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From: Taylor Blau <me@ttaylorr•com>
To: Patrick Steinhardt <ps@pks•im>
Cc: git@vger•kernel.org, Jeff King <peff@peff•net>,
	Junio C Hamano <gitster@pobox•com>
Subject: Re: [PATCH 5/6] pack-bitmap-write.c: avoid uninitialized 'write_as' field
Date: Wed, 15 May 2024 09:29:14 -0400	[thread overview]
Message-ID: <ZkS4qi5TOThOwQLO@nand.local> (raw)
In-Reply-To: <ZkR6xqHgrIvoV6OR@tanuki>

On Wed, May 15, 2024 at 11:05:10AM +0200, Patrick Steinhardt wrote:
> > diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c
> > index c0087dab12..420f17c2e0 100644
> > --- a/pack-bitmap-write.c
> > +++ b/pack-bitmap-write.c
> > @@ -112,6 +112,7 @@ static inline void push_bitmapped_commit(struct bitmap_writer *writer,
> >
> >  	writer->selected[writer->selected_nr].commit = commit;
> >  	writer->selected[writer->selected_nr].bitmap = NULL;
> > +	writer->selected[writer->selected_nr].write_as = NULL;
> >  	writer->selected[writer->selected_nr].flags = 0;
>
> Instead of having to ensure that all fields are initialized we could
> also set the whole structure to zero via `memset()`, which might be a
> bit more sustainable in the future. That alone doesn't really warrant a
> reroll though.

I had considered it, but decided against it as it seemed wasteful to

    memset(&writer->selected[writer->selected_nr], 0,
           sizeof(struct bitmapped_commit))

and then immediately un-zero some of its memory by assigning the commit
field.

Obviously not actually all that wasteful, as we're only talking about a
couple of hundred CPU cycles ;-).

Thanks,
Taylor

next prev parent reply	other threads:[~2024-05-15 13:29 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-14 19:56 [PATCH 0/6] pack-bitmap: various pack-bitmap-write cleanups Taylor Blau
2024-05-14 19:56 ` [PATCH 1/6] object.h: add flags allocated by pack-bitmap.h Taylor Blau
2024-05-14 19:56 ` [PATCH 2/6] pack-bitmap-write.c: move commit_positions into commit_pos fields Taylor Blau
2024-05-14 19:56 ` [PATCH 3/6] pack-bitmap: avoid use of static `bitmap_writer` Taylor Blau
2024-05-14 19:57 ` [PATCH 4/6] pack-bitmap: drop unused `max_bitmaps` parameter Taylor Blau
2024-05-14 19:57 ` [PATCH 5/6] pack-bitmap-write.c: avoid uninitialized 'write_as' field Taylor Blau
2024-05-15  9:05   ` Patrick Steinhardt
2024-05-15 13:29     ` Taylor Blau [this message]
2024-05-14 19:57 ` [PATCH 6/6] pack-bitmap: introduce `bitmap_writer_free()` Taylor Blau
2024-05-15  9:05   ` Patrick Steinhardt
2024-05-15 15:58     ` Taylor Blau
2024-05-15  6:18 ` [PATCH 0/6] pack-bitmap: various pack-bitmap-write cleanups Jeff King
2024-05-15  9:05 ` Patrick Steinhardt
2024-05-15 15:58   ` Taylor Blau

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