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author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-15 04:21:16 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-15 04:21:16 +0300 |
commit | 8c1dccc80380fca8db09c2a81f5deb3c49b112b2 (patch) | |
tree | fb52b154f469b3a9fc433fc450a59b3077bc99a5 /arch/x86 | |
parent | 1ac0884d5474fea8dc6ceabbd0e870d1bf4b7b42 (diff) | |
parent | 50df51d12c3175573de9c94968639bdd625ec549 (diff) | |
download | linux-8c1dccc80380fca8db09c2a81f5deb3c49b112b2.tar.xz |
Merge tag 'core-rcu-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Thomas Gleixner:
"RCU, LKMM and KCSAN updates collected by Paul McKenney.
RCU:
- Avoid cpuinfo-induced IPI pileups and idle-CPU IPIs
- Lockdep-RCU updates reducing the need for __maybe_unused
- Tasks-RCU updates
- Miscellaneous fixes
- Documentation updates
- Torture-test updates
KCSAN:
- updates for selftests, avoiding setting watchpoints on NULL pointers
- fix to watchpoint encoding
LKMM:
- updates for documentation along with some updates to example-code
litmus tests"
* tag 'core-rcu-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (72 commits)
srcu: Take early exit on memory-allocation failure
rcu/tree: Defer kvfree_rcu() allocation to a clean context
rcu: Do not report strict GPs for outgoing CPUs
rcu: Fix a typo in rcu_blocking_is_gp() header comment
rcu: Prevent lockdep-RCU splats on lock acquisition/release
rcu/tree: nocb: Avoid raising softirq for offloaded ready-to-execute CBs
rcu,ftrace: Fix ftrace recursion
rcu/tree: Make struct kernel_param_ops definitions const
rcu/tree: Add a warning if CPU being onlined did not report QS already
rcu: Clarify nocb kthreads naming in RCU_NOCB_CPU config
rcu: Fix single-CPU check in rcu_blocking_is_gp()
rcu: Implement rcu_segcblist_is_offloaded() config dependent
list.h: Update comment to explicitly note circular lists
rcu: Panic after fixed number of stalls
x86/smpboot: Move rcu_cpu_starting() earlier
rcu: Allow rcu_irq_enter_check_tick() from NMI
tools/memory-model: Label MP tests' producers and consumers
tools/memory-model: Use "buf" and "flag" for message-passing tests
tools/memory-model: Add types to litmus tests
tools/memory-model: Add a glossary of LKMM terms
...
Diffstat (limited to 'arch/x86')
-rw-r--r-- | arch/x86/kernel/cpu/aperfmperf.c | 16 | ||||
-rw-r--r-- | arch/x86/kernel/cpu/mtrr/mtrr.c | 2 | ||||
-rw-r--r-- | arch/x86/kernel/smpboot.c | 1 |
3 files changed, 16 insertions, 3 deletions
diff --git a/arch/x86/kernel/cpu/aperfmperf.c b/arch/x86/kernel/cpu/aperfmperf.c index e2f319dc992d..22911deacb6e 100644 --- a/arch/x86/kernel/cpu/aperfmperf.c +++ b/arch/x86/kernel/cpu/aperfmperf.c @@ -14,11 +14,13 @@ #include <linux/cpufreq.h> #include <linux/smp.h> #include <linux/sched/isolation.h> +#include <linux/rcupdate.h> #include "cpu.h" struct aperfmperf_sample { unsigned int khz; + atomic_t scfpending; ktime_t time; u64 aperf; u64 mperf; @@ -62,17 +64,20 @@ static void aperfmperf_snapshot_khz(void *dummy) s->aperf = aperf; s->mperf = mperf; s->khz = div64_u64((cpu_khz * aperf_delta), mperf_delta); + atomic_set_release(&s->scfpending, 0); } static bool aperfmperf_snapshot_cpu(int cpu, ktime_t now, bool wait) { s64 time_delta = ktime_ms_delta(now, per_cpu(samples.time, cpu)); + struct aperfmperf_sample *s = per_cpu_ptr(&samples, cpu); /* Don't bother re-computing within the cache threshold time. */ if (time_delta < APERFMPERF_CACHE_THRESHOLD_MS) return true; - smp_call_function_single(cpu, aperfmperf_snapshot_khz, NULL, wait); + if (!atomic_xchg(&s->scfpending, 1) || wait) + smp_call_function_single(cpu, aperfmperf_snapshot_khz, NULL, wait); /* Return false if the previous iteration was too long ago. */ return time_delta <= APERFMPERF_STALE_THRESHOLD_MS; @@ -89,6 +94,9 @@ unsigned int aperfmperf_get_khz(int cpu) if (!housekeeping_cpu(cpu, HK_FLAG_MISC)) return 0; + if (rcu_is_idle_cpu(cpu)) + return 0; /* Idle CPUs are completely uninteresting. */ + aperfmperf_snapshot_cpu(cpu, ktime_get(), true); return per_cpu(samples.khz, cpu); } @@ -108,6 +116,8 @@ void arch_freq_prepare_all(void) for_each_online_cpu(cpu) { if (!housekeeping_cpu(cpu, HK_FLAG_MISC)) continue; + if (rcu_is_idle_cpu(cpu)) + continue; /* Idle CPUs are completely uninteresting. */ if (!aperfmperf_snapshot_cpu(cpu, now, false)) wait = true; } @@ -118,6 +128,8 @@ void arch_freq_prepare_all(void) unsigned int arch_freq_get_on_cpu(int cpu) { + struct aperfmperf_sample *s = per_cpu_ptr(&samples, cpu); + if (!cpu_khz) return 0; @@ -131,6 +143,8 @@ unsigned int arch_freq_get_on_cpu(int cpu) return per_cpu(samples.khz, cpu); msleep(APERFMPERF_REFRESH_DELAY_MS); + atomic_set(&s->scfpending, 1); + smp_mb(); /* ->scfpending before smp_call_function_single(). */ smp_call_function_single(cpu, aperfmperf_snapshot_khz, NULL, 1); return per_cpu(samples.khz, cpu); diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.c b/arch/x86/kernel/cpu/mtrr/mtrr.c index 08a30c8e9431..61eb26edc6d2 100644 --- a/arch/x86/kernel/cpu/mtrr/mtrr.c +++ b/arch/x86/kernel/cpu/mtrr/mtrr.c @@ -794,8 +794,6 @@ void mtrr_ap_init(void) if (!use_intel() || mtrr_aps_delayed_init) return; - rcu_cpu_starting(smp_processor_id()); - /* * Ideally we should hold mtrr_mutex here to avoid mtrr entries * changed, but this routine will be called in cpu boot time, diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index de776b2e6046..99bdcebaedfc 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -229,6 +229,7 @@ static void notrace start_secondary(void *unused) #endif cpu_init_exception_handling(); cpu_init(); + rcu_cpu_starting(raw_smp_processor_id()); x86_cpuinit.early_percpu_clock_init(); preempt_disable(); smp_callin(); |