From: Hans Westgaard Ry <hans.westgaard.ry@oracle.com>
To: unlisted-recipients:; (no To-header on input)
Cc: "Hans Westgaard Ry" <hans.westgaard.ry@oracle.com>,
"David S. Miller" <davem@davemloft.net>,
"Alexey Kuznetsov" <kuznet@ms2.inr.ac.ru>,
"James Morris" <jmorris@namei.org>,
"Hideaki YOSHIFUJI" <yoshfuji@linux-ipv6.org>,
"Patrick McHardy" <kaber@trash.net>,
"Tom Herbert" <tom@herbertland.com>,
"Pablo Neira Ayuso" <pablo@netfilter.org>,
"Eric Dumazet" <edumazet@google.com>,
"Florian Westphal" <fw@strlen.de>,
"Jiri Pirko" <jiri@resnulli.us>,
"Alexander Duyck" <alexander.h.duyck@redhat.com>,
"Michal Hocko" <mhocko@suse.com>,
"Linus Lüssing" <linus.luessing@c0d3.blue>,
"Hannes Frederic Sowa" <hannes@stressinduktion.org>,
"Herbert Xu" <herbert@gondor.apana.org.au>,
"Tejun Heo" <tj@kernel.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Alexey Kodanev" <alexey.kodanev@oracle.com>,
"Håkon Bugge" <haakon.bugge@oracle.com>,
linux-kernel@vger.kernel.org (open list),
netdev@vger.kernel.org (open list:NETWORKING [GENERAL])
Subject: [PATCH v3] net:Add sysctl_max_skb_frags
Date: Wed, 3 Feb 2016 09:26:57 +0100 [thread overview]
Message-ID: <1454488017-8822-1-git-send-email-hans.westgaard.ry@oracle.com> (raw)
In-Reply-To: <568F87AC.60405@oracle.com>
Devices may have limits on the number of fragments in an skb they support.
Current codebase uses a constant as maximum for number of fragments one
skb can hold and use.
When enabling scatter/gather and running traffic with many small messages
the codebase uses the maximum number of fragments and may thereby violate
the max for certain devices.
The patch introduces a global variable as max number of fragments.
Signed-off-by: Hans Westgaard Ry <hans.westgaard.ry@oracle.com>
Reviewed-by: Håkon Bugge <haakon.bugge@oracle.com>
---
include/linux/skbuff.h | 1 +
net/core/skbuff.c | 2 ++
net/core/sysctl_net_core.c | 10 ++++++++++
net/ipv4/tcp.c | 4 ++--
4 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 4355129..fe47ad3 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -219,6 +219,7 @@ struct sk_buff;
#else
#define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1)
#endif
+extern int sysctl_max_skb_frags;
typedef struct skb_frag_struct skb_frag_t;
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 152b9c7..c336b97 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -79,6 +79,8 @@
struct kmem_cache *skbuff_head_cache __read_mostly;
static struct kmem_cache *skbuff_fclone_cache __read_mostly;
+int sysctl_max_skb_frags __read_mostly = MAX_SKB_FRAGS;
+EXPORT_SYMBOL(sysctl_max_skb_frags);
/**
* skb_panic - private function for out-of-line support
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 95b6139..a6beb7b 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -26,6 +26,7 @@ static int zero = 0;
static int one = 1;
static int min_sndbuf = SOCK_MIN_SNDBUF;
static int min_rcvbuf = SOCK_MIN_RCVBUF;
+static int max_skb_frags = MAX_SKB_FRAGS;
static int net_msg_warn; /* Unused, but still a sysctl */
@@ -392,6 +393,15 @@ static struct ctl_table net_core_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec
},
+ {
+ .procname = "max_skb_frags",
+ .data = &sysctl_max_skb_frags,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &one,
+ .extra2 = &max_skb_frags,
+ },
{ }
};
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index c82cca1..3dc7a2fd 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -938,7 +938,7 @@ new_segment:
i = skb_shinfo(skb)->nr_frags;
can_coalesce = skb_can_coalesce(skb, i, page, offset);
- if (!can_coalesce && i >= MAX_SKB_FRAGS) {
+ if (!can_coalesce && i >= sysctl_max_skb_frags) {
tcp_mark_push(tp, skb);
goto new_segment;
}
@@ -1211,7 +1211,7 @@ new_segment:
if (!skb_can_coalesce(skb, i, pfrag->page,
pfrag->offset)) {
- if (i == MAX_SKB_FRAGS || !sg) {
+ if (i == sysctl_max_skb_frags || !sg) {
tcp_mark_push(tp, skb);
goto new_segment;
}
--
2.4.3
next prev parent reply other threads:[~2016-02-03 8:29 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-06 13:16 [PATCH] net: add per device sg_max_frags for skb Hans Westgaard Ry
2016-01-06 13:59 ` David Laight
2016-01-08 9:55 ` Hans Westgaard Ry
2016-01-08 10:33 ` David Laight
2016-01-08 11:47 ` Hannes Frederic Sowa
2016-01-13 13:57 ` Hans Westgaard Ry
2016-01-13 14:19 ` Eric Dumazet
2016-01-13 14:20 ` Eric Dumazet
2016-01-13 15:07 ` Hannes Frederic Sowa
2016-01-13 15:38 ` David Miller
2016-01-13 15:44 ` Eric Dumazet
2016-01-13 21:07 ` Eric W. Biederman
2016-01-27 13:20 ` [PATCH v2] net:Add sysctl_tcp_sg_max_skb_frags Hans Westgaard Ry
2016-01-27 15:15 ` Eric Dumazet
2016-01-27 18:12 ` Hannes Frederic Sowa
2016-02-01 13:12 ` Hans Westgaard Ry
2016-01-27 20:13 ` David Miller
2016-02-03 8:26 ` Hans Westgaard Ry [this message]
2016-02-03 11:25 ` [PATCH v3] net:Add sysctl_max_skb_frags Herbert Xu
2016-02-03 11:36 ` Hannes Frederic Sowa
2016-02-03 12:20 ` Herbert Xu
2016-02-03 14:03 ` Hannes Frederic Sowa
2016-02-03 14:30 ` Eric Dumazet
2016-02-03 17:36 ` David Laight
2016-02-03 15:58 ` Alexander Duyck
2016-02-03 16:07 ` Eric Dumazet
2016-02-03 17:43 ` Alexander Duyck
2016-02-03 17:54 ` Eric Dumazet
2016-02-03 18:24 ` Alexander Duyck
2016-02-03 19:23 ` Eric Dumazet
2016-02-03 21:03 ` Alexander Duyck
2016-02-09 9:30 ` David Miller
2016-01-06 14:05 ` [PATCH] net: add per device sg_max_frags for skb Eric Dumazet
2016-01-08 10:01 ` Hans Westgaard Ry
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