Messages in this thread | | | Date | Tue, 28 Jul 2020 14:22:44 +0200 | From | Christoph Hellwig <> | Subject | Re: [PATCH v4 1/2] dma-direct: provide the ability to reserve per-numa CMA |
| |
On Tue, Jul 28, 2020 at 12:19:03PM +0000, Song Bao Hua (Barry Song) wrote: > I am sorry I haven't got your point yet. Do you mean something like the below? > > arch/arm64/Kconfig: > config CMDLINE > string "Default kernel command string" > - default "" > + default "pernuma_cma=16M" > help > Provide a set of default command-line options at build time by > entering them here. As a minimum, you should specify the the > root device (e.g. root=/dev/nfs).
Yes.
> A background of the current code is that Linux distributions can usually use arch/arm64/configs/defconfig > directly to build kernel. cmdline can be easily ignored during the generation of Linux distributions.
I've not actually heard of a distro shipping defconfig yet..
> > > if a way to expose this in the device tree might be useful, but people > > more familiar with the device tree and the arm code will have to chime > > in on that. > > Not sure if it is an useful user case as we are using ACPI but not device tree since it is an ARM64 > server with NUMA.
Well, than maybe ACPI experts need to chime in on this.
> > This seems to have lost the dma_contiguous_default_area NULL check. > > cma_alloc() is doing the check by returning NULL if cma is NULL. > > struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, > bool no_warn) > { > ... > if (!cma || !cma->count) > return NULL; > } > > But I agree here the code can check before calling cma_alloc_aligned.
Oh, indeed. Please split the removal of the NULL check in to a prep patch then.
| |