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From: Junio C Hamano <gitster@pobox•com>
To: Jeff King <peff@peff•net>
Cc: git@vger•kernel.org, Christian Couder <chriscool@tuxfamily•org>,
	Jakub Narebski <jnareb@gmail•com>,
	Eric Sunshine <sunshine@sunshineco•com>
Subject: Re: [PATCH 15/17] commit-slab: provide a static initializer
Date: Thu, 12 Jun 2014 11:15:49 -0700	[thread overview]
Message-ID: <xmqq7g4m6lka.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <20140610214251.GO19147@sigill.intra.peff.net> (Jeff King's message of "Tue, 10 Jun 2014 17:42:51 -0400")

Jeff King <peff@peff•net> writes:

> Callers currently must use init_foo_slab() at runtime before
> accessing a slab. For global slabs, it's much nicer if we
> can initialize them in BSS, so that each user does not have
> to add code to check-and-initialize.
>
> Signed-off-by: Jeff King <peff@peff•net>
> ---
> There was no comment on this one in v1. I'd be curious if anyone has
> comments on what I wrote in:
>
>   http://article.gmane.org/gmane.comp.version-control.git/251099

Why do we need an initialiser at this point (in other words, how
have other existing slab users coped without having one)?

I think they call init_*_slab() when the slab is needed/used the
first time (e.g. it is not even worth initialising indegree slab
unless we are sorting in topo order).

Unlike the author-date and indegree slabs, there are too many entry
points that may want access to the buffer slab (save_commit_buffer's
default being on does not help us either), so it would be much less
error prone to always initialise a static slab like this patch does,
I guess.


>  commit-slab.h | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/commit-slab.h b/commit-slab.h
> index cc114b5..375c9c7 100644
> --- a/commit-slab.h
> +++ b/commit-slab.h
> @@ -117,4 +117,16 @@ static int stat_ ##slabname## realloc
>   * catch because GCC silently parses it by default.
>   */
>  
> +/*
> + * Statically initialize a commit slab named "var". Note that this
> + * evaluates "stride" multiple times! Example:
> + *
> + *   struct indegree indegrees = COMMIT_SLAB_INIT(1, indegrees);
> + *
> + */
> +#define COMMIT_SLAB_INIT(stride, var) { \
> +	COMMIT_SLAB_SIZE / sizeof(**((var).slab)) / (stride), \
> +	(stride), 0, NULL \
> +}
> +
>  #endif /* COMMIT_SLAB_H */

  reply	other threads:[~2014-06-12 18:16 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-09 18:02 [PATCH 0/15] store length of commit->buffer Jeff King
2014-06-09 18:09 ` [PATCH 01/15] alloc: include any-object allocations in alloc_report Jeff King
2014-06-09 18:09 ` [PATCH 02/15] commit: push commit_index update into alloc_commit_node Jeff King
2014-06-10 21:31   ` Junio C Hamano
2014-06-09 18:10 ` [PATCH 03/15] do not create "struct commit" with xcalloc Jeff King
2014-06-10 21:35   ` Junio C Hamano
2014-06-10 21:49     ` Jeff King
2014-06-09 18:10 ` [PATCH 04/15] logmsg_reencode: return const buffer Jeff King
2014-06-10  1:36   ` Eric Sunshine
2014-06-09 18:10 ` [PATCH 05/15] sequencer: use logmsg_reencode in get_message Jeff King
2014-06-10 21:40   ` Junio C Hamano
2014-06-10 21:50     ` Jeff King
2014-06-09 18:11 ` [PATCH 06/15] provide a helper to free commit buffer Jeff King
2014-06-09 18:11 ` [PATCH 07/15] provide a helper to set the " Jeff King
2014-06-09 18:11 ` [PATCH 08/15] provide helpers to access " Jeff King
2014-06-10  8:00   ` Eric Sunshine
2014-06-09 18:12 ` [PATCH 09/15] use get_cached_commit_buffer where appropriate Jeff King
2014-06-09 18:12 ` [PATCH 10/15] use get_commit_buffer to avoid duplicate code Jeff King
2014-06-10  8:01   ` Eric Sunshine
2014-06-10 20:34     ` Jeff King
2014-06-09 18:13 ` [PATCH 11/15] convert logmsg_reencode to get_commit_buffer Jeff King
2014-06-09 18:13 ` [PATCH 12/15] use get_commit_buffer everywhere Jeff King
2014-06-09 22:40   ` Junio C Hamano
2014-06-10  0:02     ` Jeff King
2014-06-10  0:22       ` Jeff King
2014-06-10 16:06       ` Junio C Hamano
2014-06-10 21:27         ` Jeff King
2014-06-09 18:15 ` [PATCH 13/15] commit-slab: provide a static initializer Jeff King
2014-06-09 18:15 ` [PATCH 14/15] commit: convert commit->buffer to a slab Jeff King
2014-06-09 18:15 ` [PATCH 15/15] commit: record buffer length in cache Jeff King
2014-06-10  5:12   ` Christian Couder
2014-06-10  5:27     ` Jeff King
2014-06-10 20:33       ` Jeff King
2014-06-10 21:30         ` Christian Couder
2014-06-10 21:35 ` [PATCH v2 0/17] store length of commit->buffer Jeff King
2014-06-10 21:36   ` [PATCH 01/17] commit_tree: take a pointer/len pair rather than a const strbuf Jeff King
2014-06-10 21:38   ` [PATCH 02/17] replace dangerous uses of strbuf_attach Jeff King
2014-06-10 21:38   ` [PATCH 03/17] alloc: include any-object allocations in alloc_report Jeff King
2014-06-10 21:39   ` [PATCH 04/17] commit: push commit_index update into alloc_commit_node Jeff King
2014-06-10 21:39   ` [PATCH 05/17] do not create "struct commit" with xcalloc Jeff King
2014-06-10 21:39   ` [PATCH 06/17] logmsg_reencode: return const buffer Jeff King
2014-06-10 21:39   ` [PATCH 07/17] sequencer: use logmsg_reencode in get_message Jeff King
2014-06-10 21:40   ` [PATCH 08/17] provide a helper to free commit buffer Jeff King
2014-06-12 18:22     ` Junio C Hamano
2014-06-12 20:08       ` Jeff King
2014-06-12 22:05         ` Jeff King
2014-06-10 21:40   ` [PATCH 09/17] provide a helper to set the " Jeff King
2014-06-10 21:40   ` [PATCH 10/17] provide helpers to access " Jeff King
2014-06-10 21:40   ` [PATCH 11/17] use get_cached_commit_buffer where appropriate Jeff King
2014-06-10 21:41   ` [PATCH 12/17] use get_commit_buffer to avoid duplicate code Jeff King
2014-06-10 21:41   ` [PATCH 13/17] convert logmsg_reencode to get_commit_buffer Jeff King
2014-06-10 21:41   ` [PATCH 14/17] use get_commit_buffer everywhere Jeff King
2014-06-10 21:42   ` [PATCH 15/17] commit-slab: provide a static initializer Jeff King
2014-06-12 18:15     ` Junio C Hamano [this message]
2014-06-12 19:51       ` Jeff King
2014-06-10 21:43   ` [PATCH 16/17] commit: convert commit->buffer to a slab Jeff King
2014-06-10 21:44   ` [PATCH 17/17] commit: record buffer length in cache Jeff King
2014-06-10 21:46   ` [PATCH v2 0/17] store length of commit->buffer Jeff King
2014-06-12 17:22     ` Junio C Hamano
2014-06-13  6:32   ` [PATCH v2] reuse cached commit buffer when parsing signatures Jeff King

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