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| From | Stephen Sprunk <stephen@sprunk.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Will 'free' return the memory Immediately to the OS ? |
| Date | 2012-05-18 17:27 -0500 |
| Organization | A noiseless patient Spider |
| Message-ID | <jp6ic1$lp6$1@dont-email.me> (permalink) |
| References | <joui61$898$1@speranza.aioe.org> <5co7r7hdgsp3ijgohvueekl1h0a40cr3do@4ax.com> <jp1dmr$gen$1@dont-email.me> <i20ar71d8m427086mra7ortps5up3tqa7v@4ax.com> <jp68q1$1ra$1@reader1.panix.com> |
On 18-May-12 14:44, Joe keane wrote: > In article <i20ar71d8m427086mra7ortps5up3tqa7v@4ax.com>, > David T. Ashley <dashley@gmail.com> wrote: >> I figured with a modern PC having maybe 4G of memory, you might want >> to divide the memory into maybe 1,000 - 10,000 pages, so I would have >> figured page sizes in the range of 512K - 4M. 4K surprises me. > > The OS can have a larger page size. It's easy to make 16 KB pages on > hardware that is designed for 4 KB pages. But not the other way around. You can _emulate_ larger pages by always handling several of them at the same time, but the hardware does what the hardware does. I question whether this is a good idea. Any reduction in page faults due to loading multiple pages at a time is likely to be offset by an increase in page faults due to evicting multiple pages at a time. So, overall, you spend more time swapping pages to/from disk for no gain. > The size of a 'segment' [unit that the memory management requests more > space from the OS] would be more like 2 MB. "Segment" has a very different meaning on many architectures. Also, I would expect malloc() et al to request/release memory from the OS in whatever multiple of the page size it found convenient, not some arbitrarily large (or small, for some workloads) amount like 2MB. S -- Stephen Sprunk "God does not play dice." --Albert Einstein CCIE #3723 "God is an inveterate gambler, and He throws the K5SSS dice at every possible opportunity." --Stephen Hawking
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Will 'free' return the memory Immediately to the OS ? Raj Pashwar <raj121190@hotmail.NOSPAM.com> - 2012-05-15 21:34 +0000
Re: Will 'free' return the memory Immediately to the OS ? Ian Collins <ian-news@hotmail.com> - 2012-05-16 09:55 +1200
Re: Will 'free' return the memory Immediately to the OS ? James Kuyper <jameskuyper@verizon.net> - 2012-05-15 18:42 -0400
Re: Will 'free' return the memory Immediately to the OS ? Keith Thompson <kst-u@mib.org> - 2012-05-15 16:49 -0700
Re: Will 'free' return the memory Immediately to the OS ? Ben Pfaff <blp@cs.stanford.edu> - 2012-05-15 16:59 -0700
Re: Will 'free' return the memory Immediately to the OS ? Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-05-15 20:24 -0400
Re: Will 'free' return the memory Immediately to the OS ? David T. Ashley <dashley@gmail.com> - 2012-05-16 13:29 -0400
Re: Will 'free' return the memory Immediately to the OS ? Stephen Sprunk <stephen@sprunk.org> - 2012-05-16 18:36 -0500
Re: Will 'free' return the memory Immediately to the OS ? David T. Ashley <dashley@gmail.com> - 2012-05-17 09:47 -0400
Re: Will 'free' return the memory Immediately to the OS ? Stephen Sprunk <stephen@sprunk.org> - 2012-05-17 11:22 -0500
Re: Will 'free' return the memory Immediately to the OS ? Kaz Kylheku <kaz@kylheku.com> - 2012-05-17 16:54 +0000
Re: Will 'free' return the memory Immediately to the OS ? Stephen Sprunk <stephen@sprunk.org> - 2012-05-18 12:30 -0500
Re: Will 'free' return the memory Immediately to the OS ? Keith Thompson <kst-u@mib.org> - 2012-05-17 14:09 -0700
Re: Will 'free' return the memory Immediately to the OS ? Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-05-17 21:05 -0400
Re: Will 'free' return the memory Immediately to the OS ? Stephen Sprunk <stephen@sprunk.org> - 2012-05-18 17:41 -0500
Re: Will 'free' return the memory Immediately to the OS ? Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-05-18 20:19 -0400
Re: Will 'free' return the memory Immediately to the OS ? Stephen Sprunk <stephen@sprunk.org> - 2012-05-22 15:08 -0500
Re: Will 'free' return the memory Immediately to the OS ? Ben Pfaff <blp@cs.stanford.edu> - 2012-05-22 13:45 -0700
Re: Will 'free' return the memory Immediately to the OS ? Robert Wessel <robertwessel2@yahoo.com> - 2012-05-23 03:02 -0500
Re: Will 'free' return the memory Immediately to the OS ? Robert Miles <milesrf@Usenet-News.net> - 2012-06-24 23:49 -0500
Re: Will 'free' return the memory Immediately to the OS ? Stephen Sprunk <stephen@sprunk.org> - 2012-06-26 10:33 -0500
Re: Will 'free' return the memory Immediately to the OS ? jgk@panix.com (Joe keane) - 2012-05-18 19:44 +0000
Re: Will 'free' return the memory Immediately to the OS ? Stephen Sprunk <stephen@sprunk.org> - 2012-05-18 17:27 -0500
Re: Will 'free' return the memory Immediately to the OS ? jgk@panix.com (Joe keane) - 2012-05-22 21:52 +0000
Re: Will 'free' return the memory Immediately to the OS ? Ian Collins <ian-news@hotmail.com> - 2012-05-23 11:12 +1200
Re: Will 'free' return the memory Immediately to the OS ? Robert Wessel <robertwessel2@yahoo.com> - 2012-05-23 03:15 -0500
Re: Will 'free' return the memory Immediately to the OS ? Robert Wessel <robertwessel2@yahoo.com> - 2012-05-17 11:54 -0500
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