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References: <20240507141210.195939-1-james.clark@arm.com> <20240507141210.195939-3-james.clark@arm.com>
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From: Ian Rogers <irogers@google.com>
Date: Wed, 8 May 2024 15:06:29 -0700
Message-ID: <CAP-5=fUqaXWm0xFCoaFYzVkWVMD3Khtxu7au5natVvDVw+fvTQ@mail.gmail.com>
Subject: Re: [PATCH 2/4] perf maps: Re-use __maps__free_maps_by_name()
To: James Clark <james.clark@arm.com>
Cc: linux-perf-users@vger.kernel.org, atrajeev@linux.vnet.ibm.com, 
	Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>, 
	Arnaldo Carvalho de Melo <acme@kernel.org>, Namhyung Kim <namhyung@kernel.org>, 
	Mark Rutland <mark.rutland@arm.com>, 
	Alexander Shishkin <alexander.shishkin@linux.intel.com>, Jiri Olsa <jolsa@kernel.org>, 
	Adrian Hunter <adrian.hunter@intel.com>, "Liang, Kan" <kan.liang@linux.intel.com>, 
	linux-kernel@vger.kernel.org
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On Tue, May 7, 2024 at 7:13=E2=80=AFAM James Clark <james.clark@arm.com> wr=
ote:
>
> maps__merge_in() hard codes the steps to free the maps_by_name list. It
> seems to not map__put() each element before freeing, and it sets
> maps_by_name_sorted to true after freeing, which may be harmless but
> is inconsistent with maps__init() and other functions.
>
> maps__maps_by_name_addr() is also quite hard to read because we already
> have maps__maps_by_name() and maps__maps_by_address(), but the function
> is only used in that place so delete it.
>
> Signed-off-by: James Clark <james.clark@arm.com>
> ---
>  tools/perf/util/maps.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/tools/perf/util/maps.c b/tools/perf/util/maps.c
> index 61eb742d91e3..16b39db594f4 100644
> --- a/tools/perf/util/maps.c
> +++ b/tools/perf/util/maps.c
> @@ -124,11 +124,6 @@ static void maps__set_maps_by_address(struct maps *m=
aps, struct map **new)
>
>  }
>
> -static struct map ***maps__maps_by_name_addr(struct maps *maps)
> -{
> -       return &RC_CHK_ACCESS(maps)->maps_by_name;
> -}
> -
>  static void maps__set_nr_maps_allocated(struct maps *maps, unsigned int =
nr_maps_allocated)
>  {
>         RC_CHK_ACCESS(maps)->nr_maps_allocated =3D nr_maps_allocated;
> @@ -284,6 +279,9 @@ void maps__put(struct maps *maps)
>
>  static void __maps__free_maps_by_name(struct maps *maps)
>  {
> +       if (!maps__maps_by_name(maps))
> +               return;
> +
>         /*
>          * Free everything to try to do it from the rbtree in the next se=
arch

nit: this comment is stale, it should be maps_by_address rather than the rb=
tree.

Reviewed-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

>          */
> @@ -291,6 +289,9 @@ static void __maps__free_maps_by_name(struct maps *ma=
ps)
>                 map__put(maps__maps_by_name(maps)[i]);
>
>         zfree(&RC_CHK_ACCESS(maps)->maps_by_name);
> +
> +       /* Consistent with maps__init(). When maps_by_name =3D=3D NULL, m=
aps_by_name_sorted =3D=3D false */
> +       maps__set_maps_by_name_sorted(maps, false);
>  }
>
>  static int map__start_cmp(const void *a, const void *b)
> @@ -1167,8 +1168,7 @@ int maps__merge_in(struct maps *kmaps, struct map *=
new_map)
>         }
>         maps__set_maps_by_address(kmaps, merged_maps_by_address);
>         maps__set_maps_by_address_sorted(kmaps, true);
> -       zfree(maps__maps_by_name_addr(kmaps));
> -       maps__set_maps_by_name_sorted(kmaps, true);
> +       __maps__free_maps_by_name(kmaps);
>         maps__set_nr_maps_allocated(kmaps, merged_nr_maps_allocated);
>
>         /* Copy entries before the new_map that can't overlap. */
> --
> 2.34.1
>