Messages in this thread | | | From | (Alan Cox) | Subject | Re: Raid0 needs more memory. | Date | Wed, 2 Jul 1997 08:09:40 +0100 (BST) |
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> As someone else has already suggested to me, I suppose I should have just > fixed raid0 with vmalloc instead of "fixing" kmalloc. Probably would have > been easier. What penalties are there for using vmalloc over kmalloc, if > any?
vmalloc memory is logically but not physically contiguous and on a lot of platforms it is also slightly slower to access sometimes (its not in the single kernel 4Mb TLB on intel for example). The performance issue is miniscule, the virtual nature of its mapping means its no use for DMAing into.
Oh and finally you cannot vmalloc in an interrupt or bh
Alan
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