Messages in this thread | | | Date | Thu, 14 Jan 2021 09:04:26 +0000 (UTC) | From | Christoph Lameter <> | Subject | Re: SLUB: percpu partial object count is highly inaccurate, causing some memory wastage and maybe also worse tail latencies? |
| |
On Wed, 13 Jan 2021, Jann Horn wrote:
> Some brainstorming: > > Maybe you could have an atomic counter in kmem_cache_cpu that tracks > the number of empty frozen pages that are associated with a specific > CPU? So the freeing slowpath would do its cmpxchg_double, and if the
The latencies of these functions are so low that any additional counter will have significant performance impacts. An atomic counter would be waay out there.
> You could additionally have a plain percpu counter, not tied to the
The performance critical counters are already all per cpu. I enhanced the percpu subsystem specifically to support latency critical operations in the fast path of the slab allocators.
| |