On Mon, 2010-08-16 at 09:34 -0500, Nathan Fontenot wrote:
Even if an arch defines the override for the sysfs dir size, I still
don't think this breaks anything (it shouldn't). We move _all_ of the
directories over, all at once, to a single, uniform size. The only
apparent change to a user moving kernels would be a larger
block_size_bytes (which is certainly not changing the ABI) and a new
sysfs file for the end of the section. The new sysfs file is
_completely_ redundant at this point.
The architecture is only supposed to bump up the directory size when it
*KNOWS* that all operations will be done at the larger section size,
such as if the specific hardware has physical DIMMs which are much
larger than SECTION_SIZE.
Let's say we have a system with 20MB of memory, SECTION_SIZE of 1MB and
a sysfs dir size of 4MB.
Before the patch, we have 20 directories: one for each section. After
this patch, we have 5 directories.
The thing that I think is the next step, but that we _will_ probably
need eventually is this, take the 5 sysfs dirs in the above case:
0->3, 4->7, 8->11, 12->15, 16->19
and turn that into a single one:
0->19
*That* will require changing the ABI, but we could certainly have some
bloated and slow, but backward-compatible mode.
-- Dave
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