On 04/19/2010 01:43 PM, Peter Zijlstra wrote:
+
cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src)
{
struct pvclock_shadow_time shadow;
unsigned version;
cycle_t ret, offset;
+ u64 last;
+ do {
+ last = last_value;
Otherwise, this assignment can see a partial update.
On a 32-bit guest, that is.
Right, do bear in mind that the x86 implementation of atomic64_read() is
terrifyingly expensive, it is better to not do that read and simply use
the result of the cmpxchg.
atomic64_read() _is_ cmpxchg64b. Are you thinking of some clever
implementation for smp i386?
--
error compiling committee.c: too many arguments to function
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