| Message ID | 20161102045153.12008-1-takahiro.akashi@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Nov 02, 2016 at 01:51:53PM +0900, AKASHI Takahiro wrote: > Add memblock_cap_memory_range() which will remove all the memblock regions > except the range specified in the arguments. > > 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, 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@linaro.org> > Cc: linux-mm@kvack.org > Cc: Andrew Morton <akpm@linux-foundation.org> > --- > include/linux/memblock.h | 1 + > mm/memblock.c | 28 ++++++++++++++++++++++++++++ > 2 files changed, 29 insertions(+) > > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > index 5b759c9..0e770af 100644 > --- a/include/linux/memblock.h > +++ b/include/linux/memblock.h > @@ -334,6 +334,7 @@ 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_mem_limit_remove_map(phys_addr_t limit); > +void memblock_cap_memory_range(phys_addr_t base, phys_addr_t size); > bool memblock_is_memory(phys_addr_t addr); > int memblock_is_map_memory(phys_addr_t addr); > int memblock_is_region_memory(phys_addr_t base, phys_addr_t size); > diff --git a/mm/memblock.c b/mm/memblock.c > index 7608bc3..eb53876 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -1544,6 +1544,34 @@ void __init memblock_mem_limit_remove_map(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); > +} This duplicates a bunch of the logic in memblock_mem_limit_remove_map. Can you not implement that in terms of your new, more general, function? e.g. by passing base == 0, and size == limit? Will
Will, (+ Cc: Dennis) On Thu, Nov 10, 2016 at 05:27:20PM +0000, Will Deacon wrote: > On Wed, Nov 02, 2016 at 01:51:53PM +0900, AKASHI Takahiro wrote: > > Add memblock_cap_memory_range() which will remove all the memblock regions > > except the range specified in the arguments. > > > > 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, 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@linaro.org> > > Cc: linux-mm@kvack.org > > Cc: Andrew Morton <akpm@linux-foundation.org> > > --- > > include/linux/memblock.h | 1 + > > mm/memblock.c | 28 ++++++++++++++++++++++++++++ > > 2 files changed, 29 insertions(+) > > > > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > > index 5b759c9..0e770af 100644 > > --- a/include/linux/memblock.h > > +++ b/include/linux/memblock.h > > @@ -334,6 +334,7 @@ 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_mem_limit_remove_map(phys_addr_t limit); > > +void memblock_cap_memory_range(phys_addr_t base, phys_addr_t size); > > bool memblock_is_memory(phys_addr_t addr); > > int memblock_is_map_memory(phys_addr_t addr); > > int memblock_is_region_memory(phys_addr_t base, phys_addr_t size); > > diff --git a/mm/memblock.c b/mm/memblock.c > > index 7608bc3..eb53876 100644 > > --- a/mm/memblock.c > > +++ b/mm/memblock.c > > @@ -1544,6 +1544,34 @@ void __init memblock_mem_limit_remove_map(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); > > +} > > This duplicates a bunch of the logic in memblock_mem_limit_remove_map. Can > you not implement that in terms of your new, more general, function? e.g. > by passing base == 0, and size == limit? Obviously it's possible. I actually talked to Dennis before about merging them, but he was against my idea. Thanks, -Takahiro AKASHI > Will
On Fri, Nov 11, 2016 at 11:50:50AM +0900, AKASHI Takahiro wrote: > Will, > (+ Cc: Dennis) > > On Thu, Nov 10, 2016 at 05:27:20PM +0000, Will Deacon wrote: > > On Wed, Nov 02, 2016 at 01:51:53PM +0900, AKASHI Takahiro wrote: > > > Add memblock_cap_memory_range() which will remove all the memblock regions > > > except the range specified in the arguments. > > > > > > 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, 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@linaro.org> > > > Cc: linux-mm@kvack.org > > > Cc: Andrew Morton <akpm@linux-foundation.org> > > > --- > > > include/linux/memblock.h | 1 + > > > mm/memblock.c | 28 ++++++++++++++++++++++++++++ > > > 2 files changed, 29 insertions(+) > > > > > > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > > > index 5b759c9..0e770af 100644 > > > --- a/include/linux/memblock.h > > > +++ b/include/linux/memblock.h > > > @@ -334,6 +334,7 @@ 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_mem_limit_remove_map(phys_addr_t limit); > > > +void memblock_cap_memory_range(phys_addr_t base, phys_addr_t size); > > > bool memblock_is_memory(phys_addr_t addr); > > > int memblock_is_map_memory(phys_addr_t addr); > > > int memblock_is_region_memory(phys_addr_t base, phys_addr_t size); > > > diff --git a/mm/memblock.c b/mm/memblock.c > > > index 7608bc3..eb53876 100644 > > > --- a/mm/memblock.c > > > +++ b/mm/memblock.c > > > @@ -1544,6 +1544,34 @@ void __init memblock_mem_limit_remove_map(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); > > > +} > > > > This duplicates a bunch of the logic in memblock_mem_limit_remove_map. Can > > you not implement that in terms of your new, more general, function? e.g. > > by passing base == 0, and size == limit? > > Obviously it's possible. > I actually talked to Dennis before about merging them, > but he was against my idea. > Oops! I thought we have reached agreement in the thread:http://lists.infradead.org/pipermail/linux-arm-kernel/2016-July/442817.html So feel free to do that as Will'll do > > Thanks, > -Takahiro AKASHI > > > Will
diff --git a/include/linux/memblock.h b/include/linux/memblock.h index 5b759c9..0e770af 100644 --- a/include/linux/memblock.h +++ b/include/linux/memblock.h @@ -334,6 +334,7 @@ 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_mem_limit_remove_map(phys_addr_t limit); +void memblock_cap_memory_range(phys_addr_t base, phys_addr_t size); bool memblock_is_memory(phys_addr_t addr); int memblock_is_map_memory(phys_addr_t addr); int memblock_is_region_memory(phys_addr_t base, phys_addr_t size); diff --git a/mm/memblock.c b/mm/memblock.c index 7608bc3..eb53876 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -1544,6 +1544,34 @@ void __init memblock_mem_limit_remove_map(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); +} + static int __init_memblock memblock_search(struct memblock_type *type, phys_addr_t addr) { unsigned int left = 0, right = type->cnt;
Add memblock_cap_memory_range() which will remove all the memblock regions except the range specified in the arguments. 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, 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@linaro.org> Cc: linux-mm@kvack.org Cc: Andrew Morton <akpm@linux-foundation.org> --- include/linux/memblock.h | 1 + mm/memblock.c | 28 ++++++++++++++++++++++++++++ 2 files changed, 29 insertions(+)