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author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-09 01:45:14 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-09 01:45:14 +0300 |
commit | 46f1ec23a46940846f86a91c46f7119d8a8b5de1 (patch) | |
tree | eb2b0bf4e17cf4a9a88e970cbffd829f3daba88f /kernel/rcu/rcutorture.c | |
parent | 223cea6a4f0552b86fb25e3b8bbd00469816cd7a (diff) | |
parent | 83086d654dd08c0f57381522e6819f421677706e (diff) | |
download | linux-46f1ec23a46940846f86a91c46f7119d8a8b5de1.tar.xz |
Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Ingo Molnar:
"The changes in this cycle are:
- RCU flavor consolidation cleanups and optmizations
- Documentation updates
- Miscellaneous fixes
- SRCU updates
- RCU-sync flavor consolidation
- Torture-test updates
- Linux-kernel memory-consistency-model updates, most notably the
addition of plain C-language accesses"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (61 commits)
tools/memory-model: Improve data-race detection
tools/memory-model: Change definition of rcu-fence
tools/memory-model: Expand definition of barrier
tools/memory-model: Do not use "herd" to refer to "herd7"
tools/memory-model: Fix comment in MP+poonceonces.litmus
Documentation: atomic_t.txt: Explain ordering provided by smp_mb__{before,after}_atomic()
rcu: Don't return a value from rcu_assign_pointer()
rcu: Force inlining of rcu_read_lock()
rcu: Fix irritating whitespace error in rcu_assign_pointer()
rcu: Upgrade sync_exp_work_done() to smp_mb()
rcutorture: Upper case solves the case of the vanishing NULL pointer
torture: Suppress propagating trace_printk() warning
rcutorture: Dump trace buffer for callback pipe drain failures
torture: Add --trust-make to suppress "make clean"
torture: Make --cpus override idleness calculations
torture: Run kernel build in source directory
torture: Add function graph-tracing cheat sheet
torture: Capture qemu output
rcutorture: Tweak kvm options
rcutorture: Add trivial RCU implementation
...
Diffstat (limited to 'kernel/rcu/rcutorture.c')
-rw-r--r-- | kernel/rcu/rcutorture.c | 96 |
1 files changed, 85 insertions, 11 deletions
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index efaa5b3f4d3f..fce4e7e6f502 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -299,6 +299,7 @@ struct rcu_torture_ops { int irq_capable; int can_boost; int extendables; + int slow_gps; const char *name; }; @@ -667,9 +668,51 @@ static struct rcu_torture_ops tasks_ops = { .fqs = NULL, .stats = NULL, .irq_capable = 1, + .slow_gps = 1, .name = "tasks" }; +/* + * Definitions for trivial CONFIG_PREEMPT=n-only torture testing. + * This implementation does not necessarily work well with CPU hotplug. + */ + +static void synchronize_rcu_trivial(void) +{ + int cpu; + + for_each_online_cpu(cpu) { + rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu)); + WARN_ON_ONCE(raw_smp_processor_id() != cpu); + } +} + +static int rcu_torture_read_lock_trivial(void) __acquires(RCU) +{ + preempt_disable(); + return 0; +} + +static void rcu_torture_read_unlock_trivial(int idx) __releases(RCU) +{ + preempt_enable(); +} + +static struct rcu_torture_ops trivial_ops = { + .ttype = RCU_TRIVIAL_FLAVOR, + .init = rcu_sync_torture_init, + .readlock = rcu_torture_read_lock_trivial, + .read_delay = rcu_read_delay, /* just reuse rcu's version. */ + .readunlock = rcu_torture_read_unlock_trivial, + .get_gp_seq = rcu_no_completed, + .sync = synchronize_rcu_trivial, + .exp_sync = synchronize_rcu_trivial, + .fqs = NULL, + .stats = NULL, + .irq_capable = 1, + .name = "trivial" +}; + static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old) { if (!cur_ops->gp_diff) @@ -1010,10 +1053,17 @@ rcu_torture_writer(void *arg) !rcu_gp_is_normal(); } rcu_torture_writer_state = RTWS_STUTTER; - if (stutter_wait("rcu_torture_writer")) + if (stutter_wait("rcu_torture_writer") && + !READ_ONCE(rcu_fwd_cb_nodelay) && + !cur_ops->slow_gps && + !torture_must_stop()) for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) - if (list_empty(&rcu_tortures[i].rtort_free)) - WARN_ON_ONCE(1); + if (list_empty(&rcu_tortures[i].rtort_free) && + rcu_access_pointer(rcu_torture_current) != + &rcu_tortures[i]) { + rcu_ftrace_dump(DUMP_ALL); + WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count); + } } while (!torture_must_stop()); /* Reset expediting back to unexpedited. */ if (expediting > 0) @@ -1358,8 +1408,9 @@ rcu_torture_stats_print(void) } pr_alert("%s%s ", torture_type, TORTURE_FLAG); - pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ", + pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ", rcu_torture_current, + rcu_torture_current ? "ver" : "VER", rcu_torture_current_version, list_empty(&rcu_torture_freelist), atomic_read(&n_rcu_torture_alloc), @@ -1661,6 +1712,17 @@ static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp) spin_unlock_irqrestore(&rcu_fwd_lock, flags); } +// Give the scheduler a chance, even on nohz_full CPUs. +static void rcu_torture_fwd_prog_cond_resched(void) +{ + if (IS_ENABLED(CONFIG_PREEMPT) && IS_ENABLED(CONFIG_NO_HZ_FULL)) { + if (need_resched()) + schedule(); + } else { + cond_resched(); + } +} + /* * Free all callbacks on the rcu_fwd_cb_head list, either because the * test is over or because we hit an OOM event. @@ -1674,16 +1736,18 @@ static unsigned long rcu_torture_fwd_prog_cbfree(void) for (;;) { spin_lock_irqsave(&rcu_fwd_lock, flags); rfcp = rcu_fwd_cb_head; - if (!rfcp) + if (!rfcp) { + spin_unlock_irqrestore(&rcu_fwd_lock, flags); break; + } rcu_fwd_cb_head = rfcp->rfc_next; if (!rcu_fwd_cb_head) rcu_fwd_cb_tail = &rcu_fwd_cb_head; spin_unlock_irqrestore(&rcu_fwd_lock, flags); kfree(rfcp); freed++; + rcu_torture_fwd_prog_cond_resched(); } - spin_unlock_irqrestore(&rcu_fwd_lock, flags); return freed; } @@ -1707,6 +1771,8 @@ static void rcu_torture_fwd_prog_nr(int *tested, int *tested_tries) } /* Tight loop containing cond_resched(). */ + WRITE_ONCE(rcu_fwd_cb_nodelay, true); + cur_ops->sync(); /* Later readers see above write. */ if (selfpropcb) { WRITE_ONCE(fcs.stop, 0); cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb); @@ -1724,7 +1790,7 @@ static void rcu_torture_fwd_prog_nr(int *tested, int *tested_tries) udelay(10); cur_ops->readunlock(idx); if (!fwd_progress_need_resched || need_resched()) - cond_resched(); + rcu_torture_fwd_prog_cond_resched(); } (*tested_tries)++; if (!time_before(jiffies, stopat) && @@ -1745,6 +1811,8 @@ static void rcu_torture_fwd_prog_nr(int *tested, int *tested_tries) WARN_ON(READ_ONCE(fcs.stop) != 2); destroy_rcu_head_on_stack(&fcs.rh); } + schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */ + WRITE_ONCE(rcu_fwd_cb_nodelay, false); } /* Carry out call_rcu() forward-progress testing. */ @@ -1765,6 +1833,8 @@ static void rcu_torture_fwd_prog_cr(void) if (READ_ONCE(rcu_fwd_emergency_stop)) return; /* Get out of the way quickly, no GP wait! */ + if (!cur_ops->call) + return; /* Can't do call_rcu() fwd prog without ->call. */ /* Loop continuously posting RCU callbacks. */ WRITE_ONCE(rcu_fwd_cb_nodelay, true); @@ -1805,7 +1875,7 @@ static void rcu_torture_fwd_prog_cr(void) rfcp->rfc_gps = 0; } cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr); - cond_resched(); + rcu_torture_fwd_prog_cond_resched(); } stoppedat = jiffies; n_launders_cb_snap = READ_ONCE(n_launders_cb); @@ -1814,7 +1884,6 @@ static void rcu_torture_fwd_prog_cr(void) cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */ (void)rcu_torture_fwd_prog_cbfree(); - WRITE_ONCE(rcu_fwd_cb_nodelay, false); if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop)) { WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED); pr_alert("%s Duration %lu barrier: %lu pending %ld n_launders: %ld n_launders_sa: %ld n_max_gps: %ld n_max_cbs: %ld cver %ld gps %ld\n", @@ -1825,6 +1894,8 @@ static void rcu_torture_fwd_prog_cr(void) n_max_gps, n_max_cbs, cver, gps); rcu_torture_fwd_cb_hist(); } + schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */ + WRITE_ONCE(rcu_fwd_cb_nodelay, false); } @@ -2240,7 +2311,7 @@ rcu_torture_init(void) int firsterr = 0; static struct rcu_torture_ops *torture_ops[] = { &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, - &busted_srcud_ops, &tasks_ops, + &busted_srcud_ops, &tasks_ops, &trivial_ops, }; if (!torture_init_begin(torture_type, verbose)) @@ -2363,7 +2434,10 @@ rcu_torture_init(void) if (stutter < 0) stutter = 0; if (stutter) { - firsterr = torture_stutter_init(stutter * HZ); + int t; + + t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ; + firsterr = torture_stutter_init(stutter * HZ, t); if (firsterr) goto unwind; } |