On Fri, 2005-08-19 at 10:33 -0700, Jesse Brandeburg wrote: > On Fri, 19 Aug 2005, Ming Zhang wrote: > > This is first reported on IET list and then i redo the test with vanilla > > 2.6.12.4 kernel and everything went fine. > > > > so i suspect if there are special case caused by vendor kernel. > > > > is this 32KB ATOMIC ram allocation request only available in jumbo frame > > case? since the regular MTU case goes fine. > > > > Ahh, okay. I'm pretty sure that SuSE did some changes (not sure what) to > memory management. > > the formula for the size that the current e1000 looks for is something > like > > a = MTU roundup to next power of 2 > a += 2 (skb_reserve(NET_IP_ALIGN)) > a += 16 (skb_reserve 16 by __dev_alloc_skb) > > so, a = 2048 + 2 + 16, or 2066 > request (a) from slab, which does a power of 2 roundup > so the skb comes from the 4k (single page) slab for standard mtu. > that is wasteful.
> Jesse > > PS we have a driver in test that won't do the large contig allocations any > more. > then wait to see this. :P - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
