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    SubjectRe: [patch 5/9] Add all the necessary structures to the vsyscall page
    Date
    On Thursday 01 February 2007 10:59, jbohac@suse.cz wrote:
    > struct vxtime_data {
    > + union {
    > + struct {
    > + u64 tsc_slope; /* TSC to MT coefficient */
    > + u64 tsc_slope_avg; /* average tsc_slope */
    > + u64 mt_base; /* approximated MT at the last LAPIC tick */
    > + u64 mt_last; /* MT at the last LAPIC tick */
    > + u64 tsc_last; /* TSC at the last LAPIC tick */
    > + u64 last_mt_guess; /* ensures monotonicity in temporary MT mode */
    > + char tsc_invalid; /* don't trust the TSC now (frequency changing) */
    > + };
    > + char pad[64]; /* cacheline alignment */

    Use some variant of __cacheline_aligned_in_smp

    There are far better ways than to hardcode

    > + } cpu[NR_CPUS];

    This can become very large with default NR_CPUS==128. I would prefer
    a way that waste less space on smaller machines by only sizing the array
    num_possible_cpus()

    > long hpet_address; /* HPET base address */
    > - int last;
    > - unsigned long last_tsc;
    > - long quot;
    > - long tsc_quot;
    > + u64 mt_q; /* master timer to nsec quotient */
    > + u64 mt_wall; /* MT ticks already covered by the jiffies */
    > + s64 ns_drift; /* MT - xtime drift in the last tick in ns */

    Might make sense to duplicate those to all per cpu datas, then they
    only need to acce

    -Andi
    -
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