Subject: Re: ksyms patches.
To: None <firstname.lastname@example.org>
From: Jason Thorpe <email@example.com>
Date: 04/21/2003 08:57:54
On Monday, April 21, 2003, at 08:32 AM, <firstname.lastname@example.org> wrote:
> Yep, so I thought it would be cleaner solution if it could be loaded
> after the kernel starts, by for example "cat /netbsd > /dev/ksyms" to
> get the master table. That would replace SYMTAB_SPACE.
That's not always possible, nor desirable.
Consider the following scenarios:
1. Debugging the kernel. Userland isn't working. I'd like to
be able to use DDB in order to figure out why.
2. Embedded system. Kernel starts directly out of flash, has
a ramdisk without an extra copy of the kernel in it. Kernel
in flash is a flat binary image, possibly compressed and wrapped
in something else that decompresses it into RAM.
For both of these cases (which I happen to encounter frequently :-),
SYMTAB_SPACE is extremely valuable. For this reason, I'd like to keep
> The problem is that for modules then the symbol table and the string
> table would need to be on (at least) two extra pages for each module,
> which would require a large amount of extra memory if there are say,
> 50 modules. Maybe it's not a big problem on newer machines, but older
> would loose much of their memory.
Fair enough -- that's why I asked :-)
> That would be doable, yes. Another way is to make nlist use the
> ioctl's that are currently disabled that do the lookup in-kernel.
> That would be as fast.
Yah, I was going to suggest that, but then wondered if adding the
ioctls was a good idea, but then I noticed you'd added them already :-)
-- Jason R. Thorpe <email@example.com>