On 08/28/2005 06:40:04 AM, Kai Makisara wrote:
On Fri, 26 Aug 2005, Kai Makisara wrote: > On Thu, 25 Aug 2005, Andrew Morton wrote: > > > Could this purely be a highmem problem? Is the zero-copy DMA feature of > > st.c known to work OK with x86 highmem? > > It is _not_ known _not_ to work ;-) I.e., I have received neither any > success nor any failure reports. I have not tested it because I don't have > any machine with enough memory (and I have not hacked a kernel to use > highmem with 512 MB of memory). I hope someone seeing this thread and > using highmem with tape can comment on this subject. > OK. I booted my test i386 machine with highmem=384m and did some tests. I also added a counter to st.c to count the highmem pages used for zero-copy DMA. I could not get dd to use highmem but with tar that succeeded. No extra messages were found in syslog during these tests. BUT, at the same time I remembered that the system in the Bugzilla report was Athlon64 running FC3 x86_64. The x86_64 kernel does not have highmem.
True. I do have a machine running FC4 x86_64, but it doesn't have 4G of memory, so it doesn't do the 4G-remap that the bug report refers to.
Don't know if there is any way to make it do so (other than buy more memory). Regards, Willem Riede. - : 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
