From: Stefan Monnier <monnier@IRO.UMontreal.CA>
To: Dmitry Antipov <dmantipov@yandex.ru>
Cc: emacs-devel@gnu.org
Subject: Re: Proposal: block-based vector allocator
Date: Thu, 31 May 2012 17:16:12 -0400 [thread overview]
Message-ID: <jwvfwagt6iq.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <4FC775B5.30904@yandex.ru> (Dmitry Antipov's message of "Thu, 31 May 2012 17:44:21 +0400")
> +#define VECTOR_BLOCK_SIZE 4096
This needs a comment explaining the choice of constant. E.g. it should
say that the code makes no particular assumption about this constant, so
it does not have to be a power of 2.
> + /* On a 32-bit system, rounding up vector size (in bytes) up
> + to mult-of-8 helps to maintain mult-of-8 alignment. */
> + roundup_size = 8
IIUC what the comment should say is something more like "Used to ensure
alignment (e.g. LSB_TAG requires this to be a multiple of 8), as well as
reduce the size of the vector_free_lists array".
> +#define VECTORS_PER_BLOCK_MAX \
> + (VECTOR_BLOCK_BYTES / sizeof (struct vectorlike_header))
Unused.
> +/* We maintain one free list for each possible block-allocated
> + vector size, and this is now much of the free lists we have. */
Should "now much of the" be replace by "the number of"?
> +struct vector_block
> +{
> + unsigned char data[VECTOR_BLOCK_BYTES];
> + struct vector_block *next;
> +};
Wouldn't it be easier to define VECTOR_BLOCK_BYTES to be an arbitrary
constant, and then VECTOR_BLOCK_SIZE to be "sizeof (struct vector_block)"?
> - return (p == m->start && m->type == MEM_TYPE_VECTORLIKE);
> + if (m->type == MEM_TYPE_VECTORLIKE)
> + {
> + if (m->end - m->start == VECTOR_BLOCK_BYTES)
Please just use a new MEM_TYPE, so we don't need to worry about the
possibility of having a non-vector-block which just happens to have the
same size as a vector-block.
Other than that (and Paul's comments), this looks good, thank you very
much,
Stefan
next prev parent reply other threads:[~2012-05-31 21:16 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-06 5:22 Proposal: block-based vector allocator Dmitry Antipov
2011-12-06 13:35 ` Stefan Monnier
2011-12-06 15:14 ` Dmitry Antipov
2011-12-06 19:39 ` Stefan Monnier
2011-12-07 5:05 ` Dmitry Antipov
2011-12-07 12:27 ` Carsten Mattner
2011-12-07 13:52 ` Stefan Monnier
2011-12-07 16:08 ` Dmitry Antipov
2011-12-07 16:30 ` Stefan Monnier
2011-12-08 8:50 ` Dmitry Antipov
2011-12-08 13:52 ` Stefan Monnier
2011-12-08 1:53 ` Stephen J. Turnbull
2011-12-08 4:41 ` Dmitry Antipov
2011-12-08 14:10 ` Stefan Monnier
2011-12-08 16:48 ` Dmitry Antipov
2011-12-08 19:58 ` Stefan Monnier
2011-12-09 7:32 ` Eli Zaretskii
2011-12-09 9:04 ` Dmitry Antipov
2011-12-09 14:05 ` Stefan Monnier
2011-12-09 16:15 ` Dmitry Antipov
2011-12-09 21:04 ` Stefan Monnier
2011-12-11 13:18 ` Dmitry Antipov
2011-12-12 3:07 ` Dmitry Antipov
2011-12-12 16:24 ` Stefan Monnier
2011-12-09 4:44 ` Stephen J. Turnbull
[not found] ` <jwvaa1yjs21.fsf-monnier+emacs@gnu.org>
2012-05-17 7:58 ` Dmitry Antipov
2012-05-18 17:40 ` Stefan Monnier
2012-05-21 12:19 ` Dmitry Antipov
2012-05-21 13:02 ` Andreas Schwab
2012-05-21 13:48 ` Dmitry Antipov
2012-05-21 15:07 ` Andreas Schwab
2012-05-22 5:23 ` Ken Raeburn
2012-05-21 20:12 ` Stefan Monnier
2012-05-22 8:24 ` Dmitry Antipov
2012-05-31 13:44 ` Dmitry Antipov
2012-05-31 15:43 ` Paul Eggert
2012-06-01 5:15 ` Dmitry Antipov
2012-06-01 5:44 ` Paul Eggert
2012-06-01 9:06 ` Dmitry Antipov
2012-06-01 17:36 ` Stefan Monnier
2012-06-02 0:32 ` Paul Eggert
2012-06-02 7:41 ` Eli Zaretskii
2012-06-03 6:49 ` Paul Eggert
2012-06-03 14:26 ` Eli Zaretskii
2012-05-31 21:16 ` Stefan Monnier [this message]
2012-06-01 7:34 ` Dmitry Antipov
2012-06-01 17:40 ` Stefan Monnier
2012-06-01 17:43 ` Stefan Monnier
2012-06-06 7:02 ` Dmitry Antipov
2012-06-06 13:13 ` Stefan Monnier
2012-06-06 14:58 ` Dmitry Antipov
2012-06-06 19:18 ` Stefan Monnier
2012-06-07 10:03 ` Dmitry Antipov
2012-06-07 14:07 ` Stefan Monnier
2012-06-08 5:50 ` Dmitry Antipov
2012-06-08 6:17 ` Stefan Monnier
2012-06-08 8:49 ` Dmitry Antipov
2012-06-08 8:53 ` Eli Zaretskii
2012-06-08 9:41 ` Eli Zaretskii
2012-06-08 10:00 ` Eli Zaretskii
2012-06-08 6:57 ` Eli Zaretskii
2012-06-08 6:38 ` Paul Eggert
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