Dwarves Archive on lore.kernel.org
 help / color / Atom feed
From: Hao Luo <haoluo@google.com>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>,
	Andrii Nakryiko <andrii.nakryiko@gmail.com>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	dwarves@vger.kernel.org, Yonghong Song <yhs@fb.com>
Subject: Re: [PATCH 1/2] btf_encoder: Make encoding vars into BTF optional.
Date: Fri, 18 Sep 2020 14:26:14 -0700
Message-ID: <CA+khW7icd3ndet5x845S+dBL4YiQPbWWSJa=EVYH464gKwzp-A@mail.gmail.com> (raw)
In-Reply-To: <20200918212402.GE1996959@kernel.org>

How about '--btf_encode_vars'? It is actually encoding BTF_KIND_VAR.

Hao

On Fri, Sep 18, 2020 at 2:24 PM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> Em Fri, Sep 18, 2020 at 01:40:57PM -0700, Hao Luo escreveu:
> > Introduce an option --btf_encode_symbols to pahole so that pahole
> > will only encode global symbols upon request. On the kernel side,
> > we can add a Kconfig to turn on this feature. This would make the
> > rollout of pahole v1.18 safe against potential bugs in the feature
> > introduced in commit f3d9054ba8ff ("btf_encoder: Teach pahole to
> > store percpu variables in vmlinux BTF.").
>
> 'encode_symbols' is too generic, please rename it to
> encode_global_symbols or something like that.
>
> - Arnaldo
>
> > Signed-off-by: Hao Luo <haoluo@google.com>
> > ---
> >  btf_encoder.c |  5 ++++-
> >  btf_encoder.h |  2 +-
> >  pahole.c      | 11 ++++++++++-
> >  3 files changed, 15 insertions(+), 3 deletions(-)
> >
> > diff --git a/btf_encoder.c b/btf_encoder.c
> > index 982f59d..54ffdd1 100644
> > --- a/btf_encoder.c
> > +++ b/btf_encoder.c
> > @@ -237,7 +237,7 @@ static struct variable *hashaddr__find_variable(const struct hlist_head hashtabl
> >       return NULL;
> >  }
> >
> > -int cu__encode_btf(struct cu *cu, int verbose, bool force)
> > +int cu__encode_btf(struct cu *cu, int verbose, bool force, bool encode_symbols)
> >  {
> >       bool add_index_type = false;
> >       uint32_t type_id_off;
> > @@ -314,6 +314,9 @@ int cu__encode_btf(struct cu *cu, int verbose, bool force)
> >               }
> >       }
> >
> > +     /* if there is no request to encode symbols, just finish. */
> > +     if (!encode_symbols)
> > +             goto out;
> >
> >       if (btfe->percpu_shndx == 0 || !btfe->symtab)
> >               goto out;
> > diff --git a/btf_encoder.h b/btf_encoder.h
> > index bca2348..f2e95fe 100644
> > --- a/btf_encoder.h
> > +++ b/btf_encoder.h
> > @@ -13,6 +13,6 @@ struct cu;
> >
> >  int btf_encoder__encode();
> >
> > -int cu__encode_btf(struct cu *cu, int verbose, bool force);
> > +int cu__encode_btf(struct cu *cu, int verbose, bool force, bool encode_symbols);
> >
> >  #endif /* _BTF_ENCODER_H_ */
> > diff --git a/pahole.c b/pahole.c
> > index e1cde61..079d951 100644
> > --- a/pahole.c
> > +++ b/pahole.c
> > @@ -26,6 +26,7 @@
> >  static bool btf_encode;
> >  static bool ctf_encode;
> >  static bool first_obj_only;
> > +static bool btf_encode_symbols;
> >
> >  static uint8_t class__include_anonymous;
> >  static uint8_t class__include_nested_anonymous;
> > @@ -809,6 +810,7 @@ ARGP_PROGRAM_VERSION_HOOK_DEF = dwarves_print_version;
> >  #define ARGP_header_type        314
> >  #define ARGP_size_bytes                 315
> >  #define ARGP_range              316
> > +#define ARGP_btf_encode_symbols         317
> >
> >  static const struct argp_option pahole__options[] = {
> >       {
> > @@ -1087,6 +1089,11 @@ static const struct argp_option pahole__options[] = {
> >               .key  = 'J',
> >               .doc  = "Encode as BTF",
> >       },
> > +     {
> > +             .name = "btf_encode_symbols",
> > +             .key  = ARGP_btf_encode_symbols,
> > +             .doc  = "Encode global symbols in BTF. Off by default."
> > +     },
> >       {
> >               .name = "force",
> >               .key  = 'j',
> > @@ -1207,6 +1214,8 @@ static error_t pahole__options_parser(int key, char *arg,
> >               conf.range = arg;                       break;
> >       case ARGP_header_type:
> >               conf.header_type = arg;                 break;
> > +     case ARGP_btf_encode_symbols:
> > +             btf_encode_symbols = true;              break;
> >       default:
> >               return ARGP_ERR_UNKNOWN;
> >       }
> > @@ -2352,7 +2361,7 @@ static enum load_steal_kind pahole_stealer(struct cu *cu,
> >               goto filter_it;
> >
> >       if (btf_encode) {
> > -             cu__encode_btf(cu, global_verbose, force);
> > +             cu__encode_btf(cu, global_verbose, force, btf_encode_symbols);
> >               return LSK__KEEPIT;
> >       }
> >
> > --
> > 2.28.0.681.g6f77f65b4e-goog
> >
>
> --
>
> - Arnaldo

  reply index

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-18 20:40 [PATCH 0/2] pahole: Make encoding percpu " Hao Luo
2020-09-18 20:40 ` [PATCH 1/2] btf_encoder: Make encoding " Hao Luo
2020-09-18 21:24   ` Arnaldo Carvalho de Melo
2020-09-18 21:26     ` Hao Luo [this message]
2020-09-18 21:40       ` Arnaldo Carvalho de Melo
2020-09-18 20:40 ` [PATCH 2/2] btf_encoder: Introduce option '--btf_encode_force' Hao Luo
2020-09-19  0:57 ` [PATCH 0/2] pahole: Make encoding percpu vars into BTF optional Alexei Starovoitov
2020-09-19  4:00   ` Hao Luo
2020-09-21 12:27     ` Arnaldo Carvalho de Melo

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='CA+khW7icd3ndet5x845S+dBL4YiQPbWWSJa=EVYH464gKwzp-A@mail.gmail.com' \
    --to=haoluo@google.com \
    --cc=acme@kernel.org \
    --cc=alexei.starovoitov@gmail.com \
    --cc=andrii.nakryiko@gmail.com \
    --cc=arnaldo.melo@gmail.com \
    --cc=daniel@iogearbox.net \
    --cc=dwarves@vger.kernel.org \
    --cc=yhs@fb.com \
    /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

Dwarves Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/dwarves/0 dwarves/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 dwarves dwarves/ https://lore.kernel.org/dwarves \
		dwarves@vger.kernel.org
	public-inbox-index dwarves

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.dwarves


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git