path: root/Documentation/RCU/whatisRCU.txt
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authorPaul E. McKenney <paul.mckenney@linaro.org>2011-10-13 19:05:12 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2011-12-11 10:31:39 -0800
commita7b152d5342c06e81ab0cf7d18345f69fa7e56b5 (patch)
tree255a017e47aff33b910160161a55e7abd9d2cd5f /Documentation/RCU/whatisRCU.txt
parent416eb33cd60ef405e2860a186364e57bcb2d89f6 (diff)
powerpc: Tell RCU about idle after hcall tracing
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: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'Documentation/RCU/whatisRCU.txt')
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