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* Revert "main-loop: Disable block backend global state assertion on Cocoa"Akihiko Odaki2022-09-231-13/+0Star
| | | | | | | | | | | This reverts commit 47281859f66bdab1974fb122cab2cbb4a1c9af7f. Signed-off-by: Akihiko Odaki <akihiko.odaki@gmail.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20220819132756.74641-3-akihiko.odaki@gmail.com> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
* main loop: add missing documentation links to GS/IO macrosEmanuele Giuseppe Esposito2022-08-021-3/+15
| | | | | | | | | | | | | | If we go directly to GLOBAL_STATE_CODE, IO_CODE or IO_OR_GS_CODE definition, we just find that they "mark and check that the function is part of the {category} API". However, ther is no definition on what {category} API is, they are in include/block/block-*.h Therefore, add a comment that refers to such documentation. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-Id: <20220609122206.1016936-1-eesposit@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* util/main-loop: Introduce the main loop into QOMNicolas Saenz Julienne2022-05-091-0/+10
| | | | | | | | | | | | | | | | | | | | 'event-loop-base' provides basic property handling for all 'AioContext' based event loops. So let's define a new 'MainLoopClass' that inherits from it. This will permit tweaking the main loop's properties through qapi as well as through the command line using the '-object' keyword[1]. Only one instance of 'MainLoopClass' might be created at any time. 'EventLoopBaseClass' learns a new callback, 'can_be_deleted()' so as to mark 'MainLoop' as non-deletable. [1] For example: -object main-loop,id=main-loop,aio-max-batch=<value> Signed-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Acked-by: Markus Armbruster <armbru@redhat.com> Message-id: 20220425075723.20019-3-nsaenzju@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* Revert "main-loop: Disable GLOBAL_STATE_CODE() assertions"Hanna Reitz2022-05-041-2/+1Star
| | | | | | | | | | | | This reverts commit b1c073490553f80594b903ceedfc7c1aef6b1b19. (We wanted to do so once the 7.1 tree opens, which has happened. The issue reported in https://gitlab.com/qemu-project/qemu/-/issues/945 should be fixed by the preceding patches.) Signed-off-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20220427114057.36651-4-hreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* main-loop: Disable GLOBAL_STATE_CODE() assertionsHanna Reitz2022-03-291-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | These assertions are very useful for developers to find bugs, and so they have indeed pointed us towards bugs already. For users, it is not so useful to find these bugs. We should probably not enable them in releases until we are sufficiently certain that they will not fire during normal operation, unless something is going seriously wrong. For example, we have received a bug report that you cannot add an NBD server on a BDS in an I/O thread with `-incoming defer`. I am sure this is a real bug that needs investigation, but we do not really have that time right now, so close to release, and so I would rather disable the assertions to get time to investigate such reports. (I am just putting the link as "buglink" below, not "closes", because disabling the assertion will not fix the likely underlying bug.) Buglink: https://gitlab.com/qemu-project/qemu/-/issues/945 Signed-off-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20220329093545.52114-1-hreitz@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
* main-loop: Disable block backend global state assertion on CocoaPhilippe Mathieu-Daudé2022-03-291-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since commit 0439c5a462 ("block/block-backend.c: assertions for block-backend") QEMU crashes when using Cocoa on Darwin hosts. Example on macOS: $ qemu-system-i386 Assertion failed: (qemu_in_main_thread()), function blk_all_next, file block-backend.c, line 552. Abort trap: 6 Looking with lldb: Assertion failed: (qemu_in_main_thread()), function blk_all_next, file block-backend.c, line 552. Process 76914 stopped * thread #1, queue = 'com.apple.main-thread', stop reason = hit program assert frame #4: 0x000000010057c2d4 qemu-system-i386`blk_all_next.cold.1 at block-backend.c:552:5 [opt] 549 */ 550 BlockBackend *blk_all_next(BlockBackend *blk) 551 { --> 552 GLOBAL_STATE_CODE(); 553 return blk ? QTAILQ_NEXT(blk, link) 554 : QTAILQ_FIRST(&block_backends); 555 } Target 1: (qemu-system-i386) stopped. (lldb) bt * thread #1, queue = 'com.apple.main-thread', stop reason = hit program assert frame #0: 0x00000001908c99b8 libsystem_kernel.dylib`__pthread_kill + 8 frame #1: 0x00000001908fceb0 libsystem_pthread.dylib`pthread_kill + 288 frame #2: 0x000000019083a314 libsystem_c.dylib`abort + 164 frame #3: 0x000000019083972c libsystem_c.dylib`__assert_rtn + 300 * frame #4: 0x000000010057c2d4 qemu-system-i386`blk_all_next.cold.1 at block-backend.c:552:5 [opt] frame #5: 0x00000001003c00b4 qemu-system-i386`blk_all_next(blk=<unavailable>) at block-backend.c:552:5 [opt] frame #6: 0x00000001003d8f04 qemu-system-i386`qmp_query_block(errp=0x0000000000000000) at qapi.c:591:16 [opt] frame #7: 0x000000010003ab0c qemu-system-i386`main [inlined] addRemovableDevicesMenuItems at cocoa.m:1756:21 [opt] frame #8: 0x000000010003ab04 qemu-system-i386`main(argc=<unavailable>, argv=<unavailable>) at cocoa.m:1980:5 [opt] frame #9: 0x00000001012690f4 dyld`start + 520 As we are in passed release 7.0 hard freeze, disable the block backend assertion which, while being valuable during development, is not helpful to users. We'll restore this assertion immediately once 7.0 is released and work on a fix. Suggested-by: Akihiko Odaki <akihiko.odaki@gmail.com> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Akihiko Odaki <akihiko.odaki@gmail.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Message-Id: <20220325183707.85733-1-philippe.mathieu.daude@gmail.com>
* main loop: macros to mark GS and I/O functionsEmanuele Giuseppe Esposito2022-03-041-0/+18
| | | | | | | | | | | | | | | Righ now, IO_CODE and IO_OR_GS_CODE are nop, as there isn't really a way to check that a function is only called in I/O. On the other side, we can use qemu_in_main_thread() to check if we are in the main loop. The usage of macros makes easy to extend them in the future without making changes in all callers. They will also visually help understanding in which category each function is, without looking at the header. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-Id: <20220303151616.325444-3-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* main-loop.h: introduce qemu_in_main_thread()Emanuele Giuseppe Esposito2022-03-041-0/+24
| | | | | | | | | | | | | | | | | | | | | | | When invoked from the main loop, this function is the same as qemu_mutex_iothread_locked, and returns true if the BQL is held. When invoked from iothreads or tests, it returns true only if the current AioContext is the Main Loop. This essentially just extends qemu_mutex_iothread_locked to work also in unit tests or other users like storage-daemon, that run in the Main Loop but end up using the implementation in stubs/iothread-lock.c. Using qemu_mutex_iothread_locked in unit tests defaults to false because they use the implementation in stubs/iothread-lock, making all assertions added in next patches fail despite the AioContext is still the main loop. See the comment in the function header for more information. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-Id: <20220303151616.325444-2-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* util/async: add a human-readable name to BHs for debuggingStefan Hajnoczi2021-07-051-1/+3
| | | | | | | | | | | | | | | | | | It can be difficult to debug issues with BHs in production environments. Although BHs can usually be identified by looking up their ->cb() function pointer, this requires debug information for the program. It is also not possible to print human-readable diagnostics about BHs because they have no identifier. This patch adds a name to each BH. The name is not unique per instance but differentiates between cb() functions, which is usually enough. It's done by changing aio_bh_new() and friends to macros that stringify cb. The next patch will use the name field when reporting leaked BHs. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-Id: <20210414200247.917496-2-stefanha@redhat.com>
* main-loop: remove dead codePaolo Bonzini2021-05-111-18/+0Star
| | | | | | | qemu_add_child_watch is not called anywhere since commit 2bdb920ece ("slirp: simplify fork_exec()", 2019-01-14), remove it. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* main-loop: Fix commentStefan Weil2020-09-011-1/+1
| | | | | | | Signed-off-by: Stefan Weil <sw@weilnetz.de> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-Id: <20200827175520.32355-1-sw@weilnetz.de> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
* cpu-throttle: new module, extracted from cpus.cClaudio Fontana2020-07-111-0/+5
| | | | | | | | | | | | | | | | | | | | | | | move the vcpu throttling functionality into its own module. This functionality is not specific to any accelerator, and it is used currently by migration to slow down guests to try to have migrations converge, and by the cocoa MacOS UI to throttle speed. cpu-throttle contains the controls to adjust and inspect throttle settings, start (set) and stop vcpu throttling, and the throttling function itself that is run periodically on vcpus to make them take a nap. Execution of the throttling function on all vcpus is triggered by a timer, registered at module initialization. No functionality change. Signed-off-by: Claudio Fontana <cfontana@suse.de> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Laurent Vivier <lvivier@redhat.com> Message-Id: <20200629093504.3228-3-cfontana@suse.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* Wrapper function to wait on condition for the main loop mutexAravinda Prasad2020-02-031-0/+8
| | | | | | | | | | | | | | | Introduce a wrapper function to wait on condition for the main loop mutex. This function atomically releases the main loop mutex and causes the calling thread to block on the condition. This wrapper is required because qemu_global_mutex is a static variable. Signed-off-by: Aravinda Prasad <arawinda.p@gmail.com> Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <20200130184423.20519-2-ganeshgr@linux.ibm.com> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
* slirp: replace global polling with per-instance & notifierMarc-André Lureau2019-02-071-0/+15
| | | | | | | | Remove hard-coded dependency on slirp in main-loop, and use a "poll" notifier instead. The notifier is registered per slirp instance. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
* qsp: track BQL callers explicitlyEmilio G. Cota2018-08-231-1/+3
| | | | | | | | | | | The BQL is acquired via qemu_mutex_lock_iothread(), which makes the profiler assign the associated wait time (i.e. most of BQL wait time) entirely to that function. This loses the original call site information, which does not help diagnose BQL contention. Fix it by tracking the callers explicitly. Signed-off-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* main-loop: document IOCanReadHandlerStefan Hajnoczi2018-06-281-0/+14
| | | | | | | Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20180602085259.17853-1-stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
* main_loop: Make main_loop_wait() return voidPeter Maydell2017-07-041-1/+1
| | | | | | | | | | | | | | | | | | The last users of main_loop_wait() that cared about the return value have now been changed to no longer use it. Drop the now-useless return value and make the function return void. We avoid the awkwardness of ifdeffery to handle the 'ret' variable in main_loop_wait() only being wanted if CONFIG_SLIRP by simply dropping all the ifdefs. There are stub implementations of slirp_pollfds_poll() and slirp_pollfds_fill() already in stubs/slirp.c which do nothing, as required. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <1498584769-12439-3-git-send-email-peter.maydell@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* event_notifier: cleanups around event_notifier_set_handlerPaolo Bonzini2017-01-161-0/+15
| | | | | | | | Remove the useless is_external argument. Since the iohandler AioContext is never used for block devices, aio_disable_external is never called on it. This lets us remove stubs/iohandler.c. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* main-loop: update comment for qemu_mutex_lock/unlock_iothreadYaowei Bai2016-12-221-2/+2
| | | | | | | | | | | Commit 49cf57281b7 (vl: delay thread initialization after daemonization) makes the global mutex is taken after daemonization instead before daemonization by qemu_init_main_loop(). Signed-off-by: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Message-Id: <1480566640-27264-2-git-send-email-baiyaowei@cmss.chinamobile.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* coroutine: move entry argument to qemu_coroutine_createPaolo Bonzini2016-07-131-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In practice the entry argument is always known at creation time, and it is confusing that sometimes qemu_coroutine_enter is used with a non-NULL argument to re-enter a coroutine (this happens in block/sheepdog.c and tests/test-coroutine.c). So pass the opaque value at creation time, for consistency with e.g. aio_bh_new. Mostly done with the following semantic patch: @ entry1 @ expression entry, arg, co; @@ - co = qemu_coroutine_create(entry); + co = qemu_coroutine_create(entry, arg); ... - qemu_coroutine_enter(co, arg); + qemu_coroutine_enter(co); @ entry2 @ expression entry, arg; identifier co; @@ - Coroutine *co = qemu_coroutine_create(entry); + Coroutine *co = qemu_coroutine_create(entry, arg); ... - qemu_coroutine_enter(co, arg); + qemu_coroutine_enter(co); @ entry3 @ expression entry, arg; @@ - qemu_coroutine_enter(qemu_coroutine_create(entry), arg); + qemu_coroutine_enter(qemu_coroutine_create(entry, arg)); @ reentry @ expression co; @@ - qemu_coroutine_enter(co, NULL); + qemu_coroutine_enter(co); except for the aforementioned few places where the semantic patch stumbled (as expected) and for test_co_queue, which would otherwise produce an uninitialized variable warning. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* Clean up decorations and whitespace around header guardsMarkus Armbruster2016-07-121-1/+1
| | | | | | | Cleaned up with scripts/clean-header-guards.pl. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Richard Henderson <rth@twiddle.net>
* iohandler: Introduce iohandler_get_aio_contextFam Zheng2016-04-221-0/+1
| | | | | | Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* iohandler: Use aio APIFam Zheng2015-09-071-2/+1Star
| | | | | | | | | | | | | iohandler.c shares the same interface with aio, but with duplicated code. It's better to rebase iohandler, also because that aio is a more friendly interface to multi-threads. Create a global AioContext instance and let its GSource handle the iohandler events. Signed-off-by: Fam Zheng <famz@redhat.com> Message-Id: <1441596538-4412-1-git-send-email-famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* main-loop: introduce qemu_mutex_iothread_lockedPaolo Bonzini2015-07-011-0/+10
| | | | | | | | | | | | | | | | | | | | | | This function will be used to avoid recursive locking of the iothread lock whenever address_space_rw/ld*/st* are called with the BQL held, which is almost always the case. Tracking whether the iothread is owned is very cheap (just use a TLS variable) but requires some care because now the lock must always be taken with qemu_mutex_lock_iothread(). Previously this wasn't the case. Outside TCG mode this is not a problem. In TCG mode, we need to be careful and avoid the "prod out of compiled code" step if already in a VCPU thread. This is easily done with a check on current_cpu, i.e. qemu_in_vcpu_thread(). Hopefully, multithreaded TCG will get rid of the whole logic to kick VCPUs whenever an I/O event occurs! Cc: Frederic Konrad <fred.konrad@greensocs.com> Message-Id: <1434646046-27150-3-git-send-email-pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* iohandler: Change return type of qemu_set_fd_handler to "void"Fam Zheng2015-06-121-4/+4
| | | | | | Signed-off-by: Fam Zheng <famz@redhat.com> Message-id: 1433400324-7358-14-git-send-email-famz@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* main-loop: Drop qemu_set_fd_handler2Fam Zheng2015-06-121-48/+1Star
| | | | | | | | | All users are converted to qemu_set_fd_handler now, drop qemu_set_fd_handler2 and IOHandlerRecord.fd_read_poll. Signed-off-by: Fam Zheng <famz@redhat.com> Message-id: 1433400324-7358-9-git-send-email-famz@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* async: aio_context_new(): Handle event_notifier_init failureChrysostomos Nanakos2014-09-221-1/+1
| | | | | | | | | | | | | | | | | | | | | On a system with a low limit of open files the initialization of the event notifier could fail and QEMU exits without printing any error information to the user. The problem can be easily reproduced by enforcing a low limit of open files and start QEMU with enough I/O threads to hit this limit. The same problem raises, without the creation of I/O threads, while QEMU initializes the main event loop by enforcing an even lower limit of open files. This commit adds an error message on failure: # qemu [...] -object iothread,id=iothread0 -object iothread,id=iothread1 qemu: Failed to initialize event notifier: Too many open files in system Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* main-loop: add qemu_get_aio_context()Stefan Hajnoczi2013-03-151-0/+5
| | | | | | | | | | | | | | It is very useful to get the main loop AioContext, which is a static variable in main-loop.c. I'm not sure whether qemu_get_aio_context() will be necessary in the future once devices focus on using their own AioContext instead of the main loop AioContext, but for now it allows us to refactor code to support multiple AioContext while actually passing the main loop AioContext. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
* iohandler: switch to GPollFDStefan Hajnoczi2013-02-211-2/+2
| | | | | | | | | | Convert iohandler_select_fill() and iohandler_select_poll() to use GPollFD instead of rfds/wfds/xfds. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Message-id: 1361356113-11049-7-git-send-email-stefanha@redhat.com Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* misc: move include files to include/qemu/Paolo Bonzini2012-12-191-0/+306
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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