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From: Jeff King <peff@peff.net>
To: Michael Haggerty <mhagger@alum.mit.edu>
Cc: Junio C Hamano <gitster@pobox.com>,
	Nguyễn Thái Ngọc Duy <pclouds@gmail.com>,
	David Turner <novalis@novalis.org>,
	git@vger.kernel.org
Subject: Re: [PATCH 00/20] Separate `ref_cache` into a separate module
Date: Mon, 20 Mar 2017 14:12:45 -0400
Message-ID: <20170320181244.h5ce4rbadkharnki@sigill.intra.peff.net> (raw)
In-Reply-To: <cover.1490026594.git.mhagger@alum.mit.edu>

On Mon, Mar 20, 2017 at 05:33:05PM +0100, Michael Haggerty wrote:

> I've completed a draft of an epic 48-patch series implementing all of
> the above points on my GitHub fork [1] as branch
> `wip/mmap-packed-refs`. It dramatically speeds up performance and
> reduces memory usage for some tasks in repositories with very many
> packed references.

Having played a bit with the work-in-progress, I'm very excited about
the performance improvements.

> But the later parts of that series aren't completely polished yet, and
> such a large patch series would be indigestible anyway, so here I
> submit the first part...
> 
> This patch series extracts a `ref_cache` module out of
> `files_ref_cache`, and goes some way to disentangling those two
> modules, which until now were overly intimate with each other:
> [...]

I just read through it and didn't see anything objectionable. I had a
few questions, but I expect that most can be answered with an
explanation rather than a re-roll.

> Even after this patch series, the modules are still too intimate for
> my taste, but I think this is a big step forward, and it is enough to
> allow the other changes that I've been working on.

The resulting code looks like a big improvement in modularity to me. My
one complaint is that the virtual functions make it hard to dig through
the code. E.g., when looking at one patch I saw that we called
ref_iterator_peel(), and I wanted to know what that entailed. My editor
helpfully jumps straight to the definition, but of course it has nothing
useful; it's just a vtable wrapper. And I had to go dig up the name
"files_peel_ref()" manually.

I guess that's the price we pay for modularity.

-Peff

  parent reply index

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-20 16:33 Michael Haggerty
2017-03-20 16:33 ` [PATCH 01/20] get_ref_dir(): don't call read_loose_refs() for "refs/bisect" Michael Haggerty
2017-03-20 16:33 ` [PATCH 02/20] refs_read_raw_ref(): new function Michael Haggerty
2017-03-20 16:33 ` [PATCH 03/20] refs_ref_iterator_begin(): " Michael Haggerty
2017-03-20 16:33 ` [PATCH 04/20] refs_verify_refname_available(): implement once for all backends Michael Haggerty
2017-03-20 17:42   ` Jeff King
2017-03-20 22:20     ` Michael Haggerty
2017-03-20 16:33 ` [PATCH 05/20] refs_verify_refname_available(): use function in more places Michael Haggerty
2017-03-20 16:33 ` [PATCH 06/20] Rename `add_ref()` to `add_ref_entry()` Michael Haggerty
2017-03-20 16:33 ` [PATCH 07/20] Rename `find_ref()` to `find_ref_entry()` Michael Haggerty
2017-03-20 16:33 ` [PATCH 08/20] Rename `remove_entry()` to `remove_entry_from_dir()` Michael Haggerty
2017-03-20 16:33 ` [PATCH 09/20] refs: split `ref_cache` code into separate files Michael Haggerty
2017-03-20 17:49   ` Jeff King
2017-03-20 19:47     ` Junio C Hamano
2017-03-20 20:35       ` Stefan Beller
2017-03-20 22:40         ` Junio C Hamano
2017-03-20 16:33 ` [PATCH 10/20] ref-cache: introduce a new type, ref_cache Michael Haggerty
2017-03-20 16:33 ` [PATCH 11/20] refs: record the ref_store in ref_cache, not ref_dir Michael Haggerty
2017-03-20 17:51   ` Jeff King
2017-03-20 22:39     ` Michael Haggerty
2017-03-20 16:33 ` [PATCH 12/20] ref-cache: use a callback function to fill the cache Michael Haggerty
2017-03-20 16:33 ` [PATCH 13/20] refs: handle "refs/bisect/" in `loose_fill_ref_dir()` Michael Haggerty
2017-03-20 16:33 ` [PATCH 14/20] do_for_each_entry_in_dir(): eliminate `offset` argument Michael Haggerty
2017-03-20 16:33 ` [PATCH 15/20] get_loose_ref_dir(): function renamed from get_loose_refs() Michael Haggerty
2017-03-20 16:33 ` [PATCH 16/20] get_loose_ref_cache(): new function Michael Haggerty
2017-03-20 16:33 ` [PATCH 17/20] cache_ref_iterator_begin(): make function smarter Michael Haggerty
2017-03-20 16:33 ` [PATCH 18/20] commit_packed_refs(): use reference iteration Michael Haggerty
2017-03-20 18:05   ` Jeff King
2017-03-22  8:42     ` Michael Haggerty
2017-03-22 13:06       ` Jeff King
2017-03-20 16:33 ` [PATCH 19/20] files_pack_refs(): " Michael Haggerty
2017-03-20 16:33 ` [PATCH 20/20] do_for_each_entry_in_dir(): delete function Michael Haggerty
2017-03-20 17:25 ` [PATCH 00/20] Separate `ref_cache` into a separate module Junio C Hamano
2017-03-20 18:12 ` Jeff King [this message]
2017-03-20 18:24 ` Ævar Arnfjörð Bjarmason
2017-03-20 18:30   ` Jeff King
2017-03-20 22:32 ` Junio C Hamano
2017-03-20 22:48   ` Michael Haggerty

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