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([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id r24sm8736441edw.11.2021.03.09.02.49.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 09 Mar 2021 02:49:13 -0800 (PST) Subject: Re: [RFC PATCH 3/4] coroutine/mutex: Store the coroutine in the CoWaitRecord only once To: David Edmondson , qemu-devel@nongnu.org References: <20210309102157.365356-1-david.edmondson@oracle.com> <20210309102157.365356-4-david.edmondson@oracle.com> From: Paolo Bonzini Message-ID: <0fe082d7-acb4-a9a2-8a50-0448b32ecf11@redhat.com> Date: Tue, 9 Mar 2021 11:49:11 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <20210309102157.365356-4-david.edmondson@oracle.com> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=pbonzini@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.251, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Stefan Weil , Stefan Hajnoczi , qemu-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 09/03/21 11:21, David Edmondson wrote: > When taking the slow path for mutex acquisition, set the coroutine > value in the CoWaitRecord in push_waiter(), rather than both there and > in the caller. > > Signed-off-by: David Edmondson > --- > util/qemu-coroutine-lock.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c > index 5816bf8900..eb73cf11dc 100644 > --- a/util/qemu-coroutine-lock.c > +++ b/util/qemu-coroutine-lock.c > @@ -204,7 +204,6 @@ static void coroutine_fn qemu_co_mutex_lock_slowpath(AioContext *ctx, > unsigned old_handoff; > > trace_qemu_co_mutex_lock_entry(mutex, self); > - w.co = self; > push_waiter(mutex, &w); > > /* This is the "Responsibility Hand-Off" protocol; a lock() picks from > Reviewed-by: Paolo Bonzini