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authorLinus Torvalds <torvalds@linux-foundation.org>2012-05-21 19:26:51 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-21 19:26:51 -0700
commit226da0dbc84ed97f448523e2a4cb91c27fa68ed9 (patch)
tree3969a9f612cd5596747ecde2066e65eacbab7d2e /Documentation
parent5ec29e3149d800e6db83c1b6ff441daf319cbbe2 (diff)
parent2d84e023cb5ec00403ff5d447533c6fd58fcc7ff (diff)
downloadlinux-226da0dbc84ed97f448523e2a4cb91c27fa68ed9.tar.gz
Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU changes from Ingo Molnar: "This is the v3.5 RCU tree from Paul E. McKenney: 1) A set of improvements and fixes to the RCU_FAST_NO_HZ feature (with more on the way for 3.6). Posted to LKML: https://lkml.org/lkml/2012/4/23/324 (commits 1-3 and 5), https://lkml.org/lkml/2012/4/16/611 (commit 4), https://lkml.org/lkml/2012/4/30/390 (commit 6), and https://lkml.org/lkml/2012/5/4/410 (commit 7, combined with the other commits for the convenience of the tester). 2) Changes to make rcu_barrier() avoid disrupting execution of CPUs that have no RCU callbacks. Posted to LKML: https://lkml.org/lkml/2012/4/23/322. 3) A couple of commits that improve the efficiency of the interaction between preemptible RCU and the scheduler, these two being all that survived an abortive attempt to allow preemptible RCU's __rcu_read_lock() to be inlined. The full set was posted to LKML at https://lkml.org/lkml/2012/4/14/143, and the first and third patches of that set remain. 4) Lai Jiangshan's algorithmic implementation of SRCU, which includes call_srcu() and srcu_barrier(). A major feature of this new implementation is that synchronize_srcu() no longer disturbs the execution of other CPUs. This work is based on earlier implementations by Peter Zijlstra and Paul E. McKenney. Posted to LKML: https://lkml.org/lkml/2012/2/22/82. 5) A number of miscellaneous bug fixes and improvements which were posted to LKML at: https://lkml.org/lkml/2012/4/23/353 with subsequent updates posted to LKML." * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits) rcu: Make rcu_barrier() less disruptive rcu: Explicitly initialize RCU_FAST_NO_HZ per-CPU variables rcu: Make RCU_FAST_NO_HZ handle timer migration rcu: Update RCU maintainership rcu: Make exit_rcu() more precise and consolidate rcu: Move PREEMPT_RCU preemption to switch_to() invocation rcu: Ensure that RCU_FAST_NO_HZ timers expire on correct CPU rcu: Add rcutorture test for call_srcu() rcu: Implement per-domain single-threaded call_srcu() state machine rcu: Use single value to handle expedited SRCU grace periods rcu: Improve srcu_readers_active_idx()'s cache locality rcu: Remove unused srcu_barrier() rcu: Implement a variant of Peter's SRCU algorithm rcu: Improve SRCU's wait_idx() comments rcu: Flip ->completed only once per SRCU grace period rcu: Increment upper bit only for srcu_read_lock() rcu: Remove fast check path from __synchronize_srcu() rcu: Direct algorithmic SRCU implementation rcu: Introduce rcutorture testing for rcu_barrier() timer: Fix mod_timer_pinned() header comment ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/RCU/torture.txt15
-rw-r--r--Documentation/kernel-parameters.txt88
2 files changed, 99 insertions, 4 deletions
diff --git a/Documentation/RCU/torture.txt b/Documentation/RCU/torture.txt
index 375d3fb7143..4ddf3913fd8 100644
--- a/Documentation/RCU/torture.txt
+++ b/Documentation/RCU/torture.txt
@@ -47,6 +47,16 @@ irqreader Says to invoke RCU readers from irq level. This is currently
permit this. (Or, more accurately, variants of RCU that do
-not- permit this know to ignore this variable.)
+n_barrier_cbs If this is nonzero, RCU barrier testing will be conducted,
+ in which case n_barrier_cbs specifies the number of
+ RCU callbacks (and corresponding kthreads) to use for
+ this testing. The value cannot be negative. If you
+ specify this to be non-zero when torture_type indicates a
+ synchronous RCU implementation (one for which a member of
+ the synchronize_rcu() rather than the call_rcu() family is
+ used -- see the documentation for torture_type below), an
+ error will be reported and no testing will be carried out.
+
nfakewriters This is the number of RCU fake writer threads to run. Fake
writer threads repeatedly use the synchronous "wait for
current readers" function of the interface selected by
@@ -188,7 +198,7 @@ OUTPUT
The statistics output is as follows:
rcu-torture:--- Start of test: nreaders=16 nfakewriters=4 stat_interval=30 verbose=0 test_no_idle_hz=1 shuffle_interval=3 stutter=5 irqreader=1 fqs_duration=0 fqs_holdoff=0 fqs_stutter=3 test_boost=1/0 test_boost_interval=7 test_boost_duration=4
- rcu-torture: rtc: (null) ver: 155441 tfle: 0 rta: 155441 rtaf: 8884 rtf: 155440 rtmbe: 0 rtbke: 0 rtbre: 0 rtbf: 0 rtb: 0 nt: 3055767
+ rcu-torture: rtc: (null) ver: 155441 tfle: 0 rta: 155441 rtaf: 8884 rtf: 155440 rtmbe: 0 rtbe: 0 rtbke: 0 rtbre: 0 rtbf: 0 rtb: 0 nt: 3055767
rcu-torture: Reader Pipe: 727860534 34213 0 0 0 0 0 0 0 0 0
rcu-torture: Reader Batch: 727877838 17003 0 0 0 0 0 0 0 0 0
rcu-torture: Free-Block Circulation: 155440 155440 155440 155440 155440 155440 155440 155440 155440 155440 0
@@ -230,6 +240,9 @@ o "rtmbe": A non-zero value indicates that rcutorture believes that
rcu_assign_pointer() and rcu_dereference() are not working
correctly. This value should be zero.
+o "rtbe": A non-zero value indicates that one of the rcu_barrier()
+ family of functions is not working correctly.
+
o "rtbke": rcutorture was unable to create the real-time kthreads
used to force RCU priority inversion. This value should be zero.
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index f995195409f..0e90453e4ac 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2333,18 +2333,100 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
See Documentation/blockdev/ramdisk.txt.
- rcupdate.blimit= [KNL,BOOT]
+ rcutree.blimit= [KNL,BOOT]
Set maximum number of finished RCU callbacks to process
in one batch.
- rcupdate.qhimark= [KNL,BOOT]
+ rcutree.qhimark= [KNL,BOOT]
Set threshold of queued
RCU callbacks over which batch limiting is disabled.
- rcupdate.qlowmark= [KNL,BOOT]
+ rcutree.qlowmark= [KNL,BOOT]
Set threshold of queued RCU callbacks below which
batch limiting is re-enabled.
+ rcutree.rcu_cpu_stall_suppress= [KNL,BOOT]
+ Suppress RCU CPU stall warning messages.
+
+ rcutree.rcu_cpu_stall_timeout= [KNL,BOOT]
+ Set timeout for RCU CPU stall warning messages.
+
+ rcutorture.fqs_duration= [KNL,BOOT]
+ Set duration of force_quiescent_state bursts.
+
+ rcutorture.fqs_holdoff= [KNL,BOOT]
+ Set holdoff time within force_quiescent_state bursts.
+
+ rcutorture.fqs_stutter= [KNL,BOOT]
+ Set wait time between force_quiescent_state bursts.
+
+ rcutorture.irqreader= [KNL,BOOT]
+ Test RCU readers from irq handlers.
+
+ rcutorture.n_barrier_cbs= [KNL,BOOT]
+ Set callbacks/threads for rcu_barrier() testing.
+
+ rcutorture.nfakewriters= [KNL,BOOT]
+ Set number of concurrent RCU writers. These just
+ stress RCU, they don't participate in the actual
+ test, hence the "fake".
+
+ rcutorture.nreaders= [KNL,BOOT]
+ Set number of RCU readers.
+
+ rcutorture.onoff_holdoff= [KNL,BOOT]
+ Set time (s) after boot for CPU-hotplug testing.
+
+ rcutorture.onoff_interval= [KNL,BOOT]
+ Set time (s) between CPU-hotplug operations, or
+ zero to disable CPU-hotplug testing.
+
+ rcutorture.shuffle_interval= [KNL,BOOT]
+ Set task-shuffle interval (s). Shuffling tasks
+ allows some CPUs to go into dyntick-idle mode
+ during the rcutorture test.
+
+ rcutorture.shutdown_secs= [KNL,BOOT]
+ Set time (s) after boot system shutdown. This
+ is useful for hands-off automated testing.
+
+ rcutorture.stall_cpu= [KNL,BOOT]
+ Duration of CPU stall (s) to test RCU CPU stall
+ warnings, zero to disable.
+
+ rcutorture.stall_cpu_holdoff= [KNL,BOOT]
+ Time to wait (s) after boot before inducing stall.
+
+ rcutorture.stat_interval= [KNL,BOOT]
+ Time (s) between statistics printk()s.
+
+ rcutorture.stutter= [KNL,BOOT]
+ Time (s) to stutter testing, for example, specifying
+ five seconds causes the test to run for five seconds,
+ wait for five seconds, and so on. This tests RCU's
+ ability to transition abruptly to and from idle.
+
+ rcutorture.test_boost= [KNL,BOOT]
+ Test RCU priority boosting? 0=no, 1=maybe, 2=yes.
+ "Maybe" means test if the RCU implementation
+ under test support RCU priority boosting.
+
+ rcutorture.test_boost_duration= [KNL,BOOT]
+ Duration (s) of each individual boost test.
+
+ rcutorture.test_boost_interval= [KNL,BOOT]
+ Interval (s) between each boost test.
+
+ rcutorture.test_no_idle_hz= [KNL,BOOT]
+ Test RCU's dyntick-idle handling. See also the
+ rcutorture.shuffle_interval parameter.
+
+ rcutorture.torture_type= [KNL,BOOT]
+ Specify the RCU implementation to test.
+
+ rcutorture.verbose= [KNL,BOOT]
+ Enable additional printk() statements.
+
rdinit= [KNL]
Format: <full_path>
Run specified binary instead of /init from the ramdisk,