On Wed, 29 Nov 2023, Matthew Wilcox wrote:
In order to make the SLUB in page freelists work better you need to have
larger freelist and that comes with larger page sizes. I.e. boot with
slub_min_order=5 or so to increase performance.
That comes with its own problems, of course.
Well I thought you were solving those with the folios?
Also this means increasing TLB pressure. The in page freelists of SLUB cause
objects from the same page be served. The SLAB queueing approach
results in objects being mixed from any address and thus neighboring objects
may require more TLB entries.
Is that still a concern for modern CPUs? We're using 1GB TLB entries
these days, and there are usually thousands of TLB entries. This feels
like more of a concern for a 90s era CPU.
ARM kernel memory is mapped by 4K entries by default since rodata=full is
the default. Security concerns screw it up.
