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| author | Paul E. McKenney <paulmck@kernel.org> | 2021-09-27 14:18:51 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-11-30 17:24:47 -0800 |
| commit | e2c73a6860bdf54f2c6bf8cddc34ddc91a1343e1 (patch) | |
| tree | d8b4e1ad9c9a7131bfe6fe50235e4d66465364cc /Documentation/RCU | |
| parent | 24eab6e1ff58d33048c36b5452f5d284c3710d02 (diff) | |
| download | linux-e2c73a6860bdf54f2c6bf8cddc34ddc91a1343e1.tar.bz2 | |
rcu: Remove the RCU_FAST_NO_HZ Kconfig option
All of the uses of CONFIG_RCU_FAST_NO_HZ=y that I have seen involve
systems with RCU callbacks offloaded. In this situation, all that this
Kconfig option does is slow down idle entry/exit with an additional
allways-taken early exit. If this is the only use case, then this
Kconfig option nothing but an attractive nuisance that needs to go away.
This commit therefore removes the RCU_FAST_NO_HZ Kconfig option.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'Documentation/RCU')
| -rw-r--r-- | Documentation/RCU/stallwarn.rst | 11 |
1 files changed, 0 insertions, 11 deletions
diff --git a/Documentation/RCU/stallwarn.rst b/Documentation/RCU/stallwarn.rst index 28f8ad16db25..78404625bad2 100644 --- a/Documentation/RCU/stallwarn.rst +++ b/Documentation/RCU/stallwarn.rst @@ -254,17 +254,6 @@ period (in this case 2603), the grace-period sequence number (7075), and an estimate of the total number of RCU callbacks queued across all CPUs (625 in this case). -In kernels with CONFIG_RCU_FAST_NO_HZ, more information is printed -for each CPU:: - - 0: (64628 ticks this GP) idle=dd5/3fffffffffffffff/0 softirq=82/543 last_accelerate: a345/d342 dyntick_enabled: 1 - -The "last_accelerate:" prints the low-order 16 bits (in hex) of the -jiffies counter when this CPU last invoked rcu_try_advance_all_cbs() -from rcu_needs_cpu() or last invoked rcu_accelerate_cbs() from -rcu_prepare_for_idle(). "dyntick_enabled: 1" indicates that dyntick-idle -processing is enabled. - If the grace period ends just as the stall warning starts printing, there will be a spurious stall-warning message, which will include the following:: |