On 01/07/2011 12:26 PM, Eric Dumazet wrote:
Le vendredi 07 janvier 2011 Ã 12:09 -0800, Luis R. Rodriguez a Ãcrit :
On Fri, Jan 07, 2011 at 10:34:52AM -0800, Ben Greear wrote:
On 01/07/2011 02:58 AM, Johannes Berg wrote:
On Thu, 2011-01-06 at 16:46 -0800, greearb@xxxxxxxxxxxxxxx wrote:
From: Ben Greear<greearb@xxxxxxxxxxxxxxx>
Patch is from Eric Dumazet, as described here:
https://patchwork.kernel.org/patch/104271/
Reported-by: Michael Guntsche<mike@xxxxxxxxxxxx>
Signed-off-by: Eric Dumazet<eric.dumazet@xxxxxxxxx>
Signed-off-by: Ben Greear<greearb@xxxxxxxxxxxxxxx>
---
NOTE: This needs review by ath9k and/or other informed
people.
This doesn't make sense. It might help, but it'll probably lead to not
being able to receive all frames off the air.
If this is an issue, ath9k should do paged RX like iwlwifi.
Ok, I backed this out..but now I'm back to getting buffer allocation
failures (and this is on a system with 2GB RAM).
Seems it's coming from mac80211 instead of ath9k, at least most of
the time (I'm using 60 stations, so it probably needs to make lots of
copies in the rx path). The traffic I'm generating/receiving is 1024 byte UDP
payloads.
Does this mean I really received a packet that was 3872 bytes long,
or is the skb_copy allocating/copying empty data?
Good question. The buffer we setup for DMA should be large since we
need to support AMSDU RX up to a certain bytes of RX data for the frame.
Harwdware should tell us the right size for the RX'd data and the skb
should be set with that size, respectively. Following this logic,
skb_copy() should only allocate on the order of the required skb->len.
Remember that trick we did to force the older memory leak issues by
forcing an skb_copy() on every RX'd frame and then just discarding that
buffer immediately? You can try to do the same and print the skb->len
there, just to check what's going on.
Using skb_copy() is wrong then, since it makes a copy (order-1
allocations)
It should use :
skb_alloc( actual_size_of_frame not the 3840 thing ...)
copy(data)
We need the extra stuff copied too I think (like skb->cb).
If you could provide a bit more complete example code, I'll be happy
to test it...
Thanks,
Ben
--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc http://www.candelatech.com
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