Re: v/phy memory translationquestion
Date: Fri, 08 Oct 2004 07:23:44 +0200
> I came accros MMU section about MPC860. About v/p address tranlation
> it mentions that it support 16 virtual memory spaces (4 bit ID indentify them).
> I'm wondering how linux implementation deal with that. It's certain that we
> have more than 16 processes simultaneously.
I don't know exactly how Linux is implemented on that platform.
But Linux already run without problems on architectures that
can have only one translation at the time. On IA32 switching
to a different address space is an expensive operation, so
the kernel does lazy switchcing. The kernel itself is in every
address space, so you can switch from user mode to kernel mode
where you switch between a number of kernel threads, and back
again to any thread in the original user mode process without
having to perform this switch.
So what is the advantage of these 16 address spaces? Does it
just mean, that we can switch more efficiently between them?
If it is just a performance optimization, a good approach might
be to use one for the kernel and "cache" the 15 least recently
used user spaces.
- Re: Windows Assembly
... >> Didn't they try to add that DRI stuff or whatever to the kernel? ... > But what pisses me off is that we've had VESA for how many years ... Linux text mode. ... So it's obviously possible to switch into and out of VESA ...
- Re: 32 bit FORTH ??? Different tack! Jona
... get the whole Linux community to switch to your kernel. ... Linux is not just Linus. ... When you implement quite radical changes, you still can add a POSIX layer on ...
- Re: Task virtual space in Linux.
... > all tasks and kernel share the same one virtual space? ... I don't think the tables are created each time CR3 is changed, ... which you can switch between by changing CR3. ... So you can from a user mode thread do a system call, ...
- Re: v/phy memory translationquestion
... > I don't know exactly how Linux is implemented on that platform. ... > the kernel does lazy switchcing. ... so you can switch from user mode to kernel mode ...
- dvi cabling again!
... I got a LG L1930B lcd monitor a couple of days ago & it works very well ... Switched to a DVI-D cable & linux has a problem. ... kernel not doing something well with digital signals? ... WinXP has not encountered any problem with the switch to the DVI-D ...