All of lore.kernel.org
 help / color / mirror / Atom feed
From: Jiri Olsa <jolsa@redhat.com>
To: David Miller <davem@davemloft.net>
Cc: acme@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf: Don't clone maps from parent when synthesizing forks
Date: Wed, 31 Oct 2018 14:01:38 +0100	[thread overview]
Message-ID: <20181031130138.GA13216@krava> (raw)
In-Reply-To: <20181030.222404.2085088822877051075.davem@davemloft.net>

On Tue, Oct 30, 2018 at 10:24:04PM -0700, David Miller wrote:

SNIP

> diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
> index 111ae858cbcb..214b7979c4e7 100644
> --- a/tools/perf/util/machine.c
> +++ b/tools/perf/util/machine.c
> @@ -1708,6 +1708,7 @@ int machine__process_fork_event(struct machine *machine, union perf_event *event
>  	struct thread *parent = machine__findnew_thread(machine,
>  							event->fork.ppid,
>  							event->fork.ptid);
> +	bool do_maps_clone = true;
>  	int err = 0;
>  
>  	if (dump_trace)
> @@ -1737,8 +1738,11 @@ int machine__process_fork_event(struct machine *machine, union perf_event *event
>  	thread = machine__findnew_thread(machine, event->fork.pid,
>  					 event->fork.tid);
>  
> +	if (event->fork.header.misc & PERF_RECORD_MISC_FORK_EXEC)
> +		do_maps_clone = false;

could you please put some comment in here shortly
explaining the reason behind this flag

> +
>  	if (thread == NULL || parent == NULL ||
> -	    thread__fork(thread, parent, sample->time) < 0) {
> +	    thread__fork(thread, parent, sample->time, do_maps_clone) < 0) {
>  		dump_printf("problem processing PERF_RECORD_FORK, skipping event.\n");
>  		err = -1;
>  	}
> diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
> index 2048d393ece6..54b2c9ceba9f 100644
> --- a/tools/perf/util/thread.c
> +++ b/tools/perf/util/thread.c
> @@ -330,7 +330,8 @@ static int thread__prepare_access(struct thread *thread)
>  }
>  
>  static int thread__clone_map_groups(struct thread *thread,
> -				    struct thread *parent)
> +				    struct thread *parent,
> +				    bool do_maps_clone)
>  {
>  	/* This is new thread, we share map groups for process. */
>  	if (thread->pid_ == parent->pid_)
> @@ -341,15 +342,14 @@ static int thread__clone_map_groups(struct thread *thread,
>  			 thread->pid_, thread->tid, parent->pid_, parent->tid);
>  		return 0;
>  	}
> -
>  	/* But this one is new process, copy maps. */
> -	if (map_groups__clone(thread, parent->mg) < 0)
> +	if (do_maps_clone &&
> +	    map_groups__clone(thread, parent->mg) < 0)
>  		return -ENOMEM;
> -
>  	return 0;

we could move all this into one line:

	return do_maps_clone ? map_groups__clone(thread, parent->mg) : 0;

thanks,
jirka

>  }
>  
> -int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp)
> +int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone)
>  {
>  	if (parent->comm_set) {
>  		const char *comm = thread__comm_str(parent);
> @@ -362,7 +362,7 @@ int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp)
>  	}
>  
>  	thread->ppid = parent->tid;
> -	return thread__clone_map_groups(thread, parent);
> +	return thread__clone_map_groups(thread, parent, do_maps_clone);
>  }
>  
>  void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
> diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
> index 07606aa6998d..7e30fe99b74b 100644
> --- a/tools/perf/util/thread.h
> +++ b/tools/perf/util/thread.h
> @@ -87,7 +87,7 @@ struct comm *thread__comm(const struct thread *thread);
>  struct comm *thread__exec_comm(const struct thread *thread);
>  const char *thread__comm_str(const struct thread *thread);
>  int thread__insert_map(struct thread *thread, struct map *map);
> -int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp);
> +int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone);
>  size_t thread__fprintf(struct thread *thread, FILE *fp);
>  
>  struct thread *thread__main_thread(struct machine *machine, struct thread *thread);

  parent reply	other threads:[~2018-10-31 13:01 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-31  5:24 David Miller
2018-10-31 13:00 ` Arnaldo Carvalho de Melo
2018-10-31 13:01 ` Jiri Olsa [this message]
2018-10-31 13:06   ` Arnaldo Carvalho de Melo
2018-10-31 22:12 ` [tip:perf/urgent] perf tools: " tip-bot for David Miller

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20181031130138.GA13216@krava \
    --to=jolsa@redhat.com \
    --cc=acme@kernel.org \
    --cc=davem@davemloft.net \
    --cc=linux-kernel@vger.kernel.org \
    --subject='Re: [PATCH] perf: Don'\''t clone maps from parent when synthesizing forks' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.