On Tue, 14 Dec 2010 23:35:37 +0300 Vladislav Bolkhovitin <vst@xxxxxxxx> wrote: > What is interesting to me in this regard is how networking with 9K jumbo > frames manages to work acceptably reliable? Jumbo frames used > sufficiently often, including under high memory pressure. > > I'm not a deep networking guru, but network drivers need to allocate > physically continual memory for skbs, which means 16K per 9K packet, > which means order 2 allocations per skb. Good network drivers support fragmentation and allocate a small portion for the header and allocate pages for the rest. This requires no higher order allocation. The networking stack takes fragmented data coming in and does the necessary copy/merging to access contiguous headers. There are still some crap network drivers that require large contiguous allocation. These should not be used with jumbo frames in real environments. -- -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
