From: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu, 22 Sep 2011 09:12:44 +0000 (-0400)
Subject: cmm: provide lightweight smp_rmb/smp_wmb on PPC
X-Git-Tag: v0.6.5~11
X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=commitdiff_plain;h=0174d10df0bd3a6b1a1e4eb3601476b0536d5dfc;hp=0174d10df0bd3a6b1a1e4eb3601476b0536d5dfc

cmm: provide lightweight smp_rmb/smp_wmb on PPC

lwsync orders loads in cacheable memory with respect to other loads,
and stores in cacheable memory with respect to other stores.  Use it
to implement smp_rmb/smp_wmb.

The heavy-weight sync is still used for the "full" rmb/wmb operations,
as well as for smp_mb.

[ Edit by Mathieu Desnoyers: rephrased the comments around the memory
  barriers. ]

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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