[LSF/MM/BPF TOPIC] Waste-Free Per-CPU Userspace Memory Allocation

[LSF/MM/BPF TOPIC] Waste-Free Per-CPU Userspace Memory Allocation

[Mathieu Desnoyers]

Hi,

I submit this topic proposal for your consideration:

Introduce the librseq per-CPU user-space memory allocator. It implements
concepts similar to the Linux kernel percpu allocator in userspace, and
thus reduces waste of per-CPU data structures hot cache lines by
eliminating padding usually required to eliminate false-sharing, and in
addition tackles issues that arise from resident memory waste when
restricting processes with scheduler affinity or cpusets.

It allows prototyping kernel algorithms within the safe limits of
user-space.

I hope gathering feedback from MM experts about shortcomings of the
proposed approach.

Thanks,

Mathieu

-- 
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com

Re: [LSF/MM/BPF TOPIC] Waste-Free Per-CPU Userspace Memory Allocation

[Mathieu Desnoyers]

On 2025-01-28 10:23, Mathieu Desnoyers wrote:
> Hi,
> 
> I submit this topic proposal for your consideration:
> 
> Introduce the librseq per-CPU user-space memory allocator. It implements
> concepts similar to the Linux kernel percpu allocator in userspace, and
> thus reduces waste of per-CPU data structures hot cache lines by
> eliminating padding usually required to eliminate false-sharing, and in
> addition tackles issues that arise from resident memory waste when
> restricting processes with scheduler affinity or cpusets.
> 
> It allows prototyping kernel algorithms within the safe limits of
> user-space.
> 
> I hope gathering feedback from MM experts about shortcomings of the
> proposed approach.

Here are the slides I presented during my talk:

https://drive.google.com/file/d/1DWOP6lfbqvYyJ1puwlADoUS9UNQ64SAw/view?usp=sharing


-- 
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com