Messages in this thread | | | Date | Sun, 15 Mar 2009 06:30:18 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH 2/2 v2] tracing/syscalls: support for syscalls tracing on x86-64 |
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* Andrew Morton <akpm@linux-foundation.org> wrote:
> On Fri, 13 Mar 2009 15:42:12 +0100 Frederic Weisbecker <fweisbec@gmail.com> wrote: > > > +static struct syscall_metadata *find_syscall_meta(unsigned long *syscall) > > +{ > > + struct syscall_metadata *start; > > + struct syscall_metadata *stop; > > + char str[KSYM_SYMBOL_LEN]; > > + > > + > > + start = (struct syscall_metadata *)__start_syscalls_metadata; > > + stop = (struct syscall_metadata *)__stop_syscalls_metadata; > > + kallsyms_lookup((unsigned long) syscall, NULL, NULL, NULL, str); > > + > > + for ( ; start < stop; start++) { > > + if (start->name && !strcmp(start->name, str)) > > + return start; > > + } > > + return NULL; > > +} > > afacit this feature can be enabled when CONFIG_KALLSYMS=n. > Does that make sense?
It does not make much sense - the function will return NULL and we wont do any tracing. Frederic: FTRACE_SYSCALLS should either select KALLSYMS in kernel/trace/Kconfig, like the STACK_TRACER and FUNCTION_TRACER already does. Or perhaps, for really puritane tracing, we should emit simplified, non-symbolic trace data in the !KALLSYMS case.
Ingo
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