Stephen Hemminger, on 12/15/2010 01:23 AM wrote: > 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. I see. Thanks for clarifying it. Vlad -- 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
