From: Derrick Stolee <stolee@gmail.com>
To: Taylor Blau <me@ttaylorr.com>, git@vger.kernel.org
Cc: peff@peff.net, jrnieder@gmail.com
Subject: Re: [PATCH 16/20] builtin/gc.c: guess the size of the revindex
Date: Mon, 11 Jan 2021 06:52:24 -0500 [thread overview]
Message-ID: <87cd1b2c-7a28-da77-4ae4-99ffbbdfda72@gmail.com> (raw)
In-Reply-To: <7c17db7a7df8b524f13969efd1cb5e6e95de5a2d.1610129796.git.me@ttaylorr.com>
On 1/8/2021 1:17 PM, Taylor Blau wrote:
> 'estimate_repack_memory()' takes into account the amount of memory
> required to load the reverse index in memory by multiplying the assumed
> number of objects by the size of the 'revindex_entry' struct.
>
> Prepare for hiding the definition of 'struct revindex_entry' by removing
> a 'sizeof()' of that type from outside of pack-revindex.c. Instead,
> guess that one off_t and one uint32_t are required per object. Strictly
> speaking, this is a worse guess than asking for 'sizeof(struct
> revindex_entry)' directly, since the true size of this struct is 16
> bytes with padding on the end of the struct in order to align the offset
> field.
This is so far the only not-completely-obvious change.
> But, this is an approximation anyway, and it does remove a use of the
> 'struct revindex_entry' from outside of pack-revindex internals.
And this might be enough justification for it, but...
> - heap += sizeof(struct revindex_entry) * nr_objects;
> + heap += (sizeof(off_t) + sizeof(uint32_t)) * nr_objects;
...outside of the estimation change, will this need another change
when the rev-index is mmap'd? Should this instead be an API call,
such as estimate_rev_index_memory(nr_objects)? That would
centralize the estimate to be next to the code that currently
interacts with 'struct revindex_entry' and will later interact with
the mmap region.
Thanks,
-Stolee
next prev parent reply other threads:[~2021-01-11 11:54 UTC|newest]
Thread overview: 121+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-08 18:16 [PATCH 00/20] pack-revindex: prepare for on-disk reverse index Taylor Blau
2021-01-08 18:16 ` [PATCH 01/20] pack-revindex: introduce a new API Taylor Blau
2021-01-12 8:41 ` Jeff King
2021-01-12 9:41 ` Jeff King
2021-01-12 16:27 ` Taylor Blau
2021-01-13 8:06 ` Junio C Hamano
2021-01-13 8:54 ` Junio C Hamano
2021-01-13 13:17 ` Jeff King
2021-01-13 16:23 ` Taylor Blau
2021-01-08 18:16 ` [PATCH 02/20] write_reuse_object(): convert to new revindex API Taylor Blau
2021-01-12 8:47 ` Jeff King
2021-01-12 16:31 ` Taylor Blau
2021-01-13 13:02 ` Jeff King
2021-01-08 18:16 ` [PATCH 03/20] write_reused_pack_one(): " Taylor Blau
2021-01-12 8:50 ` Jeff King
2021-01-12 16:34 ` Taylor Blau
2021-01-08 18:16 ` [PATCH 04/20] write_reused_pack_verbatim(): " Taylor Blau
2021-01-12 8:50 ` Jeff King
2021-01-08 18:17 ` [PATCH 05/20] check_object(): " Taylor Blau
2021-01-11 11:43 ` Derrick Stolee
2021-01-11 16:15 ` Taylor Blau
2021-01-12 8:54 ` Jeff King
2021-01-12 8:51 ` Jeff King
2021-01-08 18:17 ` [PATCH 06/20] bitmap_position_packfile(): " Taylor Blau
2021-01-08 18:17 ` [PATCH 07/20] show_objects_for_type(): " Taylor Blau
2021-01-12 8:57 ` Jeff King
2021-01-12 16:35 ` Taylor Blau
2021-01-08 18:17 ` [PATCH 08/20] get_size_by_pos(): " Taylor Blau
2021-01-08 18:17 ` [PATCH 09/20] try_partial_reuse(): " Taylor Blau
2021-01-12 9:06 ` Jeff King
2021-01-12 16:47 ` Taylor Blau
2021-01-08 18:17 ` [PATCH 10/20] rebuild_existing_bitmaps(): " Taylor Blau
2021-01-08 18:17 ` [PATCH 11/20] get_delta_base_oid(): " Taylor Blau
2021-01-08 18:17 ` [PATCH 12/20] retry_bad_packed_offset(): " Taylor Blau
2021-01-08 18:17 ` [PATCH 13/20] packed_object_info(): " Taylor Blau
2021-01-12 9:11 ` Jeff King
2021-01-12 16:51 ` Taylor Blau
2021-01-08 18:17 ` [PATCH 14/20] unpack_entry(): " Taylor Blau
2021-01-12 9:22 ` Jeff King
2021-01-12 16:56 ` Taylor Blau
2021-01-08 18:17 ` [PATCH 15/20] for_each_object_in_pack(): " Taylor Blau
2021-01-08 18:17 ` [PATCH 16/20] builtin/gc.c: guess the size of the revindex Taylor Blau
2021-01-11 11:52 ` Derrick Stolee [this message]
2021-01-11 16:23 ` Taylor Blau
2021-01-11 17:09 ` Derrick Stolee
2021-01-12 9:28 ` Jeff King
2021-01-08 18:17 ` [PATCH 17/20] pack-revindex: remove unused 'find_pack_revindex()' Taylor Blau
2021-01-08 18:17 ` [PATCH 18/20] pack-revindex: remove unused 'find_revindex_position()' Taylor Blau
2021-01-11 11:57 ` Derrick Stolee
2021-01-11 16:27 ` Taylor Blau
2021-01-11 17:11 ` Derrick Stolee
2021-01-12 9:32 ` Jeff King
2021-01-12 16:59 ` Taylor Blau
2021-01-13 13:05 ` Jeff King
2021-01-08 18:18 ` [PATCH 19/20] pack-revindex: hide the definition of 'revindex_entry' Taylor Blau
2021-01-11 11:57 ` Derrick Stolee
2021-01-12 9:34 ` Jeff King
2021-01-08 18:18 ` [PATCH 20/20] pack-revindex.c: avoid direct revindex access in 'offset_to_pack_pos()' Taylor Blau
2021-01-12 9:37 ` Jeff King
2021-01-12 17:02 ` Taylor Blau
2021-01-11 12:07 ` [PATCH 00/20] pack-revindex: prepare for on-disk reverse index Derrick Stolee
2021-01-11 16:30 ` Taylor Blau
2021-01-11 17:15 ` Derrick Stolee
2021-01-11 17:29 ` Taylor Blau
2021-01-11 18:40 ` Junio C Hamano
2021-01-12 9:45 ` Jeff King
2021-01-12 17:07 ` Taylor Blau
2021-01-13 0:23 ` Junio C Hamano
2021-01-13 0:52 ` Taylor Blau
2021-01-13 2:15 ` Junio C Hamano
2021-01-13 3:23 ` Taylor Blau
2021-01-13 8:21 ` Junio C Hamano
2021-01-13 13:13 ` Jeff King
2021-01-13 15:34 ` Taylor Blau
2021-01-13 20:06 ` Junio C Hamano
2021-01-13 20:13 ` Taylor Blau
2021-01-13 20:22 ` Jeff King
2021-01-13 22:23 ` [PATCH v2 " Taylor Blau
2021-01-13 22:23 ` [PATCH v2 01/20] pack-revindex: introduce a new API Taylor Blau
2021-01-14 6:46 ` Junio C Hamano
2021-01-14 12:00 ` Derrick Stolee
2021-01-14 17:06 ` Taylor Blau
2021-01-14 19:19 ` Jeff King
2021-01-14 20:47 ` Junio C Hamano
2021-01-13 22:23 ` [PATCH v2 02/20] write_reuse_object(): convert to new revindex API Taylor Blau
2021-01-13 22:23 ` [PATCH v2 03/20] write_reused_pack_one(): " Taylor Blau
2021-01-13 22:23 ` [PATCH v2 04/20] write_reused_pack_verbatim(): " Taylor Blau
2021-01-13 22:23 ` [PATCH v2 05/20] check_object(): " Taylor Blau
2021-01-13 22:23 ` [PATCH v2 06/20] bitmap_position_packfile(): " Taylor Blau
2021-01-13 22:23 ` [PATCH v2 07/20] show_objects_for_type(): " Taylor Blau
2021-01-13 22:24 ` [PATCH v2 08/20] get_size_by_pos(): " Taylor Blau
2021-01-13 22:24 ` [PATCH v2 09/20] try_partial_reuse(): " Taylor Blau
2021-01-13 22:24 ` [PATCH v2 10/20] rebuild_existing_bitmaps(): " Taylor Blau
2021-01-13 22:24 ` [PATCH v2 11/20] get_delta_base_oid(): " Taylor Blau
2021-01-13 22:24 ` [PATCH v2 12/20] retry_bad_packed_offset(): " Taylor Blau
2021-01-13 22:24 ` [PATCH v2 13/20] packed_object_info(): " Taylor Blau
2021-01-13 22:24 ` [PATCH v2 14/20] unpack_entry(): " Taylor Blau
2021-01-13 22:24 ` [PATCH v2 15/20] for_each_object_in_pack(): " Taylor Blau
2021-01-14 6:43 ` Junio C Hamano
2021-01-14 17:00 ` Taylor Blau
2021-01-14 19:33 ` Jeff King
2021-01-14 20:11 ` Jeff King
2021-01-14 20:15 ` Taylor Blau
2021-01-15 2:22 ` Junio C Hamano
2021-01-15 2:29 ` Taylor Blau
2021-01-14 20:51 ` Junio C Hamano
2021-01-13 22:24 ` [PATCH v2 16/20] builtin/gc.c: guess the size of the revindex Taylor Blau
2021-01-14 6:33 ` Junio C Hamano
2021-01-14 16:53 ` Taylor Blau
2021-01-14 19:43 ` Jeff King
2021-01-13 22:24 ` [PATCH v2 17/20] pack-revindex: remove unused 'find_pack_revindex()' Taylor Blau
2021-01-13 22:25 ` [PATCH v2 18/20] pack-revindex: remove unused 'find_revindex_position()' Taylor Blau
2021-01-14 6:42 ` Junio C Hamano
2021-01-13 22:25 ` [PATCH v2 19/20] pack-revindex: hide the definition of 'revindex_entry' Taylor Blau
2021-01-13 22:25 ` [PATCH v2 20/20] pack-revindex.c: avoid direct revindex access in 'offset_to_pack_pos()' Taylor Blau
2021-01-14 6:42 ` Junio C Hamano
2021-01-14 16:56 ` Taylor Blau
2021-01-14 19:51 ` [PATCH v2 00/20] pack-revindex: prepare for on-disk reverse index Jeff King
2021-01-14 20:53 ` Junio C Hamano
2021-01-15 9:32 ` Jeff King
2021-01-15 9:33 ` Jeff King
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=87cd1b2c-7a28-da77-4ae4-99ffbbdfda72@gmail.com \
--to=stolee@gmail.com \
--cc=git@vger.kernel.org \
--cc=jrnieder@gmail.com \
--cc=me@ttaylorr.com \
--cc=peff@peff.net \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).