• Paul E. McKenney's avatar
    powerpc: Tell RCU about idle after hcall tracing · a7b152d5
    Paul E. McKenney authored
    The PowerPC pSeries platform (CONFIG_PPC_PSERIES=y) enables
    hypervisor-call tracing for CONFIG_TRACEPOINTS=y kernels.  One of the
    hypervisor calls that is traced is the H_CEDE call in the idle loop
    that tells the hypervisor that this OS instance no longer needs the
    current CPU.  However, tracing uses RCU, so this combination of kernel
    configuration variables needs to avoid telling RCU about the current CPU's
    idleness until after the H_CEDE-entry tracing completes on the one hand,
    and must tell RCU that the the current CPU is no longer idle before the
    H_CEDE-exit tracing starts.
    
    In all other cases, it suffices to inform RCU of CPU idleness upon
    idle-loop entry and exit.
    
    This commit makes the required adjustments.
    Signed-off-by: default avatarPaul E. McKenney <paul.mckenney@linaro.org>
    Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
    Reviewed-by: default avatarJosh Triplett <josh@joshtriplett.org>
    a7b152d5
lpar.c 15.9 KB