linux/arch/powerpc/include/asm/pgalloc-64.h
Mark Nelson 91eea67c6d 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>
2010-05-06 16:49:27 +10:00

143 lines
4 KiB
C

#ifndef _ASM_POWERPC_PGALLOC_64_H
#define _ASM_POWERPC_PGALLOC_64_H
/*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/slab.h>
#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
* handle allocation. For PTE pages (which are linked to a struct
* page for now, and drawn from the main get_free_pages() pool), the
* allocation size will be (2^index_size * sizeof(pointer)) and
* allocations are drawn from the kmem_cache in PGT_CACHE(index_size).
*
* The maximum index size needs to be big enough to allow any
* pagetable sizes we need, but small enough to fit in the low bits of
* any page table pointer. In other words all pagetables, even tiny
* ones, must be aligned to allow at least enough low 0 bits to
* contain this value. This value is also used as a mask, so it must
* be one less than a power of two.
*/
#define MAX_PGTABLE_INDEX_SIZE 0xf
extern struct kmem_cache *pgtable_cache[];
#define PGT_CACHE(shift) (pgtable_cache[(shift)-1])
static inline pgd_t *pgd_alloc(struct mm_struct *mm)
{
return kmem_cache_alloc(PGT_CACHE(PGD_INDEX_SIZE), GFP_KERNEL);
}
static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
kmem_cache_free(PGT_CACHE(PGD_INDEX_SIZE), pgd);
}
#ifndef CONFIG_PPC_64K_PAGES
#define pgd_populate(MM, PGD, PUD) pgd_set(PGD, PUD)
static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
{
return kmem_cache_alloc(PGT_CACHE(PUD_INDEX_SIZE),
GFP_KERNEL|__GFP_REPEAT);
}
static inline void pud_free(struct mm_struct *mm, pud_t *pud)
{
kmem_cache_free(PGT_CACHE(PUD_INDEX_SIZE), pud);
}
static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
{
pud_set(pud, (unsigned long)pmd);
}
#define pmd_populate(mm, pmd, pte_page) \
pmd_populate_kernel(mm, pmd, page_address(pte_page))
#define pmd_populate_kernel(mm, pmd, pte) pmd_set(pmd, (unsigned long)(pte))
#define pmd_pgtable(pmd) pmd_page(pmd)
#else /* CONFIG_PPC_64K_PAGES */
#define pud_populate(mm, pud, pmd) pud_set(pud, (unsigned long)pmd)
static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
pte_t *pte)
{
pmd_set(pmd, (unsigned long)pte);
}
#define pmd_populate(mm, pmd, pte_page) \
pmd_populate_kernel(mm, pmd, page_address(pte_page))
#define pmd_pgtable(pmd) pmd_page(pmd)
#endif /* CONFIG_PPC_64K_PAGES */
static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
{
return kmem_cache_alloc(PGT_CACHE(PMD_INDEX_SIZE),
GFP_KERNEL|__GFP_REPEAT);
}
static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
{
kmem_cache_free(PGT_CACHE(PMD_INDEX_SIZE), pmd);
}
static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
unsigned long address)
{
return (pte_t *)__get_free_page(GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO);
}
static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
unsigned long address)
{
struct page *page;
pte_t *pte;
pte = pte_alloc_one_kernel(mm, address);
if (!pte)
return NULL;
page = virt_to_page(pte);
pgtable_page_ctor(page);
return page;
}
static inline void pgtable_free(void *table, unsigned index_size)
{
if (!index_size)
free_page((unsigned long)table);
else {
BUG_ON(index_size > MAX_PGTABLE_INDEX_SIZE);
kmem_cache_free(PGT_CACHE(index_size), table);
}
}
#define __pmd_free_tlb(tlb, pmd, addr) \
pgtable_free_tlb(tlb, pmd, PMD_INDEX_SIZE)
#ifndef CONFIG_PPC_64K_PAGES
#define __pud_free_tlb(tlb, pud, addr) \
pgtable_free_tlb(tlb, pud, PUD_INDEX_SIZE)
#endif /* CONFIG_PPC_64K_PAGES */
#define check_pgt_cache() do { } while (0)
#endif /* _ASM_POWERPC_PGALLOC_64_H */