~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/kernel/rcu/Kconfig

Version: ~ [ linux-6.11.5 ] ~ [ linux-6.10.14 ] ~ [ linux-6.9.12 ] ~ [ linux-6.8.12 ] ~ [ linux-6.7.12 ] ~ [ linux-6.6.58 ] ~ [ linux-6.5.13 ] ~ [ linux-6.4.16 ] ~ [ linux-6.3.13 ] ~ [ linux-6.2.16 ] ~ [ linux-6.1.114 ] ~ [ linux-6.0.19 ] ~ [ linux-5.19.17 ] ~ [ linux-5.18.19 ] ~ [ linux-5.17.15 ] ~ [ linux-5.16.20 ] ~ [ linux-5.15.169 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.228 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.284 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.322 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.336 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.337 ] ~ [ linux-4.4.302 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.9 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

Diff markup

Differences between /kernel/rcu/Kconfig (Version linux-6.11.5) and /kernel/rcu/Kconfig (Version linux-5.14.21)


  1 # SPDX-License-Identifier: GPL-2.0-only             1 # SPDX-License-Identifier: GPL-2.0-only
  2 #                                                   2 #
  3 # RCU-related configuration options                 3 # RCU-related configuration options
  4 #                                                   4 #
  5                                                     5 
  6 menu "RCU Subsystem"                                6 menu "RCU Subsystem"
  7                                                     7 
  8 config TREE_RCU                                     8 config TREE_RCU
  9         bool                                        9         bool
 10         default y if SMP                           10         default y if SMP
 11         # Dynticks-idle tracking               << 
 12         select CONTEXT_TRACKING_IDLE           << 
 13         help                                       11         help
 14           This option selects the RCU implemen     12           This option selects the RCU implementation that is
 15           designed for very large SMP system w     13           designed for very large SMP system with hundreds or
 16           thousands of CPUs.  It also scales d     14           thousands of CPUs.  It also scales down nicely to
 17           smaller systems.                         15           smaller systems.
 18                                                    16 
 19 config PREEMPT_RCU                                 17 config PREEMPT_RCU
 20         bool                                       18         bool
 21         default y if PREEMPTION                    19         default y if PREEMPTION
 22         select TREE_RCU                            20         select TREE_RCU
 23         help                                       21         help
 24           This option selects the RCU implemen     22           This option selects the RCU implementation that is
 25           designed for very large SMP systems      23           designed for very large SMP systems with hundreds or
 26           thousands of CPUs, but for which rea     24           thousands of CPUs, but for which real-time response
 27           is also required.  It also scales do     25           is also required.  It also scales down nicely to
 28           smaller systems.                         26           smaller systems.
 29                                                    27 
 30           Select this option if you are unsure     28           Select this option if you are unsure.
 31                                                    29 
 32 config TINY_RCU                                    30 config TINY_RCU
 33         bool                                       31         bool
 34         default y if !PREEMPT_RCU && !SMP      !!  32         default y if !PREEMPTION && !SMP
 35         help                                       33         help
 36           This option selects the RCU implemen     34           This option selects the RCU implementation that is
 37           designed for UP systems from which r     35           designed for UP systems from which real-time response
 38           is not required.  This option greatl     36           is not required.  This option greatly reduces the
 39           memory footprint of RCU.                 37           memory footprint of RCU.
 40                                                    38 
 41 config RCU_EXPERT                                  39 config RCU_EXPERT
 42         bool "Make expert-level adjustments to     40         bool "Make expert-level adjustments to RCU configuration"
 43         default n                                  41         default n
 44         help                                       42         help
 45           This option needs to be enabled if y     43           This option needs to be enabled if you wish to make
 46           expert-level adjustments to RCU conf     44           expert-level adjustments to RCU configuration.  By default,
 47           no such adjustments can be made, whi     45           no such adjustments can be made, which has the often-beneficial
 48           side-effect of preventing "make oldc     46           side-effect of preventing "make oldconfig" from asking you all
 49           sorts of detailed questions about ho     47           sorts of detailed questions about how you would like numerous
 50           obscure RCU options to be set up.        48           obscure RCU options to be set up.
 51                                                    49 
 52           Say Y if you need to make expert-lev     50           Say Y if you need to make expert-level adjustments to RCU.
 53                                                    51 
 54           Say N if you are unsure.                 52           Say N if you are unsure.
 55                                                    53 
                                                   >>  54 config SRCU
                                                   >>  55         bool
                                                   >>  56         help
                                                   >>  57           This option selects the sleepable version of RCU. This version
                                                   >>  58           permits arbitrary sleeping or blocking within RCU read-side critical
                                                   >>  59           sections.
                                                   >>  60 
 56 config TINY_SRCU                                   61 config TINY_SRCU
 57         bool                                       62         bool
 58         default y if TINY_RCU                  !!  63         default y if SRCU && TINY_RCU
 59         help                                       64         help
 60           This option selects the single-CPU n     65           This option selects the single-CPU non-preemptible version of SRCU.
 61                                                    66 
 62 config TREE_SRCU                                   67 config TREE_SRCU
 63         bool                                       68         bool
 64         default y if !TINY_RCU                 !!  69         default y if SRCU && !TINY_RCU
 65         help                                       70         help
 66           This option selects the full-fledged     71           This option selects the full-fledged version of SRCU.
 67                                                    72 
 68 config NEED_SRCU_NMI_SAFE                      << 
 69         def_bool HAVE_NMI && !ARCH_HAS_NMI_SAF << 
 70                                                << 
 71 config TASKS_RCU_GENERIC                           73 config TASKS_RCU_GENERIC
 72         def_bool TASKS_RCU || TASKS_RUDE_RCU |     74         def_bool TASKS_RCU || TASKS_RUDE_RCU || TASKS_TRACE_RCU
                                                   >>  75         select SRCU
 73         help                                       76         help
 74           This option enables generic infrastr     77           This option enables generic infrastructure code supporting
 75           task-based RCU implementations.  Not     78           task-based RCU implementations.  Not for manual selection.
 76                                                    79 
 77 config FORCE_TASKS_RCU                         << 
 78         bool "Force selection of TASKS_RCU"    << 
 79         depends on RCU_EXPERT                  << 
 80         select TASKS_RCU                       << 
 81         default n                              << 
 82         help                                   << 
 83           This option force-enables a task-bas << 
 84           that uses only voluntary context swi << 
 85           idle, and user-mode execution as qui << 
 86           manual selection in most cases.      << 
 87                                                << 
 88 config NEED_TASKS_RCU                          << 
 89         bool                                   << 
 90         default n                              << 
 91                                                << 
 92 config TASKS_RCU                                   80 config TASKS_RCU
 93         bool                                   !!  81         def_bool PREEMPTION
 94         default NEED_TASKS_RCU && (PREEMPTION  << 
 95         select IRQ_WORK                        << 
 96                                                << 
 97 config FORCE_TASKS_RUDE_RCU                    << 
 98         bool "Force selection of Tasks Rude RC << 
 99         depends on RCU_EXPERT                  << 
100         select TASKS_RUDE_RCU                  << 
101         default n                              << 
102         help                                       82         help
103           This option force-enables a task-bas !!  83           This option enables a task-based RCU implementation that uses
104           that uses only context switch (inclu !!  84           only voluntary context switch (not preemption!), idle, and
105           user-mode execution as quiescent sta !!  85           user-mode execution as quiescent states.  Not for manual selection.
106           context switches on all online CPUs, << 
107           so use with caution.  Not for manual << 
108                                                    86 
109 config TASKS_RUDE_RCU                              87 config TASKS_RUDE_RCU
110         bool                                   !!  88         def_bool 0
111         default n                              << 
112         select IRQ_WORK                        << 
113                                                << 
114 config FORCE_TASKS_TRACE_RCU                   << 
115         bool "Force selection of Tasks Trace R << 
116         depends on RCU_EXPERT                  << 
117         select TASKS_TRACE_RCU                 << 
118         default n                              << 
119         help                                       89         help
120           This option enables a task-based RCU     90           This option enables a task-based RCU implementation that uses
121           explicit rcu_read_lock_trace() read- !!  91           only context switch (including preemption) and user-mode
122           these readers to appear in the idle  !!  92           execution as quiescent states.  It forces IPIs and context
123           CPU hotplug code paths.  It can forc !!  93           switches on all online CPUs, including idle ones, so use
124           including idle ones, so use with cau !!  94           with caution.
125           selection in most cases.             << 
126                                                    95 
127 config TASKS_TRACE_RCU                             96 config TASKS_TRACE_RCU
128         bool                                   !!  97         def_bool 0
129         default n                              << 
130         select IRQ_WORK                            98         select IRQ_WORK
                                                   >>  99         help
                                                   >> 100           This option enables a task-based RCU implementation that uses
                                                   >> 101           explicit rcu_read_lock_trace() read-side markers, and allows
                                                   >> 102           these readers to appear in the idle loop as well as on the CPU
                                                   >> 103           hotplug code paths.  It can force IPIs on online CPUs, including
                                                   >> 104           idle ones, so use with caution.
131                                                   105 
132 config RCU_STALL_COMMON                           106 config RCU_STALL_COMMON
133         def_bool TREE_RCU                         107         def_bool TREE_RCU
134         help                                      108         help
135           This option enables RCU CPU stall co    109           This option enables RCU CPU stall code that is common between
136           the TINY and TREE variants of RCU.      110           the TINY and TREE variants of RCU.  The purpose is to allow
137           the tiny variants to disable RCU CPU    111           the tiny variants to disable RCU CPU stall warnings, while
138           making these warnings mandatory for     112           making these warnings mandatory for the tree variants.
139                                                   113 
140 config RCU_NEED_SEGCBLIST                         114 config RCU_NEED_SEGCBLIST
141         def_bool ( TREE_RCU || TREE_SRCU || TA !! 115         def_bool ( TREE_RCU || TREE_SRCU )
142                                                   116 
143 config RCU_FANOUT                                 117 config RCU_FANOUT
144         int "Tree-based hierarchical RCU fanou    118         int "Tree-based hierarchical RCU fanout value"
145         range 2 64 if 64BIT                       119         range 2 64 if 64BIT
146         range 2 32 if !64BIT                      120         range 2 32 if !64BIT
147         depends on TREE_RCU && RCU_EXPERT         121         depends on TREE_RCU && RCU_EXPERT
148         default 64 if 64BIT                       122         default 64 if 64BIT
149         default 32 if !64BIT                      123         default 32 if !64BIT
150         help                                      124         help
151           This option controls the fanout of h    125           This option controls the fanout of hierarchical implementations
152           of RCU, allowing RCU to work efficie    126           of RCU, allowing RCU to work efficiently on machines with
153           large numbers of CPUs.  This value m    127           large numbers of CPUs.  This value must be at least the fourth
154           root of NR_CPUS, which allows NR_CPU    128           root of NR_CPUS, which allows NR_CPUS to be insanely large.
155           The default value of RCU_FANOUT shou    129           The default value of RCU_FANOUT should be used for production
156           systems, but if you are stress-testi    130           systems, but if you are stress-testing the RCU implementation
157           itself, small RCU_FANOUT values allo    131           itself, small RCU_FANOUT values allow you to test large-system
158           code paths on small(er) systems.        132           code paths on small(er) systems.
159                                                   133 
160           Select a specific number if testing     134           Select a specific number if testing RCU itself.
161           Take the default if unsure.             135           Take the default if unsure.
162                                                   136 
163 config RCU_FANOUT_LEAF                            137 config RCU_FANOUT_LEAF
164         int "Tree-based hierarchical RCU leaf-    138         int "Tree-based hierarchical RCU leaf-level fanout value"
165         range 2 64 if 64BIT && !RCU_STRICT_GRA    139         range 2 64 if 64BIT && !RCU_STRICT_GRACE_PERIOD
166         range 2 32 if !64BIT && !RCU_STRICT_GR    140         range 2 32 if !64BIT && !RCU_STRICT_GRACE_PERIOD
167         range 2 3 if RCU_STRICT_GRACE_PERIOD      141         range 2 3 if RCU_STRICT_GRACE_PERIOD
168         depends on TREE_RCU && RCU_EXPERT         142         depends on TREE_RCU && RCU_EXPERT
169         default 16 if !RCU_STRICT_GRACE_PERIOD    143         default 16 if !RCU_STRICT_GRACE_PERIOD
170         default 2 if RCU_STRICT_GRACE_PERIOD      144         default 2 if RCU_STRICT_GRACE_PERIOD
171         help                                      145         help
172           This option controls the leaf-level     146           This option controls the leaf-level fanout of hierarchical
173           implementations of RCU, and allows t    147           implementations of RCU, and allows trading off cache misses
174           against lock contention.  Systems th    148           against lock contention.  Systems that synchronize their
175           scheduling-clock interrupts for ener    149           scheduling-clock interrupts for energy-efficiency reasons will
176           want the default because the smaller    150           want the default because the smaller leaf-level fanout keeps
177           lock contention levels acceptably lo    151           lock contention levels acceptably low.  Very large systems
178           (hundreds or thousands of CPUs) will    152           (hundreds or thousands of CPUs) will instead want to set this
179           value to the maximum value possible     153           value to the maximum value possible in order to reduce the
180           number of cache misses incurred duri    154           number of cache misses incurred during RCU's grace-period
181           initialization.  These systems tend     155           initialization.  These systems tend to run CPU-bound, and thus
182           are not helped by synchronized inter    156           are not helped by synchronized interrupts, and thus tend to
183           skew them, which reduces lock conten    157           skew them, which reduces lock contention enough that large
184           leaf-level fanouts work well.  That     158           leaf-level fanouts work well.  That said, setting leaf-level
185           fanout to a large number will likely    159           fanout to a large number will likely cause problematic
186           lock contention on the leaf-level rc    160           lock contention on the leaf-level rcu_node structures unless
187           you boot with the skew_tick kernel p    161           you boot with the skew_tick kernel parameter.
188                                                   162 
189           Select a specific number if testing     163           Select a specific number if testing RCU itself.
190                                                   164 
191           Select the maximum permissible value    165           Select the maximum permissible value for large systems, but
192           please understand that you may also     166           please understand that you may also need to set the skew_tick
193           kernel boot parameter to avoid conte    167           kernel boot parameter to avoid contention on the rcu_node
194           structure's locks.                      168           structure's locks.
195                                                   169 
196           Take the default if unsure.             170           Take the default if unsure.
197                                                   171 
                                                   >> 172 config RCU_FAST_NO_HZ
                                                   >> 173         bool "Accelerate last non-dyntick-idle CPU's grace periods"
                                                   >> 174         depends on NO_HZ_COMMON && SMP && RCU_EXPERT
                                                   >> 175         default n
                                                   >> 176         help
                                                   >> 177           This option permits CPUs to enter dynticks-idle state even if
                                                   >> 178           they have RCU callbacks queued, and prevents RCU from waking
                                                   >> 179           these CPUs up more than roughly once every four jiffies (by
                                                   >> 180           default, you can adjust this using the rcutree.rcu_idle_gp_delay
                                                   >> 181           parameter), thus improving energy efficiency.  On the other
                                                   >> 182           hand, this option increases the duration of RCU grace periods,
                                                   >> 183           for example, slowing down synchronize_rcu().
                                                   >> 184 
                                                   >> 185           Say Y if energy efficiency is critically important, and you
                                                   >> 186                 don't care about increased grace-period durations.
                                                   >> 187 
                                                   >> 188           Say N if you are unsure.
                                                   >> 189 
198 config RCU_BOOST                                  190 config RCU_BOOST
199         bool "Enable RCU priority boosting"       191         bool "Enable RCU priority boosting"
200         depends on (RT_MUTEXES && PREEMPT_RCU     192         depends on (RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT) || PREEMPT_RT
201         default y if PREEMPT_RT                   193         default y if PREEMPT_RT
202         help                                      194         help
203           This option boosts the priority of p    195           This option boosts the priority of preempted RCU readers that
204           block the current preemptible RCU gr    196           block the current preemptible RCU grace period for too long.
205           This option also prevents heavy load    197           This option also prevents heavy loads from blocking RCU
206           callback invocation.                    198           callback invocation.
207                                                   199 
208           Say Y here if you are working with r    200           Say Y here if you are working with real-time apps or heavy loads
209           Say N here if you are unsure.           201           Say N here if you are unsure.
210                                                   202 
211 config RCU_BOOST_DELAY                            203 config RCU_BOOST_DELAY
212         int "Milliseconds to delay boosting af    204         int "Milliseconds to delay boosting after RCU grace-period start"
213         range 0 3000                              205         range 0 3000
214         depends on RCU_BOOST                      206         depends on RCU_BOOST
215         default 500                               207         default 500
216         help                                      208         help
217           This option specifies the time to wa    209           This option specifies the time to wait after the beginning of
218           a given grace period before priority    210           a given grace period before priority-boosting preempted RCU
219           readers blocking that grace period.     211           readers blocking that grace period.  Note that any RCU reader
220           blocking an expedited RCU grace peri    212           blocking an expedited RCU grace period is boosted immediately.
221                                                   213 
222           Accept the default if unsure.           214           Accept the default if unsure.
223                                                   215 
224 config RCU_EXP_KTHREAD                         << 
225         bool "Perform RCU expedited work in a  << 
226         depends on RCU_BOOST && RCU_EXPERT     << 
227         default !PREEMPT_RT && NR_CPUS <= 32   << 
228         help                                   << 
229           Use this option to further reduce th << 
230           grace periods at the expense of bein << 
231                                                << 
232           This option is disabled by default o << 
233           disable expedited grace periods afte << 
234           setting rcupdate.rcu_normal_after_bo << 
235                                                << 
236           Accept the default if unsure.        << 
237                                                << 
238 config RCU_NOCB_CPU                               216 config RCU_NOCB_CPU
239         bool "Offload RCU callback processing     217         bool "Offload RCU callback processing from boot-selected CPUs"
240         depends on TREE_RCU                       218         depends on TREE_RCU
241         depends on RCU_EXPERT || NO_HZ_FULL       219         depends on RCU_EXPERT || NO_HZ_FULL
242         default n                                 220         default n
243         help                                      221         help
244           Use this option to reduce OS jitter     222           Use this option to reduce OS jitter for aggressive HPC or
245           real-time workloads.  It can also be    223           real-time workloads.  It can also be used to offload RCU
246           callback invocation to energy-effici    224           callback invocation to energy-efficient CPUs in battery-powered
247           asymmetric multiprocessors.  The pri    225           asymmetric multiprocessors.  The price of this reduced jitter
248           is that the overhead of call_rcu() i    226           is that the overhead of call_rcu() increases and that some
249           workloads will incur significant inc    227           workloads will incur significant increases in context-switch
250           rates.                                  228           rates.
251                                                   229 
252           This option offloads callback invoca    230           This option offloads callback invocation from the set of CPUs
253           specified at boot time by the rcu_no    231           specified at boot time by the rcu_nocbs parameter.  For each
254           such CPU, a kthread ("rcuox/N") will    232           such CPU, a kthread ("rcuox/N") will be created to invoke
255           callbacks, where the "N" is the CPU     233           callbacks, where the "N" is the CPU being offloaded, and where
256           the "x" is "p" for RCU-preempt (PREE    234           the "x" is "p" for RCU-preempt (PREEMPTION kernels) and "s" for
257           RCU-sched (!PREEMPTION kernels).  No    235           RCU-sched (!PREEMPTION kernels).  Nothing prevents this kthread
258           from running on the specified CPUs,     236           from running on the specified CPUs, but (1) the kthreads may be
259           preempted between each callback, and    237           preempted between each callback, and (2) affinity or cgroups can
260           be used to force the kthreads to run    238           be used to force the kthreads to run on whatever set of CPUs is
261           desired.                                239           desired.
262                                                   240 
263           Say Y here if you need reduced OS ji    241           Say Y here if you need reduced OS jitter, despite added overhead.
264           Say N here if you are unsure.           242           Say N here if you are unsure.
265                                                   243 
266 config RCU_NOCB_CPU_DEFAULT_ALL                << 
267         bool "Offload RCU callback processing  << 
268         depends on RCU_NOCB_CPU                << 
269         default n                              << 
270         help                                   << 
271           Use this option to offload callback  << 
272           by default, in the absence of the rc << 
273           parameter. This also avoids the need << 
274           to achieve the effect of offloading  << 
275                                                << 
276           Say Y here if you want offload all C << 
277           Say N here if you are unsure.        << 
278                                                << 
279 config RCU_NOCB_CPU_CB_BOOST                   << 
280         bool "Offload RCU callback from real-t << 
281         depends on RCU_NOCB_CPU && RCU_BOOST   << 
282         default y if PREEMPT_RT                << 
283         help                                   << 
284           Use this option to invoke offloaded  << 
285           to avoid starvation by heavy SCHED_O << 
286           Of course, running as SCHED_FIFO dur << 
287           cause the rcuo[ps] kthreads to monop << 
288           of milliseconds or more.  Therefore, << 
289           it is your responsibility to ensure  << 
290           tasks either run with higher priorit << 
291                                                << 
292           Say Y here if you want to set RT pri << 
293           Say N here if you are building a !PR << 
294                                                << 
295 config TASKS_TRACE_RCU_READ_MB                    244 config TASKS_TRACE_RCU_READ_MB
296         bool "Tasks Trace RCU readers use memo    245         bool "Tasks Trace RCU readers use memory barriers in user and idle"
297         depends on RCU_EXPERT && TASKS_TRACE_R !! 246         depends on RCU_EXPERT
298         default PREEMPT_RT || NR_CPUS < 8         247         default PREEMPT_RT || NR_CPUS < 8
299         help                                      248         help
300           Use this option to further reduce th    249           Use this option to further reduce the number of IPIs sent
301           to CPUs executing in userspace or id    250           to CPUs executing in userspace or idle during tasks trace
302           RCU grace periods.  Given that a rea    251           RCU grace periods.  Given that a reasonable setting of
303           the rcupdate.rcu_task_ipi_delay kern    252           the rcupdate.rcu_task_ipi_delay kernel boot parameter
304           eliminates such IPIs for many worklo    253           eliminates such IPIs for many workloads, proper setting
305           of this Kconfig option is important     254           of this Kconfig option is important mostly for aggressive
306           real-time installations and for batt    255           real-time installations and for battery-powered devices,
307           hence the default chosen above.         256           hence the default chosen above.
308                                                   257 
309           Say Y here if you hate IPIs.            258           Say Y here if you hate IPIs.
310           Say N here if you hate read-side mem    259           Say N here if you hate read-side memory barriers.
311           Take the default if you are unsure.     260           Take the default if you are unsure.
312                                                << 
313 config RCU_LAZY                                << 
314         bool "RCU callback lazy invocation fun << 
315         depends on RCU_NOCB_CPU                << 
316         default n                              << 
317         help                                   << 
318           To save power, batch RCU callbacks a << 
319           pressure, or callback list growing t << 
320                                                << 
321           Requires rcu_nocbs=all to be set.    << 
322                                                << 
323           Use rcutree.enable_rcu_lazy=0 to tur << 
324                                                << 
325 config RCU_LAZY_DEFAULT_OFF                    << 
326         bool "Turn RCU lazy invocation off by  << 
327         depends on RCU_LAZY                    << 
328         default n                              << 
329         help                                   << 
330           Allows building the kernel with CONF << 
331           off. Boot time param rcutree.enable_ << 
332           it back on.                          << 
333                                                << 
334 config RCU_DOUBLE_CHECK_CB_TIME                << 
335         bool "RCU callback-batch backup time c << 
336         depends on RCU_EXPERT                  << 
337         default n                              << 
338         help                                   << 
339           Use this option to provide more prec << 
340           rcutree.rcu_resched_ns module parame << 
341           a single RCU callback might run for  << 
342           thus defeating the 32-callback batch << 
343           cost of the fine-grained but expensi << 
344                                                << 
345           This option rounds rcutree.rcu_resch << 
346           jiffy, and overrides the 32-callback << 
347           is exceeded.                         << 
348                                                << 
349           Say Y here if you need tighter callb << 
350           Say N here if you are unsure.        << 
351                                                   261 
352 endmenu # "RCU Subsystem"                         262 endmenu # "RCU Subsystem"
                                                      

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

sflogo.php