Avoid walking the list of idle symbols more than once by setting a
flag in the symbol struct.

Signed-off-by: David Ahern <dsah...@gmail.com>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Jiri Olsa <jo...@redhat.com>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Frederic Weisbecker <fweis...@gmail.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Stephane Eranian <eran...@google.com>
---
 tools/perf/util/symbol.c |   44 ++++++++++++++++++++++++++++++++++++++++++++
 tools/perf/util/symbol.h |    5 ++++-
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 77f3b95..c655b9e 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -509,6 +509,46 @@ static u8 kallsyms2elf_type(char type)
        return isupper(type) ? STB_GLOBAL : STB_LOCAL;
 }
 
+static bool is_idle_sym(const char *name)
+{
+       static const char * const idle_symbols[] = {
+               "cpu_idle",
+               "intel_idle",
+               "default_idle",
+               "native_safe_halt",
+               "enter_idle",
+               "exit_idle",
+               "mwait_idle",
+               "mwait_idle_with_hints",
+               "poll_idle",
+               "ppc64_runlatch_off",
+               "pseries_dedicated_idle_sleep",
+               NULL
+       };
+
+       int i;
+
+       for (i = 0; idle_symbols[i]; i++) {
+               if (!strcmp(idle_symbols[i], name))
+                       return true;
+       }
+
+       return false;
+}
+
+bool symbol__is_idle(struct symbol *sym)
+{
+       if (!sym)
+               return false;
+
+       if (!sym->idle_checked) {
+               sym->is_idle = is_idle_sym(sym->name);
+               sym->idle_checked = true;
+       }
+
+       return sym->is_idle;
+}
+
 static int map__process_kallsym_symbol(void *arg, const char *name,
                                       char type, u64 start)
 {
@@ -527,6 +567,10 @@ static int map__process_kallsym_symbol(void *arg, const 
char *name,
        sym = symbol__new(start, 0, kallsyms2elf_type(type), name);
        if (sym == NULL)
                return -ENOMEM;
+
+       sym->is_idle = is_idle_sym(name);
+       sym->idle_checked = true;
+
        /*
         * We will pass the symbols to the filter later, in
         * map__split_kallsyms, when we have split the maps per module
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index fd5b70e..c163ba9 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -59,7 +59,7 @@ static inline char *bfd_demangle(void __maybe_unused *v,
 
 /** struct symbol - symtab entry
  *
- * @ignore - resolvable but tools ignore it (e.g. idle routines)
+ * @ignore - resolvable but perf-top ignores it (e.g. idle routines)
  */
 struct symbol {
        struct rb_node  rb_node;
@@ -68,6 +68,8 @@ struct symbol {
        u16             namelen;
        u8              binding;
        bool            ignore;
+       bool            is_idle;  /* pertains to kernel symbols only */
+       bool            idle_checked;
        char            name[0];
 };
 
@@ -236,6 +238,7 @@ size_t symbol__fprintf(struct symbol *sym, FILE *fp);
 bool symbol_type__is_a(char symbol_type, enum map_type map_type);
 bool symbol__restricted_filename(const char *filename,
                                 const char *restricted_filename);
+bool symbol__is_idle(struct symbol *sym);
 
 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
                  struct symsrc *runtime_ss, symbol_filter_t filter,
-- 
1.7.10.1

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