diff options
| author | Nadav Amit <namit@vmware.com> | 2021-02-20 15:17:07 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2021-03-06 12:59:10 +0100 |
| commit | 4ce94eabac16b1d2c95762b40f49e5654ab288d7 (patch) | |
| tree | 16fd5d3124ad8ae61e9c22fecc24f9c91adec4e9 /arch/x86/xen | |
| parent | 6035152d8eebe16a5bb60398d3e05dc7799067b0 (diff) | |
x86/mm/tlb: Flush remote and local TLBs concurrently
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.
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com> # Hyper-v parts
Reviewed-by: Juergen Gross <jgross@suse.com> # Xen and paravirt parts
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20210220231712.2475218-5-namit@vmware.com
Diffstat (limited to 'arch/x86/xen')
| -rw-r--r-- | arch/x86/xen/mmu_pv.c | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c index cf2ade864c30..09b95c0e876e 100644 --- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -1247,8 +1247,8 @@ static void xen_flush_tlb_one_user(unsigned long addr) preempt_enable(); } -static void xen_flush_tlb_others(const struct cpumask *cpus, - const struct flush_tlb_info *info) +static void xen_flush_tlb_multi(const struct cpumask *cpus, + const struct flush_tlb_info *info) { struct { struct mmuext_op op; @@ -1258,7 +1258,7 @@ static void xen_flush_tlb_others(const struct cpumask *cpus, const size_t mc_entry_size = sizeof(args->op) + sizeof(args->mask[0]) * BITS_TO_LONGS(num_possible_cpus()); - trace_xen_mmu_flush_tlb_others(cpus, info->mm, info->start, info->end); + trace_xen_mmu_flush_tlb_multi(cpus, info->mm, info->start, info->end); if (cpumask_empty(cpus)) return; /* nothing to do */ @@ -1267,9 +1267,8 @@ static void xen_flush_tlb_others(const struct cpumask *cpus, args = mcs.args; args->op.arg2.vcpumask = to_cpumask(args->mask); - /* Remove us, and any offline CPUS. */ + /* Remove any offline CPUs */ cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask); - cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask)); args->op.cmd = MMUEXT_TLB_FLUSH_MULTI; if (info->end != TLB_FLUSH_ALL && @@ -2086,7 +2085,7 @@ static const struct pv_mmu_ops xen_mmu_ops __initconst = { .flush_tlb_user = xen_flush_tlb, .flush_tlb_kernel = xen_flush_tlb, .flush_tlb_one_user = xen_flush_tlb_one_user, - .flush_tlb_others = xen_flush_tlb_others, + .flush_tlb_multi = xen_flush_tlb_multi, .tlb_remove_table = tlb_remove_table, .pgd_alloc = xen_pgd_alloc, |