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Subject[PATCH 29/46] x86, mm: only call early_ioremap_page_table_range_init() once
Date
On 32bit, before patcheset that only set page table for ram, we only
call that one time.

Now, we are calling that during every init_memory_mapping if we have holes
under max_low_pfn.

We should only call it one time after all ranges under max_low_page get
mapped just like we did before.

Also that could avoid the risk to run out of pgt_buf in BRK.

Need to update page_table_range_init() to count the pages for kmap page table
at first, and use new added alloc_low_pages() to get pages in sequence.
That will conform to the requirement that pages need to be in low to high order.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
arch/x86/mm/init.c | 13 +++++--------
arch/x86/mm/init_32.c | 47 +++++++++++++++++++++++++++++++++++++++++------
2 files changed, 46 insertions(+), 14 deletions(-)

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index a7939ed..d2df52c 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -340,14 +340,6 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
mr[i].page_size_mask);

-#ifdef CONFIG_X86_32
- early_ioremap_page_table_range_init();
-
- load_cr3(swapper_pg_dir);
-#endif
-
- __flush_tlb_all();
-
add_pfn_range_mapped(start >> PAGE_SHIFT, ret >> PAGE_SHIFT);

return ret >> PAGE_SHIFT;
@@ -444,7 +436,12 @@ void __init init_mem_mapping(void)
/* can we preseve max_low_pfn ?*/
max_low_pfn = max_pfn;
}
+#else
+ early_ioremap_page_table_range_init();
+ load_cr3(swapper_pg_dir);
+ __flush_tlb_all();
#endif
+
early_memtest(0, max_pfn_mapped << PAGE_SHIFT);
}

diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index a7f2df1..0ae1ba8 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -135,8 +135,39 @@ pte_t * __init populate_extra_pte(unsigned long vaddr)
return one_page_table_init(pmd) + pte_idx;
}

+static unsigned long __init
+page_table_range_init_count(unsigned long start, unsigned long end)
+{
+ unsigned long count = 0;
+#ifdef CONFIG_HIGHMEM
+ int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
+ int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
+ int pgd_idx, pmd_idx;
+ unsigned long vaddr;
+
+ if (pmd_idx_kmap_begin == pmd_idx_kmap_end)
+ return 0;
+
+ vaddr = start;
+ pgd_idx = pgd_index(vaddr);
+
+ for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd_idx++) {
+ for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
+ pmd_idx++) {
+ if ((vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin &&
+ (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end)
+ count++;
+ vaddr += PMD_SIZE;
+ }
+ pmd_idx = 0;
+ }
+#endif
+ return count;
+}
+
static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
- unsigned long vaddr, pte_t *lastpte)
+ unsigned long vaddr, pte_t *lastpte,
+ void **adr)
{
#ifdef CONFIG_HIGHMEM
/*
@@ -150,16 +181,15 @@ static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,

if (pmd_idx_kmap_begin != pmd_idx_kmap_end
&& (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
- && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end
- && ((__pa(pte) >> PAGE_SHIFT) < pgt_buf_start
- || (__pa(pte) >> PAGE_SHIFT) >= pgt_buf_end)) {
+ && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) {
pte_t *newpte;
int i;

BUG_ON(after_bootmem);
- newpte = alloc_low_page();
+ newpte = *adr;
for (i = 0; i < PTRS_PER_PTE; i++)
set_pte(newpte + i, pte[i]);
+ *adr = (void *)(((unsigned long)(*adr)) + PAGE_SIZE);

paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT);
set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
@@ -193,6 +223,11 @@ page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte = NULL;
+ unsigned long count = page_table_range_init_count(start, end);
+ void *adr = NULL;
+
+ if (count)
+ adr = alloc_low_pages(count);

vaddr = start;
pgd_idx = pgd_index(vaddr);
@@ -205,7 +240,7 @@ page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
pmd++, pmd_idx++) {
pte = page_table_kmap_check(one_page_table_init(pmd),
- pmd, vaddr, pte);
+ pmd, vaddr, pte, &adr);

vaddr += PMD_SIZE;
}
--
1.7.7


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