From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (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 2929525A33F for ; Mon, 12 Jan 2026 14:32:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768228342; cv=none; b=oGHzwLSMLiSxzgvqkYx6/OQkBG4ZKpesoZCErSgw3gEzyx+n3ClnmKMiYN/BNOK9Z3x005cWSIc0KW5wF+44tkct3nenHlEQPhPD2EjopSp6uD33HOwslDlnYbCll0NIFgJI+nQrOF5xBQw9Do3SEexaBt9QY2JLTdovnOHla7o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768228342; c=relaxed/simple; bh=uro4ci5FzVrVQ55dxJ+vgU0LSvy23xZoIkKdMjaSs0k=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=LHPgvhwjqlU5DyFbRU+VDoUaBBWMl/JIHQ+DKpUvuQ/ToQIfrzyyHuA60ywbxDGZZwqZLzGrtc5879a4RWhLGjo3oNi3qWKSxQ4MTL4I8xct4TtlJdHgtcQkQJ3a7+QFiMfNcZSs5X2AL13gqN8C3csRNRBQa8piTwArH57ixbI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=h-partners.com; spf=pass smtp.mailfrom=h-partners.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=h-partners.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=h-partners.com Received: from mail.maildlp.com (unknown [172.18.224.150]) by frasgout.his.huawei.com (SkyGuard) with ESMTPS id 4dqZZm4ycNzHnGch; Mon, 12 Jan 2026 22:32:00 +0800 (CST) Received: from mscpeml500003.china.huawei.com (unknown [7.188.49.51]) by mail.maildlp.com (Postfix) with ESMTPS id CB88A4056B; Mon, 12 Jan 2026 22:32:16 +0800 (CST) Received: from [10.123.123.67] (10.123.123.67) by mscpeml500003.china.huawei.com (7.188.49.51) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Mon, 12 Jan 2026 17:32:13 +0300 Message-ID: Date: Mon, 12 Jan 2026 17:32:10 +0300 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: [RFC PATCH 0/2] mm: improve folio refcount scalability To: Kiryl Shutsemau CC: , , , , , , , , , , , , , , , , , , , , , , , , References: Content-Language: en-US From: Gladyshev Ilya In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: lhrpeml500010.china.huawei.com (7.191.174.240) To mscpeml500003.china.huawei.com (7.188.49.51) On 1/12/2026 2:49 PM, Kiryl Shutsemau wrote: > On Mon, Jan 12, 2026 at 11:30:38AM +0300, Gladyshev Ilya wrote: >> Gentle ping on this proposal > > I generally like the idea, but I would like to hear from folks who > actually understand serialization. > > Also, do you have number for "a full CAS loop when the counter is > approaching overflow" thing? > I am not sure that overflow is a real problem because you need a very specific race condition over a long time to achieve it... But as a safeguard, everything lower than 2^31 - #max concurrent accesses (~#num cpu) should work, so let's say 2^30