Messages in this thread | | | Date | Tue, 11 Nov 2003 10:57:14 -0800 | From | "Martin J. Bligh" <> | Subject | Re: 2.6 /proc/interrupts fails on systems with many CPUs |
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>> 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.
OK, I was actually trying to avoid the use of vmalloc, instead of the unconditional conversion to vmalloc, which is what the original patch did ;-)
But you are, of course, correct - in this case, it should be easy to use the seq_file stuff to do it in smaller chunks, and use a smaller buffer.
M.
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