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mm/memblock: expose only miminal interface to add/walk physmem

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"physmem" in the memblock allocator is somewhat weird: it's not actually
used for allocation, it's simply information collected during boot, which
describes the unmodified physical memory map at boot time, without any
standby/hotplugged memory. It's only used on s390 and is currently the
only reason s390 keeps using CONFIG_ARCH_KEEP_MEMBLOCK.

Physmem isn't numa aware and current users don't specify any flags. Let's
hide it from the user, exposing only for_each_physmem(), and simplify. The
interface for physmem is now really minimalistic:
- memblock_physmem_add() to add ranges
- for_each_physmem() / __next_physmem_range() to walk physmem ranges

Don't place it into an __init section and don't discard it without
CONFIG_ARCH_KEEP_MEMBLOCK. As we're reusing __next_mem_range(), remove
the __meminit notifier to avoid section mismatch warnings once
CONFIG_ARCH_KEEP_MEMBLOCK is no longer used with
CONFIG_HAVE_MEMBLOCK_PHYS_MAP.

While fixing up the documentation, sneak in some related cleanups. We can
stop setting CONFIG_ARCH_KEEP_MEMBLOCK for s390 next.

Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Message-Id: <20200701141830.18749-2-david@redhat.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
David Hildenbrand
2020-07-01 16:18:29 +02:00
committed by Heiko Carstens
parent a303e88743
commit 7764990581
3 changed files with 55 additions and 36 deletions
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28
include/linux/memblock.h
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@@ -77,16 +77,12 @@ struct memblock_type {
* @current_limit: physical address of the current allocation limit
* @memory: usable memory regions
* @reserved: reserved memory regions
* @physmem: all physical memory
*/
struct memblock {
bool bottom_up; /* is bottom up direction? */
phys_addr_t current_limit;
struct memblock_type memory;
struct memblock_type reserved;
#ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
struct memblock_type physmem;
#endif
};
extern struct memblock memblock;
@@ -145,6 +141,30 @@ void __next_reserved_mem_region(u64 *idx, phys_addr_t *out_start,
void __memblock_free_late(phys_addr_t base, phys_addr_t size);
#ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
static inline void __next_physmem_range(u64 *idx, struct memblock_type *type,
phys_addr_t *out_start,
phys_addr_t *out_end)
{
extern struct memblock_type physmem;
__next_mem_range(idx, NUMA_NO_NODE, MEMBLOCK_NONE, &physmem, type,
out_start, out_end, NULL);
}
/**
* for_each_physmem_range - iterate through physmem areas not included in type.
* @i: u64 used as loop variable
* @type: ptr to memblock_type which excludes from the iteration, can be %NULL
* @p_start: ptr to phys_addr_t for start address of the range, can be %NULL
* @p_end: ptr to phys_addr_t for end address of the range, can be %NULL
*/
#define for_each_physmem_range(i, type, p_start, p_end) \
for (i = 0, __next_physmem_range(&i, type, p_start, p_end); \
i != (u64)ULLONG_MAX; \
__next_physmem_range(&i, type, p_start, p_end))
#endif /* CONFIG_HAVE_MEMBLOCK_PHYS_MAP */
/**
* for_each_mem_range - iterate through memblock areas from type_a and not
* included in type_b. Or just type_a if type_b is NULL.