From: Jeff King <peff@peff.net>
To: Michael Haggerty <mhagger@alum.mit.edu>
Cc: "Junio C Hamano" <gitster@pobox.com>,
"Stefan Beller" <sbeller@google.com>,
"Johannes Schindelin" <Johannes.Schindelin@gmx.de>,
"Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
"Brandon Williams" <bmwill@google.com>,
git@vger.kernel.org
Subject: Re: [PATCH v2 13/21] packed_ref_cache: keep the `packed-refs` file mmapped if possible
Date: Wed, 20 Sep 2017 14:51:20 -0400 [thread overview]
Message-ID: <20170920185119.upnyomtlxobxwvlw@sigill.intra.peff.net> (raw)
In-Reply-To: <20170920184058.w3tipgsz54ig7dm5@sigill.intra.peff.net>
On Wed, Sep 20, 2017 at 02:40:58PM -0400, Jeff King wrote:
> > +enum mmap_strategy {
> > + /*
> > + * Don't use mmap() at all for reading `packed-refs`.
> > + */
> > + MMAP_NONE,
> > +
> > + /*
> > + * Can use mmap() for reading `packed-refs`, but the file must
> > + * not remain mmapped. This is the usual option on Windows,
> > + * where you cannot rename a new version of a file onto a file
> > + * that is currently mmapped.
> > + */
> > + MMAP_TEMPORARY,
>
> I suspect you originally distinguished these cases so that NO_MMAP does
> not read into a fake-mmap buffer, followed by us copying it into another
> buffer. But AFAICT we handle the "NONE" and "TEMPORARY" cases exactly
> the same (by just doing a read_in_full() into our own buffer). Do we
> actually need separate strategies?
In case you are reading these sequentially, I think I talked myself into
the utility of this during the next patch. ;)
-Peff
next prev parent reply other threads:[~2017-09-20 18:51 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-19 6:22 [PATCH v2 00/21] Read `packed-refs` using mmap() Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 01/21] ref_iterator: keep track of whether the iterator output is ordered Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 02/21] prefix_ref_iterator: break when we leave the prefix Michael Haggerty
2017-09-20 20:25 ` Stefan Beller
2017-09-21 4:59 ` Jeff King
2017-09-21 17:29 ` Stefan Beller
2017-09-21 7:42 ` Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 03/21] packed_ref_cache: add a backlink to the associated `packed_ref_store` Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 04/21] die_unterminated_line(), die_invalid_line(): new functions Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 05/21] read_packed_refs(): use mmap to read the `packed-refs` file Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 06/21] read_packed_refs(): only check for a header at the top of the file Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 07/21] read_packed_refs(): make parsing of the header line more robust Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 08/21] read_packed_refs(): read references with minimal copying Michael Haggerty
2017-09-20 18:27 ` Jeff King
2017-09-21 7:34 ` Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 09/21] packed_ref_cache: remember the file-wide peeling state Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 10/21] mmapped_ref_iterator: add iterator over a packed-refs file Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 11/21] mmapped_ref_iterator_advance(): no peeled value for broken refs Michael Haggerty
2017-09-20 18:29 ` Jeff King
2017-09-19 6:22 ` [PATCH v2 12/21] packed-backend.c: reorder some definitions Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 13/21] packed_ref_cache: keep the `packed-refs` file mmapped if possible Michael Haggerty
2017-09-19 12:44 ` Michael Haggerty
2017-09-24 6:56 ` Junio C Hamano
2017-09-20 18:40 ` Jeff King
2017-09-20 18:51 ` Jeff King [this message]
2017-09-21 8:04 ` Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 14/21] read_packed_refs(): ensure that references are ordered when read Michael Haggerty
2017-09-20 18:50 ` Jeff King
2017-09-21 8:27 ` Michael Haggerty
2017-09-25 15:44 ` Johannes Schindelin
2017-09-19 6:22 ` [PATCH v2 15/21] packed_ref_iterator_begin(): iterate using `mmapped_ref_iterator` Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 16/21] packed_read_raw_ref(): read the reference from the mmapped buffer Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 17/21] ref_store: implement `refs_peel_ref()` generically Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 18/21] packed_ref_store: get rid of the `ref_cache` entirely Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 19/21] ref_cache: remove support for storing peeled values Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 20/21] mmapped_ref_iterator: inline into `packed_ref_iterator` Michael Haggerty
2017-09-19 6:22 ` [PATCH v2 21/21] packed-backend.c: rename a bunch of things and update comments Michael Haggerty
2017-09-19 19:53 ` [PATCH v2 00/21] Read `packed-refs` using mmap() Johannes Schindelin
2017-09-20 18:57 ` Jeff King
2017-09-25 15:55 ` Johannes Schindelin
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=20170920185119.upnyomtlxobxwvlw@sigill.intra.peff.net \
--to=peff@peff.net \
--cc=Johannes.Schindelin@gmx.de \
--cc=avarab@gmail.com \
--cc=bmwill@google.com \
--cc=git@vger.kernel.org \
--cc=gitster@pobox.com \
--cc=mhagger@alum.mit.edu \
--cc=pclouds@gmail.com \
--cc=sbeller@google.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).