SGI UV cpumask: use static temp cpumask in flush_tlb

Impact: Improve tlb flush performance for UV

Calling alloc_cpumask_var a zillion times a second does affect
performance.  Replace with static cpumask.

Note: when CONFIG_X86_UV is defined, this extra PER_CPU memory
will be optimized out for non-UV configs as is_uv_system() will
then return a constant 0.

Signed-off-by: Mike Travis <travis@sgi.com>

diff --git a/arch/x86/kernel/tlb_64.c b/arch/x86/kernel/tlb_64.c
index 38836ae..7a3f989 100644 (file)
--- a/arch/x86/kernel/tlb_64.c
+++ b/arch/x86/kernel/tlb_64.c
@@ -202,16 +202,17 @@ void native_flush_tlb_others(const struct cpumask *cpumask,
                             struct mm_struct *mm, unsigned long va)
 {
        if (is_uv_system()) {
-               cpumask_var_t after_uv_flush;
-
-               if (alloc_cpumask_var(&after_uv_flush, GFP_ATOMIC)) {
-                       cpumask_andnot(after_uv_flush,
-                                      cpumask, cpumask_of(smp_processor_id()));
-                       if (!uv_flush_tlb_others(after_uv_flush, mm, va))
-                               flush_tlb_others_ipi(after_uv_flush, mm, va);
-                       free_cpumask_var(after_uv_flush);
-                       return;
-               }
+               /* FIXME: could be an percpu_alloc'd thing */
+               static DEFINE_PER_CPU(cpumask_t, flush_tlb_mask);
+               struct cpumask *after_uv_flush = &get_cpu_var(flush_tlb_mask);
+
+               cpumask_andnot(after_uv_flush, cpumask,
+                              cpumask_of(smp_processor_id()));
+               if (!uv_flush_tlb_others(after_uv_flush, mm, va))
+                       flush_tlb_others_ipi(after_uv_flush, mm, va);
+
+               put_cpu_var(flush_tlb_uv_cpumask);
+               return;
        }
        flush_tlb_others_ipi(cpumask, mm, va);
 }