[ adding Bob ] On Fri, Jul 14, 2017 at 3:11 PM, Vishal Verma <vishal.l.verma@xxxxxxxxx> wrote: > With the ACPI NFIT 'DSM' methods, acpi can be called from IO paths. > Specifically, the DSM to clear media errors is called during writes, so > that we can provide a writes-fix-errors model. > > However it is easy to imagine a scenario like: > - write through the nvdimm driver > - acpi allocation > - writeback, causes more IO through the nvdimm driver > - deadlock > > Making the acpi allocations GPF_NOIO would ensure that it doesn't > trigger writeback, and avoids the above deadlock. Another option would be to custom code an acpi_ars_clear_error() routine that manages to issue the proper DSM without needing to perform any memory allocations, but this will have implications for the common ACPICA code. -- 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
