From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 B33E6230989; Tue, 12 Nov 2024 11:45:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731411950; cv=none; b=u6knIELUQPWpE4evFkqQS6alSWbnDatIWNbUVqv8XsmBKkuCS81+xJb6mPZGVRM3wRXdq0QK9ome13wS5c0eX3QNWT3PFKDJNbyXdU2IaaPda168CJWaLFUPr8hZ2Un3bp3+JSZrkwdC4hLxw7XC8BfIFLRASXo6rLVSzFBB/Do= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731411950; c=relaxed/simple; bh=rwStpxnanly060PEUm3Ory3Ei/C3/hXuY2xfwxrCRZA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YPr5QMR49WHUlWGsWfn77bVxyLTnsmivWXOItQgF+BgfUYKfkHWes2aQDsEQ/72uk2JQLJYm1PB6xqjoa30efWTtL2s1lLcE7yHOEVZB7TjmeFlAPHyPejEmKulTfPMK9m9zEsTpmCcs/M7zsw1CkguxjWuTvVwvPh/bFkMiz8A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=HAkHWhHq; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="HAkHWhHq" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=rwStpxnanly060PEUm3Ory3Ei/C3/hXuY2xfwxrCRZA=; b=HAkHWhHqQmq0ysSeQcV2mDrJ48 q7nWiDT5YfVgVeDp+asNKOigehmNCDAMwbiyezP37Ho3nJ72/a/wS2rVc80QljLw+wY0vrS364kWC q93IwzP8NNCM1I0dvYpEHycbjt67nsusczwxVOlZQLmxCMugvd8Ly6x90tVgQLcpfvlX4a8dmCd6x QLn5r0mTSKkedro7OpxSBFQd4FGUeVbmnJiPb9vyHaoZkt3vnRuUzlteZc9eGWd5MFQjEWMi0llgI rq+TA0kv6jBPtlzZ63tJ+noGKquaxLz/jWYO8U39FbdyOvTxl2t6/tV+hmAqwOZ7/K+rTCI/mpjCq 2/DhTcGg==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1tApL6-0000000D3Rl-2Z0a; Tue, 12 Nov 2024 11:45:44 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 94D10300478; Tue, 12 Nov 2024 12:45:43 +0100 (CET) Date: Tue, 12 Nov 2024 12:45:43 +0100 From: Peter Zijlstra To: Patryk Wlazlyn Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, rafael.j.wysocki@intel.com, len.brown@intel.com, artem.bityutskiy@linux.intel.com, dave.hansen@linux.intel.com Subject: Re: [PATCH v3 0/3] SRF: Fix offline CPU preventing pc6 entry Message-ID: <20241112114543.GP22801@noisy.programming.kicks-ass.net> References: <20241108122909.763663-1-patryk.wlazlyn@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pm@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: <20241108122909.763663-1-patryk.wlazlyn@linux.intel.com> On Fri, Nov 08, 2024 at 01:29:06PM +0100, Patryk Wlazlyn wrote: > Removing the existing "kexec hack" by bringing all offlined CPUs back > online before proceeding with the kexec would make it even simpler, but > I am not sure we can do that. It looks kind of obvious to me, but for > some reason the hack exist. There's a comment there that explains why this is done. If you don't understand this, then please don't touch this code.