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author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-09 02:12:03 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-09 02:12:03 +0300 |
commit | e1928328699a582a540b105e5f4c160832a7fdcb (patch) | |
tree | f36bb303b8648189d7b5a7feb27e58fe9fe3b9f0 /lib | |
parent | 46f1ec23a46940846f86a91c46f7119d8a8b5de1 (diff) | |
parent | 9156e545765e467e6268c4814cfa609ebb16237e (diff) | |
download | linux-e1928328699a582a540b105e5f4c160832a7fdcb.tar.xz |
Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
"The main changes in this cycle are:
- rwsem scalability improvements, phase #2, by Waiman Long, which are
rather impressive:
"On a 2-socket 40-core 80-thread Skylake system with 40 reader
and writer locking threads, the min/mean/max locking operations
done in a 5-second testing window before the patchset were:
40 readers, Iterations Min/Mean/Max = 1,807/1,808/1,810
40 writers, Iterations Min/Mean/Max = 1,807/50,344/151,255
After the patchset, they became:
40 readers, Iterations Min/Mean/Max = 30,057/31,359/32,741
40 writers, Iterations Min/Mean/Max = 94,466/95,845/97,098"
There's a lot of changes to the locking implementation that makes
it similar to qrwlock, including owner handoff for more fair
locking.
Another microbenchmark shows how across the spectrum the
improvements are:
"With a locking microbenchmark running on 5.1 based kernel, the
total locking rates (in kops/s) on a 2-socket Skylake system
with equal numbers of readers and writers (mixed) before and
after this patchset were:
# of Threads Before Patch After Patch
------------ ------------ -----------
2 2,618 4,193
4 1,202 3,726
8 802 3,622
16 729 3,359
32 319 2,826
64 102 2,744"
The changes are extensive and the patch-set has been through
several iterations addressing various locking workloads. There
might be more regressions, but unless they are pathological I
believe we want to use this new implementation as the baseline
going forward.
- jump-label optimizations by Daniel Bristot de Oliveira: the primary
motivation was to remove IPI disturbance of isolated RT-workload
CPUs, which resulted in the implementation of batched jump-label
updates. Beyond the improvement of the real-time characteristics
kernel, in one test this patchset improved static key update
overhead from 57 msecs to just 1.4 msecs - which is a nice speedup
as well.
- atomic64_t cross-arch type cleanups by Mark Rutland: over the last
~10 years of atomic64_t existence the various types used by the
APIs only had to be self-consistent within each architecture -
which means they became wildly inconsistent across architectures.
Mark puts and end to this by reworking all the atomic64
implementations to use 's64' as the base type for atomic64_t, and
to ensure that this type is consistently used for parameters and
return values in the API, avoiding further problems in this area.
- A large set of small improvements to lockdep by Yuyang Du: type
cleanups, output cleanups, function return type and othr cleanups
all around the place.
- A set of percpu ops cleanups and fixes by Peter Zijlstra.
- Misc other changes - please see the Git log for more details"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (82 commits)
locking/lockdep: increase size of counters for lockdep statistics
locking/atomics: Use sed(1) instead of non-standard head(1) option
locking/lockdep: Move mark_lock() inside CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING
x86/jump_label: Make tp_vec_nr static
x86/percpu: Optimize raw_cpu_xchg()
x86/percpu, sched/fair: Avoid local_clock()
x86/percpu, x86/irq: Relax {set,get}_irq_regs()
x86/percpu: Relax smp_processor_id()
x86/percpu: Differentiate this_cpu_{}() and __this_cpu_{}()
locking/rwsem: Guard against making count negative
locking/rwsem: Adaptive disabling of reader optimistic spinning
locking/rwsem: Enable time-based spinning on reader-owned rwsem
locking/rwsem: Make rwsem->owner an atomic_long_t
locking/rwsem: Enable readers spinning on writer
locking/rwsem: Clarify usage of owner's nonspinaable bit
locking/rwsem: Wake up almost all readers in wait queue
locking/rwsem: More optimal RT task handling of null owner
locking/rwsem: Always release wait_lock before waking up tasks
locking/rwsem: Implement lock handoff to prevent lock starvation
locking/rwsem: Make rwsem_spin_on_owner() return owner state
...
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Kconfig.debug | 8 | ||||
-rw-r--r-- | lib/atomic64.c | 32 |
2 files changed, 20 insertions, 20 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 6629cab453e8..06d9c9d70385 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1095,7 +1095,7 @@ config PROVE_LOCKING select DEBUG_SPINLOCK select DEBUG_MUTEXES select DEBUG_RT_MUTEXES if RT_MUTEXES - select DEBUG_RWSEMS if RWSEM_SPIN_ON_OWNER + select DEBUG_RWSEMS select DEBUG_WW_MUTEX_SLOWPATH select DEBUG_LOCK_ALLOC select TRACE_IRQFLAGS @@ -1199,10 +1199,10 @@ config DEBUG_WW_MUTEX_SLOWPATH config DEBUG_RWSEMS bool "RW Semaphore debugging: basic checks" - depends on DEBUG_KERNEL && RWSEM_SPIN_ON_OWNER + depends on DEBUG_KERNEL help - This debugging feature allows mismatched rw semaphore locks and unlocks - to be detected and reported. + This debugging feature allows mismatched rw semaphore locks + and unlocks to be detected and reported. config DEBUG_LOCK_ALLOC bool "Lock debugging: detect incorrect freeing of live locks" diff --git a/lib/atomic64.c b/lib/atomic64.c index 7e6905751522..e98c85a99787 100644 --- a/lib/atomic64.c +++ b/lib/atomic64.c @@ -42,11 +42,11 @@ static inline raw_spinlock_t *lock_addr(const atomic64_t *v) return &atomic64_lock[addr & (NR_LOCKS - 1)].lock; } -long long atomic64_read(const atomic64_t *v) +s64 atomic64_read(const atomic64_t *v) { unsigned long flags; raw_spinlock_t *lock = lock_addr(v); - long long val; + s64 val; raw_spin_lock_irqsave(lock, flags); val = v->counter; @@ -55,7 +55,7 @@ long long atomic64_read(const atomic64_t *v) } EXPORT_SYMBOL(atomic64_read); -void atomic64_set(atomic64_t *v, long long i) +void atomic64_set(atomic64_t *v, s64 i) { unsigned long flags; raw_spinlock_t *lock = lock_addr(v); @@ -67,7 +67,7 @@ void atomic64_set(atomic64_t *v, long long i) EXPORT_SYMBOL(atomic64_set); #define ATOMIC64_OP(op, c_op) \ -void atomic64_##op(long long a, atomic64_t *v) \ +void atomic64_##op(s64 a, atomic64_t *v) \ { \ unsigned long flags; \ raw_spinlock_t *lock = lock_addr(v); \ @@ -79,11 +79,11 @@ void atomic64_##op(long long a, atomic64_t *v) \ EXPORT_SYMBOL(atomic64_##op); #define ATOMIC64_OP_RETURN(op, c_op) \ -long long atomic64_##op##_return(long long a, atomic64_t *v) \ +s64 atomic64_##op##_return(s64 a, atomic64_t *v) \ { \ unsigned long flags; \ raw_spinlock_t *lock = lock_addr(v); \ - long long val; \ + s64 val; \ \ raw_spin_lock_irqsave(lock, flags); \ val = (v->counter c_op a); \ @@ -93,11 +93,11 @@ long long atomic64_##op##_return(long long a, atomic64_t *v) \ EXPORT_SYMBOL(atomic64_##op##_return); #define ATOMIC64_FETCH_OP(op, c_op) \ -long long atomic64_fetch_##op(long long a, atomic64_t *v) \ +s64 atomic64_fetch_##op(s64 a, atomic64_t *v) \ { \ unsigned long flags; \ raw_spinlock_t *lock = lock_addr(v); \ - long long val; \ + s64 val; \ \ raw_spin_lock_irqsave(lock, flags); \ val = v->counter; \ @@ -130,11 +130,11 @@ ATOMIC64_OPS(xor, ^=) #undef ATOMIC64_OP_RETURN #undef ATOMIC64_OP -long long atomic64_dec_if_positive(atomic64_t *v) +s64 atomic64_dec_if_positive(atomic64_t *v) { unsigned long flags; raw_spinlock_t *lock = lock_addr(v); - long long val; + s64 val; raw_spin_lock_irqsave(lock, flags); val = v->counter - 1; @@ -145,11 +145,11 @@ long long atomic64_dec_if_positive(atomic64_t *v) } EXPORT_SYMBOL(atomic64_dec_if_positive); -long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n) +s64 atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n) { unsigned long flags; raw_spinlock_t *lock = lock_addr(v); - long long val; + s64 val; raw_spin_lock_irqsave(lock, flags); val = v->counter; @@ -160,11 +160,11 @@ long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n) } EXPORT_SYMBOL(atomic64_cmpxchg); -long long atomic64_xchg(atomic64_t *v, long long new) +s64 atomic64_xchg(atomic64_t *v, s64 new) { unsigned long flags; raw_spinlock_t *lock = lock_addr(v); - long long val; + s64 val; raw_spin_lock_irqsave(lock, flags); val = v->counter; @@ -174,11 +174,11 @@ long long atomic64_xchg(atomic64_t *v, long long new) } EXPORT_SYMBOL(atomic64_xchg); -long long atomic64_fetch_add_unless(atomic64_t *v, long long a, long long u) +s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u) { unsigned long flags; raw_spinlock_t *lock = lock_addr(v); - long long val; + s64 val; raw_spin_lock_irqsave(lock, flags); val = v->counter; |