Re: [PATCH v2 08/25] powerpc/8xx: Map IMMR area with 512k page at a fixed address

2015-09-28 Thread Scott Wood
On Tue, Sep 22, 2015 at 06:50:44PM +0200, Christophe Leroy wrote: > diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c > index 3fd9083..1f2fdbc 100644 > --- a/arch/powerpc/mm/pgtable_32.c > +++ b/arch/powerpc/mm/pgtable_32.c > @@ -49,6 +49,10 @@ EXPORT_SYMBOL(ioremap_bot);

RE: [PATCH v2 08/25] powerpc/8xx: Map IMMR area with 512k page at a fixed address

2015-09-25 Thread David Laight
From: Scott Wood > Sent: 24 September 2015 21:14 > > Isn't this a more general problem? > > > > If there are multiple remap requests for the same physical page > > shouldn't the kernel be just increasing a reference count somewhere > > and returning address in the same virtual page? > > This

Re: [PATCH v2 08/25] powerpc/8xx: Map IMMR area with 512k page at a fixed address

2015-09-25 Thread Scott Wood
On Fri, 2015-09-25 at 14:46 +, David Laight wrote: > From: Scott Wood > > Sent: 24 September 2015 21:14 > > > Isn't this a more general problem? > > > > > > If there are multiple remap requests for the same physical page > > > shouldn't the kernel be just increasing a reference count

RE: [PATCH v2 08/25] powerpc/8xx: Map IMMR area with 512k page at a fixed address

2015-09-24 Thread David Laight
From: Christophe Leroy > Sent: 22 September 2015 17:51 ... > Traditionaly, each driver manages one computer board which has its > own components with its own memory maps. > But on embedded chips like the MPC8xx, the SOC has all registers > located in the same IO area. > > When looking at ioremaps

Re: [PATCH v2 08/25] powerpc/8xx: Map IMMR area with 512k page at a fixed address

2015-09-24 Thread Scott Wood
On Thu, 2015-09-24 at 11:41 +, David Laight wrote: > From: Christophe Leroy > > Sent: 22 September 2015 17:51 > ... > > Traditionaly, each driver manages one computer board which has its > > own components with its own memory maps. > > But on embedded chips like the MPC8xx, the SOC has all

[PATCH v2 08/25] powerpc/8xx: Map IMMR area with 512k page at a fixed address

2015-09-22 Thread Christophe Leroy
Once the linear memory space has been mapped with 8Mb pages, as seen in the related commit, we get 11 millions DTLB missed during the reference 600s period. 77% of the missed are on user addresses and 23% are on kernel addresses (1 fourth for linear address space and 3 fourth for virtual address