- 16 Oct, 2018 1 commit
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Waiman Long authored
Remove the duplicated 'lock_class_ops' percpu array that is not used anywhere. Signed-off-by: Waiman Long <longman@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Fixes: 8ca2b56c ("locking/lockdep: Make class->ops a percpu counter and move it under CONFIG_DEBUG_LOCKDEP=y") Link: http://lkml.kernel.org/r/1539380547-16726-1-git-send-email-longman@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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- 09 Oct, 2018 2 commits
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Lance Roy authored
lockdep_assert_held() is better suited for checking locking requirements, since it won't get confused when the lock is held by some other task. This is also a step towards possibly removing spin_is_locked(). Signed-off-by: Lance Roy <ldr709@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: "Paul E. McKenney" <paulmck@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Darren Hart <dvhart@infradead.org> Link: https://lkml.kernel.org/r/20181003053902.6910-12-ldr709@gmail.com
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Waiman Long authored
A sizable portion of the CPU cycles spent on the __lock_acquire() is used up by the atomic increment of the class->ops stat counter. By taking it out from the lock_class structure and changing it to a per-cpu per-lock-class counter, we can reduce the amount of cacheline contention on the class structure when multiple CPUs are trying to acquire locks of the same class simultaneously. To limit the increase in memory consumption because of the percpu nature of that counter, it is now put back under the CONFIG_DEBUG_LOCKDEP config option. So the memory consumption increase will only occur if CONFIG_DEBUG_LOCKDEP is defined. The lock_class structure, however, is reduced in size by 16 bytes on 64-bit archs after ops removal and a minor restructuring of the fields. This patch also fixes a bug in the increment code as the counter is of the 'unsigned long' type, but atomic_inc() was used to increment it. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/d66681f3-8781-9793-1dcf-2436a284550b@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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- 03 Oct, 2018 3 commits
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Waiman Long authored
When __lock_release() is called, the most likely unlock scenario is on the innermost lock in the chain. In this case, we can skip some of the checks and provide a faster path to completion. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/1538511560-10090-4-git-send-email-longman@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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Waiman Long authored
The static __lock_acquire() function has only two callers: 1) lock_acquire() 2) reacquire_held_locks() In lock_acquire(), raw_local_irq_save() is called beforehand. So IRQs must have been disabled. So the check: DEBUG_LOCKS_WARN_ON(!irqs_disabled()) is kind of redundant in this case. So move the above check to reacquire_held_locks() to eliminate redundant code in the lock_acquire() path. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/1538511560-10090-3-git-send-email-longman@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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Waiman Long authored
The inline function add_chain_cache_classes() is defined, but has no caller. Just remove it. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/1538511560-10090-2-git-send-email-longman@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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- 02 Oct, 2018 7 commits
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Andrew Murray authored
Fix incorrect line number in example output Signed-off-by: Andrew Murray <andrew.murray@arm.com> Cc: Jiri Kosina <trivial@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-doc@vger.kernel.org Link: http://lkml.kernel.org/r/1538391663-54524-1-git-send-email-andrew.murray@arm.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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Andrea Parri authored
Amend the changes in commit: 1f03e8d2 ("locking/barriers: Replace smp_cond_acquire() with smp_cond_load_acquire()") ... by updating the documentation accordingly. Also remove some obsolete information related to the implementation. Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Cc: Akira Yokosawa <akiyks@gmail.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Daniel Lustig <dlustig@nvidia.com> Cc: David Howells <dhowells@redhat.com> Cc: Jade Alglave <j.alglave@ucl.ac.uk> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luc Maranget <luc.maranget@inria.fr> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: linux-arch@vger.kernel.org Cc: parri.andrea@gmail.com Link: http://lkml.kernel.org/r/20180926182920.27644-5-paulmck@linux.ibm.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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Paul E. McKenney authored
This commit adds more detail about compiler optimizations and not-yet-modeled Linux-kernel APIs. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Andrea Parri <andrea.parri@amarulasolutions.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: akiyks@gmail.com Cc: boqun.feng@gmail.com Cc: dhowells@redhat.com Cc: j.alglave@ucl.ac.uk Cc: linux-arch@vger.kernel.org Cc: luc.maranget@inria.fr Cc: npiggin@gmail.com Cc: parri.andrea@gmail.com Cc: stern@rowland.harvard.edu Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/20180926182920.27644-4-paulmck@linux.ibm.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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SeongJae Park authored
This commit fixes a duplicate-"the" typo in README. Signed-off-by: SeongJae Park <sj38.park@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: akiyks@gmail.com Cc: boqun.feng@gmail.com Cc: dhowells@redhat.com Cc: j.alglave@ucl.ac.uk Cc: linux-arch@vger.kernel.org Cc: luc.maranget@inria.fr Cc: npiggin@gmail.com Cc: parri.andrea@gmail.com Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/20180926182920.27644-3-paulmck@linux.ibm.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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Alan Stern authored
More than one kernel developer has expressed the opinion that the LKMM should enforce ordering of writes by locking. In other words, given the following code: WRITE_ONCE(x, 1); spin_unlock(&s): spin_lock(&s); WRITE_ONCE(y, 1); the stores to x and y should be propagated in order to all other CPUs, even though those other CPUs might not access the lock s. In terms of the memory model, this means expanding the cumul-fence relation. Locks should also provide read-read (and read-write) ordering in a similar way. Given: READ_ONCE(x); spin_unlock(&s); spin_lock(&s); READ_ONCE(y); // or WRITE_ONCE(y, 1); the load of x should be executed before the load of (or store to) y. The LKMM already provides this ordering, but it provides it even in the case where the two accesses are separated by a release/acquire pair of fences rather than unlock/lock. This would prevent architectures from using weakly ordered implementations of release and acquire, which seems like an unnecessary restriction. The patch therefore removes the ordering requirement from the LKMM for that case. There are several arguments both for and against this change. Let us refer to these enhanced ordering properties by saying that the LKMM would require locks to be RCtso (a bit of a misnomer, but analogous to RCpc and RCsc) and it would require ordinary acquire/release only to be RCpc. (Note: In the following, the phrase "all supported architectures" is meant not to include RISC-V. Although RISC-V is indeed supported by the kernel, the implementation is still somewhat in a state of flux and therefore statements about it would be premature.) Pros: The kernel already provides RCtso ordering for locks on all supported architectures, even though this is not stated explicitly anywhere. Therefore the LKMM should formalize it. In theory, guaranteeing RCtso ordering would reduce the need for additional barrier-like constructs meant to increase the ordering strength of locks. Will Deacon and Peter Zijlstra are strongly in favor of formalizing the RCtso requirement. Linus Torvalds and Will would like to go even further, requiring locks to have RCsc behavior (ordering preceding writes against later reads), but they recognize that this would incur a noticeable performance degradation on the POWER architecture. Linus also points out that people have made the mistake, in the past, of assuming that locking has stronger ordering properties than is currently guaranteed, and this change would reduce the likelihood of such mistakes. Not requiring ordinary acquire/release to be any stronger than RCpc may prove advantageous for future architectures, allowing them to implement smp_load_acquire() and smp_store_release() with more efficient machine instructions than would be possible if the operations had to be RCtso. Will and Linus approve this rationale, hypothetical though it is at the moment (it may end up affecting the RISC-V implementation). The same argument may or may not apply to RMW-acquire/release; see also the second Con entry below. Linus feels that locks should be easy for people to use without worrying about memory consistency issues, since they are so pervasive in the kernel, whereas acquire/release is much more of an "experts only" tool. Requiring locks to be RCtso is a step in this direction. Cons: Andrea Parri and Luc Maranget think that locks should have the same ordering properties as ordinary acquire/release (indeed, Luc points out that the names "acquire" and "release" derive from the usage of locks). Andrea points out that having different ordering properties for different forms of acquires and releases is not only unnecessary, it would also be confusing and unmaintainable. Locks are constructed from lower-level primitives, typically RMW-acquire (for locking) and ordinary release (for unlock). It is illogical to require stronger ordering properties from the high-level operations than from the low-level operations they comprise. Thus, this change would make while (cmpxchg_acquire(&s, 0, 1) != 0) cpu_relax(); an incorrect implementation of spin_lock(&s) as far as the LKMM is concerned. In theory this weakness can be ameliorated by changing the LKMM even further, requiring RMW-acquire/release also to be RCtso (which it already is on all supported architectures). As far as I know, nobody has singled out any examples of code in the kernel that actually relies on locks being RCtso. (People mumble about RCU and the scheduler, but nobody has pointed to any actual code. If there are any real cases, their number is likely quite small.) If RCtso ordering is not needed, why require it? A handful of locking constructs (qspinlocks, qrwlocks, and mcs_spinlocks) are built on top of smp_cond_load_acquire() instead of an RMW-acquire instruction. It currently provides only the ordinary acquire semantics, not the stronger ordering this patch would require of locks. In theory this could be ameliorated by requiring smp_cond_load_acquire() in combination with ordinary release also to be RCtso (which is currently true on all supported architectures). On future weakly ordered architectures, people may be able to implement locks in a non-RCtso fashion with significant performance improvement. Meeting the RCtso requirement would necessarily add run-time overhead. Overall, the technical aspects of these arguments seem relatively minor, and it appears mostly to boil down to a matter of opinion. Since the opinions of senior kernel maintainers such as Linus, Peter, and Will carry more weight than those of Luc and Andrea, this patch changes the model in accordance with the maintainers' wishes. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Will Deacon <will.deacon@arm.com> Reviewed-by: Andrea Parri <andrea.parri@amarulasolutions.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: akiyks@gmail.com Cc: boqun.feng@gmail.com Cc: dhowells@redhat.com Cc: j.alglave@ucl.ac.uk Cc: linux-arch@vger.kernel.org Cc: luc.maranget@inria.fr Cc: npiggin@gmail.com Cc: parri.andrea@gmail.com Link: http://lkml.kernel.org/r/20180926182920.27644-2-paulmck@linux.ibm.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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Paul E. McKenney authored
This commit documents the scheme used to generate the names for the litmus tests. [ paulmck: Apply feedback from Andrea Parri and Will Deacon. ] Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: akiyks@gmail.com Cc: boqun.feng@gmail.com Cc: dhowells@redhat.com Cc: j.alglave@ucl.ac.uk Cc: linux-arch@vger.kernel.org Cc: luc.maranget@inria.fr Cc: npiggin@gmail.com Cc: parri.andrea@gmail.com Cc: stern@rowland.harvard.edu Link: http://lkml.kernel.org/r/20180926182920.27644-1-paulmck@linux.ibm.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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Matthew Wilcox authored
Both spin locks and write locks currently do: f0 0f b1 17 lock cmpxchg %edx,(%rdi) 85 c0 test %eax,%eax 75 05 jne [slowpath] This 'test' insn is superfluous; the cmpxchg insn sets the Z flag appropriately. Peter pointed out that using atomic_try_cmpxchg_acquire() will let the compiler know this is true. Comparing before/after disassemblies show the only effect is to remove this insn. Take this opportunity to make the spin & write lock code resemble each other more closely and have similar likely() hints. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Link: http://lkml.kernel.org/r/20180820162639.GC25153@bombadil.infradead.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>
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- 11 Sep, 2018 2 commits
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Peter Zijlstra authored
Anybody trying to assert the cpu_hotplug_lock is held (lockdep_assert_cpus_held()) from AP callbacks will fail, because the lock is held by the BP. Stick in an explicit annotation in cpuhp_thread_fun() to make this work. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-tip-commits@vger.kernel.org Fixes: cb538267 ("jump_label/lockdep: Assert we hold the hotplug lock for _cpuslocked() operations") Link: http://lkml.kernel.org/r/20180911095127.GT24082@hirez.programming.kicks-ass.netSigned-off-by: Ingo Molnar <mingo@kernel.org>
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Steven Rostedt (VMware) authored
Merging v4.14.68 into v4.14-rt I tripped over a conflict in the rtmutex.c code. There I found that we had: #ifdef CONFIG_DEBUG_LOCK_ALLOC [..] #endif #ifndef CONFIG_DEBUG_LOCK_ALLOC [..] #endif Really this should be: #ifdef CONFIG_DEBUG_LOCK_ALLOC [..] #else [..] #endif This cleans up that logic. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Rosin <peda@axentia.se> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180910214638.55926030@vmware.local.homeSigned-off-by: Ingo Molnar <mingo@kernel.org>
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- 10 Sep, 2018 8 commits
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Waiman Long authored
Currently, when a reader acquires a lock, it only sets the RWSEM_READER_OWNED bit in the owner field. The other bits are simply not used. When debugging hanging cases involving rwsems and readers, the owner value does not provide much useful information at all. This patch modifies the current behavior to always store the task_struct pointer of the last rwsem-acquiring reader in a reader-owned rwsem. This may be useful in debugging rwsem hanging cases especially if only one reader is involved. However, the task in the owner field may not the real owner or one of the real owners at all when the owner value is examined, for example, in a crash dump. So it is just an additional hint about the past history. If CONFIG_DEBUG_RWSEMS=y is enabled, the owner field will be checked at unlock time too to make sure the task pointer value is valid. That does have a slight performance cost and so is only enabled as part of that debug option. From the performance point of view, it is expected that the changes shouldn't have any noticeable performance impact. A rwsem microbenchmark (with 48 worker threads and 1:1 reader/writer ratio) was ran on a 2-socket 24-core 48-thread Haswell system. The locking rates on a 4.19-rc1 based kernel were as follows: 1) Unpatched kernel: 543.3 kops/s 2) Patched kernel: 549.2 kops/s 3) Patched kernel (CONFIG_DEBUG_RWSEMS on): 546.6 kops/s There was actually a slight increase in performance (1.1%) in this particular case. Maybe it was caused by the elimination of a branch or just a testing noise. Turning on the CONFIG_DEBUG_RWSEMS option also had less than the expected impact on performance. The least significant 2 bits of the owner value are now used to designate the rwsem is readers owned and the owners are anonymous. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/1536265114-10842-1-git-send-email-longman@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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Waiman Long authored
It was discovered that a constant stream of readers with occassional writers pounding on a rwsem may cause many of the readers to enter the slowpath unnecessarily thus increasing latency and lowering performance. In the current code, a reader entering the slowpath critical section will unconditionally set the WAITING_BIAS, if not set yet, and clear its active count even if no one is in the wait queue and no writer is present. This causes some incoming readers to observe the presence of waiters in the wait queue and hence have to go into the slowpath themselves. With sufficient numbers of readers and a relatively short lock hold time, the WAITING_BIAS may be repeatedly turned on and off and a substantial portion of the readers will go into the slowpath sustaining a rather long queue in the wait queue spinlock and repeated WAITING_BIAS on/off cycle until the logjam is broken opportunistically. To avoid this situation from happening, an additional check is added to detect the special case that the reader in the critical section is the only one in the wait queue and no writer is present. When that happens, it can just exit the slowpath and return immediately as its active count has already been set in the lock. Other incoming readers won't observe the presence of waiters and so will not be forced into the slowpath. The issue was found in a customer site where they had an application that pounded on the pread64 syscalls heavily on an XFS filesystem. The application was run in a recent 4-socket boxes with a lot of CPUs. They saw significant spinlock contention in the rwsem_down_read_failed() call. With this patch applied, the system CPU usage went down from 85% to 57%, and the spinlock contention in the pread64 syscalls was gone. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Joe Mario <jmario@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1532459425-19204-1-git-send-email-longman@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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Peter Zijlstra authored
Weirdly we seem to have forgotten this... Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Ingo Molnar authored
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Borislav Petkov authored
There's no 'allocatote' - use the next best thing: 'allocate' :-) Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Jason Baron <jbaron@akamai.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180907103521.31344-1-bp@alien8.deSigned-off-by: Ingo Molnar <mingo@kernel.org>
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Thomas Hellstrom authored
The following commit: 08295b3b ("Implement an algorithm choice for Wound-Wait mutexes") introduced a reference in the documentation to a function that was removed in an earlier commit. It also forgot to remove a call to debug_mutex_add_waiter() which is now unconditionally called by __mutex_add_waiter(). Fix those bugs. Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dri-devel@lists.freedesktop.org Fixes: 08295b3b ("Implement an algorithm choice for Wound-Wait mutexes") Link: http://lkml.kernel.org/r/20180903140708.2401-1-thellstrom@vmware.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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Borislav Petkov authored
... instead of open-coding it, in static_key_mod(). No functional changes. Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jason Baron <jbaron@akamai.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180909114252.17575-1-bp@alien8.deSigned-off-by: Ingo Molnar <mingo@kernel.org>
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Linus Torvalds authored
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- 09 Sep, 2018 7 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull x86 fixes from Thomas Gleixner: "A set of fixes for x86: - Prevent multiplication result truncation on 32bit. Introduced with the early timestamp reworrk. - Ensure microcode revision storage to be consistent under all circumstances - Prevent write tearing of PTEs - Prevent confusion of user and kernel reegisters when dumping fatal signals verbosely - Make an error return value in a failure path of the vector allocation negative. Returning EINVAL might the caller assume success and causes further wreckage. - A trivial kernel doc warning fix" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm: Use WRITE_ONCE() when setting PTEs x86/apic/vector: Make error return value negative x86/process: Don't mix user/kernel regs in 64bit __show_regs() x86/tsc: Prevent result truncation on 32bit x86: Fix kernel-doc atomic.h warnings x86/microcode: Update the new microcode revision unconditionally x86/microcode: Make sure boot_cpu_data.microcode is up-to-date
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull timekeeping fixes from Thomas Gleixner: "Two fixes for timekeeping: - Revert to the previous kthread based update, which is unfortunately required due to lock ordering issues. The removal caused boot failures on old Core2 machines. Add a proper comment why the thread needs to stay to prevent accidental removal in the future. - Fix a silly typo in a function declaration" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: clocksource: Revert "Remove kthread" timekeeping: Fix declaration of read_persistent_wall_and_boot_offset()
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull irqchip fix from Thomas Gleixner: "A single fix to prevent allocating excessive memory in the GIC/ITS driver. While the subject of the patch might suggest otherwise this is a real fix as some SoCs exceed the memory allocation limits and fail to boot" * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: irqchip/gic-v3-its: Cap lpi_id_bits to reduce memory footprint
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull cpu hotplug fixes from Thomas Gleixner: "Two fixes for the hotplug state machine code: - Move the misplaces smb() in the hotplug thread function to the proper place, otherwise a half update control struct could be observed - Prevent state corruption on error rollback, which causes the state to advance by one and as a consequence skip it in the bringup sequence" * 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: cpu/hotplug: Prevent state corruption on error rollback cpu/hotplug: Adjust misplaced smb() in cpuhp_thread_fun()
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git://git.kernel.org/pub/scm/linux/kernel/git/tytso/randomLinus Torvalds authored
Pull random driver fix from Ted Ts'o: "Fix things so the choice of whether or not to trust RDRAND to initialize the CRNG is configurable via the boot option random.trust_cpu={on,off}" * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random: random: make CPU trust a boot parameter
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Linus Torvalds authored
Merge tag 'kbuild-fixes-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild fixes from Masahiro Yamada: - make setlocalversion more robust about -dirty check - loosen the pkg-config requirement for Kconfig - change missing depmod to a warning from an error - warn modules_install when System.map is missing * tag 'kbuild-fixes-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: modules_install: warn when missing System.map file kbuild: make missing $DEPMOD a Warning instead of an Error kconfig: do not require pkg-config on make {menu,n}config kconfig: remove a spurious self-assignment scripts/setlocalversion: git: Make -dirty check more robust
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Randy Dunlap authored
If there is no System.map file for "make modules_install", scripts/depmod.sh will silently exit with success, having done nothing. Since this is an unexpected situation, change it to report a Warning for the missing file. The behavior is not changed except for the Warning message. The (previous) silent success and new Warning can be reproduced by: $ make mrproper; make defconfig $ make modules; make modules_install and since System.map is produced by "make vmlinux", the steps above omit producing the System.map file. Reported-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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- 08 Sep, 2018 6 commits
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git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds authored
Pull KVM fixes from Radim Krčmář: "ARM: - Fix a VFP corruption in 32-bit guest - Add missing cache invalidation for CoW pages - Two small cleanups s390: - Fallout from the hugetlbfs support: pfmf interpretion and locking - VSIE: fix keywrapping for nested guests PPC: - Fix a bug where pages might not get marked dirty, causing guest memory corruption on migration - Fix a bug causing reads from guest memory to use the wrong guest real address for very large HPT guests (>256G of memory), leading to failures in instruction emulation. x86: - Fix out of bound access from malicious pv ipi hypercalls (introduced in rc1) - Fix delivery of pending interrupts when entering a nested guest, preventing arbitrarily late injection - Sanitize kvm_stat output after destroying a guest - Fix infinite loop when emulating a nested guest page fault and improve the surrounding emulation code - Two minor cleanups" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (28 commits) KVM: LAPIC: Fix pv ipis out-of-bounds access KVM: nVMX: Fix loss of pending IRQ/NMI before entering L2 arm64: KVM: Remove pgd_lock KVM: Remove obsolete kvm_unmap_hva notifier backend arm64: KVM: Only force FPEXC32_EL2.EN if trapping FPSIMD KVM: arm/arm64: Clean dcache to PoC when changing PTE due to CoW KVM: s390: Properly lock mm context allow_gmap_hpage_1m setting KVM: s390: vsie: copy wrapping keys to right place KVM: s390: Fix pfmf and conditional skey emulation tools/kvm_stat: re-animate display of dead guests tools/kvm_stat: indicate dead guests as such tools/kvm_stat: handle guest removals more gracefully tools/kvm_stat: don't reset stats when setting PID filter for debugfs tools/kvm_stat: fix updates for dead guests tools/kvm_stat: fix handling of invalid paths in debugfs provider tools/kvm_stat: fix python3 issues KVM: x86: Unexport x86_emulate_instruction() KVM: x86: Rename emulate_instruction() to kvm_emulate_instruction() KVM: x86: Do not re-{try,execute} after failed emulation in L2 KVM: x86: Default to not allowing emulation retry in kvm_mmu_page_fault ...
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git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-socLinus Torvalds authored
Pull ARM SoC fixes from Olof Johansson: "A few more fixes who have trickled in: - MMC bus width fixup for some Allwinner platforms - Fix for NULL deref in ti-aemif when no platform data is passed in - Fix div by 0 in SCMI code - Add a missing module alias in a new RPi driver" * tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: memory: ti-aemif: fix a potential NULL-pointer dereference firmware: arm_scmi: fix divide by zero when sustained_perf_level is zero hwmon: rpi: add module alias to raspberrypi-hwmon arm64: allwinner: dts: h6: fix Pine H64 MMC bus width
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Olof Johansson authored
Merge tag 'sunxi-fixes-for-4.19' of https://git.kernel.org/pub/scm/linux/kernel/git/sunxi/linux into fixes Allwinner fixes for 4.19 Just one fix for H6 mmc on the Pine H64: the mmc bus width was missing from the device tree. This was added in 4.19-rc1. * tag 'sunxi-fixes-for-4.19' of https://git.kernel.org/pub/scm/linux/kernel/git/sunxi/linux: arm64: allwinner: dts: h6: fix Pine H64 MMC bus width Signed-off-by: Olof Johansson <olof@lixom.net>
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Nadav Amit authored
When page-table entries are set, the compiler might optimize their assignment by using multiple instructions to set the PTE. This might turn into a security hazard if the user somehow manages to use the interim PTE. L1TF does not make our lives easier, making even an interim non-present PTE a security hazard. Using WRITE_ONCE() to set PTEs and friends should prevent this potential security hazard. I skimmed the differences in the binary with and without this patch. The differences are (obviously) greater when CONFIG_PARAVIRT=n as more code optimizations are possible. For better and worse, the impact on the binary with this patch is pretty small. Skimming the code did not cause anything to jump out as a security hazard, but it seems that at least move_soft_dirty_pte() caused set_pte_at() to use multiple writes. Signed-off-by: Nadav Amit <namit@vmware.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20180902181451.80520-1-namit@vmware.com
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Thomas Gleixner authored
activate_managed() returns EINVAL instead of -EINVAL in case of error. While this is unlikely to happen, the positive return value would cause further malfunction at the call site. Fixes: 2db1f959 ("x86/vector: Handle managed interrupts proper") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org
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git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linuxLinus Torvalds authored
Pull i2c fixes from Wolfram Sang: - bugfixes for uniphier, i801, and xiic drivers - ID removal (never produced) for imx - one MAINTAINER addition * 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: i2c: xiic: Record xilinx i2c with Zynq fragment i2c: xiic: Make the start and the byte count write atomic i2c: i801: fix DNV's SMBCTRL register offset i2c: imx-lpi2c: Remove mx8dv compatible entry dt-bindings: imx-lpi2c: Remove mx8dv compatible entry i2c: uniphier-f: issue STOP only for last message or I2C_M_STOP i2c: uniphier: issue STOP only for last message or I2C_M_STOP
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- 07 Sep, 2018 4 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arcLinus Torvalds authored
Pull ARC updates from Vineet Gupta: - Fix for atomic_fetch_#op [Will Deacon] - Enable per device IOC [Eugeniy Paltsev] - Remove redundant gcc version checks [Masahiro Yamada] - Miscll platform config/DT updates [Alexey Brodkin] * tag 'arc-4.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: ARC: don't check for HIGHMEM pages in arch_dma_alloc ARC: IOC: panic if both IOC and ZONE_HIGHMEM enabled ARC: dma [IOC] Enable per device io coherency ARC: dma [IOC]: mark DMA devices connected as dma-coherent ARC: atomics: unbork atomic_fetch_##op() arc: remove redundant GCC version checks ARC: sort Kconfig ARC: cleanup show_faulting_vma() ARC: [plat-axs*]: Enable SWAP ARC: [plat-axs*/plat-hsdk]: Allow U-Boot to pass MAC-address to the kernel ARC: configs: cleanup
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David Howells authored
Fix the cell specification mechanism to allow cells to be pre-created without having to specify at least one address (the addresses will be upcalled for). This allows the cell information preload service to avoid the need to issue loads of DNS lookups during boot to get the addresses for each cell (500+ lookups for the 'standard' cell list[*]). The lookups can be done later as each cell is accessed through the filesystem. Also remove the print statement that prints a line every time a new cell is added. [*] There are 144 cells in the list. Each cell is first looked up for an SRV record, and if that fails, for an AFSDB record. These get a list of server names, each of which then has to be looked up to get the addresses for that server. E.g.: dig srv _afs3-vlserver._udp.grand.central.org Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/shli/mdLinus Torvalds authored
Pull MD fixes from Shaohua Li: - Fix a locking issue for md-cluster (Guoqing) - Fix a sync crash for raid10 (Ni) - Fix a reshape bug with raid5 cache enabled (me) * tag 'md/4.19-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md: md-cluster: release RESYNC lock after the last resync message RAID10 BUG_ON in raise_barrier when force is true and conf->barrier is 0 md/raid5-cache: disable reshape completely
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https://github.com/ceph/ceph-clientLinus Torvalds authored
Pull ceph fixes from Ilya Dryomov: "Two rbd patches to complete support for images within namespaces that went into -rc1 and a use-after-free fix. The rbd changes have been sitting in a branch for quite a while but couldn't be included into the -rc1 pull request because of a pending wire protocol backwards compatibility fixup that only got committed early this week" * tag 'ceph-for-4.19-rc3' of https://github.com/ceph/ceph-client: rbd: support cloning across namespaces rbd: factor out get_parent_info() ceph: avoid a use-after-free in ceph_destroy_options()
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