Re: vmalloc() in interrupt context

On Tue, 27 Jun 2000, Jeff Garzik wrote:

> Use __vmalloc, that lets you provide a priority.  Requires 2.4.x though,
> doesn't exist in 2.2.x.

vmalloc of any form from an interrupt handler is doomed to failure --
Don't Do It.  Consider the fact that you have to send a tlb flush IPI on
SMP boxes; what happens when one of the other CPUs is spinning on a lock
with interrupts disabled waiting for the caller of vmalloc to release a
lock (ie the interrupt entry lock -- likely).

Let me repeat: Never ever use vmalloc from interrupts, while holding
spinlocks, in hopes of decent performance, and/or where using any other
data structure is possible.  (Hint: the flags for vmalloc really only
should be used for DMA vs normal or HIGH pages.)

		-ben