Re: [Crash-utility] x86 remap allocator in kernel 3.0

Dne St 11. ledna 2012 15:37:50 Dave Anderson napsal(a): > ----- Original Message ----- > > > Dne St 11. ledna 2012 00:37:50 Petr Tesarik napsal(a): > > > [...] > > > I can see now that this is unnecessarily complicated, because the > > > node_remap_* variables are static arrays of MAX_NUMNODES elements, so I > > > can get their size from the debuginfo at POST_GDB init and initialize a > > > machine-specific data type with it. I'll post another patch tomorrow. > > > > And here we go. Tested on my system and seems to work just fine. > > > > Petr Tesarik > > SUSE Linux > > Hi Petr, > > This looks pretty good to me. However, just to clarify the > chicken-and-egg situation here... > > When remap_init() does these 3 readmem() calls, they will pass > through x86_kvtop_remap() -- which I guess would fail because > the arrays would still be at least partially uninitialized?: Hi Dave, first of all, it's not a real issue, because kernel static data is always below the remapped addresses, but I agree, it's ugly and making non-obvious assumptions about memory layout. To make things clean, I can simply set machdep->machspec->max_numnodes as the last thing, so the loop in x86_kvtop_remap() cannot be executed until everything is initialized.

Patch attached. Petr Tesarik SUSE Linux