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| author |   Jesper Dangaard Brouer <brouer@redhat.com> | 2022-09-21 19:05:32 +0200 |
|---|---|---|
| committer |   Jakub Kicinski <kuba@kernel.org> | 2022-09-26 11:28:19 -0700 |
| commit | fb33ec016b8710281343ce73bec92bfe54bad4fa (patch) | |
| tree | f471e8b3f7980468c82d5651c112fa620bbb160c /net/core | |
| parent | net: ethernet: stmicro: stmmac: dwmac-rk: Add rv1126 support (diff) | |
| download | linux-dev-fb33ec016b8710281343ce73bec92bfe54bad4fa.tar.xz linux-dev-fb33ec016b8710281343ce73bec92bfe54bad4fa.zip | |
xdp: improve page_pool xdp_return performance
During LPC2022 I meetup with my page_pool co-maintainer Ilias. When
discussing page_pool code we realised/remembered certain optimizations
had not been fully utilised.
Since commit c07aea3ef4d4 ("mm: add a signature in struct page") struct
page have a direct pointer to the page_pool object this page was
allocated from.
Thus, with this info it is possible to skip the rhashtable_lookup to
find the page_pool object in __xdp_return().
The rcu_read_lock can be removed as it was tied to xdp_mem_allocator.
The page_pool object is still safe to access as it tracks inflight pages
and (potentially) schedules final release from a work queue.
Created a micro benchmark of XDP redirecting from mlx5 into veth with
XDP_DROP bpf-prog on the peer veth device. This increased performance
6.5% from approx 8.45Mpps to 9Mpps corresponding to using 7 nanosec
(27 cycles at 3.8GHz) less per packet.
Suggested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Link: https://lore.kernel.org/r/166377993287.1737053.10258297257583703949.stgit@firesoul
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/xdp.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/net/core/xdp.c b/net/core/xdp.c index 24420209bf0e..844c9d99dc0e 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -375,19 +375,17 @@ EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model); void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, struct xdp_buff *xdp) { - struct xdp_mem_allocator *xa; struct page *page; switch (mem->type) { case MEM_TYPE_PAGE_POOL: - rcu_read_lock(); - /* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */ - xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); page = virt_to_head_page(data); if (napi_direct && xdp_return_frame_no_direct()) napi_direct = false; - page_pool_put_full_page(xa->page_pool, page, napi_direct); - rcu_read_unlock(); + /* No need to check ((page->pp_magic & ~0x3UL) == PP_SIGNATURE) + * as mem->type knows this a page_pool page + */ + page_pool_put_full_page(page->pp, page, napi_direct); break; case MEM_TYPE_PAGE_SHARED: page_frag_free(data); |