From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f46.google.com (mail-ej1-f46.google.com [209.85.218.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D7000132117 for ; Mon, 14 Oct 2024 11:10:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.46 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728904220; cv=none; b=aMXgXuW5TpEMmWHRWqq64lOslidv7FljWLkfMiPC6RvbcuwsveG7+EFSAs+rXGH/k3S+4Dzxul9Ty48I4ninbVJgy/1Owj/SIPi9jojEn45chzhvyDkpZSo+aSs7Go/RgiC/oWMzGpOt2ltkcf46EyYO+0QoB87TAj4yKVq4APc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728904220; c=relaxed/simple; bh=X7hdAnDBRiFsp9pbNfm20bLF2XQDquP+h05zZKrsk84=; h=MIME-Version:References:In-Reply-To:From:Date:Message-ID:Subject: To:Cc:Content-Type; b=nXkiHgvBdBkuwcj++UMZ18H5c+XxxBzziZikFUKXlWCx4raX3jhkB6Wiz/s2vI7FcOrI/QS7Y2qwAh3b6UqaiO5sKeqHjTfofIzCycEnUKVK7i/Cp18iRVWVmlwDjxccHiWbeWek8PyZ7BW9gCc1mWOJ8Cl62zN/+CNyB4KCgnA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=szeredi.hu; spf=pass smtp.mailfrom=szeredi.hu; dkim=pass (1024-bit key) header.d=szeredi.hu header.i=@szeredi.hu header.b=PZTH+pTC; arc=none smtp.client-ip=209.85.218.46 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=szeredi.hu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=szeredi.hu Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=szeredi.hu header.i=@szeredi.hu header.b="PZTH+pTC" Received: by mail-ej1-f46.google.com with SMTP id a640c23a62f3a-a9a16b310f5so64816666b.0 for ; Mon, 14 Oct 2024 04:10:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=szeredi.hu; s=google; t=1728904216; x=1729509016; darn=vger.kernel.org; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=6wbDQEArnf1ZdmErEiHxbx7TqihEustaC3F8orDhSIE=; b=PZTH+pTCej4ccopCdH3z7Ob62ToJR5ptIHxW+GjNhPSSzvfbhMtosVwD/1OIJfrEc8 V74vHR/GgKm8GQwFFYTxfNO1JC2b/2nZWuxiSwR8Qmeb7DQA21ptQcdA9Zl5bcHgvqZB 6Lrb58Qm9EnzXK1XiMRJb3Mz5t9JDcZy+2bDg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1728904216; x=1729509016; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=6wbDQEArnf1ZdmErEiHxbx7TqihEustaC3F8orDhSIE=; b=KRwXGN+nvcaeeJOvfFtOLypaOSZKuUsM49+uw2WcLG8hnps6dFt2S3fgQPBotOs0Z/ qbaYw6QTZHYUUVtHTGLbk+xLRQ4eZ+Md6GOTmQxejC/0zzZvzBj1GJzgYVavjtfAYXjb MhF0FTA3CJVzm0RzWbpGUj6Q8fxXeE+mEeEKP613QkjXsVR+W3M43KrpJQHGYfs/FDwe GgHER1blSkKCqABtBvbbO2HR97GmWcAcOYLp1RKopsu4tSk+kIA0Fqnw47Q01nEJOJh4 dLCnSToIE77ZngEY7hUMAnQkH08H5MLVKOfVA0qn1JDdVa51EPgOgYNrfabpFw7UvSTW bxsQ== X-Forwarded-Encrypted: i=1; AJvYcCVf9b5bzbhwDKU2XHeb8IE6xMghJIN6QAQ8hQ0LN1cipDUek21Ha1JEVfnYpniwudoe29/S9dQi1g==@vger.kernel.org X-Gm-Message-State: AOJu0YwCNuEZxAej3u/S1msGdHgWb1GVPS2aBn6MB1AUkVo07fJPYKPC 8qkzAi968PXVJPLASZPwZ9VGDzXWb9lUPyl5qlOR8ElPANUB2t58JQitDy25tUALaWkcBMwjo3B adFsF/q/JMcE/2RmMmnz9D3g7kBl9LY4qN5gBkg== X-Google-Smtp-Source: AGHT+IFAyxM0Dt6COqUymhWCRvHXs1qGGQcy/B4h6XwURk+SCiv6QGQD0USpvcL7z7VI7PcJJpRRSLNh4p9aFeHqQZ0= X-Received: by 2002:a17:906:c14b:b0:a99:625d:22a6 with SMTP id a640c23a62f3a-a99b970bbc7mr957933866b.55.1728904215575; Mon, 14 Oct 2024 04:10:15 -0700 (PDT) Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <2fe2a3d3-4720-4d33-871e-5408ba44a543@fastmail.fm> In-Reply-To: From: Miklos Szeredi Date: Mon, 14 Oct 2024 13:10:03 +0200 Message-ID: Subject: Re: Large CQE for fuse headers To: Ming Lei Cc: Bernd Schubert , Jens Axboe , io-uring@vger.kernel.org, Pavel Begunkov , Joanne Koong , Josef Bacik Content-Type: text/plain; charset="UTF-8" On Mon, 14 Oct 2024 at 04:44, Ming Lei wrote: > It also depends on how fuse user code consumes the big CQE payload, if > fuse header needs to keep in memory a bit long, you may have to copy it > somewhere for post-processing since io_uring(kernel) needs CQE to be > returned back asap. Yes. I'm not quite sure how the libfuse interface will work to accommodate this. Currently if the server needs to delay the processing of a request it would have to copy all arguments, since validity will not be guaranteed after the callback returns. With the io_uring infrastructure the headers would need to be copied, but the data buffer would be per-request and would not need copying. This is relaxing a requirement so existing servers would continue to work fine, but would not be able to take full advantage of the multi-buffer design. Bernd do you have an idea how this would work? Thanks, Miklos