On Wed, Aug 20, 2008 at 09:03:59AM -0500, Christoph Lameter wrote: > Nick Piggin wrote: > > >> Or run purge_vma_area_lazy from keventd? > > > > Right. But that's only needed if we want to vmap from irq context too > > (otherwise we can just do the purge check at vmap time). > > > > Is there any good reason to be able to vmap or vunmap from interrupt > > time, though? > > It would be good to have vunmap work in an interrupt context like other free > operations. One may hold spinlocks while freeing structure. I don't know if just-in-case is a strong argument to make the locks interrupt safe and logic to handle deferred flushing. I'd be happy to add it if there are some specific cases though. > vmap from interrupt context would be useful f.e. for general fallback in the > page allocator to virtually mapped memory if no linear physical memory is > available (virtualizable compound pages). Without a vmap that can be run in an > interrupt context we cannot support GFP_ATOMIC allocs there. Indeed that would be a good use for it if this general fallback mechanism were to be merged. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
