Messages in this thread | | | Date | Sun, 4 Apr 2010 13:33:09 +0800 | Subject | Fwd: Can we remove the Zone_DMA? | From | tek-life <> |
| |
Thanks for your reply.And do you means that , If I use a modern PC,such as my pc (CPU:Intel dual-core 2.6GHZ; Memory 2GB; And no pci ).I can remove the ZONE_DMA .And make sure this system also run smoothly as before?
在 2010年4月4日 下午1:07,Daniel Hazelton <dhazelton@enter.net>写道:
On Sunday 04 April 2010 12:21:54 am tek-life wrote: > > I’m a newbie on the linux kernel. Now I am reading the source code of > > Linux . I have a question in the following about ZONE_DMA. > > > > > > In Linux , The Memory is divided to three zone. They are ZONE_DMA > > 、ZONE_NORMAL and ZONE_HIGHMEM. From the book of "Undstand the Linux > > kernel ", the ZONE_DMA has the effect that the Direct Memory Access > > (DMA) processors for old ISA buses have a strong limitation: they are > > able to address only the first 16 MB of RAM. SO ,we must set a zone > > for the DMA on ISA bus. And I suspect that the hardware has > > developed so quickly .And in this days the ISA has been weeded out. > > And so ,if we not defined the ZONE_DMA, is the system be effected? And > > why not remove ZONE_DMA from the kernel . If it cann‘t to do so,the > > compatibility is the only reason? > > While ISA is gone as a true peripheral interconnect for new systems it > does, > actually, still live on in a lot of systems that Linux still supports. > While > those systems, generally, are running the same kernel and userspace they > were > a decade ago I have no doubt that somebody might find an old machine and > put > Linux on it - just because they could. > > And that also discounts the non-IBM PC machines that are out there that > Linux > also supports. While I don't know enough about them to say for sure, I am > quite certain that at least some of them are still using the ISA bus. > > DRH >
-- Laboratory of Service Computing Technology and System
p-web:http://tek-life.org/blog QQ:150439216
-- Laboratory of Service Computing Technology and System
p-web:http://tek-life.org/blog QQ:150439216 -- 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/
| |