Re: [patch][rfc] acpi: do not use kmem caches

Pekka Enberg
2008-12-01T17:32:57Z

On Mon, Dec 1, 2008 at 7:25 PM, Pekka Enberg <penberg@cs.helsinki.fi> wrote:
> Though I suspect using kmem caches to combat the internal
> fragmentation caused by kmalloc() rounding is not worth it in this
> case.

Btw, just for the record, the ACPI objects are indeed a bad fit for
kmalloc() as reported by SLUB statistics:

[ The size of ACPI kmem caches with wasted bytes per object in parenthesis. ]

32-bit size 64-bit size
Acpi-Namespace 24 (8) 32 (0)
Acpi-Operand 40 (24) 72 (24)
Acpi-Parse 32 (0) 48 (16)
Acpi-ParseExt 44 (20) 72 (24)
Acpi-State 44 (20) 80 (16)

Though I suspect this situation could be improved by avoiding those
fairly big unions ACPI does (like union acpi_operand_object).