From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 009.lax.mailroute.net (009.lax.mailroute.net [199.89.1.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7469A35940; Mon, 9 Dec 2024 18:15:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=199.89.1.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733768156; cv=none; b=aFQiIVT9iNLY8NeEjnwVubVCqjoV5nH5TKV4KR6M7P65MLgknTpxqWgV74F67vyyr6WuJXWM3bTrSQ+7q9LcIPmvTvGwJwwAyaBgPlLfdMbGzajePPmFLJRqsv3w44MOG0G+7+yvguE6tWz93jquYiLXZAiOS5xmrYK/whDx0vY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733768156; c=relaxed/simple; bh=+VNaXCdCBUo8fhtWnSkUoEHA3l1GNctqMXNx4aGLi8Y=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Et+R1bb8Su9p6VzVWgdwM9XVr4TpBkEZZAHDto7zN/Kpstyxh77e7wkf2BhYe0M4QuYqSMhkso8Vh+nolp6l1zdWYkIXQrBoq5GpkTXW641t2y5gFT9B9N2IUuzwUGUpvmJYYPwTECm75o+E9mUUMTEJVXOnd0enBWwzKMSAREM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org; spf=pass smtp.mailfrom=acm.org; dkim=pass (2048-bit key) header.d=acm.org header.i=@acm.org header.b=OvG1zj3y; arc=none smtp.client-ip=199.89.1.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=acm.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=acm.org header.i=@acm.org header.b="OvG1zj3y" Received: from localhost (localhost [127.0.0.1]) by 009.lax.mailroute.net (Postfix) with ESMTP id 4Y6VLt4w3zzlfflY; Mon, 9 Dec 2024 18:12:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=acm.org; h= content-transfer-encoding:content-type:content-type:in-reply-to :from:from:content-language:references:subject:subject :user-agent:mime-version:date:date:message-id:received:received; s=mr01; t=1733767922; x=1736359923; bh=XbavAQT2tBD2N+OkH44rTIHU HOUIf131SRpW4H9G6FU=; b=OvG1zj3yKFBbYeIZ9j8he6IvAsj/VekkQ5ILAncq sLJnLVNmkrqzVCuPfp2hhVM1TR2IRjTwSyYkLmgH6K9AOsvf2DTSzH80vamGk4xM s8WUM89nhXayBB+9HVkaCYHSSdkcbaoQvj65SJbw+0HBRivsSI/RlxbeKfbg/VbF Pii3izARckdqeC3cdUkl4dHN7GEQAYrf3P3pDCTnG6iwA6PydSaM17txTn6QgPLK jpHyyPdpnaMpiYrGRv/RwSvhL7csJhHmyA4d/TkXM6XH7dQbX3OFccnZFgYgbhnU UyxSkfdo8xNa3fvTwZch5dsHnVEEV2YVRCn/c3p8tVMQug== X-Virus-Scanned: by MailRoute Received: from 009.lax.mailroute.net ([127.0.0.1]) by localhost (009.lax [127.0.0.1]) (mroute_mailscanner, port 10029) with LMTP id G_7sSOhAz231; Mon, 9 Dec 2024 18:12:02 +0000 (UTC) Received: from [192.168.50.14] (c-73-231-117-72.hsd1.ca.comcast.net [73.231.117.72]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bvanassche@acm.org) by 009.lax.mailroute.net (Postfix) with ESMTPSA id 4Y6VLh2NrQzlfflB; Mon, 9 Dec 2024 18:11:55 +0000 (UTC) Message-ID: <3e401555-e971-44c2-b9a4-5c746baaca8a@acm.org> Date: Mon, 9 Dec 2024 10:11:54 -0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC 3/3] lib/sbitmap: fix shallow_depth tag allocation To: Yu Kuai , axboe@kernel.dk, akpm@linux-foundation.org, yang.yang@vivo.com, ming.lei@redhat.com, yukuai3@huawei.com, osandov@fb.com, paolo.valente@linaro.org Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yi.zhang@huawei.com, yangerkun@huawei.com References: <20241209115522.3741093-1-yukuai1@huaweicloud.com> <20241209115522.3741093-4-yukuai1@huaweicloud.com> Content-Language: en-US From: Bart Van Assche In-Reply-To: <20241209115522.3741093-4-yukuai1@huaweicloud.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 12/9/24 7:55 PM, Yu Kuai wrote: > From: Yu Kuai > > Currently, shallow_depth is used by bfq, kyber and mq-deadline, they both > pass in the value for the whole sbitmap, while sbitmap treate the value > for just one word. Which means, shallow_depth never work as expected, > and there really is no such functional tests to covert it. treate -> treats The above text is incorrect. I have verified that shallow_depth restricts the queue depth of asynchronous requests for mq-deadline if it is reduced from its default value. The function dd_word_to_depth() in mq-deadline converts the value written into the sysfs attribute into a value that is appropriate for the sbitmap implementation. That being said, it seems like a good idea to me to modify how the sbitmap code interprets 'shallow_depth'. Thanks, Bart.