svn commit: r286658 - in head/sys: amd64/amd64 i386/i386

[Konstantin Belousov]

Author: kib
Date: Wed Aug 12 09:46:39 2015
New Revision: 286658
URL: https://svnweb.freebsd.org/changeset/base/286658

Log:
  Initialization of smp_tlb_wait does not require release semantic, no
  data is synchronized by store/load to the variable.  The
  lapic_write_icr() function ensures that store buffers are flushed
  before IPI command is issued.
  
  Discussed with:	bde
  Tested by:	pho
  Sponsored by:	The FreeBSD Foundation
  MFC after:	2 weeks

Modified:
  head/sys/amd64/amd64/mp_machdep.c
  head/sys/i386/i386/mp_machdep.c

Modified: head/sys/amd64/amd64/mp_machdep.c
==============================================================================
--- head/sys/amd64/amd64/mp_machdep.c	Wed Aug 12 09:43:12 2015	(r286657)
+++ head/sys/amd64/amd64/mp_machdep.c	Wed Aug 12 09:46:39 2015	(r286658)
@@ -440,7 +440,7 @@ smp_targeted_tlb_shootdown(cpuset_t mask
 	smp_tlb_addr1 = addr1;
 	smp_tlb_addr2 = addr2;
 	smp_tlb_pmap = pmap;
-	atomic_store_rel_int(&smp_tlb_wait, 0);
+	smp_tlb_wait =  0;
 	if (CPU_ISFULLSET(&mask)) {
 		ncpu = othercpus;
 		ipi_all_but_self(vector);

Modified: head/sys/i386/i386/mp_machdep.c
==============================================================================
--- head/sys/i386/i386/mp_machdep.c	Wed Aug 12 09:43:12 2015	(r286657)
+++ head/sys/i386/i386/mp_machdep.c	Wed Aug 12 09:46:39 2015	(r286658)
@@ -504,7 +504,7 @@ smp_tlb_shootdown(u_int vector, vm_offse
 	mtx_lock_spin(&smp_ipi_mtx);
 	smp_tlb_addr1 = addr1;
 	smp_tlb_addr2 = addr2;
-	atomic_store_rel_int(&smp_tlb_wait, 0);
+	smp_tlb_wait = 0;
 	ipi_all_but_self(vector);
 	while (smp_tlb_wait < ncpu)
 		ia32_pause();