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 C8DAF18BC38 for ; Mon, 26 Aug 2024 18:32:04 +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=1724697124; cv=none; b=NptsGy0llU5OXWjQ7R53gBlc/mlyHLypFP0nR7ZrGxLHo6IYENqCWfcXRMhaQ9mW+WDGboxjq2T3nstU2rydR+6KJ3uOZTQTBifYJVXEpTYfKSR1QmiswT5kVbcCcA55Haq86OPTAI0tMb7VSuWm/Yu5IZ5RLWt37P3UayPv728= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724697124; c=relaxed/simple; bh=vc0JmngRsZKXBHdkhwWGWQ6Qprj+zKH/xMHH2tqTvc8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Ax3jNOuBXqwvvWCG5zKpX4z9ibZAOsGRK/bKJM9/bcZKJvOdP1ytundF57i0CXfLcDgWDDGhYMQ0TNX/p92F764fuqwlUY4hCNYLfyIRCPVV1cnTkr50fZvuOjDCo7ZyLAoMcsgRsDzEt2WmTbTWdEBwgbeMMr3l359g2OG/DZ0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BcxbJS2X; 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="BcxbJS2X" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F17CC8B7C9; Mon, 26 Aug 2024 18:32:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1724697124; bh=vc0JmngRsZKXBHdkhwWGWQ6Qprj+zKH/xMHH2tqTvc8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=BcxbJS2XzALYp++nfpwj0T1C7pW7jZqHx6koBHZUqEqov+2iU2vaz6yRRtGFqrjnF SdH2b6JCL0Ms+BXZrAKNRlIMEmUyWbCEV9Y6FXIqnLRvwFxVKlNb2oWfxTfnxcY4e4 Djm28TPDKTleuzIo2Th94Qs7DDSphnqyMg8wcENDNRFoIf1Ben3TNvFeoAI5zpsVXZ KEloq/N5+CRVtTDUtSYP3ce5eDsB1uBV3J6SpnUuKFTEjdD0YTG7kRxJhMQYcI1De5 o73KS/WbriLhtVV4fow0LLASaF8GaBFXICO/tvtxXsh4bC6LXVa6s6U6kLQXeZOTr2 80lNKXVHurstw== Date: Mon, 26 Aug 2024 08:32:03 -1000 From: Tejun Heo To: Aboorva Devarajan Cc: void@manifault.com, linux-kernel@vger.kernel.org Subject: Re: [sched_ext/for-6.11]: Issue with BPF Scheduler during CPU Hotplug Message-ID: References: <8cd0ec0c4c7c1bc0119e61fbef0bee9d5e24022d.camel@linux.ibm.com> <3da12c96daecaa055c478816f5e86c7b44a04d53.camel@linux.ibm.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: <3da12c96daecaa055c478816f5e86c7b44a04d53.camel@linux.ibm.com> Hello, On Fri, Aug 23, 2024 at 02:50:01PM +0530, Aboorva Devarajan wrote: ... > I applied this patch to the almost latest sched-ext (for-6.12) branch upto > commit 89909296a51e792 ("sched_ext: Don't use double locking to migrate > tasks across CPUs") and let the test run for over 20 hours, and it completed > without any hangs on both x86 and PowerPC. > > So, indeed, making sure that both scx_fork_rwsem and cpu_hotplug_lock (read) > are only held together simulataneously when they can both be acquired seems > to be resolving the deadlock. Thanks a lot for confirming. Let me think it over a bit re. what should be applied. Thanks. -- tejun