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? Thanks, Rafael > bisect to > > ac212b6980d8d5eda705864fc5a8ecddc6d6eacc is the first bad commit > commit ac212b6980d8d5eda705864fc5a8ecddc6d6eacc > Author: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > 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 <rafael.j.wysocki@xxxxxxxxx> > Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > Reviewed-by: Toshi Kani <toshi.kani@xxxxxx> > > :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. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
