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Re: I want to ask a question...

From Joe Pfeiffer <pfeiffer@cs.nmsu.edu>
Newsgroups comp.lang.c
Subject Re: I want to ask a question...
Date 2015-08-21 09:20 -0600
Organization A noiseless patient Spider
Message-ID <1bfv3c652e.fsf@pfeifferfamily.net> (permalink)
References (8 earlier) <mr514a$688$1@dont-email.me> <slrnmtc48b.vvc.tTh@hangartistique.cispeo.fr> <mr59jh$b5v$1@dont-email.me> <mr5evc$24a$1@dont-email.me> <mr65hq$1eb$1@dont-email.me>

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James Kuyper <jameskuyper@verizon.net> writes:

> On 08/20/2015 04:58 PM, David Brown wrote:
> ...
>> I believe it is common for malloc implementations to ask the OS for 
>> large chunks of memory, then dish out parts of that as needed by the 
>> program.  This way they only bother the OS on occasion, and the overhead 
>> for malloc is much smaller (there are no context switches or system 
>> calls for most allocations).  Memory can only be returned to the OS if a 
>> whole chunk has been freed - ...
>
> I agree with all of the above.
>
>> ... and if the program has a mix of malloc's 
>> and free's, that is rarely going to happen.  It needs a program that has 
>> allocated a substantial amount of memory, freed it, and then continues 
>> running for a significant time without re-using that memory space.
>
> That doesn't strike me as a particular odd thing for a program to do.
> I've seen programs that have a memory-intensive set-up phase, after
> which they spend a lot of time waiting (sometimes for days or weeks at a
> time) for events to happen and reacting to them, without needing
> anywhere near as much memory. If I were using such a program, I'd be
> very upset that it was monopolizing it's entire initial memory
> requirement for the entire life of the program.

The stuff that was used at startup and never again gets paged out to the
swap space.  No problem.

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Thread

Re: I want to ask a question... Gareth Owen <gwowen@gmail.com> - 2015-08-07 20:00 +0100
  Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-07 19:04 +0000
  Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-07 15:30 -0700
    Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-07 22:52 +0000
      Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-07 16:46 -0700
        Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-07 23:29 +0000
          Re: I want to ask a question... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-08-08 01:37 +0100
          Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-07 18:55 -0700
            Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-08 05:51 +0000
              Re: I want to ask a question... Robert Wessel <robertwessel2@yahoo.com> - 2015-08-08 01:44 -0500
    Re: I want to ask a question... Ken Brody <kenbrody@spamcop.net> - 2015-08-10 12:46 -0400
    Re: I want to ask a question... supercat@casperkitty.com - 2015-08-19 16:43 -0700
      Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-19 18:09 -0700
        Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-20 01:00 +0000
          Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-19 20:25 -0700
            Re: I want to ask a question... supercat@casperkitty.com - 2015-08-20 08:15 -0700
              Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-20 11:38 -0700
                Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-20 18:47 +0000
                Re: I want to ask a question... supercat@casperkitty.com - 2015-08-20 14:01 -0700
            Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-20 16:43 +0000
              Re: I want to ask a question... James Kuyper <jameskuyper@verizon.net> - 2015-08-20 13:02 -0400
                Re: I want to ask a question... Tonton Th <tTh@nowhere.invalid> - 2015-08-20 17:40 +0000
                Re: I want to ask a question... James Kuyper <jameskuyper@verizon.net> - 2015-08-20 15:27 -0400
                Re: I want to ask a question... David Brown <david.brown@hesbynett.no> - 2015-08-20 22:58 +0200
                Re: I want to ask a question... James Kuyper <jameskuyper@verizon.net> - 2015-08-20 23:24 -0400
                Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-21 06:19 +0000
                Re: I want to ask a question... Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2015-08-21 09:20 -0600
                Re: I want to ask a question... supercat@casperkitty.com - 2015-08-22 12:25 -0700
                Re: I want to ask a question... Robert Wessel <robertwessel2@yahoo.com> - 2015-08-23 01:33 -0500
                Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-20 19:28 +0000
              Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-20 12:11 -0700
          Re: I want to ask a question... David Brown <david.brown@hesbynett.no> - 2015-08-20 10:02 +0200
        Re: I want to ask a question... raltbos@xs4all.nl (Richard Bos) - 2015-08-22 13:42 +0000
          Re: I want to ask a question... supercat@casperkitty.com - 2015-08-22 12:23 -0700

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