Commit 6b083650 authored by Maciej Fijalkowski's avatar Maciej Fijalkowski Committed by Daniel Borkmann
Browse files

xsk: Bump xsk_queue::queue_empty_descs in xp_can_alloc() 



We have STAT_FILL_EMPTY test case in xskxceiver that tries to process
traffic with fill queue being empty which currently fails for zero copy
ice driver after it started to use xsk_buff_can_alloc() API. That is
because xsk_queue::queue_empty_descs is currently only increased from
alloc APIs and right now if driver sees that xsk_buff_pool will be
unable to provide the requested count of buffers, it bails out early,
skipping calls to xsk_buff_alloc{_batch}().

Mentioned statistic should be handled in xsk_buff_can_alloc() from the
very beginning, so let's add this logic now. Do it by open coding
xskq_cons_has_entries() and bumping queue_empty_descs in the middle when
fill queue currently has no entries.

Signed-off-by: default avatarMaciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarMagnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20240904162808.249160-1-maciej.fijalkowski@intel.com
parent 5d162283

net/xdp/xsk_buff_pool.c

+9 −1
Original line number Diff line number Diff line
@@ -656,9 +656,17 @@ EXPORT_SYMBOL(xp_alloc_batch); 


bool xp_can_alloc(struct xsk_buff_pool *pool, u32 count)

{

	u32 req_count, avail_count;



	if (pool->free_list_cnt >= count)

		return true;

	return xskq_cons_has_entries(pool->fq, count - pool->free_list_cnt);



	req_count = count - pool->free_list_cnt;

	avail_count = xskq_cons_nb_entries(pool->fq, req_count);

	if (!avail_count)

		pool->fq->queue_empty_descs++;



	return avail_count >= req_count;

}

EXPORT_SYMBOL(xp_can_alloc);

net/xdp/xsk_queue.h

+0 −5
Original line number Diff line number Diff line
@@ -306,11 +306,6 @@ static inline u32 xskq_cons_nb_entries(struct xsk_queue *q, u32 max) 
	return entries >= max ? max : entries;

}



static inline bool xskq_cons_has_entries(struct xsk_queue *q, u32 cnt)

{

	return xskq_cons_nb_entries(q, cnt) >= cnt;

}



static inline bool xskq_cons_peek_addr_unchecked(struct xsk_queue *q, u64 *addr)

{

	if (q->cached_prod == q->cached_cons)