On Tue, Jan 10, 2017 at 11:16:18AM +0000, Will Deacon wrote:
> [adding some more folks to cc]
>
> On Wed, Dec 28, 2016 at 01:35:25PM +0900, AKASHI Takahiro wrote:
> > Add memblock_cap_memory_range() which will remove all the memblock regions
> > except the memory range specified in the arguments. In addition, rework is
> > done on memblock_mem_limit_remove_map() to re-implement it using
> > memblock_cap_memory_range().
> >
> > This function, like memblock_mem_limit_remove_map(), will not remove
> > memblocks with MEMMAP_NOMAP attribute as they may be mapped and accessed
> > later as "device memory."
> > See the commit a571d4eb55d8 ("mm/memblock.c: add new infrastructure to
> > address the mem limit issue").
> >
> > This function is used, in a succeeding patch in the series of arm64 kdump
> > suuport, to limit the range of usable memory, or System RAM, on crash dump
> > kernel.
> > (Please note that "mem=" parameter is of little use for this purpose.)
> >
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
> > Reviewed-by: Will Deacon <will.deacon at arm.com>
> > Acked-by: Catalin Marinas <catalin.marinas at arm.com>
> > Cc: linux-mm at kvack.org
> > Cc: Andrew Morton <akpm at linux-foundation.org>
> > ---
> > include/linux/memblock.h | 1 +
> > mm/memblock.c | 44 +++++++++++++++++++++++++++++---------------
> > 2 files changed, 30 insertions(+), 15 deletions(-)
>
> Whilst this patch looks fine to me, it would be nice if Dennis (author of
> memblock_mem_limit_remove_map) or one of the mm chaps could provide an ack
> before I merge it via arm64.
>
Will feel free to add
Acked-by: Dennis Chen <dennis.chen at arm.com>
Thanks,
Dennis
>
> Thanks,
>
> Will
>
> > diff --git a/include/linux/memblock.h b/include/linux/memblock.h
> > index 5b759c9acf97..fbfcacc50c29 100644
> > --- a/include/linux/memblock.h
> > +++ b/include/linux/memblock.h
> > @@ -333,6 +333,7 @@ phys_addr_t memblock_mem_size(unsigned long limit_pfn);
> > phys_addr_t memblock_start_of_DRAM(void);
> > phys_addr_t memblock_end_of_DRAM(void);
> > void memblock_enforce_memory_limit(phys_addr_t memory_limit);
> > +void memblock_cap_memory_range(phys_addr_t base, phys_addr_t size);
> > void memblock_mem_limit_remove_map(phys_addr_t limit);
> > bool memblock_is_memory(phys_addr_t addr);
> > int memblock_is_map_memory(phys_addr_t addr);
> > diff --git a/mm/memblock.c b/mm/memblock.c
> > index 7608bc305936..fea1688fef60 100644
> > --- a/mm/memblock.c
> > +++ b/mm/memblock.c
> > @@ -1514,11 +1514,37 @@ void __init memblock_enforce_memory_limit(phys_addr_t limit)
> > (phys_addr_t)ULLONG_MAX);
> > }
> >
> > +void __init memblock_cap_memory_range(phys_addr_t base, phys_addr_t size)
> > +{
> > + int start_rgn, end_rgn;
> > + int i, ret;
> > +
> > + if (!size)
> > + return;
> > +
> > + ret = memblock_isolate_range(&memblock.memory, base, size,
> > + &start_rgn, &end_rgn);
> > + if (ret)
> > + return;
> > +
> > + /* remove all the MAP regions */
> > + for (i = memblock.memory.cnt - 1; i >= end_rgn; i--)
> > + if (!memblock_is_nomap(&memblock.memory.regions[i]))
> > + memblock_remove_region(&memblock.memory, i);
> > +
> > + for (i = start_rgn - 1; i >= 0; i--)
> > + if (!memblock_is_nomap(&memblock.memory.regions[i]))
> > + memblock_remove_region(&memblock.memory, i);
> > +
> > + /* truncate the reserved regions */
> > + memblock_remove_range(&memblock.reserved, 0, base);
> > + memblock_remove_range(&memblock.reserved,
> > + base + size, (phys_addr_t)ULLONG_MAX);
> > +}
> > +
> > void __init memblock_mem_limit_remove_map(phys_addr_t limit)
> > {
> > - struct memblock_type *type = &memblock.memory;
> > phys_addr_t max_addr;
> > - int i, ret, start_rgn, end_rgn;
> >
> > if (!limit)
> > return;
> > @@ -1529,19 +1555,7 @@ void __init memblock_mem_limit_remove_map(phys_addr_t limit)
> > if (max_addr == (phys_addr_t)ULLONG_MAX)
> > return;
> >
> > - ret = memblock_isolate_range(type, max_addr, (phys_addr_t)ULLONG_MAX,
> > - &start_rgn, &end_rgn);
> > - if (ret)
> > - return;
> > -
> > - /* remove all the MAP regions above the limit */
> > - for (i = end_rgn - 1; i >= start_rgn; i--) {
> > - if (!memblock_is_nomap(&type->regions[i]))
> > - memblock_remove_region(type, i);
> > - }
> > - /* truncate the reserved regions */
> > - memblock_remove_range(&memblock.reserved, max_addr,
> > - (phys_addr_t)ULLONG_MAX);
> > + memblock_cap_memory_range(0, max_addr);
> > }
> >
> > static int __init_memblock memblock_search(struct memblock_type *type, phys_addr_t addr)
> > --
> > 2.11.0
> >
