From: Ian Campbell <ian.campbell@citrix.com>
To: netdev@vger.kernel.org
Cc: David Miller <davem@davemloft.net>,
Eric Dumazet <eric.dumazet@gmail.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Wei Liu <wei.liu2@citrix.com>,
xen-devel@lists.xen.org, Ian Campbell <ian.campbell@citrix.com>
Subject: [PATCH 05/10] net: move destructor_arg to the front of sk_buff.
Date: Tue, 10 Apr 2012 15:26:19 +0100 [thread overview]
Message-ID: <1334067984-7706-5-git-send-email-ian.campbell@citrix.com> (raw)
In-Reply-To: <1334067965.5394.22.camel@zakaz.uk.xensource.com>
As of the previous patch we align the end (rather than the start) of the struct
to a cache line and so, with 32 and 64 byte cache lines and the shinfo size
increase from the next patch, the first 8 bytes of the struct end up on a
different cache line to the rest of it so make sure it is something relatively
unimportant to avoid hitting an extra cache line on hot operations such as
kfree_skb.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
---
include/linux/skbuff.h | 15 ++++++++++-----
net/core/skbuff.c | 5 ++++-
2 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 0ad6a46..f0ae39c 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -265,6 +265,15 @@ struct ubuf_info {
* the end of the header data, ie. at skb->end.
*/
struct skb_shared_info {
+ /* Intermediate layers must ensure that destructor_arg
+ * remains valid until skb destructor */
+ void *destructor_arg;
+
+ /*
+ * Warning: all fields from here until dataref are cleared in
+ * __alloc_skb()
+ *
+ */
unsigned char nr_frags;
__u8 tx_flags;
unsigned short gso_size;
@@ -276,14 +285,10 @@ struct skb_shared_info {
__be32 ip6_frag_id;
/*
- * Warning : all fields before dataref are cleared in __alloc_skb()
+ * Warning: all fields before dataref are cleared in __alloc_skb()
*/
atomic_t dataref;
- /* Intermediate layers must ensure that destructor_arg
- * remains valid until skb destructor */
- void * destructor_arg;
-
/* must be last field, see pskb_expand_head() */
skb_frag_t frags[MAX_SKB_FRAGS];
};
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index d4e139e..b8a41d6 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -214,7 +214,10 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
/* make sure we initialize shinfo sequentially */
shinfo = skb_shinfo(skb);
- memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
+
+ memset(&shinfo->nr_frags, 0,
+ offsetof(struct skb_shared_info, dataref)
+ - offsetof(struct skb_shared_info, nr_frags));
atomic_set(&shinfo->dataref, 1);
kmemcheck_annotate_variable(shinfo->destructor_arg);
--
1.7.2.5
next prev parent reply other threads:[~2012-04-10 14:32 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-10 14:26 [PATCH v4 0/10] skb paged fragment destructors Ian Campbell
2012-04-10 14:26 ` [PATCH 01/10] net: add and use SKB_ALLOCSIZE Ian Campbell
2012-04-10 14:57 ` Eric Dumazet
2012-04-10 14:26 ` [PATCH 02/10] net: Use SKB_WITH_OVERHEAD in build_skb Ian Campbell
2012-04-10 14:58 ` Eric Dumazet
2012-04-10 14:26 ` [PATCH 03/10] chelsio: use SKB_WITH_OVERHEAD Ian Campbell
2012-04-10 14:59 ` Eric Dumazet
2012-04-10 14:26 ` [PATCH 04/10] net: pad skb data and shinfo as a whole rather than individually Ian Campbell
2012-04-10 15:01 ` Eric Dumazet
2012-04-10 14:26 ` Ian Campbell [this message]
2012-04-10 15:05 ` [PATCH 05/10] net: move destructor_arg to the front of sk_buff Eric Dumazet
2012-04-10 15:19 ` Ian Campbell
2012-04-10 18:33 ` Alexander Duyck
2012-04-10 18:41 ` Eric Dumazet
2012-04-10 19:15 ` Alexander Duyck
2012-04-11 8:00 ` Ian Campbell
2012-04-11 16:31 ` Alexander Duyck
2012-04-11 17:00 ` Ian Campbell
2012-04-11 8:20 ` Eric Dumazet
2012-04-11 16:05 ` Alexander Duyck
2012-04-11 7:56 ` Ian Campbell
2012-04-10 14:26 ` [PATCH 06/10] net: add support for per-paged-fragment destructors Ian Campbell
2012-04-26 20:44 ` [Xen-devel] " Konrad Rzeszutek Wilk
2012-04-10 14:26 ` [PATCH 07/10] net: only allow paged fragments with the same destructor to be coalesced Ian Campbell
2012-04-10 20:11 ` Ben Hutchings
2012-04-11 7:45 ` Ian Campbell
2012-04-10 14:26 ` [PATCH 08/10] net: add skb_orphan_frags to copy aside frags with destructors Ian Campbell
[not found] ` <1334067965.5394.22.camel-o4Be2W7LfRlXesXXhkcM7miJhflN2719@public.gmane.org>
2012-04-10 14:26 ` [PATCH 09/10] net: add paged frag destructor support to kernel_sendpage Ian Campbell
2012-04-10 14:26 ` [PATCH 10/10] sunrpc: use SKB fragment destructors to delay completion until page is released by network stack Ian Campbell
2012-04-10 14:58 ` [PATCH v4 0/10] skb paged fragment destructors Michael S. Tsirkin
2012-04-10 15:00 ` Michael S. Tsirkin
2012-04-10 15:46 ` Bart Van Assche
2012-04-10 15:50 ` Ian Campbell
2012-04-11 10:02 ` Bart Van Assche
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