Hello,
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.
Thank You for any help
Hartmut Manz
--
-----------------------------------------------------------------------------
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: [email protected]
Ein Mensch sieht, was vor Augen ist; der Herr aber sieht das Herz an.
------------------------------------------------------- 1. Samuel 16, 7 -----
> I tought it should be possible to allocate up to 2.9 GB of memory to a
> process, with this kernel settings.
Obviously, No.
Unfortunatly kernel do not use segments (fully). So even you have HIMEM at the kernel it's not possible to user program to address more than 4 gb a ram at the same time. And as far as i know program can not have more than 1 gm of usable readwrite memory.
THe only way for u is to use 64 bit architecture... or remap default address range splitting increase address range for pgrogram data (it's require to recompile all programs).
Agri
On Tue, 11 Feb 2003 10:15:54 +0100
Hartmut Manz <[email protected]> wrote:
> Hello,
>
> 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.
>
> Thank You for any help
>
> Hartmut Manz
>
> --
> -----------------------------------------------------------------------------
> 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: [email protected]
> Ein Mensch sieht, was vor Augen ist; der Herr aber sieht das Herz an.
> ------------------------------------------------------- 1. Samuel 16, 7 -----
>
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>
On Tue, 2003-02-11 at 09:15, Hartmut Manz wrote:
> 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.
have you tried your own anonymous mmap() with start set to getpagesize()
?
--
// Gianni Tedesco (gianni at scaramanga dot co dot uk)
lynx --source http://www.scaramanga.co.uk/gianni-at-ecsc.asc | gpg --import
8646BE7D: 6D9F 2287 870E A2C9 8F60 3A3C 91B5 7669 8646 BE7D
> 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.
#include <malloc.h>
// Test the maximum size of one linear block that is achievable with Linux
// compile with gcc --static.
#define SIZE 2943
unsigned char dummy1[1024UL*1024*SIZE/2];
unsigned char dummy2[1024UL*1024*SIZE/2];
int main(void)
{
if ((unsigned long)dummy2 != (unsigned long) ((&dummy1)+1)) {
printf("dummy1 has address %lx, ends at %lxh.\n",dummy1, (&dummy1)+1);
printf("dummy2 has address %lx.\n",dummy2);
printf("duh. something went wrong.\n");
} else {
printf("%d MB memory block starting at address %lxh available.\n",
SIZE, (unsigned long)dummy1);
}
for(;;) sleep(100);
return 0;
}
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: [email protected]
Ein Mensch sieht, was vor Augen ist; der Herr aber sieht das Herz an.
------------------------------------------------------- 1. Samuel 16, 7 -----