Since sequence count algorithm is done by hypervisor, better to not reuse seqcount. Still concerned that the code is racy. -----Original Message----- From: Thomas Gleixner [mailto:tglx@xxxxxxxxxxxxx] Sent: Friday, February 10, 2017 4:28 AM To: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> Cc: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>; x86@xxxxxxxxxx; Andy Lutomirski <luto@xxxxxxxxxxxxxx>; Ingo Molnar <mingo@xxxxxxxxxx>; H. Peter Anvin <hpa@xxxxxxxxx>; KY Srinivasan <kys@xxxxxxxxxxxxx>; Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>; Dexuan Cui <decui@xxxxxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx; devel@xxxxxxxxxxxxxxxxxxxxxx; virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx Subject: Re: [PATCH 2/2] x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method On Fri, 10 Feb 2017, Vitaly Kuznetsov wrote: > Stephen Hemminger <sthemmin@xxxxxxxxxxxxx> writes: > > > Why not use existing seqlock's? > > > > To be honest I don't quite understand how we could use it -- the > sequence locking here is done against the page updated by the > hypersior, we're not creating new structures (so I don't understand > how we could use struct seqcount which we don't have) but I may be > misunderstanding something. You can't use seqlock, but you might be able to use seqcount. Though I doubt it given the 0 check .... Thanks, tglx _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
