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doc: Get rcutree module parameters back into alpha order 

This commit puts the rcutree module parameters back into proper
alphabetical order.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Paul E. McKenney 2023-03-21 17:28:40 -07:00
parent ac9a78681b
commit 51823ca651
1 changed files with 60 additions and 60 deletions
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120
Documentation/admin-guide/kernel-parameters.txt
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@ -4736,43 +4736,6 @@
the propagation of recent CPU-hotplug changes up
the rcu_node combining tree.
rcutree.use_softirq= [KNL]
If set to zero, move all RCU_SOFTIRQ processing to
per-CPU rcuc kthreads. Defaults to a non-zero
value, meaning that RCU_SOFTIRQ is used by default.
Specify rcutree.use_softirq=0 to use rcuc kthreads.
But note that CONFIG_PREEMPT_RT=y kernels disable
this kernel boot parameter, forcibly setting it
to zero.
rcutree.rcu_fanout_exact= [KNL]
Disable autobalancing of the rcu_node combining
tree. This is used by rcutorture, and might
possibly be useful for architectures having high
cache-to-cache transfer latencies.
rcutree.rcu_fanout_leaf= [KNL]
Change the number of CPUs assigned to each
leaf rcu_node structure. Useful for very
large systems, which will choose the value 64,
and for NUMA systems with large remote-access
latencies, which will choose a value aligned
with the appropriate hardware boundaries.
rcutree.rcu_min_cached_objs= [KNL]
Minimum number of objects which are cached and
maintained per one CPU. Object size is equal
to PAGE_SIZE. The cache allows to reduce the
pressure to page allocator, also it makes the
whole algorithm to behave better in low memory
condition.
rcutree.rcu_delay_page_cache_fill_msec= [KNL]
Set the page-cache refill delay (in milliseconds)
in response to low-memory conditions. The range
of permitted values is in the range 0:100000.
rcutree.jiffies_till_first_fqs= [KNL]
Set delay from grace-period initialization to
first attempt to force quiescent states.
@ -4811,21 +4774,6 @@
When RCU_NOCB_CPU is set, also adjust the
priority of NOCB callback kthreads.
rcutree.rcu_divisor= [KNL]
Set the shift-right count to use to compute
the callback-invocation batch limit bl from
the number of callbacks queued on this CPU.
The result will be bounded below by the value of
the rcutree.blimit kernel parameter. Every bl
callbacks, the softirq handler will exit in
order to allow the CPU to do other work.
Please note that this callback-invocation batch
limit applies only to non-offloaded callback
invocation. Offloaded callbacks are instead
invoked in the context of an rcuoc kthread, which
scheduler will preempt as it does any other task.
rcutree.nocb_nobypass_lim_per_jiffy= [KNL]
On callback-offloaded (rcu_nocbs) CPUs,
RCU reduces the lock contention that would
@ -4839,14 +4787,6 @@
the ->nocb_bypass queue. The definition of "too
many" is supplied by this kernel boot parameter.
rcutree.rcu_nocb_gp_stride= [KNL]
Set the number of NOCB callback kthreads in
each group, which defaults to the square root
of the number of CPUs. Larger numbers reduce
the wakeup overhead on the global grace-period
kthread, but increases that same overhead on
each group's NOCB grace-period kthread.
rcutree.qhimark= [KNL]
Set threshold of queued RCU callbacks beyond which
batch limiting is disabled.
@ -4864,6 +4804,56 @@
on rcutree.qhimark at boot time and to zero to
disable more aggressive help enlistment.
rcutree.rcu_delay_page_cache_fill_msec= [KNL]
Set the page-cache refill delay (in milliseconds)
in response to low-memory conditions. The range
of permitted values is in the range 0:100000.
rcutree.rcu_divisor= [KNL]
Set the shift-right count to use to compute
the callback-invocation batch limit bl from
the number of callbacks queued on this CPU.
The result will be bounded below by the value of
the rcutree.blimit kernel parameter. Every bl
callbacks, the softirq handler will exit in
order to allow the CPU to do other work.
Please note that this callback-invocation batch
limit applies only to non-offloaded callback
invocation. Offloaded callbacks are instead
invoked in the context of an rcuoc kthread, which
scheduler will preempt as it does any other task.
rcutree.rcu_fanout_exact= [KNL]
Disable autobalancing of the rcu_node combining
tree. This is used by rcutorture, and might
possibly be useful for architectures having high
cache-to-cache transfer latencies.
rcutree.rcu_fanout_leaf= [KNL]
Change the number of CPUs assigned to each
leaf rcu_node structure. Useful for very
large systems, which will choose the value 64,
and for NUMA systems with large remote-access
latencies, which will choose a value aligned
with the appropriate hardware boundaries.
rcutree.rcu_min_cached_objs= [KNL]
Minimum number of objects which are cached and
maintained per one CPU. Object size is equal
to PAGE_SIZE. The cache allows to reduce the
pressure to page allocator, also it makes the
whole algorithm to behave better in low memory
condition.
rcutree.rcu_nocb_gp_stride= [KNL]
Set the number of NOCB callback kthreads in
each group, which defaults to the square root
of the number of CPUs. Larger numbers reduce
the wakeup overhead on the global grace-period
kthread, but increases that same overhead on
each group's NOCB grace-period kthread.
rcutree.rcu_kick_kthreads= [KNL]
Cause the grace-period kthread to get an extra
wake_up() if it sleeps three times longer than
@ -4885,6 +4875,16 @@
rcu_node tree with an eye towards determining
why a new grace period has not yet started.
rcutree.use_softirq= [KNL]
If set to zero, move all RCU_SOFTIRQ processing to
per-CPU rcuc kthreads. Defaults to a non-zero
value, meaning that RCU_SOFTIRQ is used by default.
Specify rcutree.use_softirq=0 to use rcuc kthreads.
But note that CONFIG_PREEMPT_RT=y kernels disable
this kernel boot parameter, forcibly setting it
to zero.
rcuscale.gp_async= [KNL]
Measure performance of asynchronous
grace-period primitives such as call_rcu().