From patchwork Fri Nov 8 12:29:08 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Patryk Wlazlyn X-Patchwork-Id: 842004 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.9]) (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 C959B1E907C; Fri, 8 Nov 2024 12:29:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.9 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731068975; cv=none; b=H3kxWk/AOxBW03E/7qptGrPD1FkfcMICdkIq8r5CYBRAeEwlQzNO14EqY9+LWJPsMEzradTcH2j/VEh3WQs9XmxNRLnuzY6YCqKojExZe2TsexnmebVz+lVP0QefLHqxGaGjW4W4vCIouZmbFLz9V1t6UdrIh2Qt7mVULt982k4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731068975; c=relaxed/simple; bh=b7srFW4ztylUzGKNKDA1PC2mqEDgmyxEsntlM8t70ig=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=h9ND68t8bvbExYwfhs0Pw5mBB/+NpcEMtICemS3vNrIyjUTeEcxIfJFC6Wv8rFVeeLqdXfzyhucR/6BJCHvAWl4N7zxODrTtIQk9sl+qTzLOxXuLHX2GoQptHe8v2cJtPXZp51fcjSbX6UMNI8CwQPukZ1jlyNW9BdzztqoM0b0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=HKbpINH0; arc=none smtp.client-ip=198.175.65.9 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="HKbpINH0" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1731068973; x=1762604973; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=b7srFW4ztylUzGKNKDA1PC2mqEDgmyxEsntlM8t70ig=; b=HKbpINH0ygkQ0QG5B0t1lGlZ36vM67tnAfxrr88e6eZ3rt5SyG/sgHdi V0Wt9AbWcwcUj7FVt9W1BHZrfSwE2khi1K9bBASOQUmZZb9uaHWDxaK4m XZ86bccWamNsO1BVRf6ZuOUwYRBu+qtIvma0KfWyHXtH3wM/drX/1mR1j yGiY9nRgupo6ARx6zNYTaYqwOIlGWZlQyB+60/Ao8ufirWrEA2Cf9Vijr DJY55xBlBj9S1LrBp93PpGZnznQGiX2SzN6lZnJQp/Cp2QFOtf2oQQ3iL gsAEF5AsoulJvxarVhwuTDnLQkeuYD/Tkq3IN3jOFacWR7wo0NYVbnuXu w==; X-CSE-ConnectionGUID: mTZgeywHTJWM/PKNIb2dTA== X-CSE-MsgGUID: UVTPy8IrRk2YGP9IWyy+MA== X-IronPort-AV: E=McAfee;i="6700,10204,11222"; a="53510361" X-IronPort-AV: E=Sophos;i="6.11,199,1725346800"; d="scan'208";a="53510361" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by orvoesa101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Nov 2024 04:29:33 -0800 X-CSE-ConnectionGUID: rIpTTDHIT9qMAd99VtFkqA== X-CSE-MsgGUID: pFoPAVBHQ56apGPXxetzDQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,137,1728975600"; d="scan'208";a="85921121" Received: from hrotuna-mobl2.ger.corp.intel.com (HELO localhost.localdomain) ([10.245.245.89]) by orviesa007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Nov 2024 04:29:31 -0800 From: Patryk Wlazlyn To: x86@kernel.org Cc: 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, patryk.wlazlyn@linux.intel.com Subject: [PATCH v3 2/3] x86/smp native_play_dead: Prefer cpuidle_play_dead() over mwait_play_dead() Date: Fri, 8 Nov 2024 13:29:08 +0100 Message-ID: <20241108122909.763663-3-patryk.wlazlyn@linux.intel.com> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241108122909.763663-1-patryk.wlazlyn@linux.intel.com> 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 The generic implementation, based on cpuid leaf 0x5, for looking up the mwait hint for the deepest cstate, depends on them to be continuous in range [0, NUM_SUBSTATES-1]. While that is correct on most Intel x86 platforms, it is not architectural and may not result in reaching the most optimized idle state on some of them. Prefer cpuidle_play_dead() over the generic mwait_play_dead() loop and fallback to the later in case of missing enter_dead() handler. Signed-off-by: Patryk Wlazlyn --- arch/x86/kernel/smpboot.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 44c40781bad6..721bb931181c 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1416,9 +1416,9 @@ void native_play_dead(void) play_dead_common(); tboot_shutdown(TB_SHUTDOWN_WFS); - mwait_play_dead(); if (cpuidle_play_dead()) - hlt_play_dead(); + mwait_play_dead(); + hlt_play_dead(); } #else /* ... !CONFIG_HOTPLUG_CPU */