On Mon, Jan 01, 2007 at 02:12:46PM -0500, Jeremy Katz wrote: > > doesn't anaconda default to this on NX capable machines? > > (all NX capable machines have PAE support as well obviously) > > We tried doing so with an FC5 test release, but things didn't go so well > so we reverted back for the final. Was that NX, or was it "If we have PAE, do PAE ?". My memory is hazy as to what exactly broke, but I wonder if we can just special case the bad eggs. > CONFIG_HIGHMEM64G also isn't that > great for laptops. > > The work really needs to get done so that pae can be done at runtime, > much like smp alternatives lets us do for smp. Separate kernels is > _always_ a losing battle for someone ;-) I think it's a bigger effort to make that happen than it was for smp-alternatives, at least in part because it needs to happen really early during boot, possibly before we even get to C code. Even with alternatives style runtime patching, I think we'd still have to end up with some stuff being conditionals at runtime whereas right now they're #defines, which the compiler can sometimes even CSE. Introducing conditionals in places like page fault handling just screams "performance hit" to me. As much as we all dislike it, a separate kernel image really is the best option here. The complexity involved in getting this stuff right is just horrific. Dave -- http://www.codemonkey.org.uk -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
