linux-kernel - Re: [PATCH 2/5] perf unwind: Do not look at globals

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Message-ID: <20180116151915.GC17819@krava>
Date:   Tue, 16 Jan 2018 16:19:15 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Jiri Olsa <jolsa@...nel.org>, Ingo Molnar <mingo@...nel.org>,
        linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        David Ahern <dsahern@...il.com>,
        Hendrick Brueckner <brueckner@...ux.vnet.ibm.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Thomas Richter <tmricht@...ux.vnet.ibm.com>,
        Wang Nan <wangnan0@...wei.com>
Subject: Re: [PATCH 2/5] perf unwind: Do not look at globals

On Tue, Jan 16, 2018 at 11:24:35AM -0300, Arnaldo Carvalho de Melo wrote:

SNIP

> Cc: Adrian Hunter <adrian.hunter@...el.com>
> Cc: David Ahern <dsahern@...il.com>
> Cc: Hendrick Brueckner <brueckner@...ux.vnet.ibm.com>
> Cc: Jiri Olsa <jolsa@...nel.org>
> Cc: Namhyung Kim <namhyung@...nel.org>
> Cc: Thomas Richter <tmricht@...ux.vnet.ibm.com>
> Cc: Wang Nan <wangnan0@...wei.com>
> Link: https://lkml.kernel.org/n/tip-skbth8ufepbtw8xar7gdsb6l@git.kernel.org
> Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
> ---
>  tools/perf/util/unwind-libunwind-local.c | 9 ---------
>  1 file changed, 9 deletions(-)
> 
> diff --git a/tools/perf/util/unwind-libunwind-local.c b/tools/perf/util/unwind-libunwind-local.c
> index 7a42f703e858..02dc5a9d8f72 100644
> --- a/tools/perf/util/unwind-libunwind-local.c
> +++ b/tools/perf/util/unwind-libunwind-local.c
> @@ -631,9 +631,6 @@ static unw_accessors_t accessors = {
>  
>  static int _unwind__prepare_access(struct thread *thread)
>  {
> -	if (callchain_param.record_mode != CALLCHAIN_DWARF)
> -		return 0;
> -

this would create thread->addr_space also for data without
dwarf callchains data, so I think we need to keep it

it should get set in apply_config_terms which calls parse_callchain_record
once it detects some 'call-graph' term setup.. something's probably wrong
there?

jirka

>  	thread->addr_space = unw_create_addr_space(&accessors, 0);
>  	if (!thread->addr_space) {
>  		pr_err("unwind: Can't create unwind address space.\n");
> @@ -646,17 +643,11 @@ static int _unwind__prepare_access(struct thread *thread)
>  
>  static void _unwind__flush_access(struct thread *thread)
>  {
> -	if (callchain_param.record_mode != CALLCHAIN_DWARF)
> -		return;
> -
>  	unw_flush_cache(thread->addr_space, 0, 0);
>  }
>  
>  static void _unwind__finish_access(struct thread *thread)
>  {
> -	if (callchain_param.record_mode != CALLCHAIN_DWARF)
> -		return;
> -
>  	unw_destroy_addr_space(thread->addr_space);
>  }
>  
> -- 
> 2.14.3
>