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* rcu/nocb: Never downgrade ->nocb_defer_wakeup in wake_nocb_gp_defer()Paul E. McKenney2019-08-131-1/+2
| | | | | | | | | | | Currently, wake_nocb_gp_defer() simply stores whatever waketype was passed in, which can result in a RCU_NOCB_WAKE_FORCE being downgraded to RCU_NOCB_WAKE, which could in turn delay callback processing. This commit therefore adds a check so that wake_nocb_gp_defer() only updates ->nocb_defer_wakeup when the update increases the forcefulness, thus avoiding downgrades. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Enable re-awakening under high callback loadPaul E. McKenney2019-08-131-2/+2
| | | | | | | | | | | | The __call_rcu_nocb_wake() function and its predecessors set ->qlen_last_fqs_check to zero for the first callback and to LONG_MAX / 2 for forced reawakenings. The former can result in a too-quick reawakening when there are many callbacks ready to invoke and the latter prevents a second reawakening. This commit therefore sets ->qlen_last_fqs_check to the current number of callbacks in both cases. While in the area, this commit also moves both assignments under ->nocb_lock. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nohz: Turn off tick for offloaded CPUsPaul E. McKenney2019-08-131-7/+9
| | | | | | | | | | | | Historically, no-CBs CPUs allowed the scheduler-clock tick to be unconditionally disabled on any transition to idle or nohz_full userspace execution (see the rcu_needs_cpu() implementations). Unfortunately, the checks used by rcu_needs_cpu() are defeated now that no-CBs CPUs use ->cblist, which might make users of battery-powered devices rather unhappy. This commit therefore adds explicit rcu_segcblist_is_offloaded() checks to return to the historical energy-efficient semantics. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Suppress uninitialized false-positive in nocb_gp_wait()Paul E. McKenney2019-08-131-2/+2
| | | | | | | | | | | Some compilers complain that wait_gp_seq might be used uninitialized in nocb_gp_wait(). This cannot actually happen because when wait_gp_seq is uninitialized, needwait_gp must be false, which prevents wait_gp_seq from being used. But this analysis is apparently beyond some compilers, so this commit adds a bogus initialization of wait_gp_seq for the sole purpose of suppressing the false-positive warning. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Use build-time no-CBs check in rcu_pending()Paul E. McKenney2019-08-131-1/+2
| | | | | | | | | | Currently, rcu_pending() invokes rcu_segcblist_is_offloaded() even in CONFIG_RCU_NOCB_CPU=n kernels, which cannot possibly be offloaded. Given that rcu_pending() is on a fastpath, it makes sense to check for CONFIG_RCU_NOCB_CPU=y before invoking rcu_segcblist_is_offloaded(). This commit therefore makes this change. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Use build-time no-CBs check in rcu_core()Paul E. McKenney2019-08-131-4/+4
| | | | | | | | | | | | Currently, rcu_core() invokes rcu_segcblist_is_offloaded() each time it needs to know whether the current CPU is a no-CBs CPU. Given that it is not possible to change the no-CBs status of a CPU after boot, and given that it is not possible to even have no-CBs CPUs in CONFIG_RCU_NOCB_CPU=n kernels, this repeated runtime invocation wastes CPU. This commit therefore created a const on-stack variable to allow this check to be done only once per rcu_core() invocation. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Use build-time no-CBs check in rcu_do_batch()Paul E. McKenney2019-08-131-5/+5
| | | | | | | | | | | | Currently, rcu_do_batch() invokes rcu_segcblist_is_offloaded() each time it needs to know whether the current CPU is a no-CBs CPU. Given that it is not possible to change the no-CBs status of a CPU after boot, and given that it is not possible to even have no-CBs CPUs in CONFIG_RCU_NOCB_CPU=n kernels, this per-callback invocation wastes CPU. This commit therefore created a const on-stack variable to allow this check to be done only once per rcu_do_batch() invocation. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Remove obsolete nocb_gp_head and nocb_gp_tail fieldsPaul E. McKenney2019-08-131-4/+2
| | | | Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Remove obsolete nocb_cb_tail and nocb_cb_head fieldsPaul E. McKenney2019-08-132-3/+0
| | | | Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Remove obsolete nocb_q_count and nocb_q_count_lazy fieldsPaul E. McKenney2019-08-133-20/+3
| | | | | | | | | This commit removes the obsolete nocb_q_count and nocb_q_count_lazy fields, also removing rcu_get_n_cbs_nocb_cpu(), adjusting rcu_get_n_cbs_cpu(), and making rcutree_migrate_callbacks() once again disable the ->cblist fields of offline CPUs. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Remove obsolete nocb_head and nocb_tail fieldsPaul E. McKenney2019-08-132-4/+0
| | | | Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Use rcu_segcblist for no-CBs CPUsPaul E. McKenney2019-08-136-384/+270
| | | | | | | | | | | | | | | | | | | | | | Currently the RCU callbacks for no-CBs CPUs are queued on a series of ad-hoc linked lists, which means that these callbacks cannot benefit from "drive-by" grace periods, thus suffering needless delays prior to invocation. In addition, the no-CBs grace-period kthreads first wait for callbacks to appear and later wait for a new grace period, which means that callbacks appearing during a grace-period wait can be delayed. These delays increase memory footprint, and could even result in an out-of-memory condition. This commit therefore enqueues RCU callbacks from no-CBs CPUs on the rcu_segcblist structure that is already used by non-no-CBs CPUs. It also restructures the no-CBs grace-period kthread to be checking for incoming callbacks while waiting for grace periods. Also, instead of waiting for a new grace period, it waits for the closest grace period that will cause some of the callbacks to be safe to invoke. All of these changes reduce callback latency and thus the number of outstanding callbacks, in turn reducing the probability of an out-of-memory condition. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Leave ->cblist enabled for no-CBs CPUsPaul E. McKenney2019-08-135-35/+11
| | | | | | | | | | As a first step towards making no-CBs CPUs use the ->cblist, this commit leaves the ->cblist enabled for these CPUs. The main reason to make no-CBs CPUs use ->cblist is to take advantage of callback numbering, which will reduce the effects of missed grace periods which in turn will reduce forward-progress problems for no-CBs CPUs. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Allow lockless use of rcu_segcblist_empty()Paul E. McKenney2019-08-132-3/+3
| | | | | | | | | | Currently, rcu_segcblist_empty() assumes that the callback list is not being changed by other CPUs, but upcoming changes will require it to operate locklessly. This commit therefore adds the needed READ_ONCE() call, along with the WRITE_ONCE() calls when updating the callback list's ->head field. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Allow lockless use of rcu_segcblist_restempty()Paul E. McKenney2019-08-132-16/+16
| | | | | | | | | | Currently, rcu_segcblist_restempty() assumes that the callback list is not being changed by other CPUs, but upcoming changes will require it to operate locklessly. This commit therefore adds the needed READ_ONCE() calls, along with the WRITE_ONCE() calls when updating the callback list. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Remove deferred wakeup checks for extended quiescent statesPaul E. McKenney2019-08-131-10/+0
| | | | | | | | | | | | | | | | | | The idea behind the checks for extended quiescent states at the end of __call_rcu_nocb() is to handle cases where call_rcu() is invoked directly from within an extended quiescent state, for example, from the idle loop. However, this will result in a timer-mediated deferred wakeup, which will cause the needed wakeup to happen within a jiffy or thereabouts. There should be no forward-progress concerns, and if there are, the proper response is to exit the extended quiescent state while executing the endless blast of call_rcu() invocations, for example, using RCU_NONIDLE(). Given the more realistic case of an isolated call_rcu() invocation, there should be no problem. This commit therefore removes the checks for invoking call_rcu() within an extended quiescent state for on no-CBs CPUs. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Check for deferred nocb wakeups before nohz_full early exitPaul E. McKenney2019-08-131-4/+4
| | | | | | | | | | | | | | | In theory, a timer is used to defer wakeups of no-CBs grace-period kthreads when the wakeup cannot be done safely directly from the call_rcu(). In practice, the one-jiffy delay is not always consistent with timely callback invocation under heavy call_rcu() loads. Therefore, there are a number of checks for a pending deferred wakeup, including from the scheduling-clock interrupt. Unfortunately, this check follows the rcu_nohz_full_cpu() early exit, which renders it useless on such CPUs. This commit therefore moves the check for the pending deferred no-CB wakeup to precede the rcu_nohz_full_cpu() early exit. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Make rcutree_migrate_callbacks() start at leaf rcu_node structurePaul E. McKenney2019-08-131-5/+6
| | | | | | | | | | | | | Because rcutree_migrate_callbacks() is invoked infrequently and because an exact snapshot of the grace-period state might save some callbacks a second trip through a grace period, this function has used the root rcu_node structure. However, this safe-second-trip optimization happens only if rcutree_migrate_callbacks() races with grace-period initialization, so it is not worth the added mental load. This commit therefore makes rcutree_migrate_callbacks() start with the leaf rcu_node structures, as is done elsewhere. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Add checks for offloaded callback processingPaul E. McKenney2019-08-131-3/+8
| | | | | | | | | | | | This commit is a preparatory patch for offloaded callbacks using the same ->cblist structure used by non-offloaded callbacks. It therefore adds rcu_segcblist_is_offloaded() calls where they will be needed when !rcu_segcblist_is_enabled() no longer flags the offloaded case. It also adds checks in rcu_do_batch() to ensure that there are no missed checks: Currently, it should not be possible for offloaded execution to reach rcu_do_batch(), though this will change later in this series. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Use separate flag to indicate offloaded ->cblistPaul E. McKenney2019-08-135-8/+33
| | | | | | | | | | | | RCU callback processing currently uses rcu_is_nocb_cpu() to determine whether or not the current CPU's callbacks are to be offloaded. This works, but it is not so good for cache locality. Plus use of ->cblist for offloaded callbacks will greatly increase the frequency of these checks. This commit therefore adds a ->offloaded flag to the rcu_segcblist structure to provide a more flexible and cache-friendly means of checking for callback offloading. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Use separate flag to indicate disabled ->cblistPaul E. McKenney2019-08-134-3/+8
| | | | | | | | | | | NULLing the RCU_NEXT_TAIL pointer was a clever way to save a byte, but forward-progress considerations would require that this pointer be both NULL and non-NULL, which, absent a quantum-computer port of the Linux kernel, simply won't happen. This commit therefore creates as separate ->enabled flag to replace the current NULL checks. [ paulmck: Add include files per 0day test robot and -next. ] Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Print gp/cb kthread hierarchy if dump_treePaul E. McKenney2019-08-131-0/+6
| | | | | | | This commit causes the no-CBs grace-period/callback hierarchy to be printed to the console when the dump_tree kernel boot parameter is set. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Rename rcu_nocb_leader_stride kernel boot parameterPaul E. McKenney2019-08-132-10/+11
| | | | | | | | This commit changes the name of the rcu_nocb_leader_stride kernel boot parameter to rcu_nocb_gp_stride in order to account for the new distinction between callback and grace-period no-CBs kthreads. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Rename and document no-CB CB kthread sleep trace eventPaul E. McKenney2019-08-132-2/+3
| | | | | | | | | The nocb_cb_wait() function traces a "FollowerSleep" trace_rcu_nocb_wake() event, which never was documented and is now misleading. This commit therefore changes "FollowerSleep" to "CBSleep", documents this, and updates the documentation for "Sleep" as well. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Rename rcu_organize_nocb_kthreads() local variablePaul E. McKenney2019-08-131-3/+3
| | | | | | | This commit renames rdp_leader to rdp_gp in order to account for the new distinction between callback and grace-period no-CBs kthreads. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Rename wake_nocb_leader_defer() to wake_nocb_gp_defer()Paul E. McKenney2019-08-131-6/+6
| | | | | | | This commit adjusts naming to account for the new distinction between callback and grace-period no-CBs kthreads. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Rename __wake_nocb_leader() to __wake_nocb_gp()Paul E. McKenney2019-08-131-9/+9
| | | | | | | | This commit adjusts naming to account for the new distinction between callback and grace-period no-CBs kthreads. While in the area, it also updates local variables. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Rename wake_nocb_leader() to wake_nocb_gp()Paul E. McKenney2019-08-131-3/+3
| | | | | | | This commit adjusts naming to account for the new distinction between callback and grace-period no-CBs kthreads. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Rename nocb_follower_wait() to nocb_cb_wait()Paul E. McKenney2019-08-131-2/+2
| | | | | | | This commit adjusts naming to account for the new distinction between callback and grace-period no-CBs kthreads. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Provide separate no-CBs grace-period kthreadsPaul E. McKenney2019-08-132-60/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, there is one no-CBs rcuo kthread per CPU, and these kthreads are divided into groups. The first rcuo kthread to come online in a given group is that group's leader, and the leader both waits for grace periods and invokes its CPU's callbacks. The non-leader rcuo kthreads only invoke callbacks. This works well in the real-time/embedded environments for which it was intended because such environments tend not to generate all that many callbacks. However, given huge floods of callbacks, it is possible for the leader kthread to be stuck invoking callbacks while its followers wait helplessly while their callbacks pile up. This is a good recipe for an OOM, and rcutorture's new callback-flood capability does generate such OOMs. One strategy would be to wait until such OOMs start happening in production, but similar OOMs have in fact happened starting in 2018. It would therefore be wise to take a more proactive approach. This commit therefore features per-CPU rcuo kthreads that do nothing but invoke callbacks. Instead of having one of these kthreads act as leader, each group has a separate rcog kthread that handles grace periods for its group. Because these rcuog kthreads do not invoke callbacks, callback floods on one CPU no longer block callbacks from reaching the rcuc callback-invocation kthreads on other CPUs. This change does introduce additional kthreads, however: 1. The number of additional kthreads is about the square root of the number of CPUs, so that a 4096-CPU system would have only about 64 additional kthreads. Note that recent changes decreased the number of rcuo kthreads by a factor of two (CONFIG_PREEMPT=n) or even three (CONFIG_PREEMPT=y), so this still represents a significant improvement on most systems. 2. The leading "rcuo" of the rcuog kthreads should allow existing scripting to affinity these additional kthreads as needed, the same as for the rcuop and rcuos kthreads. (There are no longer any rcuob kthreads.) 3. A state-machine approach was considered and rejected. Although this would allow the rcuo kthreads to continue their dual leader/follower roles, it complicates callback invocation and makes it more difficult to consolidate rcuo callback invocation with existing softirq callback invocation. The introduction of rcuog kthreads should thus be acceptable. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Update comments to prepare for forward-progress workPaul E. McKenney2019-08-132-32/+33
| | | | | | | | | | | This commit simply rewords comments to prepare for leader nocb kthreads doing only grace-period work and callback shuffling. This will mean the addition of replacement kthreads to invoke callbacks. The "leader" and "follower" thus become less meaningful, so the commit changes no-CB comments with these strings to "GP" and "CB", respectively. (Give or take the usual grammatical transformations.) Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* rcu/nocb: Rename rcu_data fields to prepare for forward-progress workPaul E. McKenney2019-08-132-46/+46
| | | | | | | | | | This commit simply renames rcu_data fields to prepare for leader nocb kthreads doing only grace-period work and callback shuffling. This will mean the addition of replacement kthreads to invoke callbacks. The "leader" and "follower" thus become less meaningful, so the commit changes no-CB fields with these strings to "gp" and "cb", respectively. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
*---. Merge branches 'consolidate.2019.08.01b', 'fixes.2019.08.12a', ↵Paul E. McKenney2019-08-1333-139/+351
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 'lists.2019.08.13a' and 'torture.2019.08.01b' into HEAD consolidate.2019.08.01b: Further consolidation cleanups fixes.2019.08.12a: Miscellaneous fixes lists.2019.08.13a: Optional lockdep arguments for RCU list macros torture.2019.08.01b: Torture-test updates
| | | * rcutorture: Aggressive forward-progress tests shouldn't block shutdownPaul E. McKenney2019-08-011-1/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The more aggressive forward-progress tests can interfere with rcutorture shutdown, resulting in false-positive diagnostics. This commit therefore ends any such tests 30 seconds prior to shutdown. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| | | * rcuperf: Make rcuperf kernel test more robust for !expedited modeJoel Fernandes (Google)2019-08-011-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is possible that the rcuperf kernel test runs concurrently with init starting up. During this time, the system is running all grace periods as expedited. However, rcuperf can also be run for normal GP tests. Right now, it depends on a holdoff time before starting the test to ensure grace periods start later. This works fine with the default holdoff time however it is not robust in situations where init takes greater than the holdoff time to finish running. Or, as in my case: I modified the rcuperf test locally to also run a thread that did preempt disable/enable in a loop. This had the effect of slowing down init. The end result was that the "batches:" counter in rcuperf was 0 causing a division by 0 error in the results. This counter was 0 because only expedited GPs seem to happen, not normal ones which led to the rcu_state.gp_seq counter remaining constant across grace periods which unexpectedly happen to be expedited. The system was running expedited RCU all the time because rcu_unexpedited_gp() would not have run yet from init. In other words, the test would concurrently with init booting in expedited GP mode. To fix this properly, this commit waits until system_state is set to SYSTEM_RUNNING before starting the test. This change is made just before kernel_init() invokes rcu_end_inkernel_boot(), and this latter is what turns off boot-time expediting of RCU grace periods. Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| | | * torture: Remove exporting of internal functionsDenis Efremov2019-08-011-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The functions torture_onoff_cleanup() and torture_shuffle_cleanup() are declared static and marked EXPORT_SYMBOL_GPL(), which is at best an odd combination. Because these functions are not used outside of the kernel/torture.c file they are defined in, this commit removes their EXPORT_SYMBOL_GPL() marking. Fixes: cc47ae083026 ("rcutorture: Abstract torture-test cleanup") Signed-off-by: Denis Efremov <efremov@linux.com> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| | | * rcutorture: Emulate userspace sojourn during call_rcu() floodsPaul E. McKenney2019-08-011-5/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | During an actual call_rcu() flood, there would be frequent trips to userspace (in-kernel call_rcu() floods must be otherwise housebroken). Userspace execution allows a great many things to interrupt execution, and rcutorture needs to also allow such interruptions. This commit therefore causes call_rcu() floods to occasionally invoke schedule(), thus preventing spurious rcutorture failures due to other parts of the kernel becoming irate at the call_rcu() flood events. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| | | * rcutorture: Test TREE03 with the threadirqs kernel boot parameterPaul E. McKenney2019-08-011-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since commit 05f415715ce45 ("rcu: Speed up expedited GPs when interrupting RCU reader") in v5.0 and through v5.1, booting with the threadirqs kernel boot parameter caused self-deadlocks, which can be reproduced using the following command on an 8-CPU system: tools/testing/selftests/rcutorture/bin/kvm.sh --duration 5 --configs "TREE03" --bootargs "threadirqs" This commit therefore adds the threadirqs kernel boot parameter to the TREE03 rcutorture scenario in order to more quickly detect future similar bugs. Link: http://lkml.kernel.org/r/20190626135447.y24mvfuid5fifwjc@linutronix.de Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Joel Fernandes <joel@joelfernandes.org>
| | | * torture: Expand last_ts variable in kvm-test-1-run.shPaul E. McKenney2019-08-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kvm-test-1-run.sh script says 'test -z "last_ts"' which always evaluates to true (AKA zero) regardless of the value of the last_ts shell variable. This commit therefore inserts the needed dollar sign ("$"). Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| | | * rcuperf: Fix perf_type module-parameter descriptionXiao Yang2019-08-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rcu_bh rcuperf type was removed by commit 620d246065cd("rcuperf: Remove the "rcu_bh" and "sched" torture types"), but it lives on in the MODULE_PARM_DESC() of perf_type. This commit therefore changes that module-parameter description to substitute srcu for rcu_bh. Signed-off-by: Xiao Yang <ice_yangxiao@163.com> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| | * | acpi: Use built-in RCU list checking for acpi_ioremaps listJoel Fernandes (Google)2019-08-131-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit applies the consolidated list_for_each_entry_rcu() support for lockdep conditions. Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| | * | x86/pci: Pass lockdep condition to pcm_mmcfg_list iteratorJoel Fernandes (Google)2019-08-131-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The pcm_mmcfg_list is traversed by list_for_each_entry_rcu() outside of an RCU read-side critical section, which is safe because the pci_mmcfg_lock is held. This commit therefore adds a lockdep expression to list_for_each_entry_rcu() in order t avoid lockdep warnings. Acked-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| | * | driver/core: Convert to use built-in RCU list checkingJoel Fernandes (Google)2019-08-133-5/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit applies the consolidated hlist_for_each_entry_rcu() support for lockdep conditions. Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| | * | ipv4: Add lockdep condition to fix for_each_entry()Joel Fernandes (Google)2019-08-091-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit applies the consolidated list_for_each_entry_rcu() support for lockdep conditions. Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| | * | rcu/sync: Remove custom check for RCU readersJoel Fernandes (Google)2019-08-091-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rcu/sync code currently does a special check for being in an RCU read-side critical section. With RCU consolidating flavors and the generic helper added earlier in this series, this check is no longer need. This commit switches to the generic helper, saving a couple of lines of code. Cc: Oleg Nesterov <oleg@redhat.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| | * | rcu: Add support for consolidated-RCU reader checkingJoel Fernandes (Google)2019-08-094-38/+108
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit adds RCU-reader checks to list_for_each_entry_rcu() and hlist_for_each_entry_rcu(). These checks are optional, and are indicated by a lockdep expression passed to a new optional argument to these two macros. If this optional lockdep expression is omitted, these two macros act as before, checking for an RCU read-side critical section. Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> [ paulmck: Update to eliminate return within macro and update comment. ] Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| | * | rcu: Remove redundant debug_locks check in rcu_read_lock_sched_held()Joel Fernandes (Google)2019-08-011-5/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The debug_locks flag can never be true at the end of rcu_read_lock_sched_held() because it is already checked by the earlier call todebug_lockdep_rcu_enabled(). This commit therefore removes this redundant check. Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| | * | treewide: Rename rcu_dereference_raw_notrace() to _check()Joel Fernandes (Google)2019-08-016-12/+12
| | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rcu_dereference_raw_notrace() API name is confusing. It is equivalent to rcu_dereference_raw() except that it also does sparse pointer checking. There are only a few users of rcu_dereference_raw_notrace(). This patches renames all of them to be rcu_dereference_raw_check() with the "_check()" indicating sparse checking. Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> [ paulmck: Fix checkpatch warnings about parentheses. ] Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| * | MAINTAINERS: Update e-mail address for Andrea ParriAndrea Parri2019-08-121-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | My @amarulasolutions.com address stopped working this July, so update to my @gmail.com address where you'll still be able to reach me. Signed-off-by: Andrea Parri <parri.andrea@gmail.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Will Deacon <will@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: David Howells <dhowells@redhat.com> Cc: Jade Alglave <j.alglave@ucl.ac.uk> Cc: Luc Maranget <luc.maranget@inria.fr> Cc: "Paul E. McKenney" <paulmck@linux.ibm.com> Cc: Akira Yokosawa <akiyks@gmail.com> Cc: Daniel Lustig <dlustig@nvidia.com> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| * | rcu: Fix spelling mistake "greate"->"great"Mukesh Ojha2019-08-121-1/+1
| | | | | | | | | | | | | | | | | | | | | This commit fixes a spelling mistake in file tree_exp.h. Signed-off-by: Mukesh Ojha <mojha@codeaurora.org> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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