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    Subject[PATCH v2 8/9] x86/mm/tlb: Remove UV special case
    Date
    SGI UV support is outdated and not maintained, and it is not clear how
    it performs relatively to non-UV. Remove the code to simplify the code.

    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Dave Hansen <dave.hansen@intel.com>
    Suggested-by: Andy Lutomirski <luto@kernel.org>
    Signed-off-by: Nadav Amit <namit@vmware.com>
    ---
    arch/x86/mm/tlb.c | 25 -------------------------
    1 file changed, 25 deletions(-)

    diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
    index b47a71820f35..64afe1215495 100644
    --- a/arch/x86/mm/tlb.c
    +++ b/arch/x86/mm/tlb.c
    @@ -689,31 +689,6 @@ void native_flush_tlb_multi(const struct cpumask *cpumask,
    trace_tlb_flush(TLB_REMOTE_SEND_IPI,
    (info->end - info->start) >> PAGE_SHIFT);

    - if (is_uv_system()) {
    - /*
    - * This whole special case is confused. UV has a "Broadcast
    - * Assist Unit", which seems to be a fancy way to send IPIs.
    - * Back when x86 used an explicit TLB flush IPI, UV was
    - * optimized to use its own mechanism. These days, x86 uses
    - * smp_call_function_many(), but UV still uses a manual IPI,
    - * and that IPI's action is out of date -- it does a manual
    - * flush instead of calling flush_tlb_func_remote(). This
    - * means that the percpu tlb_gen variables won't be updated
    - * and we'll do pointless flushes on future context switches.
    - *
    - * Rather than hooking native_flush_tlb_multi() here, I think
    - * that UV should be updated so that smp_call_function_many(),
    - * etc, are optimal on UV.
    - */
    - flush_tlb_func_local(info);
    -
    - cpumask = uv_flush_tlb_others(cpumask, info);
    - if (cpumask)
    - smp_call_function_many(cpumask, flush_tlb_func_remote,
    - (void *)info, 1);
    - return;
    - }
    -
    /*
    * If no page tables were freed, we can skip sending IPIs to
    * CPUs in lazy TLB mode. They will flush the CPU themselves
    --
    2.17.1
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