On 09/03/13 16:16, Dave Chinner wrote:
Let's just quote Linus from 2003, shall we:
|> I think it'd make more sense to only use vmalloc when it's explicitly
|> too big for kmalloc - or simply switch on num_online_cpus> 100 or
|> whatever a sensible cutoff is (ie nobody but you would ever see this ;-))
| No, please please please don't do these things.
| vmalloc() is NOT SOMETHING YOU SHOULD EVER USE! It's only valid for when
| you_need_ a big array, and you don't have any choice. It's slow, and it's
| a very restricted resource: it's a global resource that is literally
| restricted to a few tens of megabytes. It should be_very_ carefully used.
| There are basically no valid new uses of it. There's a few valid legacy
| users (I think the file descriptor array), and there are some drivers that
| use it (which is crap, but drivers are drivers), and it's_really_ valid
| only for modules. Nothing else.
| Basically: if you think you need more memory than a kmalloc() can give,
| you need to re-organize your data structures. To either not need a big
| area, or to be able to allocate it in chunks.
Linus will say exactly the same thing today....
And that is very very sad that is it funny.