On Sun, Mar 17, 2024 at 11:39:17AM +0530, Manivannan Sadhasivam wrote: > As proposed during the last year 'PCI Endpoint Subsystem Open Items > Discussion' of Linux Plumbers conference [1], let's migrate to Genalloc > framework for managing the endpoint outbound window memory allocation. > > PCI Endpoint subsystem is using a custom memory allocator in pci-epc-mem > driver from the start for managing the memory required to map the host > address space (outbound) in endpoint. Even though it works well, it > completely defeats the purpose of the 'Genalloc framework', a general > purpose memory allocator framework created to avoid various custom memory > allocators in the kernel. Nice idea. I wonder if something like this could be done for PCI BAR assignment, i.e., the stuff in setup-bus.c. There are a lot of constraints there, so maybe it wouldn't be practical. > The migration to Genalloc framework is done is such a way that the existing > API semantics are preserved. So that the callers of the EPC mem APIs do not > need any modification (apart from the pcie-designware-epc driver that > queries page size). > > Internally, the EPC mem driver now uses Genalloc framework's > 'gen_pool_first_fit_order_align' algorithm that aligns the allocated memory > based on the requested size as like the previous allocator. And the > page size passed during pci_epc_mem_init() API is used as the minimum order > for the memory allocations. /as like the previous allocator/as the previous allocator did/ > During the migration, 'struct pci_epc_mem' is removed as it is seems > redundant and the existing 'struct pci_epc_mem_window' in 'struct pci_epc' > is now used to hold the address windows of the endpoint controller. s/as it is seems/as it seems/ If this is not a logically required part of the conversion, could the pci_epc_mem removal be a separate patch? The docs refer to it as "genalloc", i.e., not capitalized: https://docs.kernel.org/core-api/genalloc.html Thanks for working on this. Bjorn
