summaryrefslogtreecommitdiffstats
path: root/kernel/rcu/rcutorture.c
Commit message (Collapse)AuthorAgeFilesLines
* srcu: Remove Classic SRCUPaul E. McKenney2017-06-081-17/+0
| | | | | | | | Classic SRCU was only ever intended to be a fallback in case of issues with Tree/Tiny SRCU, and the latter two are doing quite well in testing. This commit therefore removes Classic SRCU. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Move expediting-related access/control out of rcupdate.hPaul E. McKenney2017-06-081-0/+2
| | | | | | | | | | | | | The rcu_gp_is_normal(), rcu_gp_is_expedited(), rcu_expedite_gp(), and rcu_unexpedite_gp() functions are intended only for use within the RCU implementation itself -- the sysfs access is what should be used outside of RCU. This commit therefore moves the declarations for these functions to kernel/rcu/rcu.h, and also includes this file into kernel/rcu/rcutorture.c and kernel/rcu/rcuperf.c. This also has the beneficial effect of shrinking rcupdate.c a bit. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* srcu: Shrink Tiny SRCU a bit morePaul E. McKenney2017-06-081-1/+1
| | | | | | | This commit rearranges Tiny SRCU's srcu_struct structure, substitutes u8 for bool, and shrinks counters down to short. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* srcu: Make rcutorture writer stalls print SRCU GP statePaul E. McKenney2017-04-261-3/+5
| | | | | | | | | | | In the past, SRCU was simple enough that there was little point in making the rcutorture writer stall messages print the SRCU grace-period number state. With the advent of Tree SRCU, this has changed. This commit therefore makes Classic, Tiny, and Tree SRCU report this state to rcutorture as needed. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Mike Galbraith <efault@gmx.de>
* srcu: Parallelize callback handlingPaul E. McKenney2017-04-211-1/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Peter Zijlstra proposed using SRCU to reduce mmap_sem contention [1,2], however, there are workloads that could result in a high volume of concurrent invocations of call_srcu(), which with current SRCU would result in excessive lock contention on the srcu_struct structure's ->queue_lock, which protects SRCU's callback lists. This commit therefore moves SRCU to per-CPU callback lists, thus greatly reducing contention. Because a given SRCU instance no longer has a single centralized callback list, starting grace periods and invoking callbacks are both more complex than in the single-list Classic SRCU implementation. Starting grace periods and handling callbacks are now handled using an srcu_node tree that is in some ways similar to the rcu_node trees used by RCU-bh, RCU-preempt, and RCU-sched (for example, the srcu_node tree shape is controlled by exactly the same Kconfig options and boot parameters that control the shape of the rcu_node tree). In addition, the old per-CPU srcu_array structure is now named srcu_data and contains an rcu_segcblist structure named ->srcu_cblist for its callbacks (and a spinlock to protect this). The srcu_struct gets an srcu_gp_seq that is used to associate callback segments with the corresponding completion-time grace-period number. These completion-time grace-period numbers are propagated up the srcu_node tree so that the grace-period workqueue handler can determine whether additional grace periods are needed on the one hand and where to look for callbacks that are ready to be invoked. The srcu_barrier() function must now wait on all instances of the per-CPU ->srcu_cblist. Because each ->srcu_cblist is protected by ->lock, srcu_barrier() can remotely add the needed callbacks. In theory, it could also remotely start grace periods, but in practice doing so is complex and racy. And interestingly enough, it is never necessary for srcu_barrier() to start a grace period because srcu_barrier() only enqueues a callback when a callback is already present--and it turns out that a grace period has to have already been started for this pre-existing callback. Furthermore, it is only the callback that srcu_barrier() needs to wait on, not any particular grace period. Therefore, a new rcu_segcblist_entrain() function enqueues the srcu_barrier() function's callback into the same segment occupied by the last pre-existing callback in the list. The special case where all the pre-existing callbacks are on a different list (because they are in the process of being invoked) is handled by enqueuing srcu_barrier()'s callback into the RCU_DONE_TAIL segment, relying on the done-callbacks check that takes place after all callbacks are inovked. Note that the readers use the same algorithm as before. Note that there is a separate srcu_idx that tells the readers what counter to increment. This unfortunately cannot be combined with srcu_gp_seq because they need to be incremented at different times. This commit introduces some ugly #ifdefs in rcutorture. These will go away when I feel good enough about Tree SRCU to ditch Classic SRCU. Some crude performance comparisons, courtesy of a quickly hacked rcuperf asynchronous-grace-period capability: Callback Queuing Overhead ------------------------- # CPUS Classic SRCU Tree SRCU ------ ------------ --------- 2 0.349 us 0.342 us 16 31.66 us 0.4 us 41 --------- 0.417 us The times are the 90th percentiles, a statistic that was chosen to reject the overheads of the occasional srcu_barrier() call needed to avoid OOMing the test machine. The rcuperf test hangs when running Classic SRCU at 41 CPUs, hence the line of dashes. Despite the hacks to both the rcuperf code and that statistics, this is a convincing demonstration of Tree SRCU's performance and scalability advantages. [1] https://lwn.net/Articles/309030/ [2] https://patchwork.kernel.org/patch/5108281/ Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> [ paulmck: Fix initialization if synchronize_srcu_expedited() called first. ]
* srcu: Introduce CLASSIC_SRCU Kconfig optionPaul E. McKenney2017-04-181-1/+1
| | | | | | | | | | | | | The TREE_SRCU rewrite is large and a bit on the non-simple side, so this commit helps reduce risk by allowing the old v4.11 SRCU algorithm to be selected using a new CLASSIC_SRCU Kconfig option that depends on RCU_EXPERT. The default is to use the new TREE_SRCU and TINY_SRCU algorithms, in order to help get these the testing that they need. However, if your users do not require the update-side scalability that is to be provided by TREE_SRCU, select RCU_EXPERT and then CLASSIC_SRCU to revert back to the old classic SRCU algorithm. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* srcutorture: Print Tiny SRCU reader statisticsPaul E. McKenney2017-04-181-4/+11
| | | | | | | | The srcu_torture_stats() function is adapted to the specific srcu_struct layout traditionally used by SRCU. This commit therefore adds support for Tiny SRCU. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* srcu: Create a tiny SRCUPaul E. McKenney2017-04-181-0/+2
| | | | | | | | In response to automated complaints about modifications to SRCU increasing its size, this commit creates a tiny SRCU that is used in SMP=n && PREEMPT=n builds. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* sched/headers: Prepare to move signal wakeup & sigpending methods from ↵Ingo Molnar2017-03-021-1/+1
| | | | | | | | | | | | | <linux/sched.h> into <linux/sched/signal.h> Fix up affected files that include this signal functionality via sched.h. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-0/+1
| | | | | | | | | | | | | | | | | | <uapi/linux/sched/types.h> We are going to move scheduler ABI details to <uapi/linux/sched/types.h>, which will be used from a number of .c files. Create empty placeholder header that maps to <linux/types.h>. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* srcu: Implement more-efficient reader countsLance Roy2017-01-251-2/+17
| | | | | | | | | | | | | | | | | | | | | | | | | SRCU uses two per-cpu counters: a nesting counter to count the number of active critical sections, and a sequence counter to ensure that the nesting counters don't change while they are being added together in srcu_readers_active_idx_check(). This patch instead uses per-cpu lock and unlock counters. Because both counters only increase and srcu_readers_active_idx_check() reads the unlock counter before the lock counter, this achieves the same end without having to increment two different counters in srcu_read_lock(). This also saves a smp_mb() in srcu_readers_active_idx_check(). Possible bug: There is no guarantee that the lock counter won't overflow during srcu_readers_active_idx_check(), as there are no memory barriers around srcu_flip() (see comment in srcu_readers_active_idx_check() for details). However, this problem was already present before this patch. Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Lance Roy <ldr709@gmail.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* torture: Trace long read-side delaysPaul E. McKenney2016-11-141-1/+10
| | | | | | | | | | | Although rcutorture will occasionally do a 50-millisecond grace-period delay, these delays are quite rare. And rightly so, because otherwise the read rate would be quite low. Thie means that it can be important to identify whether or not a given run contained a long-delay read. This commit therefore inserts a trace_rcu_torture_read() event to flag runs containing long delays. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
*-. Merge branches 'doc.2016.08.22c', 'exp.2016.08.22c', 'fixes.2016.09.14a', ↵Paul E. McKenney2016-09-141-41/+21
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | 'hotplug.2016.08.22c' and 'torture.2016.08.22c' into HEAD doc.2016.08.22c: Documentation updates exp.2016.08.22c: Expedited grace-period updates fixes.2016.09.14a: Miscellaneous fixes hotplug.2016.08.22c: CPU-hotplug changes torture.2016.08.22c: Torture-test changes
| | * rcutorture: Print out barrier error as document saysSeongJae Park2016-08-221-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Tests for rcu_barrier() were introduced by commit fae4b54f28f0 ("rcu: Introduce rcutorture testing for rcu_barrier()"). This commit updated the documentation to say that the "rtbe" field in rcutorture's dmesg output indicates test failure. However, the code was not updated, only the documentation. This commit therefore updates the code to match the updated documentation. Signed-off-by: SeongJae Park <sj38.park@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| | * torture: Add task state to writer-task stall printk()sPaul E. McKenney2016-08-221-2/+5
| |/ |/| | | | | | | | | | | | | | | This commit adds a dump of the scheduler state for stalled rcutorture writer tasks. This addition provides yet more debug for the intermittent "failures to proceed", where grace periods move ahead but the rcutorture writer tasks fail to do so. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| * rcutorture: Convert to hotplug state machineSebastian Andrzej Siewior2016-08-221-38/+14
|/ | | | | | | | | | | | | Install the callbacks via the state machine and let the core invoke the callbacks on the already online CPUs. Cc: Josh Triplett <josh@joshtriplett.org> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
*-. Merge branches 'doc.2016.06.15a', 'fixes.2016.06.15b' and ↵Paul E. McKenney2016-06-151-7/+2
|\ \ | | | | | | | | | | | | | | | | | | | | | 'torture.2016.06.14a' into HEAD doc.2016.06.15a: Documentation updates fixes.2016.06.15b: Documentation updates torture.2016.06.14a: Documentation updates
| | * torture: Remove CONFIG_RCU_TORTURE_TEST_RUNNABLE, simplify codePaul E. McKenney2016-06-141-6/+1
| |/ |/| | | | | | | | | | | | | This commit removes CONFIG_RCU_TORTURE_TEST_RUNNABLE in favor of the already-existing rcutorture.torture_runnable kernel boot parameter. It also converts an #ifdef into IS_ENABLED(), saving a few lines of code. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| * rcu: Fix a typo in a commentPaul E. McKenney2016-06-151-1/+1
|/ | | | | | In the area in hot pursuit of a bug, so might as well clean it up. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcutorture: Add irqs-disabled test for call_rcu()Paul E. McKenney2016-04-211-0/+2
| | | | | | | | | | Mutation testing carried out by Iftekhar Ahmed of Oregon State University showed that rcutorture is failing to test invocations of call_rcu() having interrupts disabled. This commit therefore adds interrupt disabling around one of the existing invocations of call_rcu() (and friends). Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcutorture: Consider FROZEN hotplug notifier transitionsAnna-Maria Gleixner2016-03-311-1/+1
| | | | | | | | | | | | | | | | The hotplug notifier rcutorture_cpu_notify() doesn't consider the corresponding CPU_XXX_FROZEN transitions. They occur on suspend/resume and are usually handled the same way as the corresponding non frozen transitions. Mask the switch case action argument with '~CPU_TASKS_FROZEN' to map CPU_XXX_FROZEN hotplug transitions on corresponding non-frozen transitions. Cc: Josh Triplett <josh@joshtriplett.org> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcutorture: Remove redundant initialization to zeroPaul E. McKenney2016-03-311-2/+2
| | | | | | | | | | | The current code initializes the global per-CPU variables rcu_torture_count and rcu_torture_batch to zero. However, C does this initialization by default, and explicit initialization of per-CPU variables now needs a different syntax if "make tags" is to work. This commit therefore removes the initialization. Reported-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcutorture: Allow for rcupdate.rcu_normalPaul E. McKenney2016-03-311-2/+2
| | | | | | | | | | | | Currently, rcu_torture_writer() checks only for rcu_gp_is_expedited() when deciding whether or not to do dynamic control of RCU expediting. This means that if rcupdate.rcu_normal is specified, rcu_torture_writer() will attempt to dynamically control RCU expediting, but will nonetheless only test normal RCU grace periods. This commit therefore adds a check for !rcu_gp_is_normal(), and prints a message and desists from testing dynamic control of RCU expediting when doing so is futile. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Consolidate dumping of ftrace bufferPaul E. McKenney2016-03-311-14/+3
| | | | | | | This commit consolidates a couple definitions and several calls for single-shot ftrace-buffer dumping. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* Merge branch 'akpm' (patches from Andrew)Linus Torvalds2016-03-161-4/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge first patch-bomb from Andrew Morton: - some misc things - ofs2 updates - about half of MM - checkpatch updates - autofs4 update * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (120 commits) autofs4: fix string.h include in auto_dev-ioctl.h autofs4: use pr_xxx() macros directly for logging autofs4: change log print macros to not insert newline autofs4: make autofs log prints consistent autofs4: fix some white space errors autofs4: fix invalid ioctl return in autofs4_root_ioctl_unlocked() autofs4: fix coding style line length in autofs4_wait() autofs4: fix coding style problem in autofs4_get_set_timeout() autofs4: coding style fixes autofs: show pipe inode in mount options kallsyms: add support for relative offsets in kallsyms address table kallsyms: don't overload absolute symbol type for percpu symbols x86: kallsyms: disable absolute percpu symbols on !SMP checkpatch: fix another left brace warning checkpatch: improve UNSPECIFIED_INT test for bare signed/unsigned uses checkpatch: warn on bare unsigned or signed declarations without int checkpatch: exclude asm volatile from complex macro check mm: memcontrol: drop unnecessary lru locking from mem_cgroup_migrate() mm: migrate: consolidate mem_cgroup_migrate() calls mm/compaction: speed up pageblock_pfn_to_page() when zone is contiguous ...
| * tags: Fix DEFINE_PER_CPU expansionsPeter Zijlstra2016-03-151-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | $ make tags GEN tags ctags: Warning: drivers/acpi/processor_idle.c:64: null expansion of name pattern "\1" ctags: Warning: drivers/xen/events/events_2l.c:41: null expansion of name pattern "\1" ctags: Warning: kernel/locking/lockdep.c:151: null expansion of name pattern "\1" ctags: Warning: kernel/rcu/rcutorture.c:133: null expansion of name pattern "\1" ctags: Warning: kernel/rcu/rcutorture.c:135: null expansion of name pattern "\1" ctags: Warning: kernel/workqueue.c:323: null expansion of name pattern "\1" ctags: Warning: net/ipv4/syncookies.c:53: null expansion of name pattern "\1" ctags: Warning: net/ipv6/syncookies.c:44: null expansion of name pattern "\1" ctags: Warning: net/rds/page.c:45: null expansion of name pattern "\1" Which are all the result of the DEFINE_PER_CPU pattern: scripts/tags.sh:200: '/\<DEFINE_PER_CPU([^,]*, *\([[:alnum:]_]*\)/\1/v/' scripts/tags.sh:201: '/\<DEFINE_PER_CPU_SHARED_ALIGNED([^,]*, *\([[:alnum:]_]*\)/\1/v/' The below cures them. All except the workqueue one are within reasonable distance of the 80 char limit. TJ do you have any preference on how to fix the wq one, or shall we just not care its too long? Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Tejun Heo <tj@kernel.org> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | rcutorture: Correct no-expedite console messagesPaul E. McKenney2016-02-231-6/+8
|/ | | | | | | | | The "Disabled dynamic grace-period expediting" console message is currently printed unconditionally. This commit causes it to be output only when it is impossible to switch between normal and expedited grace periods, which was the original intent. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcutorture: Print symbolic name for rcu_torture_writer_statePaul E. McKenney2015-12-051-1/+23
| | | | | | | | | | Currently, rcu_torture_writer_state is printed as an integer, which slows debugging. This commit therefore prints a symbolic name in addition to the integer. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> [ paulmck: More "const", as suggested by Josh Triplett. ] Reviewed-by: Josh Triplett <josh@joshtriplett.org>
*---. Merge branches 'doc.2015.10.06a', 'percpu-rwsem.2015.10.06a' and ↵Paul E. McKenney2015-10-071-6/+4
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | 'torture.2015.10.06a' into HEAD doc.2015.10.06a: Documentation updates. percpu-rwsem.2015.10.06a: Optimization of per-CPU reader-writer semaphores. torture.2015.10.06a: Torture-test updates.
| | | * rcutorture: Fix unused-function warning for torturing_tasks()Paul E. McKenney2015-10-061-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The torturing_tasks() function is used only in kernels built with CONFIG_PROVE_RCU=y, so the second definition can result in unused-function compiler warnings. This commit adds __maybe_unused to suppress these warnings. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| | | * rcutorture: Fix module unwind when bad torture_type specifiedPaul E. McKenney2015-10-061-3/+3
| | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rcutorture module has a list of torture types, and specifying a type not on this list is supposed to cleanly fail the module load. Unfortunately, the "fail" happens without the "cleanly". This commit therefore adds the needed clean-up after an incorrect torture_type. Reported-by: David Miller <davem@davemloft.net> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: David Miller <davem@davemloft.net> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| | * torture: Consolidate cond_resched_rcu_qs() into stutter_wait()Paul E. McKenney2015-10-061-2/+0
| |/ | | | | | | | | | | | | | | | | This commit moves cond_resched_rcu_qs() into stutter_wait(), saving a line and also avoiding RCU CPU stall warnings from all torture loops containing a stutter_wait(). Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* | rcu: Use call_rcu_func_t to replace explicit type equivalentsBoqun Feng2015-10-061-1/+1
| | | | | | | | | | | | | | | | | | | | | | We have had the call_rcu_func_t typedef for a quite awhile, but we still use explicit function pointer types in some places. These types can confuse cscope and can be hard to read. This patch therefore replaces these types with the call_rcu_func_t typedef. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* | rcu: Use rcu_callback_t in call_rcu*() and friendsBoqun Feng2015-10-061-2/+2
|/ | | | | | | | | | | | | | As we now have rcu_callback_t typedefs as the type of rcu callbacks, we should use it in call_rcu*() and friends as the type of parameters. This could save us a few lines of code and make it clear which function requires an rcu callbacks rather than other callbacks as its argument. Besides, this can also help cscope to generate a better database for code reading. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
*-. Merge branches 'doc.2015.07.15a' and 'torture.2015.07.15a' into HEADPaul E. McKenney2015-08-041-13/+27
|\ \ | | | | | | | | | | | | doc.2015.07.15a: Documentation updates. torture.2015.07.15a: Torture-test updates.
| | * rcutorture: Add RCU-tasks qualifier to dereferencePaul E. McKenney2015-07-151-2/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Although RCU-tasks isn't really designed to support rcu_dereference() and list manipulation, that is how rcutorture tests it. Which means that lockdep-RCU complains about the rcu_dereference_check() invocations because RCU-tasks doesn't have read-side markers. This commit therefore creates a torturing_tasks() to silence the lockdep-RCU complaints from rcu_dereference_check() when RCU-tasks is being tortured. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| | * rcutorture: Fix rcu_torture_cbflood() for callback-free RCUPaul E. McKenney2015-07-151-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rcu_torture_cbflood() function correctly checks for flavors of RCU that lack analogs to call_rcu() and rcu_barrier(), but in that case it fails to terminate correctly. In fact, it terminates so incorrectly that segfaults can result. This commit therefore causes rcu_torture_cbflood() to do the proper wait-for-stop procedure. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| | * rcutorture: Bounds-check rcutorture.shuffle_intervalPaul E. McKenney2015-07-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | Specifying a negative rcutorture.shuffle_interval value will cause a negative value to be used as a sleep time. This commit therefore refuses to start shuffling unless the rcutorture.shuffle_interval value is greater than zero. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| | * rcutorture: Check nfakewriters parameterPaul E. McKenney2015-07-151-6/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, a negative value for rcutorture.nfakewriters= can cause rcutorture to pass a negative size to the memory allocator, which is not really a particularly good thing to do. This commit therefore adds bounds checking to this parameter, so that values that are less than or equal to zero disable fake writing. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| | * rcutorture: Better bounds checking for n_barrier_cbsPaul E. McKenney2015-07-151-1/+1
| |/ | | | | | | | | | | | | | | A negative value for rcutorture.n_barrier_cbs can pass a negative value to the memory allocator, so this commit instead causes rcu_barrier() testing to be disabled in this case. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* | rcu: Add RCU-sched flavors of get-state and cond-syncPaul E. McKenney2015-07-221-0/+2
|/ | | | | | | | | | | | | The get_state_synchronize_rcu() and cond_synchronize_rcu() functions allow polling for grace-period completion, with an actual wait for a grace period occurring only when cond_synchronize_rcu() is called too soon after the corresponding get_state_synchronize_rcu(). However, these functions work only for vanilla RCU. This commit adds the get_state_synchronize_sched() and cond_synchronize_sched(), which provide the same capability for RCU-sched. Reported-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcutorture: Test SRCU cleanup code pathPaul E. McKenney2015-05-271-19/+58
| | | | | | | | | | | | | | | | | | | | | The current rcutorture testing does not do any cleanup operations. This works because the srcu_struct is statically allocated, but it does represent a memory leak of the associated dynamically allocated ->per_cpu_ref per-CPU variables. However, rcutorture currently uses a statically allocated srcu_struct, which cannot legally be passed to cleanup_srcu_struct(). Therefore, this commit adds a second form of srcu (called srcud) that dynamically allocates and frees the associated per-CPU variables. This commit also adds a ->cleanup() member to rcu_torture_ops that is invoked at the end of the test, after ->cb_barriers(). This ->cleanup() pointer is NULL for all existing tests, and thus only used for scrud. Finally, the SRCU-P torture-test configuration selects scrud instead of srcu, with SRCU-N continuing to use srcu, thereby testing both static and dynamic srcu_struct structures. Reported-by: "Ahmed, Iftekhar" <ahmedi@onid.oregonstate.edu> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* rcutorture: Replace barriers with smp_store_release() and smp_load_acquire()Paul E. McKenney2015-05-271-11/+13
| | | | | | | | | The rcutorture.c file uses several explicit memory barriers that can easily be converted to smp_store_release() and smp_load_acquire(), which improves maintainability and also improves performance a bit. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* rcutorture: Allow negative values of nreaders to oversubscribePaul E. McKenney2015-05-271-1/+1
| | | | | | | | | | | | | By default, with rcutorture.nreaders equal to -1, rcutorture provisions N-1 reader kthreads, where N is the number of CPUs. This avoids rcutorture-induced stalls, but also avoids heavier levels of torture. This commit therefore allows negative values of rcutorture.nreaders to specify larger numbers of reader kthreads, so that for example rcutorture.nreaders=-2 provisions N kthreads and rcutorture.nreaders=-5 provisions N+3 kthreads. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> [ paulmck: Update documentation, as suggested by Josh Triplett. ]
* rcu: Convert ACCESS_ONCE() to READ_ONCE() and WRITE_ONCE()Paul E. McKenney2015-05-271-1/+1
| | | | | | | | This commit moves from the old ACCESS_ONCE() API to the new READ_ONCE() and WRITE_ONCE() APIs. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> [ paulmck: Updated to include kernel/torture.c as suggested by Jason Low. ]
* rcutorture: Make consistent use of variablesPaul E. McKenney2015-02-261-1/+1
| | | | | | | | | | The "if" statement at the beginning of rcu_torture_writer() should use the same set of variables. In theory, this does not matter because the corresponding variables (gp_sync and gp_sync1) have the same value at this point in the code, but in practice such puzzles should be removed. This commit therefore makes the use of variables consistent. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcu: Add rcu_expedite_gp() and rcu_unexpedite_gp() to rcutorturePaul E. McKenney2015-02-261-0/+25
| | | | Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcutorture: Add more diagnostics in rcu_barrier() test failure casePaul E. McKenney2015-01-101-0/+3
| | | | Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcutorture: Check from beginning to end of grace periodPaul E. McKenney2015-01-101-10/+27
| | | | | | | | | | | | | Currently, rcutorture's Reader Batch checks measure from the end of the previous grace period to the end of the current one. This commit tightens up these checks by measuring from the start and end of the same grace period. This involves adding rcu_batches_started() and friends corresponding to the existing rcu_batches_completed() and friends. We leave SRCU alone for the moment, as it does not yet have a way of tracking both ends of its grace periods. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* rcutorture: Drop rcu_torture_completed() and friendsPaul E. McKenney2015-01-101-13/+3
| | | | | | | | | Now that the return type of rcu_batches_completed() and friends matches that of the rcu_torture_ops structure's ->completed field, the wrapper functions can be deleted. This commit carries out that deletion, while also wiring "sched"'s ->completed field to rcu_batches_completed_sched(). Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
OpenPOWER on IntegriCloud