From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexey Starikovskiy Subject: Re: [PATCH] ACPICA: don't cond_resched() when irq_disabled or in_atomic Date: Thu, 10 Dec 2009 21:37:59 +0300 Message-ID: <4B214007.2080409@gmail.com> References: <1259900760-6424-1-git-send-email-dfeng@redhat.com> <20091210100907.GA2446@ucw.cz> <4B2136D5.1030402@gmail.com> <20091210181800.GM19454@elf.ucw.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from fg-out-1718.google.com ([72.14.220.157]:16408 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761300AbZLJShx (ORCPT ); Thu, 10 Dec 2009 13:37:53 -0500 In-Reply-To: <20091210181800.GM19454@elf.ucw.cz> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Pavel Machek Cc: Xiaotian Feng , lenb@kernel.org, ming.m.lin@intel.com, robert.moore@intel.com, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org Pavel Machek =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > On Thu 2009-12-10 20:58:45, Alexey Starikovskiy wrote: > =20 >> Hi Pavel, >> >> Please elaborate... Your comments "ugly as hell" are too often to be >> specific... >> There is only one use of ACPI_PREEMPTION_POINT(), and it is in the >> ACPICA code, >> which we all agreed to keep OS independent, thus the need for #defin= e. >> Do you see any other way to add preemption point without introducing >> Linux-specific >> code into ACPICA? >> =20 > > I believe we want linux-specific code in acpica at this point. > > =20 The point there we call cond_resched() in ACPICA is an interpreter pars= e loop. This parse loop may be executed from within atomic context and ev= en with interrupts off. In this case, cond_resched() should not be called to not make might_sleep() guards angry. Please post the code, which will do the above and will not look "ugly a= s hell". I still don't follow your vague comments. > (Or maybe... I guess other systems have concept of preemption and not > all actions are permitted from all contexts, so maybe something like > that would be important for them, too?) > =20 None of them cared about it up to this point. With the macro above we allowed them to follow Linux, but to go or not is their call. Regards, Alex. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html