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SubjectRe: [PATCH 0/6] Shrinking DT memory usage
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On 10/05/17 12:44, Rob Herring wrote:
> On kernels with a minimal config and a RAM target in the 100s of KB, DT
> is quite a hog of runtime memory usage. How much is dependent on how many
> nodes and properties in the DT which have a corresponding struct device_node
> and struct property in the kernel. Just skipping disabled nodes saves a
> lot by not creating the device_nodes in the first place[1], but there's
> more low hanging fruit by making some of the fields in struct property and
> struct device_node optional. With the changes here, the memory usage goes
> from 17KB to under 8KB on QEMU's ARM virt machine which is a relatively
> small DT.
>
> The majority of the diffstat here is just moving all the kobject/sysfs
> related code to its own file so we can avoid adding a bunch of ifdefs.
>
> There's more drastic approaches we could take such as doing the
> unflattening at build time and storing the bulk of the unflattened tree
> as const data. Grant also has some ideas on storing properties as ids
> instead. He's explained it to me, but I still don't understand it.
>
> Rob
>
> [1] https://patchwork.kernel.org/patch/9983203/
>
> Rob Herring (6):
> of: fix missing kobject init for !SYSFS && OF_DYNAMIC config
> of: remove struct property.unique_id for FDT
> of: make struct property _flags field configurable
> of: move kobj_to_device_node() into dynamic.c
> of: wrap accesses to device_node kobject
> of: make kobject and bin_attribute support configurable
>
> drivers/base/core.c | 2 +-
> drivers/of/Kconfig | 4 ++
> drivers/of/Makefile | 1 +
> drivers/of/base.c | 133 ---------------------------------------
> drivers/of/dynamic.c | 27 ++------
> drivers/of/kobj.c | 164 ++++++++++++++++++++++++++++++++++++++++++++++++
> drivers/of/of_private.h | 29 +++++++--
> include/linux/of.h | 28 +++++----
> 8 files changed, 215 insertions(+), 173 deletions(-)
> create mode 100644 drivers/of/kobj.c
>

For the entire series:

Reviewed-by: Frank Rowand <frowand.list@gmail.com>

I don't know if there will be any conflicts between my series
"[PATCH 00/12] of: overlay: clean up device tree overlay code"
and this series.

If you choose to apply this series first, I will make any needed
changes to my series.

-Frank

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