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From: Jeff King <peff@peff.net>
To: Christian Couder <christian.couder@gmail.com>
Cc: Jonathan Tan <jonathantanmy@google.com>,
	git <git@vger.kernel.org>, Junio C Hamano <gitster@pobox.com>,
	Christian Couder <chriscool@tuxfamily.org>,
	Ramsay Jones <ramsay@ramsayjones.plus.com>
Subject: Re: [RFC PATCH 04/10] ewah/bitmap: always allocate 2 more words
Date: Fri, 11 Oct 2019 14:05:07 -0400	[thread overview]
Message-ID: <20191011180507.GB20601@sigill.intra.peff.net> (raw)
In-Reply-To: <CAP8UFD0-NHCj6KcbdMG3bCwWp=wUdoYugLggsbnpvr1d6-P4yg@mail.gmail.com>

On Fri, Oct 11, 2019 at 09:49:53AM +0200, Christian Couder wrote:

> > I think this should be squashed with patch 3, adding to that commit
> > message "since word_alloc might be 0, we need to change the growth
> > function". (Or just make the minimum word_alloc be 1 or 32 or something
> > positive, if that's possible.)
> 
> Yeah, thank you for the suggestion. I still wonder why 2 is added
> instead of just 1 though.

Yeah, I think it should be squashed. I think it is not intentionally 2,
it is just that adding "1" to block makes sure we always make forward
progress. It could equally well be:

  self->word_alloc = block ? block * 2 : 1;

I think. Or probably this whole thing could be ALLOC_GROW(), as the
numbers aren't particularly important. I guess we need to make sure the
grown part is zero'd, so probably using alloc_nr() directly would make
more sense.

-Peff

  reply	other threads:[~2019-10-11 18:05 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-13 13:02 [RFC PATCH 00/10] Rewrite packfile reuse code Christian Couder
2019-09-13 13:02 ` [RFC PATCH 01/10] builtin/pack-objects: report reused packfile objects Christian Couder
2019-09-13 13:02 ` [RFC PATCH 02/10] packfile: expose get_delta_base() Christian Couder
2019-09-13 13:02 ` [RFC PATCH 03/10] ewah/bitmap: introduce bitmap_word_alloc() Christian Couder
2019-09-13 13:02 ` [RFC PATCH 04/10] ewah/bitmap: always allocate 2 more words Christian Couder
2019-10-10 23:40   ` Jonathan Tan
2019-10-11  7:49     ` Christian Couder
2019-10-11 18:05       ` Jeff King [this message]
2019-09-13 13:02 ` [RFC PATCH 05/10] pack-bitmap: don't rely on bitmap_git->reuse_objects Christian Couder
2019-10-10 23:44   ` Jonathan Tan
2019-10-11  7:50     ` Christian Couder
2019-09-13 13:02 ` [RFC PATCH 06/10] pack-bitmap: introduce bitmap_walk_contains() Christian Couder
2019-09-13 13:02 ` [RFC PATCH 07/10] csum-file: introduce hashfile_total() Christian Couder
2019-09-13 13:02 ` [RFC PATCH 08/10] pack-objects: introduce pack.allowPackReuse Christian Couder
2019-09-13 21:37   ` Junio C Hamano
2019-09-13 13:02 ` [RFC PATCH 09/10] builtin/pack-objects: introduce obj_is_packed() Christian Couder
2019-09-13 13:02 ` [RFC PATCH 10/10] pack-objects: improve partial packfile reuse Christian Couder
2019-09-13 22:29   ` Junio C Hamano
2019-09-14  2:02     ` Jeff King
2019-09-14  3:06       ` Junio C Hamano
2019-10-02 15:57         ` Jeff King
2019-10-03  2:06           ` Junio C Hamano
2019-10-03  6:55             ` Christian Couder
2019-10-10 23:59   ` Jonathan Tan
2019-10-11  7:39     ` Christian Couder
2019-10-11 18:01     ` Jeff King
2019-10-11 21:04       ` Jonathan Tan
2019-10-12  0:04       ` Junio C Hamano
2019-10-13  7:38         ` Jeff King
2019-10-17  7:03           ` Junio C Hamano
2019-10-17  7:23             ` Jeff King

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