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([2a04:ee41:4:31cb:e591:1e1e:abde:a8f1]) by smtp.gmail.com with ESMTPSA id j5sm155563ejo.171.2021.12.14.10.10.34 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 14 Dec 2021 10:10:35 -0800 (PST) Message-ID: <5fe9120f-04d7-0cfa-36b0-33c9f1680809@redhat.com> Date: Tue, 14 Dec 2021 19:10:34 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [RFC PATCH 0/6] Removal of Aiocontext lock and usage of subtree drains in aborted transactions To: Stefan Hajnoczi References: <20211213104014.69858-1-eesposit@redhat.com> From: Emanuele Giuseppe Esposito In-Reply-To: Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eesposit@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=eesposit@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -44 X-Spam_score: -4.5 X-Spam_bar: ---- X-Spam_report: (-4.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.716, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.962, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Fam Zheng , qemu-block@nongnu.org, qemu-devel@nongnu.org, Hanna Reitz , Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 13/12/2021 15:52, Stefan Hajnoczi wrote: > Off-topic: I don't understand the difference between the effects of > bdrv_drained_begin() and bdrv_subtree_drained_begin(). Both call > aio_disable_external(aio_context) and aio_poll(). bdrv_drained_begin() > only polls parents and itself, while bdrv_subtree_drained_begin() also > polls children. But why does that distinction matter? I wouldn't know > when to use one over the other. Good point. Now I am wondering the same, so it would be great if anyone could clarify it. Emanuele