From: Thomas Rast <trast@student.ethz.ch>
To: Junio C Hamano <gitster@pobox.com>
Cc: Dmitry Potapov <dpotapov@gmail.com>,
Zygo Blaxell <zblaxell@esightcorp.com>,
Ilari Liusvaara <ilari.liusvaara@elisanet.fi>,
Jonathan Nieder <jrnieder@gmail.com>, <git@vger.kernel.org>
Subject: Re: [PATCH] don't use mmap() to hash files
Date: Sun, 14 Feb 2010 12:14:14 +0100 [thread overview]
Message-ID: <201002141214.15025.trast@student.ethz.ch> (raw)
In-Reply-To: <7v8wawy0ee.fsf@alter.siamese.dyndns.org>
On Sunday 14 February 2010 04:14:01 Junio C Hamano wrote:
> Later, we might want to split the codepath again to:
>
> (0) see if it is huge or small if we are not reading from pipe;
>
> (1) if we do not know the size or if it is moderately tiny, keep doing
> what your code does;
>
> (2) if we know we are reading something huge with known size, then have a
> loop to read-a-bit-compress-and-write-it-out-while-hashing, and
> finally rename the loose resulting object to the final name. Or we
> may even want to do that into a new pack on its own.
There's a slight problem with that code (I tried to finish last
night's attempt but got stuck on this):
The create_tmpfile() and move_temp_to_file() duo goes to some lengths
to ensure that the file is created in the same directory that we want
it to end up in. However, in the block-based scheme, you cannot know
which directory this will be before you have already written the
entire output.
So again I guess there are a few possible solutions:
* Try the cross-directory rename anyway, but if it doesn't work,
copy&unlink. This of course means that you may write the same
object over network twice.
* Declare that keeping the memory usage near what it is today (the
full output buffer plus a constant) is okay.
* Give up and stick with Dmitry's patch :-)
--
Thomas Rast
trast@{inf,student}.ethz.ch
next prev parent reply other threads:[~2010-02-14 11:14 UTC|newest]
Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20100211234753.22574.48799.reportbug@gibbs.hungrycats.org>
2010-02-12 0:27 ` Bug#569505: git-core: 'git add' corrupts repository if the working directory is modified as it runs Jonathan Nieder
2010-02-12 1:23 ` Zygo Blaxell
2010-02-13 12:12 ` Jonathan Nieder
2010-02-13 13:39 ` Ilari Liusvaara
2010-02-13 14:39 ` Thomas Rast
2010-02-13 16:29 ` Ilari Liusvaara
2010-02-13 22:09 ` Dmitry Potapov
2010-02-13 22:37 ` Zygo Blaxell
2010-02-14 1:18 ` [PATCH] don't use mmap() to hash files Dmitry Potapov
2010-02-14 1:37 ` Junio C Hamano
2010-02-14 2:18 ` Dmitry Potapov
2010-02-14 3:14 ` Junio C Hamano
2010-02-14 11:14 ` Thomas Rast [this message]
2010-02-14 11:46 ` Junio C Hamano
2010-02-14 1:53 ` Johannes Schindelin
2010-02-14 2:00 ` Junio C Hamano
2010-02-14 2:42 ` Dmitry Potapov
2010-02-14 11:07 ` Jakub Narebski
2010-02-14 11:55 ` Paolo Bonzini
2010-02-14 18:10 ` Johannes Schindelin
2010-02-14 19:06 ` Dmitry Potapov
2010-02-14 19:22 ` Johannes Schindelin
2010-02-14 19:28 ` Johannes Schindelin
2010-02-14 19:56 ` Dmitry Potapov
2010-02-14 23:52 ` Zygo Blaxell
2010-02-15 5:05 ` Nicolas Pitre
2010-02-15 12:23 ` Dmitry Potapov
2010-02-15 7:48 ` Paolo Bonzini
2010-02-15 12:25 ` Dmitry Potapov
2010-02-14 19:55 ` Dmitry Potapov
2010-02-14 23:13 ` Avery Pennarun
2010-02-15 4:16 ` Nicolas Pitre
2010-02-15 5:01 ` Avery Pennarun
2010-02-15 5:48 ` Nicolas Pitre
2010-02-15 19:19 ` Avery Pennarun
2010-02-15 19:29 ` Nicolas Pitre
2010-02-14 3:05 ` [PATCH v2] " Dmitry Potapov
2010-02-18 1:16 ` [PATCH] Teach "git add" and friends to be paranoid Junio C Hamano
2010-02-18 1:20 ` Junio C Hamano
2010-02-18 15:32 ` Zygo Blaxell
2010-02-19 17:51 ` Junio C Hamano
2010-02-18 1:38 ` Jeff King
2010-02-18 4:55 ` Nicolas Pitre
2010-02-18 5:36 ` Junio C Hamano
2010-02-18 7:27 ` Wincent Colaiuta
2010-02-18 16:18 ` Zygo Blaxell
2010-02-18 18:12 ` Jonathan Nieder
2010-02-18 18:35 ` Junio C Hamano
2010-02-22 12:59 ` Paolo Bonzini
2010-02-22 13:33 ` Dmitry Potapov
2010-02-18 10:14 ` Thomas Rast
2010-02-18 18:16 ` Junio C Hamano
2010-02-18 19:58 ` Nicolas Pitre
2010-02-18 20:11 ` 16 gig, 350,000 file repository Bill Lear
2010-02-18 20:58 ` Nicolas Pitre
2010-02-19 9:27 ` Erik Faye-Lund
2010-02-22 22:20 ` Bill Lear
2010-02-22 22:31 ` Nicolas Pitre
2010-02-18 20:14 ` [PATCH] Teach "git add" and friends to be paranoid Peter Harris
2010-02-18 20:17 ` Junio C Hamano
2010-02-18 21:30 ` Nicolas Pitre
2010-02-19 1:04 ` Jonathan Nieder
2010-02-19 15:26 ` Zygo Blaxell
2010-02-19 17:52 ` Junio C Hamano
2010-02-19 19:08 ` Zygo Blaxell
2010-02-19 8:28 ` Dmitry Potapov
2010-02-19 17:52 ` Junio C Hamano
2010-02-20 19:23 ` Junio C Hamano
2010-02-21 7:21 ` Dmitry Potapov
2010-02-21 19:32 ` Junio C Hamano
2010-02-22 3:35 ` Dmitry Potapov
2010-02-22 6:59 ` Junio C Hamano
2010-02-22 12:25 ` Dmitry Potapov
2010-02-22 15:40 ` Nicolas Pitre
2010-02-22 16:01 ` Dmitry Potapov
2010-02-22 17:31 ` Zygo Blaxell
2010-02-22 18:01 ` Nicolas Pitre
2010-02-22 19:56 ` Junio C Hamano
2010-02-22 20:52 ` Nicolas Pitre
2010-02-22 18:05 ` Dmitry Potapov
2010-02-22 18:14 ` Nicolas Pitre
2010-02-14 1:36 ` mmap with MAP_PRIVATE is useless (was Re: Bug#569505: git-core: 'git add' corrupts repository if the working directory is modified as it runs) Paolo Bonzini
2010-02-14 1:53 ` mmap with MAP_PRIVATE is useless Junio C Hamano
2010-02-14 2:11 ` Paolo Bonzini
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
List information: http://vger.kernel.org/majordomo-info.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=201002141214.15025.trast@student.ethz.ch \
--to=trast@student.ethz.ch \
--cc=dpotapov@gmail.com \
--cc=git@vger.kernel.org \
--cc=gitster@pobox.com \
--cc=ilari.liusvaara@elisanet.fi \
--cc=jrnieder@gmail.com \
--cc=zblaxell@esightcorp.com \
/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.
Code repositories for project(s) associated with this public inbox
https://80x24.org/mirrors/git.git
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 read-only IMAP folder(s) and NNTP newsgroup(s).