x86, mm: only call early_ioremap_page_table_range_init() once

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>
Link: http://lkml.kernel.org/r/1353123563-3103-30-git-send-email-yinghai@kernel.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

2 files changed, 46 insertions, 14 deletions

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index cb4f8ba70ecc..bed4888c6f4f 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -343,14 +343,6 @@ 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;
@@ -447,7 +439,12 @@ 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 a7f2df1cdcfd..0ae1ba8bc1b9 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;
                 }