RE: [PATCH v7 1/3] dma-contiguous: provide the ability to reserve per-numa CMA

[Song Bao Hua (Barry Song)]

> -----Original Message-----
> From: Randy Dunlap [mailto:rdunlap@xxxxxxxxxxxxx]
> Sent: Saturday, August 22, 2020 4:08 AM
> To: Song Bao Hua (Barry Song) <song.bao.hua@xxxxxxxxxxxxx>; hch@xxxxxx;
> m.szyprowski@xxxxxxxxxxx; robin.murphy@xxxxxxx; will@xxxxxxxxxx;
> ganapatrao.kulkarni@xxxxxxxxxx; catalin.marinas@xxxxxxx;
> akpm@xxxxxxxxxxxxxxxxxxxx
> Cc: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; Zengtao (B) <prime.zeng@xxxxxxxxxxxxx>;
> huangdaode <huangdaode@xxxxxxxxxx>; Linuxarm <linuxarm@xxxxxxxxxx>;
> Jonathan Cameron <jonathan.cameron@xxxxxxxxxx>; Nicolas Saenz Julienne
> <nsaenzjulienne@xxxxxxx>; Steve Capper <steve.capper@xxxxxxx>; Mike
> Rapoport <rppt@xxxxxxxxxxxxx>
> Subject: Re: [PATCH v7 1/3] dma-contiguous: provide the ability to reserve
> per-numa CMA
> 
> On 8/21/20 4:33 AM, Barry Song wrote:
> > ---
> >  -v7: with respect to Will's comments
> >  * move to use for_each_online_node
> >  * add description if users don't specify pernuma_cma
> >  * provide default value for CONFIG_DMA_PERNUMA_CMA
> >
> >  .../admin-guide/kernel-parameters.txt         |  11 ++
> >  include/linux/dma-contiguous.h                |   6 ++
> >  kernel/dma/Kconfig                            |  11 ++
> >  kernel/dma/contiguous.c                       | 100
> ++++++++++++++++--
> >  4 files changed, 118 insertions(+), 10 deletions(-)
> >
> > diff --git a/Documentation/admin-guide/kernel-parameters.txt
> b/Documentation/admin-guide/kernel-parameters.txt
> > index bdc1f33fd3d1..c609527fc35a 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -599,6 +599,17 @@
> >  			altogether. For more information, see
> >  			include/linux/dma-contiguous.h
> >
> > +	pernuma_cma=nn[MG]
> > +			[ARM64,KNL]
> > +			Sets the size of kernel per-numa memory area for
> > +			contiguous memory allocations. A value of 0 disables
> > +			per-numa CMA altogether. And If this option is not
> > +			specificed, the default value is 0.
> > +			With per-numa CMA enabled, DMA users on node nid will
> > +			first try to allocate buffer from the pernuma area
> > +			which is located in node nid, if the allocation fails,
> > +			they will fallback to the global default memory area.
> > +
> 
> Entries in kernel-parameters.txt are supposed to be in alphabetical order
> but this one is not.  If you want to keep it near the cma= entry, you can
> rename it like Mike suggested.  Otherwise it needs to be moved.

As I've replied in Mike's comment, I'd like to rename it to cma_per...

> 
> 
> >  	cmo_free_hint=	[PPC] Format: { yes | no }
> >  			Specify whether pages are marked as being inactive
> >  			when they are freed.  This is used in CMO environments
> 
> 
> 
> --
> ~Randy

Thanks
Barry