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| author | Paolo Abeni <pabeni@redhat.com> | 2025-02-07 00:28:48 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-02-08 04:20:22 +0300 |
| commit | 011b0335903832facca86cd8ed05d7d8d94c9c76 (patch) | |
| tree | f398fa7e1a980b471303bc173583a55c1ce25a99 /include/linux | |
| parent | cb827db50a88aebec516151681adb6db10b688ee (diff) | |
| download | linux-011b0335903832facca86cd8ed05d7d8d94c9c76.tar.xz | |
Revert "net: skb: introduce and use a single page frag cache"
This reverts commit dbae2b062824 ("net: skb: introduce and use a single
page frag cache"). The intended goal of such change was to counter a
performance regression introduced by commit 3226b158e67c ("net: avoid
32 x truesize under-estimation for tiny skbs").
Unfortunately, the blamed commit introduces another regression for the
virtio_net driver. Such a driver calls napi_alloc_skb() with a tiny
size, so that the whole head frag could fit a 512-byte block.
The single page frag cache uses a 1K fragment for such allocation, and
the additional overhead, under small UDP packets flood, makes the page
allocator a bottleneck.
Thanks to commit bf9f1baa279f ("net: add dedicated kmem_cache for
typical/small skb->head"), this revert does not re-introduce the
original regression. Actually, in the relevant test on top of this
revert, I measure a small but noticeable positive delta, just above
noise level.
The revert itself required some additional mangling due to the
introduction of the SKB_HEAD_ALIGN() helper and local lock infra in the
affected code.
Suggested-by: Eric Dumazet <edumazet@google.com>
Fixes: dbae2b062824 ("net: skb: introduce and use a single page frag cache")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Link: https://patch.msgid.link/e649212fde9f0fdee23909ca0d14158d32bb7425.1738877290.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/netdevice.h | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index c0a86afb85da..365f0e2098d1 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -4115,7 +4115,6 @@ void netif_receive_skb_list(struct list_head *head); gro_result_t napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb); void napi_gro_flush(struct napi_struct *napi, bool flush_old); struct sk_buff *napi_get_frags(struct napi_struct *napi); -void napi_get_frags_check(struct napi_struct *napi); gro_result_t napi_gro_frags(struct napi_struct *napi); static inline void napi_free_frags(struct napi_struct *napi) |