Re: [PATCH] perf lock contention: Do not use BPF task local storage

Namhyung Kim
2023-01-09T22:26:09Z

On Mon, Jan 9, 2023 at 1:23 PM Martin KaFai Lau <martin.lau@linux.dev> wrote:
>
> On 1/9/23 12:56 PM, Namhyung Kim wrote:
> > Hello,
> >
> > On Mon, Nov 21, 2022 at 9:33 AM Martin KaFai Lau <martin.lau@linux.dev> wrote:
> >>
> >> On 11/18/22 11:01 AM, Namhyung Kim wrote:
> >>> We could fix the task local storage to use the safe BPF allocator,
> >>> but it takes time so let's change this until it happens actually.
> >>
> >> I also got another report on the kfree_rcu path. I am also looking into this
> >> direction on using the BPF allocator.
> >
> > Any progress on this? Are there any concerns about the change?
>
> Yep, I am working on it. It is not a direct replacement from kzalloc to
> bpf_mem_cache_alloc. eg. Some changes in the bpf mem allocator is needed to
> ensure the free list cannot be reused before the rcu grace period. There is a
> similar RFC patchset going into this direction that I am trying with.

I see. Thanks for the update!

Namhyung