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91eea67c6d
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>
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| .. | ||
| 40x_mmu.c | ||
| 44x_mmu.c | ||
| dma-noncoherent.c | ||
| fault.c | ||
| fsl_booke_mmu.c | ||
| gup.c | ||
| hash_low_32.S | ||
| hash_low_64.S | ||
| hash_native_64.c | ||
| hash_utils_64.c | ||
| highmem.c | ||
| hugetlbpage-hash64.c | ||
| hugetlbpage.c | ||
| init_32.c | ||
| init_64.c | ||
| Makefile | ||
| mem.c | ||
| mmap_64.c | ||
| mmu_context_hash32.c | ||
| mmu_context_hash64.c | ||
| mmu_context_nohash.c | ||
| mmu_decl.h | ||
| numa.c | ||
| pgtable.c | ||
| pgtable_32.c | ||
| pgtable_64.c | ||
| ppc_mmu_32.c | ||
| slb.c | ||
| slb_low.S | ||
| slice.c | ||
| stab.c | ||
| subpage-prot.c | ||
| tlb_hash32.c | ||
| tlb_hash64.c | ||
| tlb_low_64e.S | ||
| tlb_nohash.c | ||
| tlb_nohash_low.S | ||