maximalni pridelena pamet procesu

[Jiri Cerny]

Takže,

1. v tomto případě je opravdu jak vidím zbytečné použít highmem
2. jak již někdo psal je možné při splitu 3/1 využít téměř 3G RAM
3. i tyto 3G jsou dále rozděleny na 1+2G (1G pro menší alokace, 2G pro 
velké) => není možné na x86 použít souvislý kus paměti > 2G

Jiří Černý

P.S. jste docela masochista spouštět to jen ve swapu, kupte si paměť 
(pokud stačí malé kousky paměti) nebo opteron :-))

Jarda Mikulík wrote:
> vita na brtnik.isibrno.cz wrote:
> 
>> disponuji s:
>> Mem:    773908K total,   371012K used,   402896K free,    31492K buffers
>> Swap: 11711168K total,  2277740K used,  9433428K free,   171428K cached
>>
>> potreboval bych poradit, jak umoznit procesu vyuzit vice jak 2GB pameti.
>>
>> jadro jsem kompiloval s podporou highmem.
> 
> 
> Vy máte fyzicky více než 960 MiB paměti (SWAP se do toho nepočítá), že 
> tohle děláte? Pokud nemáte, tak nemáte ani důvod tohle dělat, viz. 
> dokumentace ke kernelu:
> 
> High Memory support
> CONFIG_NOHIGHMEM
>   Linux can use up to 64 Gigabytes of physical memory on x86 systems.
>   However, the address space of 32-bit x86 processors is only 4
>   Gigabytes large. That means that, if you have a large amount of
>   physical memory, not all of it can be "permanently mapped" by the
>   kernel. The physical memory that's not permanently mapped is called
>   "high memory".
> 
>   If you are compiling a kernel which will never run on a machine with
>   more than 960 megabytes of total physical RAM, answer "off" here
>   (default choice and suitable for most users). This will result in a
>   "3GB/1GB" split: 3GB are mapped so that each process sees a 3GB
>   virtual memory space and the remaining part of the 4GB virtual memory
>   space is used by the kernel to permanently map as much physical memory
>   as possible.
> 
>   If the machine has between 1 and 4 Gigabytes physical RAM, then
>   answer "4GB" here.
> 
>   If more than 4 Gigabytes is used then answer "64GB" here. This
>   selection turns Intel PAE (Physical Address Extension) mode on.
>   PAE implements 3-level paging on IA32 processors. PAE is fully
>   supported by Linux, PAE mode is implemented on all recent Intel
>   processors (Pentium Pro and better). NOTE: If you say "64GB" here,
>   then the kernel will not boot on CPUs that don't support PAE!
> 
>   The actual amount of total physical memory will either be auto
>   detected or can be forced by using a kernel command line option such
>   as "mem=256M". (Try "man bootparam" or see the documentation of your
>   boot loader (grub, lilo or loadlin) about how to pass options to the
>   kernel at boot time.)
> 
>   If unsure, say "off".
> 
> 4GB
> CONFIG_HIGHMEM4G
>   Select this if you have a 32-bit processor and between 1 and 4
>   gigabytes of physical RAM.
> 
> 64GB
> CONFIG_HIGHMEM64G
>   Select this if you have a 32-bit processor and more than 4
>   gigabytes of physical RAM.
> 
> HIGHMEM I/O support
> CONFIG_HIGHIO
>   If you want to be able to do I/O to high memory pages, say Y.
>   Otherwise low memory pages are used as bounce buffers causing a
>   degrade in performance.
> 
> 
>     Jarda
>