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([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.googlemail.com with ESMTPSA id f15sm3813914wrd.45.2022.01.19.01.51.23 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 19 Jan 2022 01:51:24 -0800 (PST) Message-ID: Date: Wed, 19 Jan 2022 10:51:23 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.0 Subject: Re: [PATCH 00/12] Removal of Aiocontext lock through drains: protect bdrv_replace_child_noperm. Content-Language: en-US To: Emanuele Giuseppe Esposito , qemu-block@nongnu.org References: <20220118162738.1366281-1-eesposit@redhat.com> From: Paolo Bonzini In-Reply-To: <20220118162738.1366281-1-eesposit@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Host-Lookup-Failed: Reverse DNS lookup failed for 2a00:1450:4864:20::332 (failed) Received-SPF: pass client-ip=2a00:1450:4864:20::332; envelope-from=paolo.bonzini@gmail.com; helo=mail-wm1-x332.google.com X-Spam_score_int: -6 X-Spam_score: -0.7 X-Spam_bar: / X-Spam_report: (-0.7 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FORGED_FROMDOMAIN=0.249, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=0.248, NICE_REPLY_A=-0.001, PDS_HP_HELO_NORDNS=0.001, RCVD_IN_DNSWL_NONE=-0.0001, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no 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 , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, Hanna Reitz , Stefan Hajnoczi , John Snow Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 1/18/22 17:27, Emanuele Giuseppe Esposito wrote: > * Finally fully enable assert_bdrv_graph_writable(), checking also for the > drains, in patch 11. Wow, this is definitely not just moving code around! It's great that you could pull this off. It gives me a lot more confidence that the locking model and the graph/IO split are correct, and also a lot more confidence about the logic to move the drains back and forth. It does add a lot more complication to the API with all the _unlocked variants, but I think we're getting closer and closer to the endgame for the AioContext lock. Paolo