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* lockable: add QemuLockablePaolo Bonzini2018-02-081-3/+2Star
| | | | | | | | | | | | | | | | | | | | QemuLockable is a polymorphic lock type that takes an object and knows which function to use for locking and unlocking. The implementation could use C11 _Generic, but since the support is not very widespread I am instead using __builtin_choose_expr and __builtin_types_compatible_p, which are already used by include/qemu/atomic.h. QemuLockable can be used to implement lock guards, or to pass around a lock in such a way that a function can release it and re-acquire it. The next patch will do this for CoQueue. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20180203153935.8056-3-pbonzini@redhat.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
* util/qemu-thread-*: add qemu_lock, locked and unlock trace eventsAlex Bennée2018-01-161-4/+35
| | | | | Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* qemu-thread: optimize QemuLockCnt with futexes on LinuxPaolo Bonzini2017-01-161-0/+2
| | | | | | | | | | This is complex, but I think it is reasonably documented in the source. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20170112180800.21085-5-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* qemu-thread: introduce QemuLockCntPaolo Bonzini2017-01-161-0/+110
| | | | | | | | | | | | | | | | | A QemuLockCnt comprises a counter and a mutex, with primitives to increment and decrement the counter, and to take and release the mutex. It can be used to do lock-free visits to a data structure whenever mutexes would be too heavy-weight and the critical section is too long for RCU. This could be implemented simply by protecting the counter with the mutex, but QemuLockCnt is harder to misuse and more efficient. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20170112180800.21085-3-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* qemu-thread: introduce QemuRecMutexPaolo Bonzini2016-10-281-0/+3
| | | | | | | | | | | | GRecMutex is new in glib 2.32, so we cannot use it. Introduce a recursive mutex in qemu-thread instead, which will be used instead of RFifoLock. Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <1477565348-5458-20-git-send-email-pbonzini@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
* Clean up ill-advised or unusual header guardsMarkus Armbruster2016-07-121-2/+2
| | | | | | | Cleaned up with scripts/clean-header-guards.pl. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Richard Henderson <rth@twiddle.net>
* qemu-thread: add simple test-and-set spinlockGuillaume Delbergue2016-06-121-0/+35
| | | | | | | | | | | | | | Reviewed-by: Sergey Fedorov <sergey.fedorov@linaro.org> Signed-off-by: Guillaume Delbergue <guillaume.delbergue@greensocs.com> [Rewritten. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [Emilio's additions: use TAS instead of atomic_xchg; emit acquire/release barriers; return bool from trylock; call cpu_relax() while spinning; optimize for uncontended locks by acquiring the lock with TAS instead of TATAS; add qemu_spin_locked().] Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <1465412133-3029-6-git-send-email-cota@braap.org> Signed-off-by: Richard Henderson <rth@twiddle.net>
* include: Clean up includesPeter Maydell2016-02-231-2/+0Star
| | | | | | | | | | | | | | Clean up includes so that osdep.h is included first and headers which it implies are not included manually. This commit was created with scripts/clean-includes. NB: If this commit breaks compilation for your out-of-tree patchseries or fork, then you need to make sure you add #include "qemu/osdep.h" to any new .c files that you have. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Eric Blake <eblake@redhat.com>
* rcu: add rcu libraryPaolo Bonzini2015-02-021-3/+0Star
| | | | | | | | | | | | | | | | | | This includes a (mangled) copy of the liburcu code. The main changes are: 1) removing dependencies on many other header files in liburcu; 2) removing for simplicity the tentative busy waiting in synchronize_rcu, which has limited performance effects; 3) replacing futexes in synchronize_rcu with QemuEvents for Win32 portability. The API is the same as liburcu, so it should be possible in the future to require liburcu on POSIX systems for example and use our copy only on Windows. Among the various versions available I chose urcu-mb, which is the least invasive implementation even though it does not have the fastest rcu_read_{lock,unlock} implementation. The urcu flavor can be changed later, after benchmarking. Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* qemu-thread: add per-thread atexit functionsPaolo Bonzini2015-01-131-0/+4
| | | | | | | | | | | | | | | | | | | Destructors are the main additional feature of pthread TLS compared to __thread. If we were using C++ (hint, hint!) we could have used thread-local objects with a destructor. Since we are not, instead, we add a simple Notifier-based API. Note that the notifier must be per-thread as well. We can add a global list as well later, perhaps. The Win32 implementation has some complications because a) detached threads used not to have a QemuThreadData; b) the main thread does not go through win32_start_routine, so we have to use atexit too. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 1417518350-6167-3-git-send-email-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* Add a 'name' parameter to qemu_thread_createDr. David Alan Gilbert2014-03-091-1/+1
| | | | | | | | | | If enabled, set the thread name at creation (on GNU systems with pthread_set_np) Fix up all the callers with a thread name Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
* Add 'debug-threads' suboption to --nameDr. David Alan Gilbert2014-03-091-0/+1
| | | | | | | | Add flag storage to qemu-thread-* to store the namethreads flag Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
* qemu-thread: add QemuEventPaolo Bonzini2013-10-171-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This emulates Win32 manual-reset events using futexes or conditional variables. Typical ways to use them are with multi-producer, single-consumer data structures, to test for a complex condition whose elements come from different threads: for (;;) { qemu_event_reset(ev); ... test complex condition ... if (condition is true) { break; } qemu_event_wait(ev); } Or more efficiently (but with some duplication): ... evaluate condition ... while (!condition) { qemu_event_reset(ev); ... evaluate condition ... if (!condition) { qemu_event_wait(ev); ... evaluate condition ... } } QemuEvent provides a very fast userspace path in the common case when no other thread is waiting, or the event is not changing state. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* misc: move include files to include/qemu/Paolo Bonzini2012-12-191-0/+56
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>