On Wed, Oct 17, 2012 at 4:19 AM, Andrew Morton
<a...@linux-foundation.org> wrote:
>
> The patch seems reasonable to me. I'd like to see some examples of
> these resume-time callsite which are performing the GFP_KERNEL
> allocations, please. You have found some kernel bugs, so those should
> be fully described.
OK, there are two examples of GFP_KERNEL allocation in subsystem
runtime resume path:
1), almost all devices in some pci platform
acpi_os_allocate
<-acpi_ut_allocate
<-ACPI_ALLOCATE_ZEROED
<-acpi_evaluate_object
<-__acpi_bus_set_power
<-acpi_bus_set_power
<-acpi_pci_set_power_state
<-platform_pci_set_power_state
<-pci_platform_power_transition
<-__pci_complete_power_transition
<-pci_set_power_state
<-pci_restore_standard_config
<-pci_pm_runtime_resume
2), all devices in usb subsystem
usb_get_status
<-finish_port_resume
<-usb_port_resume
<-generic_resume
<-usb_resume_device
<-usb_resume_both
<-usb_runtime_resume
I also have many examples in which GFP_KERNEL allocation
is involved in runtime resume path of individual drivers.
The above two examples just show how difficult to solve the problem
by traditional way, :-)
Also as pointed by Oliver, network driver need memory allocation with
no io in iSCSI runtime resume situation too.
Thanks,
--
Ming Lei
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