On Thu, 12 Dec 2013 12:50:47 +0000 David Vrabel <david.vrabel@xxxxxxxxxx> wrote: > > each time. But that would require difficult tuning of N. > > > > I suppose we could just do > > > > if (!in_interrupt()) > > cond_resched(); > > > > in vunmap_pmd_range(), but that's pretty specific to ghes.c and doesn't > > permit unmap-inside-spinlock. > > > > So I can't immediately think of a suitable fix apart from adding a new > > unmap_kernel_range_atomic(). Then add a `bool atomic' arg to > > vunmap_page_range() and pass that all the way down. > > That would work for the unmap, but looking at the GHES driver some more > and it looks like it's call to ioremap_page_range() is already unsafe -- > it may need to allocate a new PTE page with a non-atomic alloc in > pte_alloc_one_kernel(). > > Perhaps what's needed here is a pair of ioremap_page_atomic() and > iounmap_page_atomic() calls? With some prep function to sure the PTE > pages (etc.) are preallocated. Is ghes.c the only problem source here? If so then a suitable solution would be to declare that driver hopelessly busted and proceed as if it didn't exist :( Just from a quick look, the thing is doing ioremap() from NMI context! ioremap has to do a bunch of memory allocations, takes spinlocks etc. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
