From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932295Ab3E1XsN (ORCPT ); Tue, 28 May 2013 19:48:13 -0400 Received: from hydra.sisk.pl ([212.160.235.94]:53687 "EHLO hydra.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759335Ab3E1XsJ (ORCPT ); Tue, 28 May 2013 19:48:09 -0400 From: "Rafael J. Wysocki" To: Yinghai Lu Cc: ACPI Devel Maling List , Linux Kernel Mailing List Subject: Re: System slow down from udev Date: Wed, 29 May 2013 01:57:03 +0200 Message-ID: <1826731.cQudjZKeXZ@vostro.rjw.lan> User-Agent: KMail/4.9.5 (Linux/3.10.0-rc3+; KDE/4.9.5; x86_64; ; ) In-Reply-To: References: <4790010.08sMRz00G6@vostro.rjw.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, May 28, 2013 04:46:30 PM Yinghai Lu wrote: > On Tue, May 28, 2013 at 4:50 PM, Rafael J. Wysocki wrote: > > On Tuesday, May 28, 2013 04:39:37 PM Yinghai Lu wrote: > >> Raphael: > >> > >> Found one commit in your linus-pm cause user space very slow... > >> at least from udev start... > > > > I obviously can't reproduce it, so it would be great if you could give me > > more details. > > > > Is there anything unusual about your test system? > > they are normal nehalem ex, westmere ex and ivybridge ex 8 sockets system. Do all of them have the same problem? What distro is running there? Rafael > >> bisect to > >> > >> ac212b6980d8d5eda705864fc5a8ecddc6d6eacc is the first bad commit > >> commit ac212b6980d8d5eda705864fc5a8ecddc6d6eacc > >> Author: Rafael J. Wysocki > >> Date: Fri May 3 00:26:22 2013 +0200 > >> > >> ACPI / processor: Use common hotplug infrastructure > >> > >> Split the ACPI processor driver into two parts, one that is > >> non-modular, resides in the ACPI core and handles the enumeration > >> and hotplug of processors and one that implements the rest of the > >> existing processor driver functionality. > >> > >> The non-modular part uses an ACPI scan handler object to enumerate > >> processors on the basis of information provided by the ACPI namespace > >> and to hook up with the common ACPI hotplug infrastructure. It also > >> populates the ACPI handle of each processor device having a > >> corresponding object in the ACPI namespace, which allows the driver > >> proper to bind to those devices, and makes the driver bind to them > >> if it is readily available (i.e. loaded) when the scan handler's > >> .attach() routine is running. > >> > >> There are a few reasons to make this change. > >> > >> First, switching the ACPI processor driver to using the common ACPI > >> hotplug infrastructure reduces code duplication and size considerably, > >> even though a new file is created along with a header comment etc. > >> > >> Second, since the common hotplug code attempts to offline devices > >> before starting the (non-reversible) removal procedure, it will abort > >> (and possibly roll back) hot-remove operations involving processors > >> if cpu_down() returns an error code for one of them instead of > >> continuing them blindly (if /sys/firmware/acpi/hotplug/force_remove > >> is unset). That is a more desirable behavior than what the current > >> code does. > >> > >> Finally, the separation of the scan/hotplug part from the driver > >> proper makes it possible to simplify the driver's .remove() routine, > >> because it doesn't need to worry about the possible cleanup related > >> to processor removal any more (the scan/hotplug part is responsible > >> for that now) and can handle device removal and driver removal > >> symmetricaly (i.e. as appropriate). > >> > >> Some user-visible changes in sysfs are made (for example, the > >> 'sysdev' link from the ACPI device node to the processor device's > >> directory is gone and a 'physical_node' link is present instead > >> and a corresponding 'firmware_node' is present in the processor > >> device's directory, the processor driver is now visible under > >> /sys/bus/cpu/drivers/ and bound to the processor device), but > >> that shouldn't affect the functionality that users care about > >> (frequency scaling, C-states and thermal management). > >> > >> Tested on my venerable Toshiba Portege R500. > >> > >> Signed-off-by: Rafael J. Wysocki > >> Acked-by: Greg Kroah-Hartman > >> Reviewed-by: Toshi Kani > >> > >> :040000 040000 24925fd62fd97295be145d62f8d849004eeca284 > >> 30c7f7f9ff26f17eaabf1770eb7d0b69c2767ba8 M drivers > >> :040000 040000 8374b2dcd64a21abc1f65d3c7779ffa71adb01ba > >> 9375e83719e970b6f4b9a61fe6080bd638dfc51c M include > > -- > > I speak only for myself. > > Rafael J. Wysocki, Intel Open Source Technology Center. -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.