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  • Paul E. McKenney's avatar
    rcu: Avoid redundant quiescent-state chasing · 3563a438
    Paul E. McKenney authored
    
    
    Currently, __note_gp_changes() checks to see if the CPU has slept through
    multiple grace periods.  If it has, it resynchronizes that CPU's view
    of the grace-period state, which includes whether or not the current
    grace period needs a quiescent state from this CPU.  The fact of this
    need (or lack thereof) needs to be in two places, rdp->cpu_no_qs.b.norm
    and rdp->core_needs_qs.  The former tells RCU's context-switch code to
    go get a quiescent state and the latter says that it needs to be reported.
    The current code unconditionally sets the former to true, but correctly
    sets the latter.
    
    This does not result in failures, but it does unnecessarily increase
    the amount of work done on average at context-switch time.  This commit
    therefore correctly sets both fields.
    
    Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
    3563a438