On Mon, Mar 18, 2024 at 12:08:43PM -0500, Bjorn Helgaas wrote: > 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. > I took a quick look at it and I share the same view. > > 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? > genalloc migration essentially makes the 'struct pci_epc_mem' unused. So I thought it makes sense to remove it in the same patch. But I do not have a stronger opinion to not split it. So, I can split it in next version. > The docs refer to it as "genalloc", i.e., not capitalized: > https://docs.kernel.org/core-api/genalloc.html > Ok. Will change it. - Mani -- மணிவண்ணன் சதாசிவம்
