Re: [discuss] Re: x86_64: 2.6.14-rc4 swiotlb broken

[Alex Williamson <alex.williamson@hp.com>]

On Tue, 2005-10-18 at 19:22 -0600, Alex Williamson wrote:
> On Tue, 2005-10-18 at 16:22 -0700, Ravikiran G Thirumalai wrote:
> 
> > Hope the following works.   Using __alloc_bootmem_node now with a hard coded
> > goal to avoid 16MB DMA zone.  It is ugly :( and hope it works this time
> > <fingers crossed>. 
> 
>    Nope, it still gives me memory above 4GB.  If I change goal to 0x0 it
> works.

   BTW, the reason 16MB fails is this test in __alloc_bootmem_core():

     if (bdata->last_success >= preferred)
            preferred = bdata->last_success;

That pretty much negates most of usefulness of passing in a goal other
than 0 or !0.  If I comment out this test, the 16MB goal works as
expected, but I get an uninitialized timer in the sym53c8xx driver.  Not
sure what's happening there, but apparently the test has some purpose
other than optimization.  Thanks,

	Alex