From: Ilias Apalodimas <ilias.apalodimas@linaro.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Matteo Croce <mcroce@linux.microsoft.com>,
netdev@vger.kernel.org, linux-mm@kvack.org,
Ayush Sawal <ayush.sawal@chelsio.com>,
Vinay Kumar Yadav <vinay.yadav@chelsio.com>,
Rohit Maheshwari <rohitm@chelsio.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
Marcin Wojtas <mw@semihalf.com>,
Russell King <linux@armlinux.org.uk>,
Mirko Lindner <mlindner@marvell.com>,
Stephen Hemminger <stephen@networkplumber.org>,
Tariq Toukan <tariqt@nvidia.com>,
Jesper Dangaard Brouer <hawk@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
John Fastabend <john.fastabend@gmail.com>,
Boris Pismenny <borisp@nvidia.com>, Arnd Bergmann <arnd@arndb.de>,
Andrew Morton <akpm@linux-foundation.org>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Vlastimil Babka <vbabka@suse.cz>, Yu Zhao <yuzhao@google.com>,
Will Deacon <will@kernel.org>, Fenghua Yu <fenghua.yu@intel.com>,
Roman Gushchin <guro@fb.com>, Hugh Dickins <hughd@google.com>,
Peter Xu <peterx@redhat.com>, Jason Gunthorpe <jgg@ziepe.ca>,
Jonathan Lemon <jonathan.lemon@gmail.com>,
Alexander Lobakin <alobakin@pm.me>,
Cong Wang <cong.wang@bytedance.com>, wenxu <wenxu@ucloud.cn>,
Kevin Hao <haokexin@gmail.com>,
Jakub Sitnicki <jakub@cloudflare.com>,
Marco Elver <elver@google.com>,
Willem de Bruijn <willemb@google.com>,
Miaohe Lin <linmiaohe@huawei.com>,
Yunsheng Lin <linyunsheng@huawei.com>,
Guillaume Nault <gnault@redhat.com>,
linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org,
bpf@vger.kernel.org, Eric Dumazet <edumazet@google.com>,
David Ahern <dsahern@gmail.com>,
Lorenzo Bianconi <lorenzo@kernel.org>,
Saeed Mahameed <saeedm@nvidia.com>, Andrew Lunn <andrew@lunn.ch>,
Paolo Abeni <pabeni@redhat.com>,
Sven Auhagen <sven.auhagen@voleatech.de>
Subject: Re: [PATCH net-next v7 3/5] page_pool: Allow drivers to hint on SKB recycling
Date: Mon, 7 Jun 2021 07:51:56 +0300 [thread overview]
Message-ID: <YL2l7OxN4m7+d303@Iliass-MBP> (raw)
In-Reply-To: <YLqCAEVG+aLNGlIi@casper.infradead.org>
On Fri, Jun 04, 2021 at 08:41:52PM +0100, Matthew Wilcox wrote:
> On Fri, Jun 04, 2021 at 08:33:47PM +0200, Matteo Croce wrote:
> > diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> > index 7fcfea7e7b21..057b40ad29bd 100644
> > --- a/include/linux/skbuff.h
> > +++ b/include/linux/skbuff.h
> > @@ -40,6 +40,9 @@
> > #if IS_ENABLED(CONFIG_NF_CONNTRACK)
> > #include <linux/netfilter/nf_conntrack_common.h>
> > #endif
> > +#ifdef CONFIG_PAGE_POOL
> > +#include <net/page_pool.h>
> > +#endif
>
> I'm not a huge fan of conditional includes ... any reason to not include
> it always?
I think we can. I'll check and change it.
>
> > @@ -3088,7 +3095,13 @@ static inline void skb_frag_ref(struct sk_buff *skb, int f)
> > */
> > static inline void __skb_frag_unref(skb_frag_t *frag, bool recycle)
> > {
> > - put_page(skb_frag_page(frag));
> > + struct page *page = skb_frag_page(frag);
> > +
> > +#ifdef CONFIG_PAGE_POOL
> > + if (recycle && page_pool_return_skb_page(page_address(page)))
> > + return;
>
> It feels weird to have a page here, convert it back to an address,
> then convert it back to a head page in page_pool_return_skb_page().
> How about passing 'page' here, calling compound_head() in
> page_pool_return_skb_page() and calling virt_to_page() in skb_free_head()?
>
Sure, sounds reasonable.
> > @@ -251,4 +253,11 @@ static inline void page_pool_ring_unlock(struct page_pool *pool)
> > spin_unlock_bh(&pool->ring.producer_lock);
> > }
> >
> > +/* Store mem_info on struct page and use it while recycling skb frags */
> > +static inline
> > +void page_pool_store_mem_info(struct page *page, struct page_pool *pp)
> > +{
> > + page->pp = pp;
>
> I'm not sure this wrapper needs to exist.
>
> > +}
> > +
> > #endif /* _NET_PAGE_POOL_H */
> > diff --git a/net/core/page_pool.c b/net/core/page_pool.c
> > index e1321bc9d316..a03f48f45696 100644
> > --- a/net/core/page_pool.c
> > +++ b/net/core/page_pool.c
> > @@ -628,3 +628,26 @@ void page_pool_update_nid(struct page_pool *pool, int new_nid)
> > }
> > }
> > EXPORT_SYMBOL(page_pool_update_nid);
> > +
> > +bool page_pool_return_skb_page(void *data)
> > +{
> > + struct page_pool *pp;
> > + struct page *page;
> > +
> > + page = virt_to_head_page(data);
> > + if (unlikely(page->pp_magic != PP_SIGNATURE))
> > + return false;
> > +
> > + pp = (struct page_pool *)page->pp;
>
> You don't need the cast any more.
>
True
> > + /* Driver set this to memory recycling info. Reset it on recycle.
> > + * This will *not* work for NIC using a split-page memory model.
> > + * The page will be returned to the pool here regardless of the
> > + * 'flipped' fragment being in use or not.
> > + */
> > + page->pp = NULL;
> > + page_pool_put_full_page(pp, page, false);
> > +
> > + return true;
> > +}
> > +EXPORT_SYMBOL(page_pool_return_skb_page);
> > diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> > index 12b7e90dd2b5..f769f08e7b32 100644
> > --- a/net/core/skbuff.c
> > +++ b/net/core/skbuff.c
> > @@ -70,6 +70,9 @@
> > #include <net/xfrm.h>
> > #include <net/mpls.h>
> > #include <net/mptcp.h>
> > +#ifdef CONFIG_PAGE_POOL
> > +#include <net/page_pool.h>
> > +#endif
> >
> > #include <linux/uaccess.h>
> > #include <trace/events/skb.h>
> > @@ -645,10 +648,15 @@ static void skb_free_head(struct sk_buff *skb)
> > {
> > unsigned char *head = skb->head;
> >
> > - if (skb->head_frag)
> > + if (skb->head_frag) {
> > +#ifdef CONFIG_PAGE_POOL
> > + if (skb->pp_recycle && page_pool_return_skb_page(head))
> > + return;
> > +#endif
>
> put this in a header file:
>
> static inline bool skb_pp_recycle(struct sk_buff *skb, void *data)
> {
> if (!IS_ENABLED(CONFIG_PAGE_POOL) || !skb->pp_recycle)
> return false;
> return page_pool_return_skb_page(virt_to_page(data));
> }
>
> then this becomes:
>
> if (skb->head_frag) {
> if (skb_pp_recycle(skb, head))
> return;
> > skb_free_frag(head);
> > - else
> > + } else {
> > kfree(head);
> > + }
> > }
> >
ok
Thanks for having a look
Cheers
/Ilias
next prev parent reply other threads:[~2021-06-07 4:53 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-04 18:33 [PATCH net-next v7 0/5] page_pool: recycle buffers Matteo Croce
2021-06-04 18:33 ` [PATCH net-next v7 1/5] mm: add a signature in struct page Matteo Croce
2021-06-04 19:07 ` Matthew Wilcox
2021-06-04 22:59 ` Matteo Croce
2021-06-05 14:32 ` Matthew Wilcox
2021-06-06 1:50 ` Matteo Croce
2021-06-07 13:52 ` Matthew Wilcox
2021-06-07 13:58 ` Matteo Croce
2021-06-04 18:33 ` [PATCH net-next v7 2/5] skbuff: add a parameter to __skb_frag_unref Matteo Croce
2021-06-04 18:33 ` [PATCH net-next v7 3/5] page_pool: Allow drivers to hint on SKB recycling Matteo Croce
2021-06-04 19:41 ` Matthew Wilcox
2021-06-07 4:51 ` Ilias Apalodimas [this message]
2021-06-07 14:55 ` Matteo Croce
2021-06-04 18:33 ` [PATCH net-next v7 4/5] mvpp2: recycle buffers Matteo Croce
2021-06-04 19:48 ` Matthew Wilcox
2021-06-06 1:59 ` Matteo Croce
2021-06-04 18:33 ` [PATCH net-next v7 5/5] mvneta: " Matteo Croce
2021-06-04 18:57 ` [PATCH net-next v7 0/5] page_pool: " Matthew Wilcox
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