user/sven/linux.git/include/linux/trace_seq.h, branch v3.18.104

tracing: Add trace_seq_buffer_ptr() helper function

2014-07-01T11:13:39Z

There's several locations in the kernel that open code the calculation of the next location in the trace_seq buffer. This is usually done with p->buffer + p->len Instead of having this open coded, supply a helper function in the header to do it for them. This function is called trace_seq_buffer_ptr(). Link: http://lkml.kernel.org/p/20140626220129.452783019@goodmis.org Acked-by: Paolo Bonzini Signed-off-by: Steven Rostedt

tracing: Remove trace_seq_reserve()

2014-07-01T11:13:37Z

trace_seq_reserve() has no users in the kernel, it just wastes space. Remove it. Cc: Eduard - Gabriel Munteanu Signed-off-by: Steven Rostedt

tracing: Make trace_seq_putmem_hex() more robust

2014-07-01T11:13:37Z

Currently trace_seq_putmem_hex() can only take as a parameter a pointer to something that is 8 bytes or less, otherwise it will overflow the buffer. This is protected by a macro that encompasses the call to trace_seq_putmem_hex() that has a BUILD_BUG_ON() for the variable before it is passed in. This is not very robust and if trace_seq_putmem_hex() ever gets used outside that macro it will cause issues. Instead of only being able to produce a hex output of memory that is for a single word, change it to be more robust and allow any size input. Signed-off-by: Steven Rostedt

tracing: Clean up trace_seq.c

2014-07-01T11:13:36Z

For using trace_seq_*() functions in NMI context, I posted a patch to move it to the lib/ directory. This caused Andrew Morton to take a look at the code. He went through and gave a lot of comments about missing kernel doc, inconsistent types for the save variable, mix match of EXPORT_SYMBOL_GPL() and EXPORT_SYMBOL() as well as missing EXPORT_SYMBOL*()s. There were a few comments about the way variables were being compared (int vs uint). All these were good review comments and should be implemented regardless of if trace_seq.c should be moved to lib/ or not. Signed-off-by: Steven Rostedt

tracing: Move the trace_seq_* functions into its own trace_seq.c file

2014-07-01T11:13:35Z

The trace_seq_*() functions are a nice utility that allows users to manipulate buffers with printf() like formats. It has its own trace_seq.h header in include/linux and should be in its own file. Being tied with trace_output.c is rather awkward. Signed-off-by: Steven Rostedt

tracing: Add __bitmask() macro to trace events to cpumasks and other bitmasks

2014-05-15T15:29:37Z

Being able to show a cpumask of events can be useful as some events may affect only some CPUs. There is no standard way to record the cpumask and converting it to a string is rather expensive during the trace as traces happen in hotpaths. It would be better to record the raw event mask and be able to parse it at print time. The following macros were added for use with the TRACE_EVENT() macro: __bitmask() __assign_bitmask() __get_bitmask() To test this, I added this to the sched_migrate_task event, which looked like this: TRACE_EVENT(sched_migrate_task, TP_PROTO(struct task_struct *p, int dest_cpu, const struct cpumask *cpus), TP_ARGS(p, dest_cpu, cpus), TP_STRUCT__entry( __array( char, comm, TASK_COMM_LEN ) __field( pid_t, pid ) __field( int, prio ) __field( int, orig_cpu ) __field( int, dest_cpu ) __bitmask( cpumask, num_possible_cpus() ) ), TP_fast_assign( memcpy(__entry->comm, p->comm, TASK_COMM_LEN); __entry->pid = p->pid; __entry->prio = p->prio; __entry->orig_cpu = task_cpu(p); __entry->dest_cpu = dest_cpu; __assign_bitmask(cpumask, cpumask_bits(cpus), num_possible_cpus()); ), TP_printk("comm=%s pid=%d prio=%d orig_cpu=%d dest_cpu=%d cpumask=%s", __entry->comm, __entry->pid, __entry->prio, __entry->orig_cpu, __entry->dest_cpu, __get_bitmask(cpumask)) ); With the output of: ksmtuned-3613 [003] d..2 485.220508: sched_migrate_task: comm=ksmtuned pid=3615 prio=120 orig_cpu=3 dest_cpu=2 cpumask=00000000,0000000f migration/1-13 [001] d..5 485.221202: sched_migrate_task: comm=ksmtuned pid=3614 prio=120 orig_cpu=1 dest_cpu=0 cpumask=00000000,0000000f awk-3615 [002] d.H5 485.221747: sched_migrate_task: comm=rcu_preempt pid=7 prio=120 orig_cpu=0 dest_cpu=1 cpumask=00000000,000000ff migration/2-18 [002] d..5 485.222062: sched_migrate_task: comm=ksmtuned pid=3615 prio=120 orig_cpu=2 dest_cpu=3 cpumask=00000000,0000000f Link: http://lkml.kernel.org/r/1399377998-14870-6-git-send-email-javi.merino@arm.com Link: http://lkml.kernel.org/r/20140506132238.22e136d1@gandalf.local.home Suggested-by: Javi Merino Tested-by: Javi Merino Signed-off-by: Steven Rostedt

constify path argument of trace_seq_path()

2012-03-21T01:29:40Z

Signed-off-by: Al Viro

treewide: use printf not attribute__((format(printf,...)))

2011-11-01T00:30:54Z

Standardize the style for compiler based printf format verification. Standardized the location of __printf too. Done via script and a little typing. $ grep -rPl --include=*.[ch] -w "__attribute__" * | \ grep -vP "^(tools|scripts|include/linux/compiler-gcc.h)" | \ xargs perl -n -i -e 'local $/; while (<>) { s/\b__attribute__\s*$\s*\(\s*format\s*\(\s*printf\s*,\s*(.+)\s*,\s*(.+)\s*$\s*\)\s*\)/__printf($1, $2)/g ; print; }' [akpm@linux-foundation.org: revert arch bits] Signed-off-by: Joe Perches Cc: "Kirill A. Shutemov" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

tracing: Add full state to trace_seq

2009-12-09T19:05:49Z

The trace_seq buffer might fill up, and right now one needs to check the return value of each printf into the buffer to check for that. Instead, have the buffer keep track of whether it is full or not, and reject more input if it is full or would have overflowed with an input that wasn't added. Cc: Lai Jiangshan Signed-off-by: Johannes Berg Signed-off-by: Steven Rostedt

tracing: Buffer the output of seq_file in case of filled buffer

2009-12-09T18:55:26Z

If the seq_read fills the buffer it will call s_start again on the next itertation with the same position. This causes a problem with the function_graph tracer because it consumes the iteration in order to determine leaf functions. What happens is that the iterator stores the entry, and the function graph plugin will look at the next entry. If that next entry is a return of the same function and task, then the function is a leaf and the function_graph plugin calls ring_buffer_read which moves the ring buffer iterator forward (the trace iterator still points to the function start entry). The copying of the trace_seq to the seq_file buffer will fail if the seq_file buffer is full. The seq_read will not show this entry. The next read by userspace will cause seq_read to again call s_start which will reuse the trace iterator entry (the function start entry). But the function return entry was already consumed. The function graph plugin will think that this entry is a nested function and not a leaf. To solve this, the trace code now checks the return status of the seq_printf (trace_print_seq). If the writing to the seq_file buffer fails, we set a flag in the iterator (leftover) and we do not reset the trace_seq buffer. On the next call to s_start, we check the leftover flag, and if it is set, we just reuse the trace_seq buffer and do not call into the plugin print functions. Before this patch: 2) | fput() { 2) | __fput() { 2) 0.550 us | inotify_inode_queue_event(); 2) | __fsnotify_parent() { 2) 0.540 us | inotify_dentry_parent_queue_event(); After the patch: 2) | fput() { 2) | __fput() { 2) 0.550 us | inotify_inode_queue_event(); 2) 0.548 us | __fsnotify_parent(); 2) 0.540 us | inotify_dentry_parent_queue_event(); [ Updated the patch to fix a missing return 0 from the trace_print_seq() stub when CONFIG_TRACING is disabled. Reported-by: Ingo Molnar ] Reported-by: Jiri Olsa Cc: Frederic Weisbecker Signed-off-by: Steven Rostedt