Hi Andi

I was considering re-submiting patch to group together 
xtime_lock/xtime/jiffies in the same cache line. Before doing so, I believe 
the following cleanup patch could prepare the x86_64 port to be similar with 
other arches.

Thank you

[PATCH] x86_64 : Suppress __jiffies

x86_64 arch currently specially defines __jiffies, as a relic of old vsyscall 
implementation. It is currently used to validate vgetcpu() user cache as a 
token. If we use another token, more opaque like the seqlock sequence, we can 
get rid of special __jiffies handling. As a result, jiffies_64 is no more 
included in vsyscall page. This patch prepares the introduction of time_data.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>