On Tue, 2007-03-06 at 14:15 +0100, Ingo Molnar wrote: > * Rusty Russell <[EMAIL PROTECTED]> wrote: > > > Xen wants page-aligned GDT (and PDA must not cross a page-boundary, > > but that doesn't happen at the moment since it's so close to start of > > page). Let's allow page-alignment in general for per-cpu data. > > > > Because larger alignments can use more room, we increase the max > > per-cpu memory to 64k rather than 32k: it's getting a little tight. > > i recently needed page-aligned per-cpu data too for KVM-paravirt. Btw., > what's the size increase of the native kernel?
To clarify for those reading fast, this patch doesn't increase at all, since noone uses page-alignment. For the next patch which aligns the gdt, it's about +12k (21k -> 33k), but then we take away the pda in the next patch and it drops back to +8k (the pda is in the same file as the gdt, and on my system at least it ends up getting its own 4k alignment too). AFAICT, we could save the wasted partial page in three ways: by trying to link it first, if it's only a case of one file, by having a special page-aligned percpu data section, or by having a smarter linker. Cheers, Rusty. - 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/
