s, return TRACE_TYPE_HANDLED; /* No real adata, just filling the column with spaces */ - switch (duration) { - case DURATION_FILL_FULL: + switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) { + case FLAGS_FILL_FULL: ret = trace_seq_puts(s, " | "); return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; - case DURATION_FILL_START: + case FLAGS_FILL_START: ret = trace_seq_puts(s, " "); return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; - case DURATION_FILL_END: + case FLAGS_FILL_END: ret = trace_seq_puts(s, " |"); return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; } @@ -902,7 +902,7 @@ print_graph_entry_nested(struct trace_iterator *iter, } /* No time */ - ret = print_graph_duration(DURATION_FILL_FULL, s, flags); + ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL); if (ret != TRACE_TYPE_HANDLED) return ret; @@ -1222,7 +1222,7 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent, return TRACE_TYPE_PARTIAL_LINE; /* No time */ - ret = print_graph_duration(DURATION_FILL_FULL, s, flags); + ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL); if (ret != TRACE_TYPE_HANDLED) return ret; -- cgit v1.2.3