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 Changelog v2->v3: coverletter: refer a link related to this work [2/3]: drop @flags of find_static_vm_vaddr Rebased on v3.8-rc4 v1->v2: [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 | 54 +++++---- arch/arm/mm/static_vm.c | 94 +++++++++++++++ arch/arm/mm/vmregion.c | 205 --------------------------------- arch/arm/mm/vmregion.h | 31 ----- 8 files changed, 204 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 -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/