diff options
authorEric Dumazet <edumazet@google.com>2013-10-30 13:10:44 -0700
committerDavid S. Miller <davem@davemloft.net>2013-11-03 23:19:00 -0500
commit74d332c13b2148ae934ea94dac1745ae92efe8e5 (patch)
parentb397f99921827e114d7f5600447e172a99c50165 (diff)
net: extend net_device allocation to vmalloc()
Joby Poriyath provided a xen-netback patch to reduce the size of xenvif structure as some netdev allocation could fail under memory pressure/fragmentation. This patch is handling the problem at the core level, allowing any netdev structures to use vmalloc() if kmalloc() failed. As vmalloc() adds overhead on a critical network path, add __GFP_REPEAT to kzalloc() flags to do this fallback only when really needed. Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Joby Poriyath <joby.poriyath@citrix.com> Cc: Ben Hutchings <bhutchings@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
4 files changed, 24 insertions, 11 deletions
diff --git a/Documentation/networking/netdevices.txt b/Documentation/networking/netdevices.txt
index c7ecc7080494..0b1cf6b2a592 100644
--- a/Documentation/networking/netdevices.txt
+++ b/Documentation/networking/netdevices.txt
@@ -10,12 +10,12 @@ network devices.
struct net_device allocation rules
Network device structures need to persist even after module is unloaded and
-must be allocated with kmalloc. If device has registered successfully,
-it will be freed on last use by free_netdev. This is required to handle the
-pathologic case cleanly (example: rmmod mydriver </sys/class/net/myeth/mtu )
+must be allocated with alloc_netdev_mqs() and friends.
+If device has registered successfully, it will be freed on last use
+by free_netdev(). This is required to handle the pathologic case cleanly
+(example: rmmod mydriver </sys/class/net/myeth/mtu )
-There are routines in net_init.c to handle the common cases of
-alloc_etherdev, alloc_netdev. These reserve extra space for driver
+alloc_netdev_mqs()/alloc_netdev() reserve extra space for driver
private data which gets freed when the network device is freed. If
separately allocated data is attached to the network device
(netdev_priv(dev)) then it is up to the module exit handler to free that.
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index cb1d918ecdf1..e6353cafbf05 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1800,6 +1800,7 @@ static inline void unregister_netdevice(struct net_device *dev)
int netdev_refcnt_read(const struct net_device *dev);
void free_netdev(struct net_device *dev);
+void netdev_freemem(struct net_device *dev);
void synchronize_net(void);
int init_dummy_netdev(struct net_device *dev);
diff --git a/net/core/dev.c b/net/core/dev.c
index 0054c8c75f50..0e6136546a8c 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6196,6 +6196,16 @@ void netdev_set_default_ethtool_ops(struct net_device *dev,
+void netdev_freemem(struct net_device *dev)
+ char *addr = (char *)dev - dev->padded;
+ if (is_vmalloc_addr(addr))
+ vfree(addr);
+ else
+ kfree(addr);
* alloc_netdev_mqs - allocate network device
* @sizeof_priv: size of private data to allocate space for
@@ -6239,7 +6249,9 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
/* ensure 32-byte alignment of whole construct */
alloc_size += NETDEV_ALIGN - 1;
- p = kzalloc(alloc_size, GFP_KERNEL);
+ p = kzalloc(alloc_size, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
+ if (!p)
+ p = vzalloc(alloc_size);
if (!p)
return NULL;
@@ -6248,7 +6260,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
dev->pcpu_refcnt = alloc_percpu(int);
if (!dev->pcpu_refcnt)
- goto free_p;
+ goto free_dev;
if (dev_addr_init(dev))
goto free_pcpu;
@@ -6301,8 +6313,8 @@ free_pcpu:
- kfree(p);
+ netdev_freemem(dev);
return NULL;
@@ -6339,7 +6351,7 @@ void free_netdev(struct net_device *dev)
/* Compatibility with error handling in drivers */
if (dev->reg_state == NETREG_UNINITIALIZED) {
- kfree((char *)dev - dev->padded);
+ netdev_freemem(dev);
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index d954b56b4e47..d03f2c9750fa 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1263,7 +1263,7 @@ static void netdev_release(struct device *d)
BUG_ON(dev->reg_state != NETREG_RELEASED);
- kfree((char *)dev - dev->padded);
+ netdev_freemem(dev);
static const void *net_namespace(struct device *d)