[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH net-next] xen-netback: allocate xenvif arrays using vzalloc.
On Tue, Oct 29, 2013 at 04:32:12PM -0700, Eric Dumazet wrote: > On Tue, 2013-10-29 at 16:24 -0700, Eric Dumazet wrote: > > On Tue, 2013-10-29 at 18:46 +0000, Joby Poriyath wrote: > > > On Tue, Oct 29, 2013 at 08:43:50AM -0700, Eric Dumazet wrote: > > > > On Tue, 2013-10-29 at 15:27 +0000, Joby Poriyath wrote: > > > > > This will reduce memory pressure when allocating struct xenvif. > > > > > > > > > > The size of xenvif struct has increased from 168 to 36632 bytes (on > > > > > x86-32). > > > > > See commit b3f980bd827e6e81a050c518d60ed7811a83061d. This resulted in > > > > > occasional netdev allocation failure in dom0 with 752MiB RAM, due to > > > > > fragmented memory. > > > > > > > > This looks overkill. > > > > > > > > Replacing a single allocation of ~36 KB into 5 vmalloc() looks like you > > > > did not really tried other things... > > > > > > > > This should be done generically in alloc_netdev_mqs() > > > > > > Sorry Eric, I didn't quite understand how this can be generically done. > > > > > > The netback interfaces are tied to the Xen guests (VMs) and these are > > > created > > > when guests are started and deleted when guest are halted. > > > > They are created by alloc_netdev_mqs() > > Something like the following should be fine. > > > Thanks for the patch. > diff --git a/net/core/dev.c b/net/core/dev.c > index 0054c8c..874a57a 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -6239,7 +6239,9 @@ 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; > The net_device allocation rule {linux/Documentation/networking/netdevices.txt} states that net_device struct must be allocated using kmalloc. Is this safe to do? > @@ -6302,7 +6304,10 @@ free_pcpu: > #endif > > free_p: > - kfree(p); > + if (is_vmalloc_addr(p)) > + vfree(p); > + else > + kfree(p); > return NULL; > } > EXPORT_SYMBOL(alloc_netdev_mqs); > @@ -6339,7 +6344,12 @@ void free_netdev(struct net_device *dev) > > /* Compatibility with error handling in drivers */ > if (dev->reg_state == NETREG_UNINITIALIZED) { > - kfree((char *)dev - dev->padded); > + char *addr = (char *)dev - dev->padded; > + > + if (is_vmalloc_addr(addr)) > + vfree(addr); > + else > + kfree(addr); > return; > } > > diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c > index d954b56..406c54b 100644 > --- a/net/core/net-sysfs.c > +++ b/net/core/net-sysfs.c > @@ -1259,11 +1259,16 @@ exit: > static void netdev_release(struct device *d) > { > struct net_device *dev = to_net_dev(d); > + char *addr; > > BUG_ON(dev->reg_state != NETREG_RELEASED); > > kfree(dev->ifalias); > - kfree((char *)dev - dev->padded); > + addr = (char *)dev - dev->padded; > + if (is_vmalloc_addr(addr)) > + vfree(addr); > + else > + kfree(addr); > } > > static const void *net_namespace(struct device *d) > > Thanks, Joby _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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