On Tue, 2013-05-14 at 09:19 -0700, Michael Chan wrote: > We relocate once and then drop the packet if we encounter additional > errors, including OOM, DMA mapping error, 4G boundary, etc. The new > linear skb should not hit the 4G boundary again. The room between the > end of this current buffer and 4G isn't big enough for the new linear > skb. This remind me an issue on bnx2x : bnx2x FW has a limitation on GSO packets : A single mss can not span more than 10 fragments. After "net: use a per task frag allocator" patch, its possible for an application interleaving small write() on several sockets to build pathological skbs using 16 fragments (aka MAX_SKB_FRAGS) but small amount of payload. Fast path should build skbs with 2 or 3 fragments, as fragments can be order-3 pages. bnx2x driver performs an expensive skb_linearize() call and this can fail if memory is fragmented : skb->len can be around 64K, and including the skb_shared_info overhead, we might need order-5 pages. -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html