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perf: generalize perf_callchain

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. avoid walking the stack when there is no room left in the buffer
. generalize get_perf_callchain() to be called from bpf helper

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alexei Starovoitov
2016-02-17 19:58:57 -08:00
committed by David S. Miller
parent 6b83d28a55
commit 568b329a02
8 changed files with 51 additions and 29 deletions
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18
arch/x86/kernel/stacktrace.c
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@@ -14,30 +14,34 @@ static int save_stack_stack(void *data, char *name)
return 0;
}
static void
static int
__save_stack_address(void *data, unsigned long addr, bool reliable, bool nosched)
{
struct stack_trace *trace = data;
#ifdef CONFIG_FRAME_POINTER
if (!reliable)
return;
return 0;
#endif
if (nosched && in_sched_functions(addr))
return;
return 0;
if (trace->skip > 0) {
trace->skip--;
return;
return 0;
}
if (trace->nr_entries < trace->max_entries)
if (trace->nr_entries < trace->max_entries) {
trace->entries[trace->nr_entries++] = addr;
return 0;
} else {
return -1; /* no more room, stop walking the stack */
}
}
static void save_stack_address(void *data, unsigned long addr, int reliable)
static int save_stack_address(void *data, unsigned long addr, int reliable)
{
return __save_stack_address(data, addr, reliable, false);
}
static void
static int
save_stack_address_nosched(void *data, unsigned long addr, int reliable)
{
return __save_stack_address(data, addr, reliable, true);