[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] x86: don't map more than the allocated spacefor frame_table
>>> Keir Fraser <keir.fraser@xxxxxxxxxxxxx> 20.05.09 15:56 >>> >On 20/05/2009 06:28, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote: > >> Also, make frame_table a 'mostly read' variable. Actually, I don't >> really understand why this has to be a variable on x86 at all - >> address calculations involving it could be cheaper if this was just >> a #define. Perhaps kexec is the only thing that needs this to be a >> variable, but if that indeed is the only reason, kexec should define >> its own static variable. > >Would it really be much cheaper? Pointer load versus a 64-bit constant? If >you're sure it would be an improvement I would take a patch. Certainly not much (especially with it now sitting in __read_mostly), but the official latencies are still <= 1 vs >= 2, and additionally memory clobbers wouldn't matter anymore for the compiler's scheduling decisions. Since I wasn't sure, I didn't submit a patch right away... Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
|
![]() |
Lists.xenproject.org is hosted with RackSpace, monitoring our |