Re: [PATCH] mm: Fix boot crash in mm_alloc()

[KOSAKI Motohiro]

(2011/05/30 3:43), Linus Torvalds wrote:
> On Sun, May 29, 2011 at 10:19 AM, Linus Torvalds
> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>>
>> STILL TOTALLY UNTESTED! The fixes were just from eyeballing it a bit
>> more, not from any actual testing.
> 
> Ok, I eyeballed it some more, and tested both the OFFSTACK and ONSTACK
> case, and decided that I had better commit it now rather than wait any
> later since I'll do the -rc1 later today, and will be on an airplane
> most of tomorrow.
> 
> The exact placement of the cpu_vm_mask_var is up for grabs. For
> example, I started thinking that it might be better to put it *after*
> the mm_context_t, since for the non-OFFSTACK case it's generally
> touched at the beginning rather than the end.
> 
> And the actual change to make the mm_cachep kmem_cache_create() use a
> variable-sized allocation for the OFFSTACK case is similarly left as
> an exercise for the the reader. So effectively, this reverts a lot of
> de03c72cfce5, but does so in a way that should make very it easy to
> get back to where KOSAKI was aiming for.
> 
> Whatever. I was hoping to get comments on it, but I think I need to
> rather push it out to get tested and public than wait any longer. The
> patch *looks* fine, tests ok on my machine, and removes more lines
> than it adds despite the new big comment.

Hi

Thank you Linus and I'm sorry for bother you and guys. So, if I understand
this thread correctly, rest my homework is 1) make cpumask_allocation variable
size 2) remove NR_CPUS bit fill/copy from fork/exec path. Right?

I think (2) is big matter than (1). NR_CPUS(=4096) bits copy easily screw up
cache behavior. Anyway, will do. Thank you!



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