Re: [PATCH v5 0/2] sched/numa: Skip VMA scanning on memory pinned to one NUMA node via cpuset.mems

[Aithal, Srikanth]

On 4/24/2025 8:15 AM, Libo Chen wrote:
> v1->v2:
> 1. add perf improvment numbers in commit log. Yet to find perf diff on
> will-it-scale, so not included here. Plan to run more workloads.
> 2. add tracepoint.
> 3. To peterz's comment, this will make it impossible to attract tasks to
> those memory just like other VMA skippings. This is the current
> implementation, I think we can improve that in the future, but at the
> moment it's probabaly better to keep it consistent.
>
> v2->v3:
> 1. add enable_cpuset() based on Mel's suggestion but again I think it's
> redundant.
> 2. print out nodemask with %*p.. format in the tracepoint.
>
> v3->v4:
> 1. fix an unsafe dereference of a pointer to content not on ring buffer,
> namely mem_allowed_ptr in the tracepoint.
>
> v4->v5:
> 1. add BUILD_BUG_ON() in TP_fast_assign() to guard against future
> changes (particularly in size) in nodemask_t.
>
> Libo Chen (2):
>    sched/numa: Skip VMA scanning on memory pinned to one NUMA node via
>      cpuset.mems
>    sched/numa: Add tracepoint that tracks the skipping of numa balancing
>      due to cpuset memory pinning
>
>   include/trace/events/sched.h | 33 +++++++++++++++++++++++++++++++++
>   kernel/sched/fair.c          |  9 +++++++++
>   2 files changed, 42 insertions(+)

Tested on top of next-20250424. The boot warning[1] is fixed with this 
version.

Tested-by: Srikanth Aithal <sraithal@xxxxxxx>


[1]: https://lore.kernel.org/all/20250422205740.02c4893a@xxxxxxxxxxxxxxxx/