From: Alexander Duyck <alexander.duyck@gmail.com>
To: Alexander Lobakin <alobakin@pm.me>
Cc: "David S. Miller" <davem@davemloft.net>,
"Jakub Kicinski" <kuba@kernel.org>,
"Jonathan Lemon" <jonathan.lemon@gmail.com>,
"Eric Dumazet" <edumazet@google.com>,
"Dmitry Vyukov" <dvyukov@google.com>,
"Willem de Bruijn" <willemb@google.com>,
"Randy Dunlap" <rdunlap@infradead.org>,
"Kevin Hao" <haokexin@gmail.com>,
"Pablo Neira Ayuso" <pablo@netfilter.org>,
"Jakub Sitnicki" <jakub@cloudflare.com>,
"Marco Elver" <elver@google.com>,
"Dexuan Cui" <decui@microsoft.com>,
"Paolo Abeni" <pabeni@redhat.com>,
"Jesper Dangaard Brouer" <brouer@redhat.com>,
"Alexander Duyck" <alexanderduyck@fb.com>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Andrii Nakryiko" <andriin@fb.com>,
"Taehee Yoo" <ap420073@gmail.com>,
"Cong Wang" <xiyou.wangcong@gmail.com>,
"Björn Töpel" <bjorn@kernel.org>,
"Miaohe Lin" <linmiaohe@huawei.com>,
"Guillaume Nault" <gnault@redhat.com>,
"Yonghong Song" <yhs@fb.com>, zhudi <zhudi21@huawei.com>,
"Michal Kubecek" <mkubecek@suse.cz>,
"Marcelo Ricardo Leitner" <marcelo.leitner@gmail.com>,
"Dmitry Safonov" <0x7f454c46@gmail.com>,
"Yang Yingliang" <yangyingliang@huawei.com>,
"Florian Westphal" <fw@strlen.de>,
"Edward Cree" <ecree.xilinx@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
Netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH v5 net-next 09/11] skbuff: allow to optionally use NAPI cache from __alloc_skb()
Date: Thu, 11 Feb 2021 19:18:45 -0800 [thread overview]
Message-ID: <CAKgT0UejU=YC-3xnORHh8uj_uuf79yYMGTdFvo9o7aY03eGeqA@mail.gmail.com> (raw)
In-Reply-To: <20210211185220.9753-10-alobakin@pm.me>
On Thu, Feb 11, 2021 at 11:00 AM Alexander Lobakin <alobakin@pm.me> wrote:
>
> Reuse the old and forgotten SKB_ALLOC_NAPI to add an option to get
> an skbuff_head from the NAPI cache instead of inplace allocation
> inside __alloc_skb().
> This implies that the function is called from softirq or BH-off
> context, not for allocating a clone or from a distant node.
>
> Signed-off-by: Alexander Lobakin <alobakin@pm.me>
> ---
> net/core/skbuff.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index 9e1a8ded4acc..a0b457ae87c2 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -397,15 +397,20 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
> struct sk_buff *skb;
> u8 *data;
> bool pfmemalloc;
> + bool clone;
>
> - cache = (flags & SKB_ALLOC_FCLONE)
> - ? skbuff_fclone_cache : skbuff_head_cache;
> + clone = !!(flags & SKB_ALLOC_FCLONE);
The boolean conversion here is probably unnecessary. I would make
clone an int like flags and work with that. I suspect the compiler is
doing it already, but it is better to be explicit.
> + cache = clone ? skbuff_fclone_cache : skbuff_head_cache;
>
> if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX))
> gfp_mask |= __GFP_MEMALLOC;
>
> /* Get the HEAD */
> - skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
> + if ((flags & SKB_ALLOC_NAPI) && !clone &&
Rather than having to do two checks you could just check for
SKB_ALLOC_NAPI and SKB_ALLOC_FCLONE in a single check. You could just
do something like:
if ((flags & (SKB_ALLOC_FCLONE | SKB_ALLOC_NAPI) == SKB_ALLOC_NAPI)
That way you can avoid the extra conditional jumps and can start
computing the flags value sooner.
> + likely(node == NUMA_NO_NODE || node == numa_mem_id()))
> + skb = napi_skb_cache_get();
> + else
> + skb = kmem_cache_alloc_node(cache, gfp_mask & ~GFP_DMA, node);
> if (unlikely(!skb))
> return NULL;
> prefetchw(skb);
> @@ -436,7 +441,7 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
> __build_skb_around(skb, data, 0);
> skb->pfmemalloc = pfmemalloc;
>
> - if (flags & SKB_ALLOC_FCLONE) {
> + if (clone) {
> struct sk_buff_fclones *fclones;
>
> fclones = container_of(skb, struct sk_buff_fclones, skb1);
> --
> 2.30.1
>
>
next prev parent reply other threads:[~2021-02-12 3:19 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-11 18:52 [PATCH v5 net-next 00/11] skbuff: introduce skbuff_heads bulking and reusing Alexander Lobakin
2021-02-11 18:52 ` [PATCH v5 net-next 01/11] skbuff: move __alloc_skb() next to the other skb allocation functions Alexander Lobakin
2021-02-11 18:53 ` [PATCH v5 net-next 02/11] skbuff: simplify kmalloc_reserve() Alexander Lobakin
2021-02-11 18:53 ` [PATCH v5 net-next 03/11] skbuff: make __build_skb_around() return void Alexander Lobakin
2021-02-11 18:53 ` [PATCH v5 net-next 04/11] skbuff: simplify __alloc_skb() a bit Alexander Lobakin
2021-02-11 18:53 ` [PATCH v5 net-next 05/11] skbuff: use __build_skb_around() in __alloc_skb() Alexander Lobakin
2021-02-11 18:54 ` [PATCH v5 net-next 06/11] skbuff: remove __kfree_skb_flush() Alexander Lobakin
2021-02-12 3:28 ` Alexander Duyck
2021-02-13 13:56 ` Alexander Lobakin
2021-02-11 18:54 ` [PATCH v5 net-next 07/11] skbuff: move NAPI cache declarations upper in the file Alexander Lobakin
2021-02-11 18:54 ` [PATCH v5 net-next 08/11] skbuff: introduce {,__}napi_build_skb() which reuses NAPI cache heads Alexander Lobakin
2021-02-11 18:54 ` [PATCH v5 net-next 09/11] skbuff: allow to optionally use NAPI cache from __alloc_skb() Alexander Lobakin
2021-02-12 3:18 ` Alexander Duyck [this message]
2021-02-13 11:53 ` Alexander Lobakin
2021-02-11 18:55 ` [PATCH v5 net-next 10/11] skbuff: allow to use NAPI cache from __napi_alloc_skb() Alexander Lobakin
2021-02-11 18:55 ` [PATCH v5 net-next 11/11] skbuff: queue NAPI_MERGED_FREE skbs into NAPI cache instead of freeing Alexander Lobakin
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