Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.c > #72132

Re: Cheap malloc()

Show all headers | View raw

On 06.10.2015 14:47, Bartc wrote:
> On 05/10/2015 13:09, Philipp Klaus Krause wrote:
> 
>> But I didn't find something on
>> making memory management cheaper in terms of overhead.
>>
>> So I came up with the following idea, which seems quite natural to me,
>> but I haven't seen it anywhere else. It only stores a single pointer per
>> allocated block, and has thus quite low overhead.
> 
>> It uses a linked list of blocks. Each block is either allocated or free.
>> The list of free blocks comes and no memory cost, since it is stored in
>> free blocks only
> 
> How does it know the size of each block? Or is each block always linked
> to the next sequential one?

Yes. Each one is linked to the next one. That is the one pointer stored
in every block, and the only overhead.

> 
>> Are there other malloc() implementations with such low overhead around?
> 
>> P.S.: The malloc() is intended to replace the current one in SDCC, and
>> thus is intended to work well for SDCC's target architectures - 8-bit
>> with no alignment restrictions, typically 128B to 64KB of RAM; the XDATA
>> is defined as a named address space for sometarget architectures (8051
>> and related).
> 
> If this is to replace a normal malloc() and thus have to support
> conventional malloc/free calls of someone else's code, then your hands
> are tied somewhat.
> 
> […]
> 

It is supposed to replace the memory management that SDCC currently
provides.

Philipp

Back to comp.lang.c | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

Cheap malloc() Philipp Klaus Krause <pkk@spth.de> - 2015-10-05 14:09 +0200
  Re: Cheap malloc() Robert Wessel <robertwessel2@yahoo.com> - 2015-10-05 09:52 -0500
  Re: Cheap malloc() Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-05 11:04 -0400
    Re: Cheap malloc() BGB <cr88192@hotmail.com> - 2015-10-05 20:36 -0500
    Re: Cheap malloc() Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-06 07:54 -0400
      Re: Cheap malloc() BGB <cr88192@hotmail.com> - 2015-10-06 08:06 -0500
        Re: Cheap malloc() Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-07 07:46 -0400
          Re: Cheap malloc() BGB <cr88192@hotmail.com> - 2015-10-07 07:35 -0500
      Re: Cheap malloc() glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-06 23:29 +0000
  Re: Cheap malloc() supercat@casperkitty.com - 2015-10-05 08:12 -0700
  Re: Cheap malloc() glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-05 16:34 +0000
    Re: Cheap malloc() Philipp Klaus Krause <pkk@spth.de> - 2015-10-07 14:50 +0200
      Re: Cheap malloc() BGB <cr88192@hotmail.com> - 2015-10-07 08:45 -0500
        Re: Cheap malloc() Philipp Klaus Krause <pkk@spth.de> - 2015-10-07 19:33 +0200
          Re: Cheap malloc() BGB <cr88192@hotmail.com> - 2015-10-07 15:40 -0500
      Re: Cheap malloc() glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-10-08 01:10 +0000
        Re: Cheap malloc() Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-08 08:08 -0400
  Re: Cheap malloc() Bartc <bc@freeuk.com> - 2015-10-06 13:47 +0100
    Re: Cheap malloc() Philipp Klaus Krause <pkk@spth.de> - 2015-10-07 14:48 +0200

csiph-web