From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C3271511E64; Mon, 7 Sep 2026 16:09:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788797357; cv=none; b=T8GiO42BOgKeg51r0Oal0+arnGwrjvp7TuaaBlT+F2EpxQjCxx6mHtrPcFB7uDZNpGtidjJjeyt26fcq2Ge3OsoJ/P440s7NCphEekD88PKAv/orErE4Fe+Gs36OU9W6VrN0PhtgVq7CS0CDINNHKkNDF86JIsvvzp1a6eF0TDQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788797357; c=relaxed/simple; bh=FQk1qflooDTc9IyeYbUP6lJJEX0Q/x/3M++RyKRSDyY=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=ryyPpoesURYSPLdMcaN8nH5spk18EfQd1GRccW0lBJh+ugRA6QNi3jNIHVVadpVbN31+rT1WBwhI+lVHM4QE8pBOTZXMyd+3sCfRJclFsWJsWGiMRd8pinmJOjJaNjGBShjuTLTdIhaDCMNlJXttQB29oetwg/Rhhhk0b1THQDg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cEiQkVdU; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cEiQkVdU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ADF0D1F00A3A; Mon, 7 Sep 2026 16:09:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788797354; bh=O21OXkT+CO7kqHAIkqKNXoWsWUnuD40f1pEYCtLNhCo=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=cEiQkVdU3k2uimP58cQap5UFd+2E9hqvHmiPVuJwfNEU5UvTqgMzyHYZsn0UDnwab kN0BhXkeg/iHcOkcZ+sGQ2fFUTx1H4HDhOnoVlwPbuMCdPnJA8hoRu7PhWwY+qnZCU y6Xumq4PL1Rf8qukmZ8FWTbF8FmtdwkktGy/Bprd5czk3PV1JURDY4HBqSuhzpzxcQ zK0vuKOEB+FdeQU39MmAfxvLDEgpWTvj0yLMjlTE2eabdO+Wa32GCz18B850nplZid qmfDpn7XgByUQok2hEInOTRaMsLh23W1crnCVhGv8yaB8rP1KfXd+Ud+w6ZnpR6gAB Qn3rXNpNPjfeA== From: Thomas Gleixner To: Alice Ryhl Cc: Dmitry Ilvokhin , Mathieu Desnoyers , Peter Zijlstra , "Paul E. McKenney" , Boqun Feng , Dmitry Vyukov , Jonathan Corbet , Shuah Khan , Randy Dunlap , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, "Paul E. McKenney" Subject: Re: [PATCH] rseq: defer time slice extension yield for sys_futex_wakey In-Reply-To: References: <20260831-sys-futex-wake-time-slice-v1-1-814bb95cc339@google.com> <87ld9ha8wu.ffs@fw13> <87cxur5ux4.ffs@fw13> Date: Mon, 07 Sep 2026 18:09:11 +0200 Message-ID: <87fqzl2gd4.ffs@fw13> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Mon, Sep 07 2026 at 13:21, Alice Ryhl wrote: > On Sat, Sep 05, 2026 at 10:01:59PM +0200, Thomas Gleixner wrote: >> What is the actual problem you are trying to solve? > > Basically in Tokio we have a bunch of critical regions that look like > this: > > mutex_lock(); > list_add_tail(&my_list, new_item); > mutex_unlock(); > > and this: > > mutex_lock(); > next_job = list_first_entry(&my_list); > list_del(&next_job); > mutex_unlock(); > > except in Rust. > > People are reporting bugs to me saying that this particular list in > Tokio is causing significant contention for real-world workloads in > production. The context here is backend/web servers. > > Thus, I am looking at various solutions to improving contention here. Have you looked at lockless lists or queues? The above use case looks more like a queue than a list. I'm sure there is some Rust implementation by now. Thanks, tglx