From 2226f3dc05a988ce81308bfc3d125f5d0b0d592c Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 16 May 2023 07:02:01 -0700 Subject: rcuscale: Permit blocking delays between writers Some workloads do isolated RCU work, and this can affect operation latencies. This commit therefore adds a writer_holdoff_jiffies module parameter that causes writers to block for the specified number of jiffies between each pair of consecutive write-side operations. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcuscale.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel/rcu/rcuscale.c') diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c index d1221731c7cf..4277037e0996 100644 --- a/kernel/rcu/rcuscale.c +++ b/kernel/rcu/rcuscale.c @@ -93,6 +93,7 @@ torture_param(bool, shutdown, RCUSCALE_SHUTDOWN, "Shutdown at end of scalability tests."); torture_param(int, verbose, 1, "Enable verbose debugging printk()s"); torture_param(int, writer_holdoff, 0, "Holdoff (us) between GPs, zero to disable"); +torture_param(int, writer_holdoff_jiffies, 0, "Holdoff (jiffies) between GPs, zero to disable"); torture_param(int, kfree_rcu_test, 0, "Do we run a kfree_rcu() scale test?"); torture_param(int, kfree_mult, 1, "Multiple of kfree_obj size to allocate."); torture_param(int, kfree_by_call_rcu, 0, "Use call_rcu() to emulate kfree_rcu()?"); @@ -414,6 +415,7 @@ rcu_scale_writer(void *arg) struct rcu_head *rhp = NULL; bool started = false, done = false, alldone = false; u64 t; + DEFINE_TORTURE_RANDOM(tr); u64 *wdp; u64 *wdpp = writer_durations[me]; @@ -448,6 +450,8 @@ rcu_scale_writer(void *arg) do { if (writer_holdoff) udelay(writer_holdoff); + if (writer_holdoff_jiffies) + schedule_timeout_idle(torture_random(&tr) % writer_holdoff_jiffies + 1); wdp = &wdpp[i]; *wdp = ktime_get_mono_fast_ns(); if (gp_async) { -- cgit v1.2.3-73-gaa49b From ee7516a16350ce2c1d45314a8c79bc93750fca8f Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 16 May 2023 08:21:17 -0700 Subject: rcuscale: Fix gp_async_max typo: s/reader/writer/ Signed-off-by: Paul E. McKenney --- kernel/rcu/rcuscale.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/rcu/rcuscale.c') diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c index 4277037e0996..15edd8c82933 100644 --- a/kernel/rcu/rcuscale.c +++ b/kernel/rcu/rcuscale.c @@ -84,7 +84,7 @@ MODULE_AUTHOR("Paul E. McKenney "); #endif torture_param(bool, gp_async, false, "Use asynchronous GP wait primitives"); -torture_param(int, gp_async_max, 1000, "Max # outstanding waits per reader"); +torture_param(int, gp_async_max, 1000, "Max # outstanding waits per writer"); torture_param(bool, gp_exp, false, "Use expedited GP wait primitives"); torture_param(int, holdoff, 10, "Holdoff time before test start (s)"); torture_param(int, nreaders, -1, "Number of RCU reader threads"); -- cgit v1.2.3-73-gaa49b From 7221f493c5ff8bee5c39de1e43cb8a8997c2cda5 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 16 May 2023 08:22:31 -0700 Subject: rcuscale: Add minruntime module parameter By default, rcuscale collects only 100 points of data per writer, but arranging for all kthreads to be actively collecting (if not recording) data during the time that any kthread might be recording. This works well, but does not allow much time to bring external performance tools to bear. This commit therefore adds a minruntime module parameter that specifies a minimum data-collection interval in seconds. Signed-off-by: Paul E. McKenney --- Documentation/admin-guide/kernel-parameters.txt | 6 ++++++ kernel/rcu/rcuscale.c | 5 ++++- 2 files changed, 10 insertions(+), 1 deletion(-) (limited to 'kernel/rcu/rcuscale.c') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 5ba231b786f8..a6888e3dfc20 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4953,6 +4953,12 @@ Number of loops doing rcuscale.kfree_alloc_num number of allocations and frees. + rcuscale.minruntime= [KNL] + Set the minimum test run time in seconds. This + does not affect the data-collection interval, + but instead allows better measurement of things + like CPU consumption. + rcuscale.nreaders= [KNL] Set number of RCU readers. The value -1 selects N, where N is the number of CPUs. A value diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c index 15edd8c82933..7c5bab5a4f19 100644 --- a/kernel/rcu/rcuscale.c +++ b/kernel/rcu/rcuscale.c @@ -87,6 +87,7 @@ torture_param(bool, gp_async, false, "Use asynchronous GP wait primitives"); torture_param(int, gp_async_max, 1000, "Max # outstanding waits per writer"); torture_param(bool, gp_exp, false, "Use expedited GP wait primitives"); torture_param(int, holdoff, 10, "Holdoff time before test start (s)"); +torture_param(int, minruntime, 0, "Minimum run time (s)"); torture_param(int, nreaders, -1, "Number of RCU reader threads"); torture_param(int, nwriters, -1, "Number of RCU updater threads"); torture_param(bool, shutdown, RCUSCALE_SHUTDOWN, @@ -411,6 +412,7 @@ rcu_scale_writer(void *arg) { int i = 0; int i_max; + unsigned long jdone; long me = (long)arg; struct rcu_head *rhp = NULL; bool started = false, done = false, alldone = false; @@ -447,6 +449,7 @@ rcu_scale_writer(void *arg) } } + jdone = jiffies + minruntime * HZ; do { if (writer_holdoff) udelay(writer_holdoff); @@ -479,7 +482,7 @@ retry: if (!started && atomic_read(&n_rcu_scale_writer_started) >= nrealwriters) started = true; - if (!done && i >= MIN_MEAS) { + if (!done && i >= MIN_MEAS && time_after(jiffies, jdone)) { done = true; sched_set_normal(current, 0); pr_alert("%s%s rcu_scale_writer %ld has %d measurements\n", -- cgit v1.2.3-73-gaa49b From c68465dfaac3a36e2a72030f834811e651da8097 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 16 May 2023 13:45:16 -0700 Subject: rcuscale: Print out full set of module parameters Signed-off-by: Paul E. McKenney --- kernel/rcu/rcuscale.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/rcu/rcuscale.c') diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c index 7c5bab5a4f19..18f1b0e13604 100644 --- a/kernel/rcu/rcuscale.c +++ b/kernel/rcu/rcuscale.c @@ -525,8 +525,8 @@ static void rcu_scale_print_module_parms(struct rcu_scale_ops *cur_ops, const char *tag) { pr_alert("%s" SCALE_FLAG - "--- %s: nreaders=%d nwriters=%d verbose=%d shutdown=%d\n", - scale_type, tag, nrealreaders, nrealwriters, verbose, shutdown); + "--- %s: gp_async=%d gp_async_max=%d gp_exp=%d holdoff=%d minruntime=%d nreaders=%d nwriters=%d writer_holdoff=%d writer_holdoff_jiffies=%d verbose=%d shutdown=%d\n", + scale_type, tag, gp_async, gp_async_max, gp_exp, holdoff, minruntime, nrealreaders, nrealwriters, writer_holdoff, writer_holdoff_jiffies, verbose, shutdown); } /* -- cgit v1.2.3-73-gaa49b From bb7bad3dae42b669cfe471716f0073ac611e7f75 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 16 May 2023 16:04:52 -0700 Subject: rcuscale: Print out full set of kfree_rcu parameters Signed-off-by: Paul E. McKenney Cc: Uladzislau Rezki (Sony) --- kernel/rcu/rcuscale.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel/rcu/rcuscale.c') diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c index 18f1b0e13604..821a3e65c54a 100644 --- a/kernel/rcu/rcuscale.c +++ b/kernel/rcu/rcuscale.c @@ -708,6 +708,10 @@ kfree_scale_init(void) unsigned long jif_start; unsigned long orig_jif; + pr_alert("%s" SCALE_FLAG + "--- kfree_rcu_test: kfree_mult=%d kfree_by_call_rcu=%d kfree_nthreads=%d kfree_alloc_num=%d kfree_loops=%d kfree_rcu_test_double=%d kfree_rcu_test_single=%d\n", + scale_type, kfree_mult, kfree_by_call_rcu, kfree_nthreads, kfree_alloc_num, kfree_loops, kfree_rcu_test_double, kfree_rcu_test_single); + // Also, do a quick self-test to ensure laziness is as much as // expected. if (kfree_by_call_rcu && !IS_ENABLED(CONFIG_RCU_LAZY)) { -- cgit v1.2.3-73-gaa49b From 5f8e3202696f5e94d3fc54cfed75d270ae843ee9 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 17 May 2023 05:01:28 -0700 Subject: rcuscale: Measure grace-period kthread CPU time This commit adds the ability to output the CPU time consumed by the grace-period kthread for the RCU variant under test. The CPU time is whatever is in the designated task's current->stime field, and thus is controlled by whatever CPU-time accounting scheme is in effect. This output appears in microseconds as follows on the console: rcu_scale: Grace-period kthread CPU time: 42367.037 [ paulmck: Apply feedback from Stephen Rothwell and kernel test robot. ] Signed-off-by: Paul E. McKenney Tested-by: Yujie Liu --- include/linux/rcupdate_trace.h | 1 + kernel/rcu/rcuscale.c | 21 +++++++++++++++++++++ kernel/rcu/tasks.h | 6 ++++++ 3 files changed, 28 insertions(+) (limited to 'kernel/rcu/rcuscale.c') diff --git a/include/linux/rcupdate_trace.h b/include/linux/rcupdate_trace.h index 9bc8cbb33340..eda493200663 100644 --- a/include/linux/rcupdate_trace.h +++ b/include/linux/rcupdate_trace.h @@ -87,6 +87,7 @@ static inline void rcu_read_unlock_trace(void) void call_rcu_tasks_trace(struct rcu_head *rhp, rcu_callback_t func); void synchronize_rcu_tasks_trace(void); void rcu_barrier_tasks_trace(void); +struct task_struct *get_rcu_tasks_trace_gp_kthread(void); #else /* * The BPF JIT forms these addresses even when it doesn't call these diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c index 821a3e65c54a..7fba3ab66e35 100644 --- a/kernel/rcu/rcuscale.c +++ b/kernel/rcu/rcuscale.c @@ -141,6 +141,7 @@ struct rcu_scale_ops { void (*gp_barrier)(void); void (*sync)(void); void (*exp_sync)(void); + struct task_struct *(*rso_gp_kthread)(void); const char *name; }; @@ -336,6 +337,7 @@ static struct rcu_scale_ops tasks_tracing_ops = { .gp_barrier = rcu_barrier_tasks_trace, .sync = synchronize_rcu_tasks_trace, .exp_sync = synchronize_rcu_tasks_trace, + .rso_gp_kthread = get_rcu_tasks_trace_gp_kthread, .name = "tasks-tracing" }; @@ -563,6 +565,8 @@ static struct task_struct **kfree_reader_tasks; static int kfree_nrealthreads; static atomic_t n_kfree_scale_thread_started; static atomic_t n_kfree_scale_thread_ended; +static struct task_struct *kthread_tp; +static u64 kthread_stime; struct kfree_obj { char kfree_obj[8]; @@ -808,6 +812,18 @@ rcu_scale_cleanup(void) if (gp_exp && gp_async) SCALEOUT_ERRSTRING("No expedited async GPs, so went with async!"); + // If built-in, just report all of the GP kthread's CPU time. + if (IS_BUILTIN(CONFIG_RCU_SCALE_TEST) && !kthread_tp && cur_ops->rso_gp_kthread) + kthread_tp = cur_ops->rso_gp_kthread(); + if (kthread_tp) { + u32 ns; + u64 us; + + kthread_stime = kthread_tp->stime - kthread_stime; + us = div_u64_rem(kthread_stime, 1000, &ns); + pr_info("rcu_scale: Grace-period kthread CPU time: %llu.%03u us\n", us, ns); + show_rcu_gp_kthreads(); + } if (kfree_rcu_test) { kfree_scale_cleanup(); return; @@ -921,6 +937,11 @@ rcu_scale_init(void) if (cur_ops->init) cur_ops->init(); + if (cur_ops->rso_gp_kthread) { + kthread_tp = cur_ops->rso_gp_kthread(); + if (kthread_tp) + kthread_stime = kthread_tp->stime; + } if (kfree_rcu_test) return kfree_scale_init(); diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index b770add3f843..990a6cf5fa35 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -1830,6 +1830,12 @@ void show_rcu_tasks_trace_gp_kthread(void) EXPORT_SYMBOL_GPL(show_rcu_tasks_trace_gp_kthread); #endif // !defined(CONFIG_TINY_RCU) +struct task_struct *get_rcu_tasks_trace_gp_kthread(void) +{ + return rcu_tasks_trace.kthread_ptr; +} +EXPORT_SYMBOL_GPL(get_rcu_tasks_trace_gp_kthread); + #else /* #ifdef CONFIG_TASKS_TRACE_RCU */ static void exit_tasks_rcu_finish_trace(struct task_struct *t) { } #endif /* #else #ifdef CONFIG_TASKS_TRACE_RCU */ -- cgit v1.2.3-73-gaa49b From 271a8467a5f7ab7654f06541d2483b5340bb7192 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 2 Jun 2023 14:38:44 -0700 Subject: rcuscale: Measure RCU Tasks Trace grace-period kthread CPU time This commit causes RCU Tasks Trace to output the CPU time consumed by its grace-period kthread. The CPU time is whatever is in the designated task's current->stime field, and thus is controlled by whatever CPU-time accounting scheme is in effect. This output appears in microseconds as follows on the console: rcu_scale: Grace-period kthread CPU time: 42367.037 [ paulmck: Apply Willy Tarreau feedback. ] Signed-off-by: Paul E. McKenney --- kernel/rcu/rcu.h | 3 +++ kernel/rcu/rcuscale.c | 1 + kernel/rcu/tasks.h | 6 ++++++ 3 files changed, 10 insertions(+) (limited to 'kernel/rcu/rcuscale.c') diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index 98c1544cf572..d58bc0e86769 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -505,6 +505,9 @@ void rcu_async_relax(void); void rcupdate_announce_bootup_oddness(void); #ifdef CONFIG_TASKS_RCU_GENERIC void show_rcu_tasks_gp_kthreads(void); +# ifdef CONFIG_TASKS_RCU +struct task_struct *get_rcu_tasks_gp_kthread(void); +# endif // # ifdef CONFIG_TASKS_RCU #else /* #ifdef CONFIG_TASKS_RCU_GENERIC */ static inline void show_rcu_tasks_gp_kthreads(void) {} #endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */ diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c index 7fba3ab66e35..35e06c86acc9 100644 --- a/kernel/rcu/rcuscale.c +++ b/kernel/rcu/rcuscale.c @@ -298,6 +298,7 @@ static struct rcu_scale_ops tasks_ops = { .gp_barrier = rcu_barrier_tasks, .sync = synchronize_rcu_tasks, .exp_sync = synchronize_rcu_tasks, + .rso_gp_kthread = get_rcu_tasks_gp_kthread, .name = "tasks" }; diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 990a6cf5fa35..0f03de023097 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -1042,6 +1042,12 @@ void show_rcu_tasks_classic_gp_kthread(void) EXPORT_SYMBOL_GPL(show_rcu_tasks_classic_gp_kthread); #endif // !defined(CONFIG_TINY_RCU) +struct task_struct *get_rcu_tasks_gp_kthread(void) +{ + return rcu_tasks.kthread_ptr; +} +EXPORT_SYMBOL_GPL(get_rcu_tasks_gp_kthread); + /* * Contribute to protect against tasklist scan blind spot while the * task is exiting and may be removed from the tasklist. See -- cgit v1.2.3-73-gaa49b From a15ec57cfcf83858aced058e00a7feb824322fa4 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sat, 3 Jun 2023 09:07:44 -0700 Subject: rcuscale: Add RCU Tasks Rude testing Add a "tasks-rude" option to the rcuscale.scale_type module parameter. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcu.h | 3 +++ kernel/rcu/rcuscale.c | 31 +++++++++++++++++++++- kernel/rcu/tasks.h | 7 +++++ .../selftests/rcutorture/configs/rcuscale/CFcommon | 2 ++ 4 files changed, 42 insertions(+), 1 deletion(-) (limited to 'kernel/rcu/rcuscale.c') diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index d58bc0e86769..9829d8161b21 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -508,6 +508,9 @@ void show_rcu_tasks_gp_kthreads(void); # ifdef CONFIG_TASKS_RCU struct task_struct *get_rcu_tasks_gp_kthread(void); # endif // # ifdef CONFIG_TASKS_RCU +# ifdef CONFIG_TASKS_RUDE_RCU +struct task_struct *get_rcu_tasks_rude_gp_kthread(void); +# endif // # ifdef CONFIG_TASKS_RUDE_RCU #else /* #ifdef CONFIG_TASKS_RCU_GENERIC */ static inline void show_rcu_tasks_gp_kthreads(void) {} #endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */ diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c index 35e06c86acc9..5ce3b4e7ce71 100644 --- a/kernel/rcu/rcuscale.c +++ b/kernel/rcu/rcuscale.c @@ -310,6 +310,35 @@ static struct rcu_scale_ops tasks_ops = { #endif // #else // #ifdef CONFIG_TASKS_RCU +#ifdef CONFIG_TASKS_RUDE_RCU + +/* + * Definitions for RCU-tasks-rude scalability testing. + */ + +static struct rcu_scale_ops tasks_rude_ops = { + .ptype = RCU_TASKS_RUDE_FLAVOR, + .init = rcu_sync_scale_init, + .readlock = tasks_scale_read_lock, + .readunlock = tasks_scale_read_unlock, + .get_gp_seq = rcu_no_completed, + .gp_diff = rcu_seq_diff, + .async = call_rcu_tasks_rude, + .gp_barrier = rcu_barrier_tasks_rude, + .sync = synchronize_rcu_tasks_rude, + .exp_sync = synchronize_rcu_tasks_rude, + .rso_gp_kthread = get_rcu_tasks_rude_gp_kthread, + .name = "tasks-rude" +}; + +#define TASKS_RUDE_OPS &tasks_rude_ops, + +#else // #ifdef CONFIG_TASKS_RUDE_RCU + +#define TASKS_RUDE_OPS + +#endif // #else // #ifdef CONFIG_TASKS_RUDE_RCU + #ifdef CONFIG_TASKS_TRACE_RCU /* @@ -913,7 +942,7 @@ rcu_scale_init(void) long i; int firsterr = 0; static struct rcu_scale_ops *scale_ops[] = { - &rcu_ops, &srcu_ops, &srcud_ops, TASKS_OPS TASKS_TRACING_OPS + &rcu_ops, &srcu_ops, &srcud_ops, TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS }; if (!torture_init_begin(scale_type, verbose)) diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 0f03de023097..0372c5cbc83b 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -1194,6 +1194,13 @@ void show_rcu_tasks_rude_gp_kthread(void) } EXPORT_SYMBOL_GPL(show_rcu_tasks_rude_gp_kthread); #endif // !defined(CONFIG_TINY_RCU) + +struct task_struct *get_rcu_tasks_rude_gp_kthread(void) +{ + return rcu_tasks_rude.kthread_ptr; +} +EXPORT_SYMBOL_GPL(get_rcu_tasks_rude_gp_kthread); + #endif /* #ifdef CONFIG_TASKS_RUDE_RCU */ //////////////////////////////////////////////////////////////////////// diff --git a/tools/testing/selftests/rcutorture/configs/rcuscale/CFcommon b/tools/testing/selftests/rcutorture/configs/rcuscale/CFcommon index 6a00157bee5b..b1ffd7c67604 100644 --- a/tools/testing/selftests/rcutorture/configs/rcuscale/CFcommon +++ b/tools/testing/selftests/rcutorture/configs/rcuscale/CFcommon @@ -2,5 +2,7 @@ CONFIG_RCU_SCALE_TEST=y CONFIG_PRINTK_TIME=y CONFIG_FORCE_TASKS_RCU=y #CHECK#CONFIG_TASKS_RCU=y +CONFIG_FORCE_TASKS_RUDE_RCU=y +#CHECK#CONFIG_TASKS_RUDE_RCU=y CONFIG_FORCE_TASKS_TRACE_RCU=y #CHECK#CONFIG_TASKS_TRACE_RCU=y -- cgit v1.2.3-73-gaa49b From e0a34641eb551e3c51e1588ef7874f2de2844a06 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Fri, 9 Jun 2023 14:05:14 +0200 Subject: rcuscale: fix building with RCU_TINY Both the CONFIG_TASKS_RCU and CONFIG_TASKS_RUDE_RCU options are broken when RCU_TINY is enabled as well, as some functions are missing a declaration. In file included from kernel/rcu/update.c:649: kernel/rcu/tasks.h:1271:21: error: no previous prototype for 'get_rcu_tasks_rude_gp_kthread' [-Werror=missing-prototypes] 1271 | struct task_struct *get_rcu_tasks_rude_gp_kthread(void) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/rcu/rcuscale.c:330:27: error: 'get_rcu_tasks_rude_gp_kthread' undeclared here (not in a function); did you mean 'get_rcu_tasks_trace_gp_kthread'? 330 | .rso_gp_kthread = get_rcu_tasks_rude_gp_kthread, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | get_rcu_tasks_trace_gp_kthread In file included from /home/arnd/arm-soc/kernel/rcu/update.c:649: kernel/rcu/tasks.h:1113:21: error: no previous prototype for 'get_rcu_tasks_gp_kthread' [-Werror=missing-prototypes] 1113 | struct task_struct *get_rcu_tasks_gp_kthread(void) | ^~~~~~~~~~~~~~~~~~~~~~~~ Also, building with CONFIG_TASKS_RUDE_RCU but not CONFIG_TASKS_RCU is broken because of some missing stub functions: kernel/rcu/rcuscale.c:322:27: error: 'tasks_scale_read_lock' undeclared here (not in a function); did you mean 'srcu_scale_read_lock'? 322 | .readlock = tasks_scale_read_lock, | ^~~~~~~~~~~~~~~~~~~~~ | srcu_scale_read_lock kernel/rcu/rcuscale.c:323:27: error: 'tasks_scale_read_unlock' undeclared here (not in a function); did you mean 'srcu_scale_read_unlock'? 323 | .readunlock = tasks_scale_read_unlock, | ^~~~~~~~~~~~~~~~~~~~~~~ | srcu_scale_read_unlock Move the declarations outside of the RCU_TINY #ifdef and duplicate the shared stub functions to address all of the above. Fixes: 88d7ff818f0ce ("rcuscale: Add RCU Tasks Rude testing") Fixes: 755f1c5eb416b ("rcuscale: Measure RCU Tasks Trace grace-period kthread CPU time") Signed-off-by: Arnd Bergmann Signed-off-by: Paul E. McKenney --- kernel/rcu/rcu.h | 14 ++++++++------ kernel/rcu/rcuscale.c | 13 +++++++++++-- 2 files changed, 19 insertions(+), 8 deletions(-) (limited to 'kernel/rcu/rcuscale.c') diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index 9829d8161b21..5befd8780dcd 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -505,18 +505,20 @@ void rcu_async_relax(void); void rcupdate_announce_bootup_oddness(void); #ifdef CONFIG_TASKS_RCU_GENERIC void show_rcu_tasks_gp_kthreads(void); -# ifdef CONFIG_TASKS_RCU -struct task_struct *get_rcu_tasks_gp_kthread(void); -# endif // # ifdef CONFIG_TASKS_RCU -# ifdef CONFIG_TASKS_RUDE_RCU -struct task_struct *get_rcu_tasks_rude_gp_kthread(void); -# endif // # ifdef CONFIG_TASKS_RUDE_RCU #else /* #ifdef CONFIG_TASKS_RCU_GENERIC */ static inline void show_rcu_tasks_gp_kthreads(void) {} #endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */ void rcu_request_urgent_qs_task(struct task_struct *t); #endif /* #else #ifdef CONFIG_TINY_RCU */ +#ifdef CONFIG_TASKS_RCU +struct task_struct *get_rcu_tasks_gp_kthread(void); +#endif // # ifdef CONFIG_TASKS_RCU + +#ifdef CONFIG_TASKS_RUDE_RCU +struct task_struct *get_rcu_tasks_rude_gp_kthread(void); +#endif // # ifdef CONFIG_TASKS_RUDE_RCU + #define RCU_SCHEDULER_INACTIVE 0 #define RCU_SCHEDULER_INIT 1 #define RCU_SCHEDULER_RUNNING 2 diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c index 5ce3b4e7ce71..a0eae1900708 100644 --- a/kernel/rcu/rcuscale.c +++ b/kernel/rcu/rcuscale.c @@ -316,11 +316,20 @@ static struct rcu_scale_ops tasks_ops = { * Definitions for RCU-tasks-rude scalability testing. */ +static int tasks_rude_scale_read_lock(void) +{ + return 0; +} + +static void tasks_rude_scale_read_unlock(int idx) +{ +} + static struct rcu_scale_ops tasks_rude_ops = { .ptype = RCU_TASKS_RUDE_FLAVOR, .init = rcu_sync_scale_init, - .readlock = tasks_scale_read_lock, - .readunlock = tasks_scale_read_unlock, + .readlock = tasks_rude_scale_read_lock, + .readunlock = tasks_rude_scale_read_unlock, .get_gp_seq = rcu_no_completed, .gp_diff = rcu_seq_diff, .async = call_rcu_tasks_rude, -- cgit v1.2.3-73-gaa49b From e60c122a1614b4f65b29a7bef9d83b9fd30e937a Mon Sep 17 00:00:00 2001 From: Zqiang Date: Fri, 16 Jun 2023 15:39:26 +0800 Subject: rcuscale: Move rcu_scale_writer() schedule_timeout_uninterruptible() to _idle() The rcuscale.holdoff module parameter can be used to delay the start of rcu_scale_writer() kthread. However, the hung-task timeout will trigger when the timeout specified by rcuscale.holdoff is greater than hung_task_timeout_secs: runqemu kvm nographic slirp qemuparams="-smp 4 -m 2048M" bootparams="rcuscale.shutdown=0 rcuscale.holdoff=300" [ 247.071753] INFO: task rcu_scale_write:59 blocked for more than 122 seconds. [ 247.072529] Not tainted 6.4.0-rc1-00134-gb9ed6de8d4ff #7 [ 247.073400] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 247.074331] task:rcu_scale_write state:D stack:30144 pid:59 ppid:2 flags:0x00004000 [ 247.075346] Call Trace: [ 247.075660] [ 247.075965] __schedule+0x635/0x1280 [ 247.076448] ? __pfx___schedule+0x10/0x10 [ 247.076967] ? schedule_timeout+0x2dc/0x4d0 [ 247.077471] ? __pfx_lock_release+0x10/0x10 [ 247.078018] ? enqueue_timer+0xe2/0x220 [ 247.078522] schedule+0x84/0x120 [ 247.078957] schedule_timeout+0x2e1/0x4d0 [ 247.079447] ? __pfx_schedule_timeout+0x10/0x10 [ 247.080032] ? __pfx_rcu_scale_writer+0x10/0x10 [ 247.080591] ? __pfx_process_timeout+0x10/0x10 [ 247.081163] ? __pfx_sched_set_fifo_low+0x10/0x10 [ 247.081760] ? __pfx_rcu_scale_writer+0x10/0x10 [ 247.082287] rcu_scale_writer+0x6b1/0x7f0 [ 247.082773] ? mark_held_locks+0x29/0xa0 [ 247.083252] ? __pfx_rcu_scale_writer+0x10/0x10 [ 247.083865] ? __pfx_rcu_scale_writer+0x10/0x10 [ 247.084412] kthread+0x179/0x1c0 [ 247.084759] ? __pfx_kthread+0x10/0x10 [ 247.085098] ret_from_fork+0x2c/0x50 [ 247.085433] This commit therefore replaces schedule_timeout_uninterruptible() with schedule_timeout_idle(). Signed-off-by: Zqiang Signed-off-by: Paul E. McKenney --- kernel/rcu/rcuscale.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/rcu/rcuscale.c') diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c index a0eae1900708..ffdb30495e3c 100644 --- a/kernel/rcu/rcuscale.c +++ b/kernel/rcu/rcuscale.c @@ -469,7 +469,7 @@ rcu_scale_writer(void *arg) sched_set_fifo_low(current); if (holdoff) - schedule_timeout_uninterruptible(holdoff * HZ); + schedule_timeout_idle(holdoff * HZ); /* * Wait until rcu_end_inkernel_boot() is called for normal GP tests -- cgit v1.2.3-73-gaa49b