On 19.07.19 02:58, Nadav Amit wrote:
To improve TLB shootdown performance, flush the remote and local TLBs concurrently. Introduce flush_tlb_multi() that does so. Introduce paravirtual versions of flush_tlb_multi() for KVM, Xen and hyper-v (Xen and hyper-v are only compile-tested). While the updated smp infrastructure is capable of running a function on a single local core, it is not optimized for this case. The multiple function calls and the indirect branch introduce some overhead, and might make local TLB flushes slower than they were before the recent changes. Before calling the SMP infrastructure, check if only a local TLB flush is needed to restore the lost performance in this common case. This requires to check mm_cpumask() one more time, but unless this mask is updated very frequently, this should impact performance negatively. Cc: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx> Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> Cc: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx> Cc: Sasha Levin <sashal@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: x86@xxxxxxxxxx Cc: Juergen Gross <jgross@xxxxxxxx> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> Cc: linux-hyperv@xxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx Cc: kvm@xxxxxxxxxxxxxxx Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx Signed-off-by: Nadav Amit <namit@xxxxxxxxxx> --- arch/x86/hyperv/mmu.c | 10 +++--- arch/x86/include/asm/paravirt.h | 6 ++-- arch/x86/include/asm/paravirt_types.h | 4 +-- arch/x86/include/asm/tlbflush.h | 8 ++--- arch/x86/include/asm/trace/hyperv.h | 2 +- arch/x86/kernel/kvm.c | 11 +++++-- arch/x86/kernel/paravirt.c | 2 +- arch/x86/mm/tlb.c | 47 ++++++++++++++++++--------- arch/x86/xen/mmu_pv.c | 11 +++---- include/trace/events/xen.h | 2 +- 10 files changed, 62 insertions(+), 41 deletions(-)
Xen and paravirt parts: Reviewed-by: Juergen Gross <jgross@xxxxxxxx> Juergen
