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xsk: Bump xsk_queue::queue_empty_descs in xp_can_alloc()

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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: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20240904162808.249160-1-maciej.fijalkowski@intel.com
This commit is contained in:
Maciej Fijalkowski 2024-09-04 18:28:08 +02:00 committed by Daniel Borkmann
parent 5d16228310
commit 6b083650a3
2 changed files with 9 additions and 6 deletions
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10
net/xdp/xsk_buff_pool.c
View File

@ -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);

5
net/xdp/xsk_queue.h
View File

@ -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)