From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 97EAFCDB465 for ; Thu, 19 Oct 2023 04:49:37 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=nrG9hfkG; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4S9wHN1NTMz3cNt for ; Thu, 19 Oct 2023 15:49:36 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=nrG9hfkG; dkim-atps=neutral Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4S9wGT221Tz2xdY for ; Thu, 19 Oct 2023 15:48:49 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ellerman.id.au; s=201909; t=1697690929; bh=HSBVb0/6PKzVd/BXIi0nFqaJ/m0nLqwjF6CLo8nWfJQ=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=nrG9hfkGjdJ8PvVVCnQKQ+Qfmxsr4+knCkz3c05OZTbzy9MYDUfvYgATbRUl2cNg6 ZvWMBYpsXDzLQ62vsYjy0z3Bb1kAEbaSB9w/46q/y+qXE88YVE8604Py5oaZhu1/Ot puJ8sTEUN6oRljLbxy7AYwf9IPYCG9IAGspWIeCVxFZBgQ9yCJZ0ysodf8wQm2j7QZ Sna8LOFq0HXyH4Nx+toSPZ7Nw03a115OBsAqBBGIO4itk+6pmSlDfRvrivuVkBrfrR klJK3MBlRM1jH6p2BHaO0A/Te2JDtz44iKdaklLMKGlY9Ds+Ixa0lg+udnzeqRchix L3zcp2f1Uj9bg== Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4S9wGS5XSkz4x80; Thu, 19 Oct 2023 15:48:48 +1100 (AEDT) From: Michael Ellerman To: Srikar Dronamraju Subject: Re: [PATCH v2 4/6] powerpc/smp: Disable MC domain for shared processor In-Reply-To: <20231018163751.2423181-5-srikar@linux.vnet.ibm.com> References: <20231018163751.2423181-1-srikar@linux.vnet.ibm.com> <20231018163751.2423181-5-srikar@linux.vnet.ibm.com> Date: Thu, 19 Oct 2023 15:48:48 +1100 Message-ID: <87pm1b5ia7.fsf@mail.lhotse> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Valentin Schneider , Srikar Dronamraju , Peter Zijlstra , linux-kernel@vger.kernel.org, Rohan McLure , Nicholas Piggin , linuxppc-dev , Josh Poimboeuf Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Srikar Dronamraju writes: > Like L2-cache info, coregroup information which is used to determine MC > sched domains is only present on dedicated LPARs. i.e PowerVM doesn't > export coregroup information for shared processor LPARs. Hence disable > creating MC domains on shared LPAR Systems. > > Signed-off-by: Srikar Dronamraju > --- > arch/powerpc/kernel/smp.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c > index 498c2d51fc20..29da9262cb17 100644 > --- a/arch/powerpc/kernel/smp.c > +++ b/arch/powerpc/kernel/smp.c > @@ -1046,6 +1046,10 @@ static struct cpumask *cpu_coregroup_mask(int cpu) > > static bool has_coregroup_support(void) > { > + /* Coregroup identification not available on shared systems */ > + if (is_shared_processor()) > + return 0; That will catch guests running under KVM too right? Do we want that? > return coregroup_enabled; What does coregroup_enabled mean now? I'd rather this was actually checking the presence of something, rather than just hard coding that shared processor means no coregroup support. cheers