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bcef044150
linux/kernel/trace
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Kalesh Singh bcef044150 tracing: Add division and multiplication support for hist triggers 
Adds basic support for division and multiplication operations for
hist trigger variable expressions.

For simplicity this patch only supports, division and multiplication
for a single operation expression (e.g. x=$a/$b), as currently
expressions are always evaluated right to left. This can lead to some
incorrect results:

	e.g. echo 'hist:keys=common_pid:x=8-4-2' >> event/trigger

	     8-4-2 should evaluate to 2 i.e. (8-4)-2
	     but currently x evaluate to  6 i.e. 8-(4-2)

Multiplication and division in sub-expressions will work correctly, once
correct operator precedence support is added (See next patch in this
series).

For the undefined case of division by 0, the histogram expression
evaluates to (u64)(-1). Since this cannot be detected when the
expression is created, it is the responsibility of the user to be
aware and account for this possibility.

Examples:
	echo 'hist:keys=common_pid:a=8,b=4,x=$a/$b' \
                   >> event/trigger

	echo 'hist:keys=common_pid:y=5*$b' \
                   >> event/trigger

Link: https://lkml.kernel.org/r/20211025200852.3002369-3-kaleshsingh@google.com

Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-10-26 20:27:19 -04:00
..
blktrace.c blktrace: Fix uaf in blk_trace access after removing by sysfs 2021-09-24 11:06:15 -06:00
bpf_trace.c bpf: Fix bpf-next builds without CONFIG_BPF_EVENTS 2021-08-25 19:41:39 -07:00
bpf_trace.h
error_report-traces.c tracing: add error_report_end trace point 2021-02-26 09:41:02 -08:00
fgraph.c x86/ftrace: Make function graph use ftrace directly 2021-10-20 23:44:43 -04:00
ftrace_internal.h
ftrace.c ftrace: Make ftrace_profile_pages_init static 2021-10-25 22:27:07 -04:00
Kconfig tracing: Simplify the Kconfig dependency of FTRACE 2021-08-16 11:37:20 -04:00
kprobe_event_gen_test.c
Makefile tracing: Place trace_pid_list logic into abstract functions 2021-10-05 17:30:08 -04:00
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_benchmark.c
ring_buffer.c tracing/perf: Add interrupt_context_level() helper 2021-10-19 20:33:20 -04:00
rpm-traces.c
synth_event_gen_test.c tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
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 tracing: Fix some alloc_event_probe() error handling bugs 2021-09-07 20:58:23 -04:00
trace_event_perf.c tracing: Have dynamic events have a ref counter 2021-08-18 18:13:47 -04:00
trace_events_filter_test.h
trace_events_filter.c tracing: Update create_system_filter() kernel-doc comment 2021-03-25 16:04:35 -04:00
trace_events_hist.c tracing: Add division and multiplication support for hist triggers 2021-10-26 20:27:19 -04:00
trace_events_inject.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_events_synth.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_events_trigger.c tracing: Add a probe that attaches to trace events 2021-08-20 14:18:40 -04:00
trace_events.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_export.c tracing: Fix some typos in comments 2020-11-10 20:39:40 -05:00
trace_functions_graph.c tracing: in_irq() cleanup 2021-10-13 18:19:41 -04:00
trace_functions.c tracing: Add "func_no_repeats" option for function tracing 2021-04-15 14:50:02 -04:00
trace_hwlat.c tracing/hwlat: Make some internal symbols static 2021-10-26 09:18:28 -04:00
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_selftest.c
trace_kprobe_selftest.h
trace_kprobe.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
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 trace/timerlat: Add migrate-disabled field to the timerlat header 2021-10-25 23:02:36 -04:00
trace_output.c tracing: Show kretprobe unknown indicator only for kretprobe_trampoline 2021-09-30 21:24:08 -04:00
trace_output.h ftrace: Add recording of functions that caused recursion 2020-11-06 08:42:26 -05:00
trace_preemptirq.c
trace_printk.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
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_probe.c tracing: Add a probe that attaches to trace events 2021-08-20 14:18:40 -04:00
trace_probe.h tracing: Add a probe that attaches to trace events 2021-08-20 14:18:40 -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
trace_sched_wakeup.c tracing: Change variable type as bool for clean-up 2021-06-30 09:19:14 -04:00
trace_selftest_dynamic.c
trace_selftest.c tracing: Fix selftest config check for function graph start up test 2021-10-21 14:18:48 -04:00
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: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_uprobe.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace.h tracing: in_irq() cleanup 2021-10-13 18:19:41 -04:00
tracing_map.c tracing/cfi: Fix cmp_entries_* functions signature mismatch 2021-10-19 20:33:20 -04:00
tracing_map.h tracing: Fix some typos in comments 2020-11-10 20:39:40 -05:00