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![Masami Hiramatsu](/assets/img/avatar_default.png)
Trace a magic number as immediate value if the target variable is not found at some probe points which is based on one probe event. This feature is good for the case if you trace a source code line with some local variables, which is compiled into several instructions and some of the variables are optimized out on some instructions. Even if so, with this feature, perf probe trace a magic number instead of such disappeared variables and fold those probes on one event. E.g. without this patch: # perf probe -D "pud_page_vaddr pud" Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. Failed to find 'pud' in this function. p:probe/pud_page_vaddr _text+23480787 pud=%ax:x64 p:probe/pud_page_vaddr _text+23808453 pud=%bp:x64 p:probe/pud_page_vaddr _text+23558082 pud=%ax:x64 p:probe/pud_page_vaddr _text+328373 pud=%r8:x64 p:probe/pud_page_vaddr _text+348448 pud=%bx:x64 p:probe/pud_page_vaddr _text+23816818 pud=%bx:x64 With this patch: # perf probe -D "pud_page_vaddr pud" | head spurious_kernel_fault is blacklisted function, skip it. vmalloc_fault is blacklisted function, skip it. p:probe/pud_page_vaddr _text+23480787 pud=%ax:x64 p:probe/pud_page_vaddr _text+149051 pud=\deade12d:x64 p:probe/pud_page_vaddr _text+23808453 pud=%bp:x64 p:probe/pud_page_vaddr _text+315926 pud=\deade12d:x64 p:probe/pud_page_vaddr _text+23807209 pud=\deade12d:x64 p:probe/pud_page_vaddr _text+23557365 pud=%ax:x64 p:probe/pud_page_vaddr _text+314097 pud=%di:x64 p:probe/pud_page_vaddr _text+314015 pud=\deade12d:x64 p:probe/pud_page_vaddr _text+313893 pud=\deade12d:x64 p:probe/pud_page_vaddr _text+324083 pud=\deade12d:x64 Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Link: http://lore.kernel.org/lkml/157406476931.24476.6261475888681844285.stgit@devnote2 Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
200 lines
6.3 KiB
C
200 lines
6.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _PROBE_EVENT_H
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#define _PROBE_EVENT_H
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#include <linux/compiler.h>
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#include <stdbool.h>
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struct intlist;
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struct nsinfo;
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/* Probe related configurations */
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struct probe_conf {
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bool show_ext_vars;
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bool show_location_range;
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bool force_add;
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bool no_inlines;
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bool cache;
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int max_probes;
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unsigned long magic_num;
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};
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extern struct probe_conf probe_conf;
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extern bool probe_event_dry_run;
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#define DEFAULT_PROBE_MAGIC_NUM 0xdeade12d /* u32: 3735937325 */
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struct symbol;
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/* kprobe-tracer and uprobe-tracer tracing point */
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struct probe_trace_point {
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char *realname; /* function real name (if needed) */
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char *symbol; /* Base symbol */
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char *module; /* Module name */
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unsigned long offset; /* Offset from symbol */
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unsigned long ref_ctr_offset; /* SDT reference counter offset */
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unsigned long address; /* Actual address of the trace point */
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bool retprobe; /* Return probe flag */
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};
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/* probe-tracer tracing argument referencing offset */
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struct probe_trace_arg_ref {
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struct probe_trace_arg_ref *next; /* Next reference */
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long offset; /* Offset value */
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bool user_access; /* User-memory access */
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};
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/* kprobe-tracer and uprobe-tracer tracing argument */
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struct probe_trace_arg {
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char *name; /* Argument name */
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char *value; /* Base value */
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char *type; /* Type name */
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struct probe_trace_arg_ref *ref; /* Referencing offset */
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};
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/* kprobe-tracer and uprobe-tracer tracing event (point + arg) */
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struct probe_trace_event {
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char *event; /* Event name */
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char *group; /* Group name */
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struct probe_trace_point point; /* Trace point */
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int nargs; /* Number of args */
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bool uprobes; /* uprobes only */
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struct probe_trace_arg *args; /* Arguments */
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};
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/* Perf probe probing point */
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struct perf_probe_point {
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char *file; /* File path */
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char *function; /* Function name */
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int line; /* Line number */
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bool retprobe; /* Return probe flag */
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char *lazy_line; /* Lazy matching pattern */
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unsigned long offset; /* Offset from function entry */
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unsigned long abs_address; /* Absolute address of the point */
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};
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/* Perf probe probing argument field chain */
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struct perf_probe_arg_field {
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struct perf_probe_arg_field *next; /* Next field */
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char *name; /* Name of the field */
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long index; /* Array index number */
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bool ref; /* Referencing flag */
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};
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/* Perf probe probing argument */
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struct perf_probe_arg {
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char *name; /* Argument name */
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char *var; /* Variable name */
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char *type; /* Type name */
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struct perf_probe_arg_field *field; /* Structure fields */
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bool user_access; /* User-memory access */
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};
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/* Perf probe probing event (point + arg) */
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struct perf_probe_event {
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char *event; /* Event name */
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char *group; /* Group name */
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struct perf_probe_point point; /* Probe point */
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int nargs; /* Number of arguments */
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bool sdt; /* SDT/cached event flag */
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bool uprobes; /* Uprobe event flag */
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char *target; /* Target binary */
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struct perf_probe_arg *args; /* Arguments */
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struct probe_trace_event *tevs;
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int ntevs;
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struct nsinfo *nsi; /* Target namespace */
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};
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/* Line range */
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struct line_range {
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char *file; /* File name */
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char *function; /* Function name */
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int start; /* Start line number */
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int end; /* End line number */
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int offset; /* Start line offset */
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char *path; /* Real path name */
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char *comp_dir; /* Compile directory */
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struct intlist *line_list; /* Visible lines */
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};
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struct strlist;
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/* List of variables */
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struct variable_list {
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struct probe_trace_point point; /* Actual probepoint */
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struct strlist *vars; /* Available variables */
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};
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struct map;
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int init_probe_symbol_maps(bool user_only);
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void exit_probe_symbol_maps(void);
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/* Command string to events */
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int parse_perf_probe_command(const char *cmd, struct perf_probe_event *pev);
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int parse_probe_trace_command(const char *cmd, struct probe_trace_event *tev);
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/* Events to command string */
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char *synthesize_perf_probe_command(struct perf_probe_event *pev);
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char *synthesize_probe_trace_command(struct probe_trace_event *tev);
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char *synthesize_perf_probe_arg(struct perf_probe_arg *pa);
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char *synthesize_perf_probe_point(struct perf_probe_point *pp);
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int perf_probe_event__copy(struct perf_probe_event *dst,
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struct perf_probe_event *src);
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bool perf_probe_with_var(struct perf_probe_event *pev);
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/* Check the perf_probe_event needs debuginfo */
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bool perf_probe_event_need_dwarf(struct perf_probe_event *pev);
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/* Release event contents */
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void clear_perf_probe_event(struct perf_probe_event *pev);
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void clear_probe_trace_event(struct probe_trace_event *tev);
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/* Command string to line-range */
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int parse_line_range_desc(const char *cmd, struct line_range *lr);
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/* Release line range members */
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void line_range__clear(struct line_range *lr);
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/* Initialize line range */
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int line_range__init(struct line_range *lr);
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int add_perf_probe_events(struct perf_probe_event *pevs, int npevs);
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int convert_perf_probe_events(struct perf_probe_event *pevs, int npevs);
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int apply_perf_probe_events(struct perf_probe_event *pevs, int npevs);
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int show_probe_trace_events(struct perf_probe_event *pevs, int npevs);
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void cleanup_perf_probe_events(struct perf_probe_event *pevs, int npevs);
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struct strfilter;
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int del_perf_probe_events(struct strfilter *filter);
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int show_perf_probe_event(const char *group, const char *event,
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struct perf_probe_event *pev,
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const char *module, bool use_stdout);
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int show_perf_probe_events(struct strfilter *filter);
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int show_line_range(struct line_range *lr, const char *module,
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struct nsinfo *nsi, bool user);
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int show_available_vars(struct perf_probe_event *pevs, int npevs,
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struct strfilter *filter);
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int show_available_funcs(const char *module, struct nsinfo *nsi,
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struct strfilter *filter, bool user);
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void arch__fix_tev_from_maps(struct perf_probe_event *pev,
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struct probe_trace_event *tev, struct map *map,
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struct symbol *sym);
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/* If there is no space to write, returns -E2BIG. */
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int e_snprintf(char *str, size_t size, const char *format, ...) __printf(3, 4);
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/* Maximum index number of event-name postfix */
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#define MAX_EVENT_INDEX 1024
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int copy_to_probe_trace_arg(struct probe_trace_arg *tvar,
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struct perf_probe_arg *pvar);
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struct map *get_target_map(const char *target, struct nsinfo *nsi, bool user);
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void arch__post_process_probe_trace_events(struct perf_probe_event *pev,
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int ntevs);
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#endif /*_PROBE_EVENT_H */
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