From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 3327C37AA92 for ; Sun, 10 May 2026 14:02:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778421755; cv=none; b=HZifxFHDfuesdEFCwct5wOgugIMTKd2V31gYczIoDIc6GygY1e9es1SRQ3lseRBR+KGhxxEpaYa+S2mGlvIUhMHkcTeKLRbUqmmuapqMsiXJSQvY+0m2w6ftJip6gndVchhSIhzf+wPKpkhIK94imVTPtedT+pHcqB9gfWV5HWU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778421755; c=relaxed/simple; bh=7Sf0D//qh0TXbgQFOYzbkNGB7dW0WFvf28k2a9ijlTc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=lW071iv6z8af/5npnRt8QOP17wimxCvzTbpH/H1D3NloM/iA644pHuIoO/0mPW9mVWpQG1s7bWvIUzMRsW4o/97A3Q0cnqAkN3HhT7lmLUAzFfXaRADuJeJSyRylki8R6wQ4aFOjyjUxjHPn2qSzCOxOOZ2vews/nkn3wW3DYkE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OWIDq373; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OWIDq373" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B6590C2BCB8; Sun, 10 May 2026 14:02:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778421754; bh=7Sf0D//qh0TXbgQFOYzbkNGB7dW0WFvf28k2a9ijlTc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=OWIDq373jaqYdSXxzHILaNVJ1qlj1P1z1h+OUI4qdThyP1kyKN6uSUTQYyOL/eeQO 1gml1A9neV9lmxO8Ib9MfZgcPLfUmWcPK5JGMuAYDr4D32h80tRxMjTAP1KXLi+t8L 4omumq7XTOO20FbkJ9VI2VSlwHjtQP5HZHxbaQXoEXtS8vCyU6Sj8A6opLL/z2A3Zr 9K0iUgxrexDfW0ZJiDIrw8r/yiKRgvS6kl6HfcDIeqvShT/czFod+vaYsPDwxdWIt2 F5U8OwqWe0snVCjUvFRxV0nh1YILG7UE1COGt+Xxwobp+U5DS9VBKXziH5SMEp3lw6 k50LcDsSWcuIA== Date: Sun, 10 May 2026 04:02:33 -1000 From: Tejun Heo To: Andrea Righi Cc: Cheng-Yang Chou , sched-ext@lists.linux.dev, David Vernet , Changwoo Min , Kuba Piecuch , Ching-Chun Huang , Chia-Ping Tsai Subject: Re: [PATCH v3 1/2] sched_ext: Add dispatch transaction API Message-ID: References: <20260509191223.168648-1-yphbchou0911@gmail.com> <20260509191223.168648-2-yphbchou0911@gmail.com> Precedence: bulk X-Mailing-List: sched-ext@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Hello, On Sat, May 09, 2026 at 11:24:12PM +0200, Andrea Righi wrote: > Why not passing slice to scx_bpf_dsq_insert_commit()? Is it because of the BPF > args limitation? In that case we could introduce a struct similar to > scx_bpf_dsq_insert_vtime_args. > > Speaking of vtime, we may also need a scx_bpf_dsq_insert_vtime_commit() that > accepts dsq_vtime as well, otherwise how do we use priority DSQs with this new > transaction variant? Given that these are only meaningful when targeting local DSQs, I don't think vtime interface is necessary. It'd probably be a good idea to explicitly restrict usage to local DSQs. > > To support explicit token passing, rename scx_dsq_insert_commit() to > > scx_dsq_insert_buf() and add a qseq parameter. All existing callers > > preserve the original behavior. > > > > This mechanism is intended for schedulers that do not implement > > properly synchronized dequeue. A scheduler whose ops.dequeue() > > synchronizes atomically with the dispatch path does not need this API. > > I'm wondering if we should validate qseq also in mark_direct_dispatch(), it > seems that we're not validating qseq in the direct dispatch path, or am I > missing something? In DD path, the task can't be lost and it'd be a bit silly to use this interface. Again, probably good idea to at least start with just allowing in dispatch path. Thanks. -- tejun