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envelope-from=vsementsov@virtuozzo.com; helo=EUR03-AM5-obe.outbound.protection.outlook.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MSGID_FROM_MTA_HEADER=0.001, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 12.05.2021 09:56, Paolo Bonzini wrote: > On 16/04/21 10:08, Vladimir Sementsov-Ogievskiy wrote: >> With the following patch we want to call wake coroutine from thread. >> And it doesn't work with aio_co_wake: >> Assume we have no iothreads. >> Assume we have a coroutine A, which waits in the yield point for >> external aio_co_wake(), and no progress can be done until it happen. >> Main thread is in blocking aio_poll() (for example, in blk_read()). >> >> Now, in a separate thread we do aio_co_wake(). It calls  aio_co_enter(), >> which goes through last "else" branch and do aio_context_acquire(ctx). > > I don't understand.  Why doesn't aio_co_enter go through the ctx != qemu_get_current_aio_context() branch and just do aio_co_schedule?  That was at least the idea behind aio_co_wake and aio_co_enter. > Because ctx is exactly qemu_get_current_aio_context(), as we are not in iothread but in nbd connection thread. So, qemu_get_current_aio_context() returns qemu_aio_context. -- Best regards, Vladimir