Messages in this thread | | | Date | Tue, 9 Sep 2014 09:53:52 -0700 | Subject | Re: [Linux-nvdimm] [PATCH v2] pmem: Initial version of persistent memory driver | From | Dan Williams <> |
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On Tue, Sep 9, 2014 at 9:23 AM, Boaz Harrosh <boaz@plexistor.com> wrote: > From: Ross Zwisler <ross.zwisler@linux.intel.com> > > PMEM is a new driver that presents a reserved range of memory as a > block device. This is useful for developing with NV-DIMMs, and > can be used with volatile memory as a development platform. > > [boaz] > SQUASHME: pmem: Remove unused #include headers > SQUASHME: pmem: Request from fdisk 4k alignment > SQUASHME: pmem: Let each device manage private memory region > SQUASHME: pmem: Support of multiple memory regions > > The API to pmem module a single string parameter named "map" > of the form: > map=mapS[,mapS...] > > where mapS=nn[KMG]$ss[KMG], > or mapS=nn[KMG]@ss[KMG], > > nn=size, ss=offset > > Just like the Kernel command line map && memmap parameters, > so anything you did at grub just copy/paste to here. > > The "@" form is exactly the same as the "$" form only that > at bash prompt we need to escape the "$" with \$ so also > support the '@' char for convenience.
Hmm this looks like a "ACPI/DeviceTree-over-kernel-command-line" description language. I understand that this is borrowed from the memmap= precedent, but, if I'm not mistaken, that's really more for debug rather than a permanent platform-device descriptor. <strawman> Since this looks like firmware why not go ahead and use request_firmware() to request a pmem range descriptor blob</strawman>? Given you can compile such a blob into a kernel image or provide it in an initrd I think it makes deployment more straightforward, also the descriptor format can be extended going forward whereas the command line approach mandates ever increasingly complicated strings.
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