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 758E8322C73; Tue, 10 Feb 2026 23:54:40 +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=1770767680; cv=none; b=s+WlKpUvikt5h/NVl7YVorb4kkyXwiCT/9CpwObQd7YthNj6y/QxV10pvGqLFl1fCIjRFVhG/lxSghPzSRB6LDxBIhZBhmFfwmWyxiiljkPFeqghYr7Zug7IHuTD+kSxSydkdy7PzHStboP0g5ZOAkwoxEivJLZKEPO5DM6seCw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770767680; c=relaxed/simple; bh=Mr+wFX9eNldoiIQyoF7xkBtFIRX1Gg/MG23I+GZ3NtM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=gXXTLJkQH5LCMqXibFI1Jybn2JhODmXcGT/nIyAyhwHjGaKlZV/tXKun1UbrOZqa0UpC+5sIS2olf6zjQ2FHljsPK+3kA4YJF8AnvIKK982CTttPIb3EMcwWytnV9w1JpoKRiMxO7ev+YdZteGjvOxFool0a28Cc/jXOQwV3Klc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pYKqTRlH; 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="pYKqTRlH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E53D4C116C6; Tue, 10 Feb 2026 23:54:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770767680; bh=Mr+wFX9eNldoiIQyoF7xkBtFIRX1Gg/MG23I+GZ3NtM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pYKqTRlHCjjM1sCjRWoA1Eapv5WXDw8kaup5uxjnKpewDNuM1mKH1VjnYUJqP4ub5 rRmqVCD9U+/vh8mis/Ub8pWruhBH3Wrfpb0Ge+5pwm/drVFZVutGxCj7s1Yx1TlObX 5PjGJNnRLxsnbCTv2HaWN3OvDPf6+vYph4VCpKgcdg/NUHqeSguh7/BvMGGNNFlB1E e5osO/FWft77IbI0CmrDt7zofBLJiXiwYuz2wkXSbK1gMJNHB+6ar1bujeat5PTPJU K/38g8vu2JQKCn6/tArdJrc1rscO5H6Jf2Q2G72J1LuSTGbi1ko05vipfEsMPUUPsp kG4vYee+Pkesg== Date: Tue, 10 Feb 2026 13:54:39 -1000 From: Tejun Heo To: Andrea Righi Cc: David Vernet , Changwoo Min , Kuba Piecuch , Emil Tsalapatis , Christian Loehle , Daniel Hodges , sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] sched_ext: Fix ops.dequeue() semantics Message-ID: References: <20260210212813.796548-1-arighi@nvidia.com> <20260210212813.796548-2-arighi@nvidia.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260210212813.796548-2-arighi@nvidia.com> One more comment. On Tue, Feb 10, 2026 at 10:26:04PM +0100, Andrea Righi wrote: > @@ -1407,13 +1446,19 @@ static void do_enqueue_task(struct rq *rq, struct task_struct *p, u64 enq_flags, > * dequeue may be waiting. The store_release matches their load_acquire. > */ > atomic_long_set_release(&p->scx.ops_state, SCX_OPSS_QUEUED | qseq); > + > + /* > + * Task is now in BPF scheduler's custody. Set %SCX_TASK_IN_CUSTODY > + * so ops.dequeue() is called when it leaves custody. > + */ > + p->scx.flags |= SCX_TASK_IN_CUSTODY; As this is protected by task's rq lock, doing it here is okay but can you move this above atomic_long_set_release()? That's conceptually more straightforward as that set_release() is supposed to be the "I'm done with this task" point. Thanks. -- tejun