Re: [PATCH v3] mm/lruvec: trace LRU add drains and drain-all requests

[Shakeel Butt]

On Wed, Jun 10, 2026 at 12:52:20PM -0700, JP Kobryn wrote:
> LRU add batches can be drained before they reach capacity. This can be a
> source of LRU lock contention, but it is not currently possible to
> attribute these drains to callers with existing tracepoints.
> 
> Add mm_lru_add_drain to report the CPU and lru_add batch count when an
> lru_add batch is drained. This allows tracing to distinguish full drains
> from partial drains and attribute them to the calling stack.
> 
> Add mm_lru_add_drain_all to capture callers of __lru_add_drain_all and
> whether they set the force flag for all CPUs. The tracepoint resembles
> the signature of the enclosing function, but is needed because of
> potential inlining.
> 
> Signed-off-by: JP Kobryn <jp.kobryn@xxxxxxxxx>

Acked-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>