Messages in this thread | | | From | Hartmut Manz <> | Subject | Re: allocate more than 2 GB on IA32 | Date | Thu, 20 Feb 2003 18:40:21 +0100 |
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On Tuesday 11 February 2003 17:11, Martin J. Bligh wrote: > > i would like to allocate more than 2 GB of memory on an IA32 > > architecture. > > > > The machine is a dual XEON_DP with 3 GB of Ram and 4 GB of swap space. > > > > I have tried with the default SUSE 8.1 kernel as well as with a > > 2.4.20-pre4aa1 Kernel compile by my own using these Options: > > > > CONFIG_HIGHMEM4G=y > > CONFIG_HIGHMEM=y > > CONFIG_1GB=y > > > > but I am only able to allocate 2 GB with a single malloc call. > > I tought it should be possible to allocate up to 2.9 GB of memory to a > > process, with this kernel settings. > > Well, assuming you had no user-space code or data, or a stack, or any > shared libraries to fit into that space as well ;-) > > Try shifting TASK_UNMAPPED_BASE down from 1GB to 0.5GB - that should give > you some more breathing room, though you'll never get to 2.9GB. > > M.
First of all I would like to say THANK YOU for your help.
I am now able to allocate up to ~3.2 GB of memory on a 4 GB Machine, even with shared libraries.
This is what I have done.
1. I have activated the kernel option in Kernel 2.4.21pre4aa3 CONFIG_05GB=y This gives the following: a: TASK_UNMAPPED_BASE is now 0xe000000 wich is 224 MB b: Upper Limit for User-Space memory is now at 3.5 GB So I have the potential to allocated up to 3360 MB of memory
2. I have exchanged malloc with anonymous mmap, since malloc was still only able to allocate about 2 GB.
-- ----------------------------------------------------------------------------- Hartmut Manz WWW: http://www.intes.de INTES GmbH Phone: +49-711-78499-29 Schulze-Delitzsch-Str. 16 Fax: +49-711-78499-10 D-70565 Stuttgart E-mail: manz@intes.de Ein Mensch sieht, was vor Augen ist; der Herr aber sieht das Herz an. ------------------------------------------------------- 1. Samuel 16, 7 -----
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