From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 5F406377AA5 for ; Tue, 22 Sep 2026 15:45:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790091944; cv=none; b=EXe8OIQm4DDEsvqrb8nA+zJZDGuv2bpEvQ/LroUY6/xdrfysEvlsTU/pDGxX2EXjmKFmRLkr8sQl60HSVJgBzhAIjdhcK4/OOXezTCDR3aKdkaBwt0uJMKsDNXvmRfwS/T17zbD/JJDYWkFBtaGt0e5gV7CcWHxpW/bIgd9si6s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790091944; c=relaxed/simple; bh=MqIzpojt+/I1XeMCGiVa2Ocs3zllmSi07mu4FmVzEyY=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=R4QTrAHLXz0d2sDbncFSPbkhb5ZFxlSJmGUvtxFqqAUbH/zT87omo3hsVaISvPWHDuog0L2TT9nH5lDHrvfYAc9fSAx4kXKFYW1XwYf1jkVjLN3Usn/bVekjK+Umx5j61RYIYUsM3TI9GrirLPtvNUkyA9Ann4wbdr3zS6cOB64= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eaYeUYSB; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eaYeUYSB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4EF051F000FF; Tue, 22 Sep 2026 15:45:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790091940; bh=MqIzpojt+/I1XeMCGiVa2Ocs3zllmSi07mu4FmVzEyY=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=eaYeUYSBsZJTLNXJp/e7ZF1aByu8WPpNwcgo9uTRTZftYKMX1IaF2NnPx6stXbV8n lTvYdrR3PBpZVvviplnk1CxXTolchIiyCsnciDaEL63vpG5Y42h90Yel+ntLDwc5Vr yD8Y+/YeZ87ujJ+jTKHE0rF4dAk96wMCkE9EWG1Wom4yuserYO7VcmEgauwYDVNmse 1gMf4nuOmf07TRL268l1Xf9vao55RKw8c+i6G9QReHXQtKfcmzP+5vr3ODj0bTl5Vc sfA6Om0nM9q+ecQL5v8xu07po5TzlD9QbSlP+qkHc5QPQPSHBD7YgZZcuqFc8z+oJ9 ia9YJKG+rK85Q== From: sashiko-bot@kernel.org Subject: Re: [PATCH v4 03/12] mm: enable MMU_GATHER_RCU_TABLE_FREE for MMU riscv Reply-To: sashiko-reviews@lists.linux.dev To: =?utf-8?b?TG9yZW56byBTdG9ha2VzIChBUk0p?= Cc: "Vasily Gorbik" , "Alexander Gordeev" , "Christian Borntraeger" , linux-s390@vger.kernel.org, "Heiko Carstens" In-Reply-To: <20260922-rcu-pagetable-freeing-v4-3-fe1ad1f1e303@kernel.org> References: <20260922-rcu-pagetable-freeing-v4-0-fe1ad1f1e303@kernel.org> <20260922-rcu-pagetable-freeing-v4-3-fe1ad1f1e303@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 22 Sep 2026 15:45:39 +0000 Message-Id: <20260922154540.4EF051F000FF@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > Currently riscv gates MMU_GATHER_RCU_TABLE_FREE on CONFIG_SMP and > CONFIG_MMU. >=20 > Commit 69be3fb111e7 ("riscv: enable MMU_GATHER_RCU_TABLE_FREE for SMP && > MMU") enabled CONFIG_MMU_GATHER_RCU_TABLE_FREE for CONFIG_SMP, CONFIG_MMU > riscv builds. >=20 > This is expressly for the safety of GUP-fast walkers (CONFIG_HAVE_GUP_FAST > is enabled if CONFIG_MMU is enabled). >=20 > Naturally a single core system does not encounter issues with software pa= ge > table walkers being correctly synchronised across cores, as there is only= a > single core. >=20 > However, CONFIG_PREEMPT_RCU is still available on a riscv UP system, so f= or > a future RCU-only page table walker, this guarantee is required to prevent > concurrent page table teardown. >=20 > All page table freeing is already done via tlb_remove_ptdesc() so the > conditions of CONFIG_MMU_GATHER_RCU_TABLE_FREE are already met. >=20 > This forms part of an overall effort to switch every architecture to this > mode. >=20 > Acked-by: Kiryl Shutsemau (Meta) > Signed-off-by: Lorenzo Stoakes (ARM) Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260922-rcu-pageta= ble-freeing-v4-0-fe1ad1f1e303@kernel.org?part=3D3