(Note... reply list substantially reduced) What is the status for getting virtualization preparatory changes into the kernel? Approx. how many have/are going into which releases? At what release is it expected that Linux for Xen (or the Vmware PVI) will be buildable in a released kernel? I have a virtualization prep patch for Linux/ia64 (entirely contained in archdep for ia64) and have been getting push-back from Tony (the Linux/ia64 maintainer) that he isn't in any hurry to apply it in part because the x86 stuff isn't going in yet. So I'd appreciate any info. Thanks, Dan > -----Original Message----- > From: virtualization-bounces@xxxxxxxxxxxxxx > [mailto:virtualization-bounces@xxxxxxxxxxxxxx] On Behalf Of > Zachary Amsden > Sent: Thursday, September 22, 2005 1:35 AM > To: Linus Torvalds; Jeffrey Sheldon; Ole Agesen; Shai > Fultheim; Andrew Morton; Jack Lo; Ingo Molnar; Linux Kernel > Mailing List; Virtualization Mailing List; Chris Wright; > Martin Bligh; Pratap Subrahmanyam; Christopher Li; H. Peter > Anvin; Zwane Mwaikambo; Andi Kleen; Zachary Amsden > Subject: [PATCH 0/3] GDT virtualization performance > > Three patches to clean up GDT access in Linux to make it friendly to > virtualization environments. The basic problem is that the GDT must > be write protected, which causes spurious overhead when the GDT lies > on the same page as other data. This problem exists both for VMware > and Xen; Xen actually requires page isolation, so we have implemented > the most general and compatible solution. > > Patch 1 deprecates a broken GDT reference; > Patch 2 adds a per-cpu GDT accessor; > Patch 3 moves the GDT out of the per-cpu area and makes it page > padded and page aligned. > > The GDTs for secondary processors are allocated dynamically to avoid > bloating kernel static data with GDTs for not-present processors. > > This could be adapted to drop and reallocate GDTs for CPU hotplug > if desired, although the space savings (1 page) are dubious, so > I have not implemented that at this time. > > Testing: 4 way SMP boot-halts, kernel compiles, stress. > > Zachary Amsden <zach@xxxxxxxxxx> >
