On Tue, Apr 12, 2011 at 01:00:18PM -0500, Larry Finger wrote: > On 04/12/2011 10:38 AM, Igor Plyatov wrote: > > >kworker/u:1: page allocation failure. order:1, mode:0x20 mode:0x20 corresponds with GFP_ATOMIC > >[<c0279450>] (dev_alloc_skb+0x0/0x44) from [<c0226698>] > >(rt2x00queue_alloc_rxskb+0x4c/0xc4) > >[<c022664c>] (rt2x00queue_alloc_rxskb+0x0/0xc4) from [<c0223480>] > >(rt2x00lib_rxdone+0x44/0x298) > > --snip-- > > >Normal: 403*4kB 2*8kB 2*16kB 2*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB > >0*2048kB 0*4096kB = 1724kB > > Your system is failing to get a receive buffer of size 8kB > (order:1). If we look at the last line above, you have quite a bit > of memory free, but it is highly fragmented - almost all of it is in > 4kB pieces. This condition is not fatal, but it can be avoided by > changing the NIC parameters so that each RX buffer fits in 4k. > > If you look at the ifconfig output for this device, the MTU is > likely 1500. By reducing this, you should be able to get all buffers > to be of order 0. I would start with 1400 to see if it makes the > problem go away. Reducing this quantity has the potential to slow > the network transfers, but you won't see it as the default block > size for dd is 512. Any such slowdown will be much less severe than > the delay causes by missing a buffer allocation. I don't think the allocation uses the MTU, rather rt2x00queue_alloc_rxskb() uses some hw specific constants. No idea if these can be reduced, but multi-page GFP_ATOMIC allocations can easily fail. However, I'm not sure why an 8kB allocation fails if the oom dump says 2*8kB are available. I guess it has something to do with the GFP_ATOMIC. Johannes -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
