From: Jiri Olsa <olsajiri@gmail.com>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>, Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
lkml <linux-kernel@vger.kernel.org>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@chromium.org>
Subject: Re: [RFC bpf-next 1/4] kallsyms: Add kallsyms_lookup_names function
Date: Wed, 13 Apr 2022 09:27:40 +0200 [thread overview]
Message-ID: <YlZ7bAY1lDQWxUgH@krava> (raw)
In-Reply-To: <20220408095701.54aea15c3cafcf66dd628a95@kernel.org>
On Fri, Apr 08, 2022 at 09:57:01AM +0900, Masami Hiramatsu wrote:
SNIP
> > /*
> > * These will be re-linked against their real values
> > @@ -572,6 +574,52 @@ int sprint_backtrace_build_id(char *buffer, unsigned long address)
> > return __sprint_symbol(buffer, address, -1, 1, 1);
> > }
> >
> > +static int symbols_cmp(const void *a, const void *b)
> > +{
> > + const char **str_a = (const char **) a;
> > + const char **str_b = (const char **) b;
> > +
> > + return strcmp(*str_a, *str_b);
> > +}
> > +
> > +struct kallsyms_data {
> > + unsigned long *addrs;
> > + const char **syms;
> > + u32 cnt;
> > + u32 found;
>
> BTW, why do you use 'u32' for this arch independent code?
> I think 'size_t' will make its role clearer.
right, will change
>
> > +};
> > +
> > +static int kallsyms_callback(void *data, const char *name,
> > + struct module *mod, unsigned long addr)
> > +{
> > + struct kallsyms_data *args = data;
> > +
> > + if (!bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp))
> > + return 0;
> > +
> > + addr = ftrace_location(addr);
> > + if (!addr)
> > + return 0;
> > +
> > + args->addrs[args->found++] = addr;
> > + return args->found == args->cnt ? 1 : 0;
> > +}
> > +
> > +int kallsyms_lookup_names(const char **syms, u32 cnt, unsigned long *addrs)
>
> Ditto. I think 'size_t cnt' is better.
ok, thanks
jirka
>
> Thank you,
>
> > +{
> > + struct kallsyms_data args;
> > +
> > + sort(syms, cnt, sizeof(*syms), symbols_cmp, NULL);
> > +
> > + args.addrs = addrs;
> > + args.syms = syms;
> > + args.cnt = cnt;
> > + args.found = 0;
> > + kallsyms_on_each_symbol(kallsyms_callback, &args);
> > +
> > + return args.found == args.cnt ? 0 : -EINVAL;
> > +}
> > +
> > /* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
> > struct kallsym_iter {
> > loff_t pos;
> > --
> > 2.35.1
> >
>
>
> --
> Masami Hiramatsu <mhiramat@kernel.org>
next prev parent reply other threads:[~2022-04-13 7:27 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-07 12:52 [RFC bpf-next 0/4] bpf: Speed up symbol resolving in kprobe multi link Jiri Olsa
2022-04-07 12:52 ` [RFC bpf-next 1/4] kallsyms: Add kallsyms_lookup_names function Jiri Olsa
2022-04-08 0:57 ` Masami Hiramatsu
2022-04-13 7:27 ` Jiri Olsa [this message]
2022-04-08 23:19 ` Alexei Starovoitov
2022-04-09 20:24 ` Jiri Olsa
2022-04-12 20:46 ` Jiri Olsa
2022-04-15 0:47 ` Masami Hiramatsu
2022-04-15 22:39 ` Jiri Olsa
2022-04-11 22:15 ` Andrii Nakryiko
2022-04-12 20:28 ` Jiri Olsa
2022-04-07 12:52 ` [RFC bpf-next 2/4] fprobe: Resolve symbols with kallsyms_lookup_names Jiri Olsa
2022-04-08 0:58 ` Masami Hiramatsu
2022-04-07 12:52 ` [RFC bpf-next 3/4] bpf: Resolve symbols with kallsyms_lookup_names for kprobe multi link Jiri Olsa
2022-04-08 23:26 ` Alexei Starovoitov
2022-04-09 20:24 ` Jiri Olsa
2022-04-11 22:15 ` Andrii Nakryiko
2022-04-11 22:15 ` Andrii Nakryiko
2022-04-12 18:42 ` Jiri Olsa
2022-04-07 12:52 ` [RFC bpf-next 4/4] selftests/bpf: Add attach bench test Jiri Olsa
2022-04-11 22:15 ` Andrii Nakryiko
2022-04-12 0:49 ` Masami Hiramatsu
2022-04-12 22:51 ` Andrii Nakryiko
2022-04-16 14:21 ` Masami Hiramatsu
2022-04-18 17:33 ` Steven Rostedt
2022-04-28 13:58 ` Steven Rostedt
2022-04-28 13:59 ` Steven Rostedt
2022-04-28 18:59 ` Alexei Starovoitov
2022-04-28 20:05 ` Steven Rostedt
2022-04-28 23:32 ` Andrii Nakryiko
2022-04-28 23:53 ` Steven Rostedt
2022-04-29 0:09 ` Steven Rostedt
2022-04-29 0:31 ` Steven Rostedt
2022-04-13 16:44 ` Steven Rostedt
2022-04-13 16:45 ` Andrii Nakryiko
2022-04-13 16:59 ` Steven Rostedt
2022-04-13 19:02 ` Andrii Nakryiko
2022-04-12 15:44 ` Jiri Olsa
2022-04-12 22:59 ` Andrii Nakryiko
2022-04-08 23:29 ` [RFC bpf-next 0/4] bpf: Speed up symbol resolving in kprobe multi link Alexei Starovoitov
2022-04-09 20:24 ` Jiri Olsa
2022-04-11 22:15 ` Andrii Nakryiko
2022-04-11 22:18 ` Alexei Starovoitov
2022-04-11 22:21 ` Andrii Nakryiko
2022-04-12 15:46 ` Jiri Olsa
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