1bc191051d
- New user_events interface. User space can register an event with the kernel describing the format of the event. Then it will receive a byte in a page mapping that it can check against. A privileged task can then enable that event like any other event, which will change the mapped byte to true, telling the user space application to start writing the event to the tracing buffer. - Add new "ftrace_boot_snapshot" kernel command line parameter. When set, the tracing buffer will be saved in the snapshot buffer at boot up when the kernel hands things over to user space. This will keep the traces that happened at boot up available even if user space boot up has tracing as well. - Have TRACE_EVENT_ENUM() also update trace event field type descriptions. Thus if a static array defines its size with an enum, the user space trace event parsers can still know how to parse that array. - Add new TRACE_CUSTOM_EVENT() macro. This acts the same as the TRACE_EVENT() macro, but will attach to an existing tracepoint. This will make one tracepoint be able to trace different content and not be stuck at only what the original TRACE_EVENT() macro exports. - Fixes to tracing error logging. - Better saving of cmdlines to PIDs when tracing (use the wakeup events for mapping). -----BEGIN PGP SIGNATURE----- iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCYjiO3RQccm9zdGVkdEBn b29kbWlzLm9yZwAKCRAp5XQQmuv6qhQzAQDtek5p80p/zkMGymm14wSH6qq0NdgN Kv7fTBwEewUa0gD/UCOVLw4Oj+JtHQhCa3sCGZopmRv0BT1+4UQANqosKQY= =Au08 -----END PGP SIGNATURE----- Merge tag 'trace-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from Steven Rostedt: - New user_events interface. User space can register an event with the kernel describing the format of the event. Then it will receive a byte in a page mapping that it can check against. A privileged task can then enable that event like any other event, which will change the mapped byte to true, telling the user space application to start writing the event to the tracing buffer. - Add new "ftrace_boot_snapshot" kernel command line parameter. When set, the tracing buffer will be saved in the snapshot buffer at boot up when the kernel hands things over to user space. This will keep the traces that happened at boot up available even if user space boot up has tracing as well. - Have TRACE_EVENT_ENUM() also update trace event field type descriptions. Thus if a static array defines its size with an enum, the user space trace event parsers can still know how to parse that array. - Add new TRACE_CUSTOM_EVENT() macro. This acts the same as the TRACE_EVENT() macro, but will attach to an existing tracepoint. This will make one tracepoint be able to trace different content and not be stuck at only what the original TRACE_EVENT() macro exports. - Fixes to tracing error logging. - Better saving of cmdlines to PIDs when tracing (use the wakeup events for mapping). * tag 'trace-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (30 commits) tracing: Have type enum modifications copy the strings user_events: Add trace event call as root for low permission cases tracing/user_events: Use alloc_pages instead of kzalloc() for register pages tracing: Add snapshot at end of kernel boot up tracing: Have TRACE_DEFINE_ENUM affect trace event types as well tracing: Fix strncpy warning in trace_events_synth.c user_events: Prevent dyn_event delete racing with ioctl add/delete tracing: Add TRACE_CUSTOM_EVENT() macro tracing: Move the defines to create TRACE_EVENTS into their own files tracing: Add sample code for custom trace events tracing: Allow custom events to be added to the tracefs directory tracing: Fix last_cmd_set() string management in histogram code user_events: Fix potential uninitialized pointer while parsing field tracing: Fix allocation of last_cmd in last_cmd_set() user_events: Add documentation file user_events: Add sample code for typical usage user_events: Add self-test for validator boundaries user_events: Add self-test for perf_event integration user_events: Add self-test for dynamic_events integration user_events: Add self-test for ftrace integration ...
97 lines
2.4 KiB
C
97 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Like the headers that use TRACE_EVENT(), the TRACE_CUSTOM_EVENT()
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* needs a header that allows for multiple inclusions.
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*
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* Test for a unique name (here we have _TRACE_CUSTOM_SCHED_H),
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* also allowing to continue if TRACE_CUSTOM_MULTI_READ is defined.
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*/
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#if !defined(_TRACE_CUSTOM_SCHED_H) || defined(TRACE_CUSTOM_MULTI_READ)
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#define _TRACE_CUSTOM_SCHED_H
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/* Include linux/trace_events.h for initial defines of TRACE_CUSTOM_EVENT() */
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#include <linux/trace_events.h>
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/*
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* TRACE_CUSTOM_EVENT() is just like TRACE_EVENT(). The first parameter
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* is the event name of an existing event where the TRACE_EVENT has been included
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* in the C file before including this file.
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*/
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TRACE_CUSTOM_EVENT(sched_switch,
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/*
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* The TP_PROTO() and TP_ARGS must match the trace event
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* that the custom event is using.
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*/
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TP_PROTO(bool preempt,
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unsigned int prev_state,
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struct task_struct *prev,
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struct task_struct *next),
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TP_ARGS(preempt, prev_state, prev, next),
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/*
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* The next fields are where the customization happens.
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* The TP_STRUCT__entry() defines what will be recorded
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* in the ring buffer when the custom event triggers.
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*
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* The rest is just like the TRACE_EVENT() macro except that
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* it uses the custom entry.
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*/
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TP_STRUCT__entry(
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__field( unsigned short, prev_prio )
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__field( unsigned short, next_prio )
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__field( pid_t, next_pid )
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),
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TP_fast_assign(
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__entry->prev_prio = prev->prio;
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__entry->next_pid = next->pid;
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__entry->next_prio = next->prio;
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),
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TP_printk("prev_prio=%d next_pid=%d next_prio=%d",
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__entry->prev_prio, __entry->next_pid, __entry->next_prio)
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)
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TRACE_CUSTOM_EVENT(sched_waking,
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TP_PROTO(struct task_struct *p),
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TP_ARGS(p),
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TP_STRUCT__entry(
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__field( pid_t, pid )
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__field( unsigned short, prio )
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),
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TP_fast_assign(
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__entry->pid = p->pid;
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__entry->prio = p->prio;
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),
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TP_printk("pid=%d prio=%d", __entry->pid, __entry->prio)
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)
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#endif
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/*
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* Just like the headers that create TRACE_EVENTs, the below must
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* be outside the protection of the above #if block.
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*/
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/*
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* It is required that the Makefile includes:
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* CFLAGS_<c_file>.o := -I$(src)
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*/
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#undef TRACE_INCLUDE_PATH
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#undef TRACE_INCLUDE_FILE
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#define TRACE_INCLUDE_PATH .
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/*
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* It is requred that the TRACE_INCLUDE_FILE be the same
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* as this file without the ".h".
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*/
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#define TRACE_INCLUDE_FILE trace_custom_sched
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#include <trace/define_custom_trace.h>
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