On Tuesday, May 21, 2013 03:34:37 PM Xishi Qiu wrote:
> On 2013/5/19 7:34, Rafael J. Wysocki wrote:
>
> > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> >
> > As indicated by comments in mm/memory_hotplug.c:remove_memory(),
> > if CONFIG_MEMCG is set, it may not be possible to offline all of the
> > memory blocks held by one module (FRU) in one pass (because one of
> > them may be used by the others to store page cgroup in that case
> > and that block has to be offlined before the other ones).
> >
> > To handle that arguably corner case, add a second pass of companion
> > device offlining to acpi_scan_hot_remove() and make it ignore errors
> > returned in the first pass (and make it skip the second pass if the
> > first one is successful).
> >
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > ---
> > drivers/acpi/scan.c | 67 ++++++++++++++++++++++++++++++++++++++--------------
> > 1 file changed, 50 insertions(+), 17 deletions(-)
> >
> > Index: linux-pm/drivers/acpi/scan.c
> > ===================================================================
> > --- linux-pm.orig/drivers/acpi/scan.c
> > +++ linux-pm/drivers/acpi/scan.c
> > @@ -131,6 +131,7 @@ static acpi_status acpi_bus_offline_comp
> > {
> > struct acpi_device *device = NULL;
> > struct acpi_device_physical_node *pn;
> > + bool second_pass = (bool)data;
> > acpi_status status = AE_OK;
> >
> > if (acpi_bus_get_device(handle, &device))
> > @@ -141,15 +142,26 @@ static acpi_status acpi_bus_offline_comp
> > list_for_each_entry(pn, &device->physical_node_list, node) {
> > int ret;
> >
> > + if (second_pass) {
> > + /* Skip devices offlined by the first pass. */
> > + if (pn->put_online)
>
> should it be "if (!pn->put_online)" ?
No, I don't think so.
pn->put_online set means that the device has been offlined by the first pass,
so we don't need to try it in the second one.
Thanks,
Rafael
> > + continue;
> > + } else {
> > + pn->put_online = false;
> > + }
> > ret = device_offline(pn->dev);
> > if (acpi_force_hot_remove)
> > continue;
> >
> > - if (ret < 0) {
> > - status = AE_ERROR;
> > - break;
> > + if (ret >= 0) {
> > + pn->put_online = !ret;
> > + } else {
> > + *ret_p = pn->dev;
> > + if (second_pass) {
> > + status = AE_ERROR;
> > + break;
> > + }
> > }
> > - pn->put_online = !ret;
> > }
> >
> > mutex_unlock(&device->physical_node_lock);
>
>
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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