Re: [PATCH v5 0/3] introduce static_vm for ARM-specific static mapped area

Joonsoo Kim
2013-02-06T02:09:39Z

Hello, Santosh.

On Tue, Feb 05, 2013 at 02:32:06PM +0530, Santosh Shilimkar wrote:
> On Tuesday 05 February 2013 06:01 AM, Joonsoo Kim wrote:
> >In current implementation, we used ARM-specific flag, that is,
> >VM_ARM_STATIC_MAPPING, for distinguishing ARM specific static mapped area.
> >The purpose of static mapped area is to re-use static mapped area when
> >entire physical address range of the ioremap request can be covered
> >by this area.
> >
> >This implementation causes needless overhead for some cases.
> >For example, assume that there is only one static mapped area and
> >vmlist has 300 areas. Every time we call ioremap, we check 300 areas for
> >deciding whether it is matched or not. Moreover, even if there is
> >no static mapped area and vmlist has 300 areas, every time we call
> >ioremap, we check 300 areas in now.
> >
> >If we construct a extra list for static mapped area, we can eliminate
> >above mentioned overhead.
> >With a extra list, if there is one static mapped area,
> >we just check only one area and proceed next operation quickly.
> >
> >In fact, it is not a critical problem, because ioremap is not frequently
> >used. But reducing overhead is better idea.
> >
> >Another reason for doing this work is for removing vm_struct list management,
> >entirely. For more information, look at the following link.
> >http://lkml.org/lkml/2012/12/6/184
> >
>
> [..]
>
> >
> >Joonsoo Kim (3):
> > ARM: vmregion: remove vmregion code entirely
> > ARM: ioremap: introduce an infrastructure for static mapped area
> > ARM: mm: use static_vm for managing static mapped areas
> >
> > arch/arm/mm/Makefile | 2 +-
> > arch/arm/mm/ioremap.c | 135 +++++++++++++++++++++----------
> > arch/arm/mm/mm.h | 12 +++
> > arch/arm/mm/mmu.c | 34 ++++----
> > arch/arm/mm/vmregion.c | 205 ------------------------------------------------
> > arch/arm/mm/vmregion.h | 31 --------
> > 6 files changed, 123 insertions(+), 296 deletions(-)
> > delete mode 100644 arch/arm/mm/vmregion.c
> > delete mode 100644 arch/arm/mm/vmregion.h
> >
> Nice Clean-up. I tested this series on OMAP which uses few static
> mappings. Feel free to add,
>
> Tested-by: Santosh Shilimkar<santosh.shilimkar@ti.com>

I will re-send v6 with your Tested-by.

Thanks for testing this.

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