Re: [net-next v7 1/4] page_pool: Add allocation stats

[Ilias Apalodimas <ilias.apalodimas@linaro.org>]

On Mon, 28 Feb 2022 at 09:07, Jesper Dangaard Brouer <jbrouer@redhat.com> wrote:
>
>
> On 25/02/2022 18.41, Joe Damato wrote:
> > Add per-pool statistics counters for the allocation path of a page pool.
> > These stats are incremented in softirq context, so no locking or per-cpu
> > variables are needed.
> >
> > This code is disabled by default and a kernel config option is provided for
> > users who wish to enable them.
> >
> > The statistics added are:
> >       - fast: successful fast path allocations
> >       - slow: slow path order-0 allocations
> >       - slow_high_order: slow path high order allocations
> >       - empty: ptr ring is empty, so a slow path allocation was forced.
> >       - refill: an allocation which triggered a refill of the cache
> >       - waive: pages obtained from the ptr ring that cannot be added to
> >         the cache due to a NUMA mismatch.
> >
> > Signed-off-by: Joe Damato<jdamato@fastly.com>
> > ---
> >   include/net/page_pool.h | 18 ++++++++++++++++++
> >   net/Kconfig             | 13 +++++++++++++
> >   net/core/page_pool.c    | 24 ++++++++++++++++++++----
> >   3 files changed, 51 insertions(+), 4 deletions(-)
> >
> > diff --git a/include/net/page_pool.h b/include/net/page_pool.h
> > index 97c3c19..1f27e8a4 100644
> > --- a/include/net/page_pool.h
> > +++ b/include/net/page_pool.h
> > @@ -84,6 +84,19 @@ struct page_pool_params {
> >       void *init_arg;
> >   };
> >
> > +#ifdef CONFIG_PAGE_POOL_STATS
> > +struct page_pool_alloc_stats {
> > +     u64 fast; /* fast path allocations */
> > +     u64 slow; /* slow-path order 0 allocations */
> > +     u64 slow_high_order; /* slow-path high order allocations */
> > +     u64 empty; /* failed refills due to empty ptr ring, forcing
> > +                 * slow path allocation
> > +                 */
> > +     u64 refill; /* allocations via successful refill */
> > +     u64 waive;  /* failed refills due to numa zone mismatch */
> > +};
> > +#endif
> > +
> >   struct page_pool {
> >       struct page_pool_params p;
> >
> > @@ -96,6 +109,11 @@ struct page_pool {
> >       unsigned int frag_offset;
> >       struct page *frag_page;
> >       long frag_users;
> > +
> > +#ifdef CONFIG_PAGE_POOL_STATS
> > +     /* these stats are incremented while in softirq context */
> > +     struct page_pool_alloc_stats alloc_stats;
> > +#endif
> >       u32 xdp_mem_id;
>
> I like the cache-line placement.
>
> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
>

Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>