On Thu, Feb 10, 2005 at 12:17:24PM +0100, Fruhwirth Clemens wrote: > On Thu, 2005-02-10 at 02:33 -0800, Andrew Morton wrote: > > Fruhwirth Clemens <[EMAIL PROTECTED]> wrote: > > > > > > On Wed, 2005-02-09 at 17:19 -0800, Andrew Morton wrote: > > > > Fruhwirth Clemens <[EMAIL PROTECTED]> wrote: > > > > Adding a few more fixmap slots wouldn't hurt anyone. But if you want an > > > > arbitrarily large number of them then no, we cannot do that. > > > > > > What magnitude is "few more"? 2, 10, 100? > > > > Not 100. 10 would seem excessive. > > Out of curiosity: Where does this limitation even come from? What > prevents kmap_atomic from adding slots dynamically?
There's a single page of PTEs for mapping high memory and the atomic slots are a small subset of that. They're fixed in number for complexity reasons - we don't want to have an allocator here: /* * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because * no global lock is needed and because the kmap code must perform a global TLB * invalidation when the kmap pool wraps. * -- Mathematics is the supreme nostalgia of our time. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
