> + n = kmalloc(sizeof *n, GFP_KERNEL | __GFP_NOWARN); > + if (!n) > + n = vmalloc(sizeof *n); I'm slightly confused by this construct. I thought kmalloc(... GFP_KERNEL) would sleep waiting for memory (rather than return NULL). I realise that (for multi-page sizes) that kmalloc() and vmalloc() both need to find a contiguous block of kernel virtual addresses - in different address ranges, and that vmalloc() then has to find physical memory pages (which will not be contiguous). I think this means that kmalloc() is likely to be faster (if it doesn't have to sleep), but that vmalloc() is allocating from a much larger resource. This make me that that large allocations that are not temporary should probably be allocated with vmalloc(). Is there a 'NO_SLEEP' flag to kmalloc()? is that all GFP_ATOMIC requests? If so you might try a non-sleeping kmalloc() with a vmalloc() if it fails. This all looks as though there should be a GFP_NONCONTIG flag (or similar) so that kmalloc() can make a decision itself. Of at least a wrapper - like the one for free(). David -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
