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Date: Wed, 30 Oct 2013 13:10:44 -0700
From: Eric Dumazet <eric.dumazet@...il.com>
To: Joby Poriyath <joby.poriyath@...rix.com>,
Ben Hutchings <bhutchings@...arflare.com>
Cc: David Miller <davem@...emloft.net>, netdev@...r.kernel.org,
wei.liu2@...rix.com, ian.campbell@...rix.com,
xen-devel@...ts.xen.org, andrew.bennieston@...rix.com,
david.vrabel@...rix.com, malcolm.crossley@...rix.com
Subject: [PATCH v2 net-next] net: extend net_device allocation to vmalloc()
From: Eric Dumazet <edumazet@...gle.com>
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@...gle.com>
Reported-by: Joby Poriyath <joby.poriyath@...rix.com>
Cc: Ben Hutchings <bhutchings@...arflare.com>
---
v2: change the Documentation to point to alloc_netdev_mqs()
instead of kmalloc()/vzalloc(), from Ben
Documentation/networking/netdevices.txt | 10 +++++-----
include/linux/netdevice.h | 1 +
net/core/dev.c | 22 +++++++++++++++++-----
net/core/net-sysfs.c | 2 +-
4 files changed, 24 insertions(+), 11 deletions(-)
diff --git a/Documentation/networking/netdevices.txt b/Documentation/networking/netdevices.txt
index c7ecc70..7d8d79f 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 cb1d918..e6353ca 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 0054c8c..0e61365 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,
}
EXPORT_SYMBOL_GPL(netdev_set_default_ethtool_ops);
+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(dev->_rx);
#endif
-free_p:
- kfree(p);
+free_dev:
+ netdev_freemem(dev);
return NULL;
}
EXPORT_SYMBOL(alloc_netdev_mqs);
@@ -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);
return;
}
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index d954b56..d03f2c9 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(dev->ifalias);
- kfree((char *)dev - dev->padded);
+ netdev_freemem(dev);
}
static const void *net_namespace(struct device *d)
--
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