On Thu, May 12, 2016 at 08:27:08AM -0700, David Daney wrote: > On 05/12/2016 02:49 AM, Catalin Marinas wrote: > >On Wed, May 11, 2016 at 05:06:13PM -0700, David Daney wrote: > >>On 05/11/2016 03:39 AM, Catalin Marinas wrote: > [...] > >>> > >>>I wonder whether you could replace the get_mpidr_in_madt() function with > >>>something like acpi_get_phys_id(). It looks like get_mpidr_in_madt() > >>>duplicates functionality already available elsewhere. > >> > >>I just tried that, and it doesn't work. > >> > >>The problem is that this code is being run very early in the boot, and > >>kmalloc cannot be used. acpi_get_phys_id() and its ilk can only be used > >>once we have working kmalloc. We need to extract the NUMA information early > >>like this precisely because it is needed to initializing the slab system > >> > >>Notice that we are using early_acpi_os_unmap_memory() et al. in > >>get_mpidr_in_madt() explicitly for this reason. > >> > >>In summary: I don't think we need another revision of this patch, it is like > >>this for a good reason. > > > >Slightly confusing, in another reply you said you are going to address > >my comment. So, is it doable? > > I don't think so. > > My previous reply, to the thread in 0/14, was prematurely made with the > incorrect assumption that it was a simple change. Now, after really digging > in to the code, and attempting to do as you suggested, I have changed my > mind. Would the snippet below help with avoiding any kmalloc calls? At a quick look, it seems that it's only map_mat_entry() that ends up using kmalloc() calls. Alternatively, exporting map_madt_entry() may work as well. diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c index 33a38d604630..77af0a7df914 100644 --- a/drivers/acpi/processor_core.c +++ b/drivers/acpi/processor_core.c @@ -152,6 +152,9 @@ static phys_cpuid_t map_mat_entry(acpi_handle handle, int type, u32 acpi_id) struct acpi_subtable_header *header; phys_cpuid_t phys_id = PHYS_CPUID_INVALID; + if (!acpi_gbl_permanent_mmap) + return phys_id; + if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer))) goto exit; -- Catalin -- 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
