linux/kernel/trace
Christophe Leroy 18bfee3216 ftrace: Make ftrace_graph_is_dead() a static branch
ftrace_graph_is_dead() is used on hot paths, it just reads a variable
in memory and is not worth suffering function call constraints.

For instance, at entry of prepare_ftrace_return(), inlining it avoids
saving prepare_ftrace_return() parameters to stack and restoring them
after calling ftrace_graph_is_dead().

While at it using a static branch is even more performant and is
rather well adapted considering that the returned value will almost
never change.

Inline ftrace_graph_is_dead() and replace 'kill_ftrace_graph' bool
by a static branch.

The performance improvement is noticeable.

Link: https://lkml.kernel.org/r/e0411a6a0ed3eafff0ad2bc9cd4b0e202b4617df.1648623570.git.christophe.leroy@csgroup.eu

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-02 08:40:09 -04:00
..
blktrace.c blktrace: fix use after free for struct blk_trace 2022-02-28 06:36:33 -07:00
bpf_trace.c bpf: Add MEM_RDONLY for helper args that are pointers to rdonly mem. 2021-12-18 13:27:41 -08:00
bpf_trace.h bpf: Use dedicated bpf_trace_printk event instead of trace_printk() 2020-07-13 16:55:49 -07:00
error_report-traces.c tracing: add error_report_end trace point 2021-02-26 09:41:02 -08:00
fgraph.c ftrace: Make ftrace_graph_is_dead() a static branch 2022-04-02 08:40:09 -04:00
ftrace.c Tracing updates for 5.18: 2022-03-23 11:40:25 -07:00
ftrace_internal.h
Kconfig tracing: Set user_events to BROKEN 2022-04-02 08:40:09 -04:00
kprobe_event_gen_test.c
Makefile user_events: Add minimal support for trace_event into ftrace 2022-02-10 22:36:46 -05:00
pid_list.c tracing: Initialize upper and lower vars in pid_list_refill_irq() 2021-10-07 09:56:38 -04:00
pid_list.h tracing: Create a sparse bitmask for pid filtering 2021-10-05 17:38:45 -04:00
power-traces.c
preemptirq_delay_test.c kernel: trace: preemptirq_delay_test: add cpu affinity 2021-02-02 17:02:07 -05:00
ring_buffer.c ring-buffer: make use of the helper function kthread_run_on_cpu() 2022-01-15 16:30:23 +02:00
ring_buffer_benchmark.c sched,tracing: Convert to sched_set_fifo() 2020-07-29 11:43:53 +02:00
rpm-traces.c
synth_event_gen_test.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace.c Tracing updates for 5.18: 2022-03-23 11:40:25 -07:00
trace.h Tracing updates for 5.18: 2022-03-23 11:40:25 -07:00
trace_benchmark.c tracing: Fix some typos in comments 2020-11-10 20:39:40 -05:00
trace_benchmark.h
trace_boot.c tracing: Fix missing trace_boot_init_histograms kstrdup NULL checks 2021-10-26 09:18:10 -04:00
trace_branch.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_clock.c tracing: Do no increment trace_clock_global() by one 2021-06-18 09:10:00 -04:00
trace_dynevent.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_dynevent.h tracing: Add DYNAMIC flag for dynamic events 2021-08-18 18:10:32 -04:00
trace_entries.h trace: Add timerlat tracer 2021-06-25 19:57:24 -04:00
trace_eprobe.c eprobes: Remove redundant event type information 2022-02-25 12:07:01 -05:00
trace_event_perf.c tracing: Show size of requested perf buffer 2021-10-27 12:25:09 -04:00
trace_events.c Tracing updates for 5.18: 2022-03-23 11:40:25 -07:00
trace_events_filter.c tracing: Add ustring operation to filtering string pointers 2022-01-14 03:42:24 -05:00
trace_events_filter_test.h
trace_events_hist.c Tracing updates for 5.18: 2022-03-23 11:40:25 -07:00
trace_events_inject.c tracing: Support __rel_loc relative dynamic data location attribute 2021-12-06 15:37:21 -05:00
trace_events_synth.c tracing: Fix strncpy warning in trace_events_synth.c 2022-03-11 11:49:24 -05:00
trace_events_trigger.c tracing: Uninline trace_trigger_soft_disabled() partly 2022-02-25 12:07:01 -05:00
trace_events_user.c tracing/user_events: Remove eBPF interfaces 2022-04-02 08:40:09 -04:00
trace_export.c tracing: Fix some typos in comments 2020-11-10 20:39:40 -05:00
trace_functions.c ftrace: disable preemption when recursion locked 2021-10-27 11:21:49 -04:00
trace_functions_graph.c tracing: in_irq() cleanup 2021-10-13 18:19:41 -04:00
trace_hwlat.c trace/hwlat: make use of the helper function kthread_run_on_cpu() 2022-01-15 16:30:24 +02:00
trace_irqsoff.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_kdb.c kdb: Rename members of struct kdbtab_t 2021-07-27 17:05:06 +01:00
trace_kprobe.c tracing: Fix return value of __setup handlers 2022-03-04 13:46:13 -05:00
trace_kprobe_selftest.c
trace_kprobe_selftest.h
trace_mmiotrace.c tracing: Remove definition of DEBUG in trace_mmiotrace.c 2021-02-02 17:02:07 -05:00
trace_nop.c
trace_osnoise.c Linux 5.17-rc8 2022-03-15 10:28:12 +01:00
trace_output.c tracing: Account bottom half disabled sections. 2022-01-13 16:23:04 -05:00
trace_output.h ftrace: Add recording of functions that caused recursion 2020-11-06 08:42:26 -05:00
trace_preemptirq.c lockdep: fix order in trace_hardirqs_off_caller() 2020-09-14 10:08:07 +02:00
trace_printk.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_probe.c eprobes: Remove redundant event type information 2022-02-25 12:07:01 -05:00
trace_probe.h eprobes: Remove redundant event type information 2022-02-25 12:07:01 -05:00
trace_probe_tmpl.h tracing/probes: Have process_fetch_insn() take a void * instead of pt_regs 2021-08-19 09:09:03 -04:00
trace_recursion_record.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_sched_switch.c Tracing updates for 5.18: 2022-03-23 11:40:25 -07:00
trace_sched_wakeup.c sched/tracing: Don't re-read p->state when emitting sched_switch event 2022-03-01 16:18:39 +01:00
trace_selftest.c tracing: Fix selftest config check for function graph start up test 2022-02-25 21:05:29 -05:00
trace_selftest_dynamic.c
trace_seq.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
trace_stack.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_stat.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_stat.h
trace_synth.h tracing: synth events: increase max fields count 2021-09-08 15:29:16 -04:00
trace_syscalls.c tracing: Have syscall trace events use trace_event_buffer_lock_reserve() 2022-01-13 16:23:05 -05:00
trace_uprobe.c Tracing updates for 5.17: 2022-01-16 10:15:32 +02:00
tracing_map.c tracing: Fix a kmemleak false positive in tracing_map 2021-12-01 21:04:34 -05:00
tracing_map.h tracing: Fix some typos in comments 2020-11-10 20:39:40 -05:00