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Date:   Sun, 31 Jan 2021 12:11:52 +0000
To:     "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>
From:   Alexander Lobakin <alobakin@pm.me>
Cc:     John Hubbard <jhubbard@nvidia.com>,
        David Rientjes <rientjes@google.com>,
        Yisen Zhuang <yisen.zhuang@huawei.com>,
        Salil Mehta <salil.mehta@huawei.com>,
        Jesse Brandeburg <jesse.brandeburg@intel.com>,
        Tony Nguyen <anthony.l.nguyen@intel.com>,
        Saeed Mahameed <saeedm@nvidia.com>,
        Leon Romanovsky <leon@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jesper Dangaard Brouer <brouer@redhat.com>,
        Ilias Apalodimas <ilias.apalodimas@linaro.org>,
        Jonathan Lemon <jonathan.lemon@gmail.com>,
        Willem de Bruijn <willemb@google.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        Pablo Neira Ayuso <pablo@netfilter.org>,
        Dexuan Cui <decui@microsoft.com>,
        Jakub Sitnicki <jakub@cloudflare.com>,
        Marco Elver <elver@google.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Alexander Lobakin <alobakin@pm.me>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, intel-wired-lan@lists.osuosl.org,
        linux-rdma@vger.kernel.org, linux-mm@kvack.org
Reply-To: Alexander Lobakin <alobakin@pm.me>
Subject: [PATCH v3 net-next 3/5] net: introduce common dev_page_is_reusable()
Message-ID: <20210131120844.7529-4-alobakin@pm.me>
In-Reply-To: <20210131120844.7529-1-alobakin@pm.me>
References: <20210131120844.7529-1-alobakin@pm.me>
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Precedence: bulk

A bunch of drivers test the page before reusing/recycling for two
common conditions:
 - if a page was allocated under memory pressure (pfmemalloc page);
 - if a page was allocated at a distant memory node (to exclude
   slowdowns).

Introduce a new common inline for doing this, with likely() already
folded inside to make driver code a bit simpler.

Suggested-by: David Rientjes <rientjes@google.com>
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Acked-by: David Rientjes <rientjes@google.com>
---
 include/linux/skbuff.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index b027526da4f9..0e42c53b8ca9 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2938,6 +2938,22 @@ static inline struct page *dev_alloc_page(void)
 =09return dev_alloc_pages(0);
 }
=20
+/**
+ * dev_page_is_reusable - check whether a page can be reused for network R=
x
+ * @page: the page to test
+ *
+ * A page shouldn't be considered for reusing/recycling if it was allocate=
d
+ * under memory pressure or at a distant memory node.
+ *
+ * Returns false if this page should be returned to page allocator, true
+ * otherwise.
+ */
+static inline bool dev_page_is_reusable(const struct page *page)
+{
+=09return likely(page_to_nid(page) =3D=3D numa_mem_id() &&
+=09=09      !page_is_pfmemalloc(page));
+}
+
 /**
  *=09skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated a=
fter RX page
  *=09@page: The page that was allocated from skb_alloc_page
--=20
2.30.0