Re: [PATCH v2 0/3] introduce static_vm for ARM-specific static mapped area
From: JoonSoo Kim
Date: Thu Dec 06 2012 - 11:18:06 EST
2012/11/28 Joonsoo Kim <js1304@xxxxxxxxx>:
> 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 architecture dependency
> on vmalloc layer. I think that vmlist and vmlist_lock is internal data
> structure for vmalloc layer. Some codes for debugging and stat inevitably
> use vmlist and vmlist_lock. But it is preferable that they are used
> as least as possible in outside of vmalloc.c
> [2/3]: patch description is improved.
> Rebased on v3.7-rc7
> Joonsoo Kim (3):
> ARM: vmregion: remove vmregion code entirely
> ARM: static_vm: introduce an infrastructure for static mapped area
> ARM: mm: use static_vm for managing static mapped areas
> arch/arm/include/asm/mach/static_vm.h | 51 ++++++++
> arch/arm/mm/Makefile | 2 +-
> arch/arm/mm/ioremap.c | 69 ++++-------
> arch/arm/mm/mm.h | 10 --
> arch/arm/mm/mmu.c | 55 +++++----
> arch/arm/mm/static_vm.c | 97 ++++++++++++++++
> arch/arm/mm/vmregion.c | 205 ---------------------------------
> arch/arm/mm/vmregion.h | 31 -----
> 8 files changed, 208 insertions(+), 312 deletions(-)
> create mode 100644 arch/arm/include/asm/mach/static_vm.h
> create mode 100644 arch/arm/mm/static_vm.c
> delete mode 100644 arch/arm/mm/vmregion.c
> delete mode 100644 arch/arm/mm/vmregion.h
Could you review this patchset, please?
I send another patchset to mm community on top of this.
That one is related to this patchset,
so I want to get a review about this patchset :)
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