The page pool keeps track of the number of pages in flight, and
it isn't safe to remove the pool until all pages are returned.
Disallow removing the pool until all pages are back, so the pool
is always available for page producers.
Make the page pool responsible for its own delayed destruction
instead of relying on XDP, so the page pool can be used without
the xdp memory model.
When all pages are returned, free the pool and notify xdp if the
pool is registered with the xdp memory system. Have the callback
perform a table walk since some drivers (cpsw) may share the pool
among multiple xdp_rxq_info.
Note that the increment of pages_state_release_cnt may result in
inflight == 0, resulting in the pool being released.
Fixes: d956a048cd ("xdp: force mem allocator removal and periodic warning")
Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
These tracepoints make it easier to troubleshoot XDP mem id disconnect.
The xdp:mem_disconnect tracepoint cannot be replaced via kprobe. It is
placed at the last stable place for the pointer to struct xdp_mem_allocator,
just before it's scheduled for RCU removal. It also extract info on
'safe_to_remove' and 'force'.
Detailed info about in-flight pages is not available at this layer. The next
patch will added tracepoints needed at the page_pool layer for this.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
