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From: Patrick Steinhardt <ps@pks.im>
To: Taylor Blau <me@ttaylorr.com>
Cc: git@vger.kernel.org, Jeff King <peff@peff.net>,
	Elijah Newren <newren@gmail.com>,
	Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH v2 06/23] pack-bitmap-write: support storing pseudo-merge commits
Date: Fri, 10 May 2024 13:47:06 +0200	[thread overview]
Message-ID: <Zj4JOv4wJQh7GuIB@tanuki> (raw)
In-Reply-To: <Zjkl6vMHCeDsJKdR@nand.local>

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On Mon, May 06, 2024 at 02:48:10PM -0400, Taylor Blau wrote:
> On Mon, May 06, 2024 at 01:52:56PM +0200, Patrick Steinhardt wrote:
> > On Mon, Apr 29, 2024 at 04:43:15PM -0400, Taylor Blau wrote:
> > [snip]
> > > @@ -46,6 +48,11 @@ struct bitmap_writer {
> > >
> > >  static struct bitmap_writer writer;
> > >
> > > +static inline int bitmap_writer_selected_nr(void)
> > > +{
> > > +	return writer.selected_nr - writer.pseudo_merges_nr;
> > > +}
> >
> > This function may use a comment to explain what its meaning actually is.
> > Like, `bitmap_writer_selected_nr()` is obviously not the same as the
> > `selected_nr` of the `bitmap_writer`, which is quite confusing. So why
> > do we subtract values and why are there two different `selected_nr`s?
> 
> selected_nr is the total number of bitmaps we are writing (including
> pseudo-merges), and writer.pseudo_merges_nr is the number of those
> bitmaps which are pseudo-merges.
> 
> I renamed this function to bitmap_writer_nr_selected_commits() which
> should clarify things, let me know if that works!

Yup, that's clearer, thanks.

> > [snip]
> > > diff --git a/pack-bitmap.h b/pack-bitmap.h
> > > index dae2d68a338..ca9acd2f735 100644
> > > --- a/pack-bitmap.h
> > > +++ b/pack-bitmap.h
> > > @@ -21,6 +21,7 @@ struct bitmap_disk_header {
> > >  	unsigned char checksum[GIT_MAX_RAWSZ];
> > >  };
> > >
> > > +#define BITMAP_PSEUDO_MERGE (1u<<21)
> > >  #define NEEDS_BITMAP (1u<<22)
> >
> > This flag is already used by "builtin/pack-objects.c", which may be fine.
> > But in any case, shouldn't we update "object.h" with both of these flags?
> 
> I can't see where in builtin/pack-objects.c this flag is used. The table
> in object.h says that bit 21 is used in:

Yeah, no idea. I must've been seeing ghosts here.

>   - list-objects-filter.c
>   - builtin/index-pack.c
>   - builtin/unpack-objects.c
> 
> But I think those are all fine. We don't call unpack-objects from the
> bitmap writing paths, and the same is true of index-pack (since we're
> writing the pack out directly).
> 
> list-objects-filter.c should also be OK, since I am 99% sure that these
> two code paths do not collide, but even if they do, that field is only
> set on tree objects from the list-objects-filter.c code path, and the
> new bits in pack-bitmap.h are only set on commit objects.

Okay, thanks for the explanation!

Patrick

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  reply	other threads:[~2024-05-10 11:47 UTC|newest]

Thread overview: 157+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-20 22:04 [PATCH 00/24] pack-bitmap: pseudo-merge reachability bitmaps Taylor Blau
2024-03-20 22:05 ` [PATCH 01/24] Documentation/technical: describe pseudo-merge bitmaps format Taylor Blau
2024-03-21 21:24   ` Junio C Hamano
2024-03-21 22:13     ` Taylor Blau
2024-03-21 22:22       ` Junio C Hamano
2024-03-20 22:05 ` [PATCH 02/24] config: repo_config_get_expiry() Taylor Blau
2024-04-10 17:54   ` Jeff King
2024-04-29 19:39     ` Taylor Blau
2024-03-20 22:05 ` [PATCH 03/24] ewah: implement `ewah_bitmap_is_subset()` Taylor Blau
2024-04-10 18:05   ` Jeff King
2024-04-29 19:47     ` Taylor Blau
2024-03-20 22:05 ` [PATCH 04/24] pack-bitmap: drop unused `max_bitmaps` parameter Taylor Blau
2024-04-10 18:06   ` Jeff King
2024-03-20 22:05 ` [PATCH 05/24] pack-bitmap: move some initialization to `bitmap_writer_init()` Taylor Blau
2024-04-10 18:10   ` Jeff King
2024-03-20 22:05 ` [PATCH 06/24] pseudo-merge.ch: initial commit Taylor Blau
2024-03-20 22:05 ` [PATCH 07/24] pack-bitmap-write: support storing pseudo-merge commits Taylor Blau
2024-03-20 22:05 ` [PATCH 08/24] pack-bitmap: implement `bitmap_writer_has_bitmapped_object_id()` Taylor Blau
2024-03-20 22:05 ` [PATCH 09/24] pack-bitmap: make `bitmap_writer_push_bitmapped_commit()` public Taylor Blau
2024-03-20 22:05 ` [PATCH 10/24] pseudo-merge: implement support for selecting pseudo-merge commits Taylor Blau
2024-03-20 22:05 ` [PATCH 11/24] pack-bitmap-write.c: select " Taylor Blau
2024-03-20 22:05 ` [PATCH 12/24] pack-bitmap-write.c: write pseudo-merge table Taylor Blau
2024-03-20 22:05 ` [PATCH 13/24] pack-bitmap: extract `read_bitmap()` function Taylor Blau
2024-03-20 22:05 ` [PATCH 14/24] pseudo-merge: scaffolding for reads Taylor Blau
2024-03-20 22:05 ` [PATCH 15/24] pack-bitmap.c: read pseudo-merge extension Taylor Blau
2024-03-20 22:05 ` [PATCH 16/24] pseudo-merge: implement support for reading pseudo-merge commits Taylor Blau
2024-03-20 22:05 ` [PATCH 17/24] ewah: implement `ewah_bitmap_popcount()` Taylor Blau
2024-03-20 22:05 ` [PATCH 18/24] pack-bitmap: implement test helpers for pseudo-merge Taylor Blau
2024-03-20 22:05 ` [PATCH 19/24] t/test-lib-functions.sh: support `--date` in `test_commit_bulk()` Taylor Blau
2024-03-20 22:05 ` [PATCH 20/24] pack-bitmap.c: use pseudo-merges during traversal Taylor Blau
2024-03-20 22:06 ` [PATCH 21/24] pack-bitmap: extra trace2 information Taylor Blau
2024-03-20 22:06 ` [PATCH 22/24] ewah: `bitmap_equals_ewah()` Taylor Blau
2024-03-20 22:06 ` [PATCH 23/24] pseudo-merge: implement support for finding existing merges Taylor Blau
2024-03-20 22:06 ` [PATCH 24/24] t/perf: implement performace tests for pseudo-merge bitmaps Taylor Blau
2024-03-21 19:50 ` [PATCH 00/24] pack-bitmap: pseudo-merge reachability bitmaps Junio C Hamano
2024-04-29 20:42 ` [PATCH v2 00/23] " Taylor Blau
2024-04-29 20:42   ` [PATCH v2 01/23] Documentation/technical: describe pseudo-merge bitmaps format Taylor Blau
2024-05-06 11:52     ` Patrick Steinhardt
2024-05-06 16:37       ` Taylor Blau
2024-05-10 11:46         ` Patrick Steinhardt
2024-05-13 19:47           ` Taylor Blau
2024-05-14  6:33             ` Patrick Steinhardt
2024-04-29 20:43   ` [PATCH v2 02/23] ewah: implement `ewah_bitmap_is_subset()` Taylor Blau
2024-04-29 20:43   ` [PATCH v2 03/23] pack-bitmap: drop unused `max_bitmaps` parameter Taylor Blau
2024-04-29 20:43   ` [PATCH v2 04/23] pack-bitmap: move some initialization to `bitmap_writer_init()` Taylor Blau
2024-05-06 11:52     ` Patrick Steinhardt
2024-05-06 18:24       ` Taylor Blau
2024-04-29 20:43   ` [PATCH v2 05/23] pseudo-merge.ch: initial commit Taylor Blau
2024-04-29 20:43   ` [PATCH v2 06/23] pack-bitmap-write: support storing pseudo-merge commits Taylor Blau
2024-05-06 11:52     ` Patrick Steinhardt
2024-05-06 18:48       ` Taylor Blau
2024-05-10 11:47         ` Patrick Steinhardt [this message]
2024-05-13 18:42     ` Jeff King
2024-05-13 20:19       ` Taylor Blau
2024-04-29 20:43   ` [PATCH v2 07/23] pack-bitmap: implement `bitmap_writer_has_bitmapped_object_id()` Taylor Blau
2024-04-29 20:43   ` [PATCH v2 08/23] pack-bitmap: make `bitmap_writer_push_bitmapped_commit()` public Taylor Blau
2024-05-13 18:50     ` Jeff King
2024-05-14  0:54       ` Taylor Blau
2024-04-29 20:43   ` [PATCH v2 09/23] pseudo-merge: implement support for selecting pseudo-merge commits Taylor Blau
2024-05-06 11:53     ` Patrick Steinhardt
2024-05-06 19:58       ` Taylor Blau
2024-05-13 19:03     ` Jeff King
2024-05-14  0:58       ` Taylor Blau
2024-05-16  8:07         ` Jeff King
2024-05-16 22:43           ` Junio C Hamano
2024-04-29 20:43   ` [PATCH v2 10/23] pack-bitmap-write.c: select " Taylor Blau
2024-05-06 11:53     ` Patrick Steinhardt
2024-05-06 20:05       ` Taylor Blau
2024-05-10 11:47         ` Patrick Steinhardt
2024-04-29 20:43   ` [PATCH v2 11/23] pack-bitmap-write.c: write pseudo-merge table Taylor Blau
2024-04-29 20:43   ` [PATCH v2 12/23] pack-bitmap: extract `read_bitmap()` function Taylor Blau
2024-04-29 20:43   ` [PATCH v2 13/23] pseudo-merge: scaffolding for reads Taylor Blau
2024-04-29 20:43   ` [PATCH v2 14/23] pack-bitmap.c: read pseudo-merge extension Taylor Blau
2024-04-29 20:44   ` [PATCH v2 15/23] pseudo-merge: implement support for reading pseudo-merge commits Taylor Blau
2024-04-29 20:44   ` [PATCH v2 16/23] ewah: implement `ewah_bitmap_popcount()` Taylor Blau
2024-04-29 20:44   ` [PATCH v2 17/23] pack-bitmap: implement test helpers for pseudo-merge Taylor Blau
2024-04-29 20:44   ` [PATCH v2 18/23] t/test-lib-functions.sh: support `--date` in `test_commit_bulk()` Taylor Blau
2024-04-29 20:44   ` [PATCH v2 19/23] pack-bitmap.c: use pseudo-merges during traversal Taylor Blau
2024-04-29 20:44   ` [PATCH v2 20/23] pack-bitmap: extra trace2 information Taylor Blau
2024-04-29 20:44   ` [PATCH v2 21/23] ewah: `bitmap_equals_ewah()` Taylor Blau
2024-04-29 20:44   ` [PATCH v2 22/23] pseudo-merge: implement support for finding existing merges Taylor Blau
2024-04-29 20:44   ` [PATCH v2 23/23] t/perf: implement performace tests for pseudo-merge bitmaps Taylor Blau
2024-04-30 20:03   ` [PATCH v2 00/23] pack-bitmap: pseudo-merge reachability bitmaps Junio C Hamano
2024-05-01 14:40     ` Taylor Blau
2024-05-21 19:01 ` [PATCH v3 00/30] " Taylor Blau
2024-05-21 19:01   ` [PATCH v3 01/30] object.h: add flags allocated by pack-bitmap.h Taylor Blau
2024-05-21 19:06     ` Taylor Blau
2024-05-21 19:01   ` [PATCH v3 07/30] Documentation/gitpacking.txt: initial commit Taylor Blau
2024-05-21 19:02   ` [PATCH v3 08/30] Documentation/gitpacking.txt: describe pseudo-merge bitmaps Taylor Blau
2024-05-21 19:02   ` [PATCH v3 09/30] Documentation/technical: describe pseudo-merge bitmaps format Taylor Blau
2024-05-21 19:02   ` [PATCH v3 10/30] ewah: implement `ewah_bitmap_is_subset()` Taylor Blau
2024-05-21 19:02   ` [PATCH v3 11/30] pack-bitmap: move some initialization to `bitmap_writer_init()` Taylor Blau
2024-05-21 19:02   ` [PATCH v3 12/30] pseudo-merge.ch: initial commit Taylor Blau
2024-05-21 19:02   ` [PATCH v3 13/30] pack-bitmap-write: support storing pseudo-merge commits Taylor Blau
2024-05-21 19:02   ` [PATCH v3 14/30] pack-bitmap: implement `bitmap_writer_has_bitmapped_object_id()` Taylor Blau
2024-05-21 19:02   ` [PATCH v3 15/30] pack-bitmap: make `bitmap_writer_push_bitmapped_commit()` public Taylor Blau
2024-05-21 19:02   ` [PATCH v3 16/30] config: introduce git_config_float() Taylor Blau
2024-05-23 10:02     ` Jeff King
2024-05-23 17:51       ` Taylor Blau
2024-05-21 19:02   ` [PATCH v3 17/30] pseudo-merge: implement support for selecting pseudo-merge commits Taylor Blau
2024-05-23 10:12     ` Jeff King
2024-05-23 17:56       ` Taylor Blau
2024-05-21 19:02   ` [PATCH v3 18/30] pack-bitmap-write.c: write pseudo-merge table Taylor Blau
2024-05-21 19:02   ` [PATCH v3 19/30] pack-bitmap: extract `read_bitmap()` function Taylor Blau
2024-05-21 19:02   ` [PATCH v3 20/30] pseudo-merge: scaffolding for reads Taylor Blau
2024-05-21 19:02   ` [PATCH v3 21/30] pack-bitmap.c: read pseudo-merge extension Taylor Blau
2024-05-21 19:02   ` [PATCH v3 22/30] pseudo-merge: implement support for reading pseudo-merge commits Taylor Blau
2024-05-23 10:40     ` Jeff King
2024-05-23 18:09       ` Taylor Blau
2024-05-21 19:02   ` [PATCH v3 23/30] ewah: implement `ewah_bitmap_popcount()` Taylor Blau
2024-05-21 19:02   ` [PATCH v3 24/30] pack-bitmap: implement test helpers for pseudo-merge Taylor Blau
2024-05-21 19:02   ` [PATCH v3 25/30] t/test-lib-functions.sh: support `--date` in `test_commit_bulk()` Taylor Blau
2024-05-23 10:42     ` Jeff King
2024-05-23 15:45       ` Junio C Hamano
2024-05-23 18:23         ` Taylor Blau
2024-05-21 19:03   ` [PATCH v3 26/30] pack-bitmap.c: use pseudo-merges during traversal Taylor Blau
2024-05-23 10:48     ` Jeff King
2024-05-23 18:23       ` Taylor Blau
2024-05-21 19:03   ` [PATCH v3 27/30] pack-bitmap: extra trace2 information Taylor Blau
2024-05-21 19:03   ` [PATCH v3 28/30] ewah: `bitmap_equals_ewah()` Taylor Blau
2024-05-21 19:03   ` [PATCH v3 29/30] pseudo-merge: implement support for finding existing merges Taylor Blau
2024-05-21 19:03   ` [PATCH v3 30/30] t/perf: implement performace tests for pseudo-merge bitmaps Taylor Blau
2024-05-23 10:54     ` Jeff King
2024-05-23 19:53       ` Taylor Blau
2024-05-25  3:13         ` Jeff King
2024-05-23 11:05   ` [PATCH v3 00/30] pack-bitmap: pseudo-merge reachability bitmaps Jeff King
2024-05-23 20:04     ` Taylor Blau
2024-05-25  3:15       ` Jeff King
2024-05-23 20:42     ` Taylor Blau
2024-05-23 21:26 ` [PATCH v4 00/24] " Taylor Blau
2024-05-23 21:26   ` [PATCH v4 01/24] Documentation/gitpacking.txt: initial commit Taylor Blau
2024-05-23 21:26   ` [PATCH v4 02/24] Documentation/gitpacking.txt: describe pseudo-merge bitmaps Taylor Blau
2024-05-23 21:26   ` [PATCH v4 03/24] Documentation/technical: describe pseudo-merge bitmaps format Taylor Blau
2024-05-23 21:26   ` [PATCH v4 04/24] ewah: implement `ewah_bitmap_is_subset()` Taylor Blau
2024-05-23 21:26   ` [PATCH v4 05/24] pack-bitmap: move some initialization to `bitmap_writer_init()` Taylor Blau
2024-05-23 21:26   ` [PATCH v4 06/24] pseudo-merge.ch: initial commit Taylor Blau
2024-05-23 21:26   ` [PATCH v4 07/24] pack-bitmap-write: support storing pseudo-merge commits Taylor Blau
2024-05-23 21:26   ` [PATCH v4 08/24] pack-bitmap: implement `bitmap_writer_has_bitmapped_object_id()` Taylor Blau
2024-05-23 21:26   ` [PATCH v4 09/24] pack-bitmap: make `bitmap_writer_push_bitmapped_commit()` public Taylor Blau
2024-05-23 21:26   ` [PATCH v4 10/24] config: introduce `git_config_double()` Taylor Blau
2024-05-23 21:26   ` [PATCH v4 11/24] pseudo-merge: implement support for selecting pseudo-merge commits Taylor Blau
2024-05-25  3:22     ` Jeff King
2024-05-23 21:26   ` [PATCH v4 12/24] pack-bitmap-write.c: write pseudo-merge table Taylor Blau
2024-05-23 21:26   ` [PATCH v4 13/24] pack-bitmap: extract `read_bitmap()` function Taylor Blau
2024-05-23 21:26   ` [PATCH v4 14/24] pseudo-merge: scaffolding for reads Taylor Blau
2024-05-23 21:26   ` [PATCH v4 15/24] pack-bitmap.c: read pseudo-merge extension Taylor Blau
2024-05-23 21:26   ` [PATCH v4 16/24] pseudo-merge: implement support for reading pseudo-merge commits Taylor Blau
2024-05-23 21:27   ` [PATCH v4 17/24] ewah: implement `ewah_bitmap_popcount()` Taylor Blau
2024-05-23 21:27   ` [PATCH v4 18/24] pack-bitmap: implement test helpers for pseudo-merge Taylor Blau
2024-05-23 21:27   ` [PATCH v4 19/24] t/test-lib-functions.sh: support `--notick` in `test_commit_bulk()` Taylor Blau
2024-05-25  3:25     ` Jeff King
2024-05-23 21:27   ` [PATCH v4 20/24] pack-bitmap.c: use pseudo-merges during traversal Taylor Blau
2024-05-23 21:27   ` [PATCH v4 21/24] pack-bitmap: extra trace2 information Taylor Blau
2024-05-23 21:27   ` [PATCH v4 22/24] ewah: `bitmap_equals_ewah()` Taylor Blau
2024-05-23 21:27   ` [PATCH v4 23/24] pseudo-merge: implement support for finding existing merges Taylor Blau
2024-05-23 21:27   ` [PATCH v4 24/24] t/perf: implement performance tests for pseudo-merge bitmaps Taylor Blau
2024-05-25  3:26   ` [PATCH v4 00/24] pack-bitmap: pseudo-merge reachability bitmaps Jeff King

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