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author | Mark Nelson <markn@au1.ibm.com> | 2010-04-21 16:21:03 +0000 |
---|---|---|
committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2010-05-06 16:49:27 +1000 |
commit | 91eea67c6d8704396a98226508c56a8501e141e3 (patch) | |
tree | 94d65c6bae001fa3835398056fea936720e86ed7 | |
parent | 13bb5339966d49942878a46b0a7fda0639d7db5f (diff) | |
download | op-kernel-dev-91eea67c6d8704396a98226508c56a8501e141e3.zip op-kernel-dev-91eea67c6d8704396a98226508c56a8501e141e3.tar.gz |
powerpc/mm: Track backing pages allocated by vmemmap_populate()
We need to keep track of the backing pages that get allocated by
vmemmap_populate() so that when we use kdump, the dump-capture kernel knows
where these pages are.
We use a simple linked list of structures that contain the physical address
of the backing page and corresponding virtual address to track the backing
pages.
To save space, we just use a pointer to the next struct vmemmap_backing. We
can also do this because we never remove nodes. We call the pointer "list"
to be compatible with changes made to the crash utility.
vmemmap_populate() is called either at boot-time or on a memory hotplug
operation. We don't have to worry about the boot-time calls because they
will be inherently single-threaded, and for a memory hotplug operation
vmemmap_populate() is called through:
sparse_add_one_section()
|
V
kmalloc_section_memmap()
|
V
sparse_mem_map_populate()
|
V
vmemmap_populate()
and in sparse_add_one_section() we're protected by pgdat_resize_lock().
So, we don't need a spinlock to protect the vmemmap_list.
We allocate space for the vmemmap_backing structs by allocating whole pages
in vmemmap_list_alloc() and then handing out chunks of this to
vmemmap_list_populate().
This means that we waste at most just under one page, but this keeps the code
is simple.
Signed-off-by: Mark Nelson <markn@au1.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
-rw-r--r-- | arch/powerpc/include/asm/pgalloc-64.h | 6 | ||||
-rw-r--r-- | arch/powerpc/mm/init_64.c | 43 |
2 files changed, 49 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/pgalloc-64.h b/arch/powerpc/include/asm/pgalloc-64.h index 605f5c5..292725c 100644 --- a/arch/powerpc/include/asm/pgalloc-64.h +++ b/arch/powerpc/include/asm/pgalloc-64.h @@ -11,6 +11,12 @@ #include <linux/cpumask.h> #include <linux/percpu.h> +struct vmemmap_backing { + struct vmemmap_backing *list; + unsigned long phys; + unsigned long virt_addr; +}; + /* * Functions that deal with pagetables that could be at any level of * the table need to be passed an "index_size" so they know how to diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c index d7fa50b..e267f22 100644 --- a/arch/powerpc/mm/init_64.c +++ b/arch/powerpc/mm/init_64.c @@ -252,6 +252,47 @@ static void __meminit vmemmap_create_mapping(unsigned long start, } #endif /* CONFIG_PPC_BOOK3E */ +struct vmemmap_backing *vmemmap_list; + +static __meminit struct vmemmap_backing * vmemmap_list_alloc(int node) +{ + static struct vmemmap_backing *next; + static int num_left; + + /* allocate a page when required and hand out chunks */ + if (!next || !num_left) { + next = vmemmap_alloc_block(PAGE_SIZE, node); + if (unlikely(!next)) { + WARN_ON(1); + return NULL; + } + num_left = PAGE_SIZE / sizeof(struct vmemmap_backing); + } + + num_left--; + + return next++; +} + +static __meminit void vmemmap_list_populate(unsigned long phys, + unsigned long start, + int node) +{ + struct vmemmap_backing *vmem_back; + + vmem_back = vmemmap_list_alloc(node); + if (unlikely(!vmem_back)) { + WARN_ON(1); + return; + } + + vmem_back->phys = phys; + vmem_back->virt_addr = start; + vmem_back->list = vmemmap_list; + + vmemmap_list = vmem_back; +} + int __meminit vmemmap_populate(struct page *start_page, unsigned long nr_pages, int node) { @@ -276,6 +317,8 @@ int __meminit vmemmap_populate(struct page *start_page, if (!p) return -ENOMEM; + vmemmap_list_populate(__pa(p), start, node); + pr_debug(" * %016lx..%016lx allocated at %p\n", start, start + page_size, p); |