[PATCH net-next v13 0/3] add hisilicon hip04 ethernet driver

On 2015/1/15 20:39, Alexander Graf wrote:

On 15.01.15 10:42, Arnd Bergmann wrote:

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On Thursday 15 January 2015 16:37:23 Ding Tianhong wrote:

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On 2015/1/14 18:19, Alexander Graf wrote:

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From a 10000 feet perspective it looks like two problems to me

  1) Allocation failure doesn't get handled properly somewhere

This is the bug that Eric pointed out as well.

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  2) We fail to allocate with order=0 - I don't see why

GFP_ATOMIC. When allocating from a the napi poll function in softirq
context, you have to use nonblocking allocations, which occasionally
fail. This should not cause any harm other than dropped packets.

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is it easy to repetition this bug? how big is your memory on your board,
is it happened in your previous hip04 driver?

It should be independent of memory size, but may be more likely if you
don't have swap space configured.

With the previous driver I was unable to get this far - I ended up in
random memory corruption and had a ~90% packet loss after about an hour
of uptime.

I'm not sure whether it's easy to reproduce, I merely started up a few
VMs, did some disk I/O and started to compile QEMU in the background ;).

I'll happily give your follow up patch that's going to fix the memory
allocation problems a try though.

Thanks for your work, I am sure we could make it much more better:)

Ding

Alex

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