On Thu, Jun 09, 2016 at 01:23:23PM +0200, Paolo Bonzini wrote: > The version field in struct pvclock_vcpu_time_info basically implements > a seqcount. Wrap it with the usual read_begin and read_retry functions, > and use these APIs instead of peppering the code with smp_rmb()s. > While at it, change it to the more pedantically correct virt_rmb(). > > With this change, __pvclock_read_cycles can be simplified noticeably. > > Signed-off-by: Paolo Bonzini <[email protected]> > --- > arch/x86/entry/vdso/vclock_gettime.c | 25 +++++------------------ > arch/x86/include/asm/pvclock.h | 39 > +++++++++++++++++++++--------------- > arch/x86/kernel/pvclock.c | 17 ++++++---------- > 3 files changed, 34 insertions(+), 47 deletions(-) [...] > --- a/arch/x86/include/asm/pvclock.h > +++ b/arch/x86/include/asm/pvclock.h [...] > @@ -69,23 +87,12 @@ static inline u64 pvclock_scale_delta(u64 delta, u32 > mul_frac, int shift) > } > > static __always_inline > -unsigned __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src, > - cycle_t *cycles, u8 *flags) > +cycle_t __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src) > { > - unsigned version; > - cycle_t offset; > - u64 delta; > - > - version = src->version; > - /* Make the latest version visible */ > - smp_rmb();
This is on top of Minfei's patch, right? It isn't in Linus' tree yet so I wonder if it makes sense to merge the two patches into one. Will you post it to stable, too? Anyway Reviewed-by: Roman Kagan <[email protected]> Roman.
