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x86: simplify 32-bit cpa largepage splitting 

simplify 32-bit cpa largepage splitting: do a pure split and repeat
the pte lookup to get the new pte modified.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Ingo Molnar 2008-01-30 13:33:55 +01:00
parent 78c94abaea
commit 97f99fedf2
1 changed files with 8 additions and 6 deletions
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14
arch/x86/mm/pageattr_32.c
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@ -38,7 +38,7 @@ pte_t *lookup_address(unsigned long address, int *level)
}
static struct page *
split_large_page(unsigned long address, pgprot_t prot, pgprot_t ref_prot)
split_large_page(unsigned long address, pgprot_t ref_prot)
{
unsigned long addr;
struct page *base;
@ -58,10 +58,9 @@ split_large_page(unsigned long address, pgprot_t prot, pgprot_t ref_prot)
pbase = (pte_t *)page_address(base);
paravirt_alloc_pt(&init_mm, page_to_pfn(base));
for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE) {
set_pte(&pbase[i], pfn_pte(addr >> PAGE_SHIFT,
addr == address ? prot : ref_prot));
}
for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE)
set_pte(&pbase[i], pfn_pte(addr >> PAGE_SHIFT, ref_prot));
return base;
}
@ -101,6 +100,7 @@ static int __change_page_attr(struct page *page, pgprot_t prot)
BUG_ON(PageHighMem(page));
address = (unsigned long)page_address(page);
repeat:
kpte = lookup_address(address, &level);
if (!kpte)
return -EINVAL;
@ -128,7 +128,8 @@ static int __change_page_attr(struct page *page, pgprot_t prot)
set_pte_atomic(kpte, mk_pte(page, prot));
} else {
struct page *split;
split = split_large_page(address, prot, ref_prot);
split = split_large_page(address, ref_prot);
if (!split)
return -ENOMEM;
@ -136,6 +137,7 @@ static int __change_page_attr(struct page *page, pgprot_t prot)
* There's a small window here to waste a bit of RAM:
*/
set_pmd_pte(kpte, address, mk_pte(split, ref_prot));
goto repeat;
}
return 0;
}