Re: [PATCH v4 28/39] unwind_user/deferred: Add deferred unwinding interface

Peter Zijlstra
2025-01-22T13:37:47Z

On Tue, Jan 21, 2025 at 06:31:20PM -0800, Josh Poimboeuf wrote:
> +/*
> + * The context cookie is a unique identifier which allows post-processing to
> + * correlate kernel trace(s) with user unwinds. The high 12 bits are the CPU

s/12/16/ ?

> + * id; the lower 48 bits are a per-CPU entry counter.
> + */
> +static u64 ctx_to_cookie(u64 cpu, u64 ctx)
> +{
> + BUILD_BUG_ON(NR_CPUS > 65535);
> + return (ctx & ((1UL << 48) - 1)) | (cpu << 48);
> +}