Re: [Crash-utility] x86 remap allocator in kernel 3.0
----- 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?:
+ readmem(start_vaddr, KVADDR, ms->remap_start_vaddr,
+ ms->max_numnodes * sizeof(ulong), "node_remap_start_vaddr",
+ FAULT_ON_ERROR);
+ readmem(end_vaddr, KVADDR, ms->remap_end_vaddr,
+ ms->max_numnodes * sizeof(ulong), "node_remap_end_vaddr",
+ FAULT_ON_ERROR);
+ readmem(start_pfn, KVADDR, ms->remap_start_pfn,
+ ms->max_numnodes * sizeof(ulong), "node_remap_end_vaddr",
+ FAULT_ON_ERROR);
To fortify this (and put my mind at ease), can we also set a "remap_state"
flag in the machdep structure that describes the remap data structures in
maybe two states:
UNINITIALIZED - set at SETUP_ENV time, then cleared in x86_init() before
remap_init() is called
NOT_USED - if remap_init() fails
Then have x86_kvtop_remap() -- which will get called on every readmem() or kvtop()
for the rest of time, check for (UNINITIALIZED|NOT_USED), and return FALSE immediately
if either are set?
What do you think?
Dave