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 9838E1A9F82; Mon, 11 Aug 2025 15:52:59 +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=1754927579; cv=none; b=F+cAnkP+fitdEjzCxjZ7wegfNLXsFCXHU2myPjLlV6cQ24P3gqnZx37sDEzawiYygjzXEe8COhI+BJYr/M2L+qvZ/KRLDi4iszVy9ntkZI82wbTIutLTjbZzv1ZQghwFubI2sbezao2sR2Pld21AgFcdc3ivgaKFxPQnAqmMmYg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754927579; c=relaxed/simple; bh=rMAHxsfqve86pCW8MJDJEH5uaWy14+2/Iq+hyWRBEUs=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=NIB654bZXKDTBATPaGA8/v0OxE59FhsfiQB/wvpXUumuaiZUOKHMxDdFE08piBTnlMgZkKQSBxwpHDJZgqxorOyQ9y687wp3K7yiGNhN2IDjO3/rpFkFBPY6k9opT5zb8+t8ebJ7syjy4I6tSB67s1Bo+jZaDnmmEuWxlZMMRWU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OOUCdw7L; 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="OOUCdw7L" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5690C4CEED; Mon, 11 Aug 2025 15:52:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754927579; bh=rMAHxsfqve86pCW8MJDJEH5uaWy14+2/Iq+hyWRBEUs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=OOUCdw7LbqNkf7g5Y1hq0i0sPm09zLZ2pYuVG0L4uBDskjAf17FRBJLkI/Y9t5lUd EKqeYDEwsDHKCZ2Hic9gmj+qbeuvpfDtW9dsvMqrpYiF5a5wDBWoB2q78lqDZmJ79K 3FZNyxD29rJ3cplNz3W8hoxmpgR5fXQzAcxtEIVjyvgU8zevPqL4ciBtyjfWWo16yl pZ5HeOf15EpYlnCcZQaP5fWCuDBvnMcXe8TA/rSh3njcUbjRreMRBRyzvNiLaCZkZ6 rp9TvDB/UQn515sdg4gBCnUdw/3QHtoDx7S1WuV0dbja7rvHMVBkKMeBfHfAFn0YA9 SKpA6+QgUamuw== Date: Mon, 11 Aug 2025 08:52:58 -0700 From: Jakub Kicinski To: Joe Damato Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, andrew+netdev@lunn.ch, horms@kernel.org, willemdebruijn.kernel@gmail.com, skhawaja@google.com, sdf@fomichev.me, shuah@kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH net v2 0/3] net: prevent deadlocks and mis-configuration with per-NAPI threaded config Message-ID: <20250811085258.4b6cfa79@kernel.org> In-Reply-To: References: <20250809001205.1147153-1-kuba@kernel.org> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Sat, 9 Aug 2025 18:59:27 -0700 Joe Damato wrote: > On Fri, Aug 08, 2025 at 05:12:02PM -0700, Jakub Kicinski wrote: > > Running the test added with a recent fix on a driver with persistent > > NAPI config leads to a deadlock. The deadlock is fixed by patch 3, > > patch 2 is I think a more fundamental problem with the way we > > implemented the config. > > > > I hope the fix makes sense, my own thinking is definitely colored > > by my preference (IOW how the per-queue config RFC was implemented). > > Maybe it's too late now, but I am open to revisiting how the whole per-queue > NAPI config works after a conversation we had a couple months ago (IIRC ?). > > I think you had proposed something that made sense to me at the time (although > I can't recall what that was or what thread that was in). FWIW the discussion was whether setting things at the device level should override all the per-NAPI settings, or should we treat the device level as lower priority and only apply it if user didn't set per-NAPI override. I guess it doesn't make a huge difference, other than that resetting the unused NAPIs to "unset" would remove the need for patch 2.