From a2974133b7e0a31c71fabe86aad42a61db4f01ed Mon Sep 17 00:00:00 2001 From: Mike Rapoport Date: Mon, 11 Mar 2019 23:30:54 -0700 Subject: mm: memblock: update comments and kernel-doc * Remove comments mentioning bootmem * Extend "DOC: memblock overview" * Add kernel-doc comments for several more functions [akpm@linux-foundation.org: fix copy-n-paste error] Link: http://lkml.kernel.org/r/1549626347-25461-1-git-send-email-rppt@linux.ibm.com Signed-off-by: Mike Rapoport Reviewed-by: Andrew Morton Cc: Jonathan Corbet Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memblock.c | 60 ++++++++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 43 insertions(+), 17 deletions(-) (limited to 'mm') diff --git a/mm/memblock.c b/mm/memblock.c index dfe90bc210d9..e7665cf914b1 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -76,8 +76,19 @@ * :c:func:`memblock_set_node`. The :c:func:`memblock_add_node` * performs such an assignment directly. * - * Once memblock is setup the memory can be allocated using either - * memblock or bootmem APIs. + * Once memblock is setup the memory can be allocated using one of the + * API variants: + * + * * :c:func:`memblock_phys_alloc*` - these functions return the + * **physical** address of the allocated memory + * * :c:func:`memblock_alloc*` - these functions return the **virtual** + * address of the allocated memory. + * + * Note, that both API variants use implict assumptions about allowed + * memory ranges and the fallback methods. Consult the documentation + * of :c:func:`memblock_alloc_internal` and + * :c:func:`memblock_alloc_range_nid` functions for more elaboarte + * description. * * As the system boot progresses, the architecture specific * :c:func:`mem_init` function frees all the memory to the buddy page @@ -435,17 +446,7 @@ static int __init_memblock memblock_double_array(struct memblock_type *type, else in_slab = &memblock_reserved_in_slab; - /* Try to find some space for it. - * - * WARNING: We assume that either slab_is_available() and we use it or - * we use MEMBLOCK for allocations. That means that this is unsafe to - * use when bootmem is currently active (unless bootmem itself is - * implemented on top of MEMBLOCK which isn't the case yet) - * - * This should however not be an issue for now, as we currently only - * call into MEMBLOCK while it's still active, or much later when slab - * is active for memory hotplug operations - */ + /* Try to find some space for it */ if (use_slab) { new_array = kmalloc(new_size, GFP_KERNEL); addr = new_array ? __pa(new_array) : 0; @@ -989,7 +990,7 @@ static bool should_skip_region(struct memblock_region *m, int nid, int flags) } /** - * __next__mem_range - next function for for_each_free_mem_range() etc. + * __next_mem_range - next function for for_each_free_mem_range() etc. * @idx: pointer to u64 loop variable * @nid: node selector, %NUMA_NO_NODE for all nodes * @flags: pick from blocks based on memory attributes @@ -1335,6 +1336,18 @@ done: return found; } +/** + * memblock_phys_alloc_range - allocate a memory block inside specified range + * @size: size of memory block to be allocated in bytes + * @align: alignment of the region and block's size + * @start: the lower bound of the memory region to allocate (physical address) + * @end: the upper bound of the memory region to allocate (physical address) + * + * Allocate @size bytes in the between @start and @end. + * + * Return: physical address of the allocated memory block on success, + * %0 on failure. + */ phys_addr_t __init memblock_phys_alloc_range(phys_addr_t size, phys_addr_t align, phys_addr_t start, @@ -1343,6 +1356,19 @@ phys_addr_t __init memblock_phys_alloc_range(phys_addr_t size, return memblock_alloc_range_nid(size, align, start, end, NUMA_NO_NODE); } +/** + * memblock_phys_alloc_try_nid - allocate a memory block from specified MUMA node + * @size: size of memory block to be allocated in bytes + * @align: alignment of the region and block's size + * @nid: nid of the free area to find, %NUMA_NO_NODE for any node + * + * Allocates memory block from the specified NUMA node. If the node + * has no available memory, attempts to allocated from any node in the + * system. + * + * Return: physical address of the allocated memory block on success, + * %0 on failure. + */ phys_addr_t __init memblock_phys_alloc_try_nid(phys_addr_t size, phys_addr_t align, int nid) { return memblock_alloc_range_nid(size, align, 0, @@ -1469,13 +1495,13 @@ void * __init memblock_alloc_try_nid( } /** - * __memblock_free_late - free bootmem block pages directly to buddy allocator + * __memblock_free_late - free pages directly to buddy allocator * @base: phys starting address of the boot memory block * @size: size of the boot memory block in bytes * - * This is only useful when the bootmem allocator has already been torn + * This is only useful when the memblock allocator has already been torn * down, but we are still initializing the system. Pages are released directly - * to the buddy allocator, no bootmem metadata is updated because it is gone. + * to the buddy allocator. */ void __init __memblock_free_late(phys_addr_t base, phys_addr_t size) { -- cgit v1.2.3-59-g8ed1b