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From: "Jayachandran C." <jchandra@FreeBSD.org>
Date: Thu, 12 Aug 2010 09:15:27 +0000 (UTC)
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Subject: svn commit: r211216 - head/sys/mips/mips
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Author: jchandra
Date: Thu Aug 12 09:15:27 2010
New Revision: 211216
URL: http://svn.freebsd.org/changeset/base/211216

Log:
  Optimization for pmap_kenter(), call pmap_update_page() only when
  necessary.  On SMP, pmap_update_page() can be costly as it needs a
  a smp_rendezvous().
  
  Reviewed by:	alc, neel
  Obtained from:	jmallett (http://svn.freebsd.org/base/user/jmallett/octeon)

Modified:
  head/sys/mips/mips/pmap.c

Modified: head/sys/mips/mips/pmap.c
==============================================================================
--- head/sys/mips/mips/pmap.c	Thu Aug 12 09:03:21 2010	(r211215)
+++ head/sys/mips/mips/pmap.c	Thu Aug 12 09:15:27 2010	(r211216)
@@ -810,7 +810,8 @@ pmap_kenter(vm_offset_t va, vm_paddr_t p
 	pte = pmap_pte(kernel_pmap, va);
 	opte = *pte;
 	*pte = npte;
-	pmap_update_page(kernel_pmap, va, npte);
+	if (pte_test(&opte, PTE_V) && opte != npte)
+		pmap_update_page(kernel_pmap, va, npte);
 }
 
 /*