Messages in this thread | | | Date | Mon, 27 Dec 2004 18:17:32 +0100 | From | Patrick McHardy <> | Subject | Re: PATCH: kmalloc packet slab |
| |
Alan Cox wrote: > The networking world runs in 1514 byte packets pretty much all the time. > This adds a 1620 byte slab for such objects and is one of the internally > generated Red Hat patches we use on things like Fedora Core 3. Original: > Arjan van de Ven. > > Signed-off-by: Alan Cox <alan@redhat.com>
Why 1620 bytes ? Most drivers allocate packet_size + 2 bytes. dev_alloc_skb adds another 16 bytes, finally alloc_skb adds sizeof(struct skb_shared_info). So we get:
(32bit): 1514b + 2b + 16b + 160b = 1692b (64bit): 1514b + 2b + 16b + 312b = 1844b
On paths using alloc_skb instead of dev_alloc_skb it's 16 bytes less, but 1620 bytes is still too small for full-sized packets.
Regards Patrick - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |