PI futex for the kernel?

ReDress — Fri, 08 Aug 2025 09:34:23 +0000

"...Priority inversion comes about when a low-priority task holds a resource that is also needed by a high-priority task, preventing the latter from running. This problem is made much worse if the low-priority task is unable to gain access to the CPU and, as a result, cannot complete its work and free the resources it holds. Proxy execution is a potential solution to this problem, but it is a complex solution that has been under development for several years; LWN first looked at it in 2020. The 6.17 kernel is likely to contain an important step forward for this long-running project..."

From the problem description, this sounds exactly like the problem PI futex solves but for userspace.

Lock convoy

nksingh — Thu, 31 Jul 2025 04:29:59 +0000

Sounds like the handoff implied by the last couple paragraphs is a recipe for lock convoy.

LWN: Comments on "A proxy-execution baby step"

PI futex for the kernel?

Lock convoy