From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792547603; b=FNvgTifgHpQGnRNyhid1ZGzrQF2KPOHVqL/JiYsfOzM5cLYxRJm/aWR2i4jFSPkltAg1 oKP2OIDUH4oW73+Sprd6seEU2jBVAgry1Aw7WPrfRNUNDyTjgXL2HGnDoZukviCA85qmJ AZhBiWANiMEoig/N2jHMKA2TfTzFvJtNd/A/Bi2pmTCRevGTc0zZRW/Ngln74lPTI5yoy fy5KLfGFzVwinLzMoZ3jjP8f/thO6j0Ltp1fJFgw/lbHfV/xpimDmDywLF2O60roz/2qp bpGSir0ZoDBT+Ly+9PdekfhIRt0i6FibIWlya2+1+sseW1XSH0X1G/HS34a6I6mMGKA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792547603; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: In-Reply-To:References:MIME-Version:Content-Type: Content-Transfer-Encoding; bh=0zaTOm2gabGZSGcUZLYd973mBB0BoYe5ql4/IuZHCDg=; b=w4snHTRPR6JsG2r/4xC3NjZQOOhJpc3qJLxwC195YBoN3sDBe4b9+4azl2TmXZlTq9Io W07Y6vhzzWR8w0/ALnaV5EP1Hg6lwHtfXfjcr8WajYeQjNp6fa9ETvFC7MZNVsQ1q2gzJ MT9sZRymuKQhZnNZx446aEVSKcQXfbf+14BXGyCDma+29JldYBqwyLWTpnLiqPfdm0P4G x4PFxGCXIOswpB3nJRNgcYZzwWrQcTDt2olwrfCanXUBiV55AYXvfustRPvcsrhyjHNLp zOeCYzuIcf2uvbgvn6ESb5Ej/0ndXeIEnz3zu+OLpmYrFdEULoTLBkjqndmULhtFzwA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=SAdqq4CI; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 571C1606A31B; Wed, 21 Oct 2026 01:53:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=SAdqq4CI Received: by smtp.kernel.org (Postfix) with ESMTPSA id A93991F000C9; Wed, 21 Oct 2026 01:53:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792547603; bh=0zaTOm2gabGZSGcUZLYd973mBB0BoYe5ql4/IuZHCDg=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=SAdqq4CIHbITapplM4OVDYtuAVJtNhGsum0nw7HoitCnFuscBQc7xcaNacQJJ0pOt KL6pkU25Lgr0NAalo9CkLyBhVdATGfIXeqXQQ165ZtdVkBebJmSVd41s5zfyMcC9/T EEQoOE9AVwtmnVFosn+7dsSLlm2jUmJeuIquhwk4NdGmqvc00s5AfY1rTuGDept2i0 9y+P3axukuoFHe0b9chRcg2vEZPArrpgXgm5LI3I8Cb3aWK7O6eunuVey2jeCa6jdE xRFRu8K9+NLUPSLVvFXzIQsMqFOv9sZ+7H7TuAK1JnjihNK19IHNh/5MrRV/k2a7wF MlW034BXHl/CA== Date: Tue, 20 Oct 2026 18:53:22 -0700 From: Jakub Kicinski To: Vlad Poenaru Cc: netdev@vger.kernel.org, Jamal Hadi Salim , Jiri Pirko , "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Peter Zijlstra , Ingo Molnar , Will Deacon , Boqun Feng , Waiman Long , Bart Van Assche , Davide Caratti , Breno Leitao , Nilay Shroff , linux-kernel@vger.kernel.org, Vlad Poenaru Subject: Re: [PATCH net-next 0/2] net/sched: don't wait for RCU when destroying qdisc lockdep keys Message-ID: <20261020185322.4297d962@kernel.org> In-Reply-To: <20261019170225.729789-1-vlad.wing@gmail.com> References: <20261019170225.729789-1-vlad.wing@gmail.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 19 Oct 2026 10:02:23 -0700 Vlad Poenaru wrote: > On kernels with CONFIG_PROVE_LOCKING, every qdisc except ingress, clsact > and noqueue has a dynamic lockdep key, and destroying the qdisc calls > lockdep_unregister_key(), which waits for an expedited RCU grace period. > Replacing an mq root destroys one qdisc per TX queue under RTNL, so a > single "tc qdisc replace dev eth0 root mq" waits for that many grace > periods. Commit 7a3cedafccf8 ("lockdep: Speed up lockdep_unregister_key() > with expedited RCU synchronization") made each wait shorter as a > temporary workaround until hazard pointers are available. ## Form letter - net-next-closed The merge window for Linux v7.4 has begun, and the net-next tree is now closed for new drivers, features, code refactoring and optimizations. We are currently accepting bug fixes only. Please repost when net-next reopens. There is some uncertainty about how long this merge window will last, so please check https://netdev.bots.linux.dev/net-next.html before reposting. net-next _may_ reopen on Nov 2nd. See: https://www.kernel.org/doc/html/next/process/maintainer-netdev.html#development-cycle -- pw-bot: defer pv-bot: closed