Do not invalidate remote TLB entries with new mappings because the

virtual addresses really should not have TLB hits. This reduces IPIs.

diff --git a/sys/arch/mips64/mips64/pmap.c b/sys/arch/mips64/mips64/pmap.c
index a6fe6f3..6041a64 100644 (file)
--- a/sys/arch/mips64/mips64/pmap.c
+++ b/sys/arch/mips64/mips64/pmap.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: pmap.c,v 1.104 2017/06/13 13:41:15 visa Exp $ */
+/*     $OpenBSD: pmap.c,v 1.105 2017/06/13 14:06:39 visa Exp $ */
 
 /*
  * Copyright (c) 2001-2004 Opsycon AB  (www.opsycon.se / www.opsycon.com)
@@ -1024,7 +1024,7 @@ pmap_protect(pmap_t pmap, vaddr_t sva, vaddr_t eva, vm_prot_t prot)
 int
 pmap_enter(pmap_t pmap, vaddr_t va, paddr_t pa, vm_prot_t prot, int flags)
 {
-       pt_entry_t **pde, *pte, npte;
+       pt_entry_t **pde, *pte, npte, opte;
        vm_page_t pg;
        struct cpu_info *ci = curcpu();
        u_long cpuid = ci->ci_cpuid;
@@ -1134,9 +1134,11 @@ pmap_enter(pmap_t pmap, vaddr_t va, paddr_t pa, vm_prot_t prot, int flags)
                /*
                 * Update the same virtual address entry.
                 */
+               opte = *pte;
                *pte = npte;
                pmap_update_kernel_page(va, npte);
-               pmap_shootdown_page(pmap_kernel(), va);
+               if ((opte & PG_V) != 0)
+                       pmap_shootdown_page(pmap_kernel(), va);
                if (pg != NULL)
                        mtx_leave(&pg->mdpage.pv_mtx);
                pmap_unlock(pmap);
@@ -1236,9 +1238,11 @@ pmap_enter(pmap_t pmap, vaddr_t va, paddr_t pa, vm_prot_t prot, int flags)
        }
 #endif
 
+       opte = *pte;
        *pte = npte;
        pmap_update_user_page(pmap, va, npte);
-       pmap_shootdown_page(pmap, va);
+       if ((opte & PG_V) != 0)
+               pmap_shootdown_page(pmap, va);
 
        /*
         * If mapping an executable page, invalidate ICache
@@ -1262,7 +1266,7 @@ pmap_enter(pmap_t pmap, vaddr_t va, paddr_t pa, vm_prot_t prot, int flags)
 void
 pmap_kenter_pa(vaddr_t va, paddr_t pa, vm_prot_t prot)
 {
-       pt_entry_t *pte, npte;
+       pt_entry_t *pte, npte, opte;
 
        DPRINTF(PDB_FOLLOW|PDB_ENTER,
                ("pmap_kenter_pa(%p, %p, 0x%x)\n", (void *)va, (void *)pa, prot));
@@ -1288,9 +1292,11 @@ pmap_kenter_pa(vaddr_t va, paddr_t pa, vm_prot_t prot)
                if ((*pte & PG_WIRED) == 0)
                        atomic_inc_long(&pmap_kernel()->pm_stats.wired_count);
        }
+       opte = *pte;
        *pte = npte;
        pmap_update_kernel_page(va, npte);
-       pmap_shootdown_page(pmap_kernel(), va);
+       if ((opte & PG_V) != 0)
+               pmap_shootdown_page(pmap_kernel(), va);
 }
 
 /*