On Sat, May 9, 2015 at 9:11 PM, Konstantin Belousov <k...@freebsd.org> wrote: > Author: kib > Date: Sat May 9 19:11:01 2015 > New Revision: 282684 > URL: https://svnweb.freebsd.org/changeset/base/282684 > > Log: > Rewrite amd64 PCID implementation to follow an algorithm described in > the Vahalia' "Unix Internals" section 15.12 "Other TLB Consistency > Algorithms". The same algorithm is already utilized by the MIPS pmap > to handle ASIDs. > > The PCID for the address space is now allocated per-cpu during context > switch to the thread using pmap, when no PCID on the cpu was ever > allocated, or the current PCID is invalidated. If the PCID is reused, > bit 63 of %cr3 can be set to avoid TLB flush. > > Each cpu has PCID' algorithm generation count, which is saved in the > pmap pcpu block when pcpu PCID is allocated. On invalidation, the > pmap generation count is zeroed, which signals the context switch code > that already allocated PCID is no longer valid. The implication is > the TLB shootdown for the given cpu/address space, due to the > allocation of new PCID. > > The pm_save mask is no longer has to be tracked, which (significantly) > reduces the targets of the TLB shootdown IPIs. Previously, pm_save > was reset only on pmap_invalidate_all(), which made it accumulate the > cpuids of all processors on which the thread was scheduled between > full TLB shootdowns. > > Besides reducing the amount of TLB shootdowns and removing atomics to > update pm_saves in the context switch code, the algorithm is much > simpler than the maintanence of pm_save and selection of the right > address space in the shootdown IPI handler. > > Reviewed by: alc > Tested by: pho > Sponsored by: The FreeBSD Foundation > MFC after: 3 weeks > > Modified: > head/sys/amd64/amd64/apic_vector.S > head/sys/amd64/amd64/cpu_switch.S > head/sys/amd64/amd64/genassym.c > head/sys/amd64/amd64/machdep.c > head/sys/amd64/amd64/mp_machdep.c > head/sys/amd64/amd64/pmap.c > head/sys/amd64/amd64/vm_machdep.c > head/sys/amd64/include/cpufunc.h > head/sys/amd64/include/pcpu.h > head/sys/amd64/include/pmap.h > head/sys/amd64/include/smp.h > head/sys/x86/include/specialreg.h > head/sys/x86/xen/xen_apic.c > > Modified: head/sys/amd64/amd64/apic_vector.S >
[snip] Hi! Are you still plan to MFC back these PCID related changes to 10-STABLE, or there is a good reason no merge them back or the MFC was just have forgotten? Thanks, Oliver _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
