x86: make 32-bit init_memory_mapping range change more like 64-bit

Impact: cleanup

make code more readable and more like 64-bit

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <49AE48B4.8010907@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 67bdb59..37aeaf3 100644 (file)
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -885,29 +885,55 @@ static void __init find_early_table_space(unsigned long end, int use_pse)
                (table_start << PAGE_SHIFT) + tables);
 }
 
+struct map_range {
+       unsigned long start;
+       unsigned long end;
+       unsigned page_size_mask;
+};
+
+#define NR_RANGE_MR 3
+
+static int save_mr(struct map_range *mr, int nr_range,
+                  unsigned long start_pfn, unsigned long end_pfn,
+                  unsigned long page_size_mask)
+{
+       if (start_pfn < end_pfn) {
+               if (nr_range >= NR_RANGE_MR)
+                       panic("run out of range for init_memory_mapping\n");
+               mr[nr_range].start = start_pfn<<PAGE_SHIFT;
+               mr[nr_range].end   = end_pfn<<PAGE_SHIFT;
+               mr[nr_range].page_size_mask = page_size_mask;
+               nr_range++;
+       }
+
+       return nr_range;
+}
+
 unsigned long __init_refok init_memory_mapping(unsigned long start,
                                                unsigned long end)
 {
        pgd_t *pgd_base = swapper_pg_dir;
+       unsigned long page_size_mask = 0;
        unsigned long start_pfn, end_pfn;
-       unsigned long big_page_start;
+       unsigned long pos;
+
+       struct map_range mr[NR_RANGE_MR];
+       int nr_range, i;
+       int use_pse;
+
+       printk(KERN_INFO "init_memory_mapping: %08lx-%08lx\n", start, end);
+
 #ifdef CONFIG_DEBUG_PAGEALLOC
        /*
         * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
         * This will simplify cpa(), which otherwise needs to support splitting
         * large pages into small in interrupt context, etc.
         */
-       int use_pse = 0;
+       use_pse = 0;
 #else
-       int use_pse = cpu_has_pse;
+       use_pse = cpu_has_pse;
 #endif
 
-       /*
-        * Find space for the kernel direct mapping tables.
-        */
-       if (!after_init_bootmem)
-               find_early_table_space(end, use_pse);
-
 #ifdef CONFIG_X86_PAE
        set_nx();
        if (nx_enabled)
@@ -924,45 +950,81 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
                __supported_pte_mask |= _PAGE_GLOBAL;
        }
 
+       memset(mr, 0, sizeof(mr));
+       nr_range = 0;
+
+       if (use_pse)
+               page_size_mask |= 1 << PG_LEVEL_2M;
+
        /*
         * Don't use a large page for the first 2/4MB of memory
         * because there are often fixed size MTRRs in there
         * and overlapping MTRRs into large pages can cause
         * slowdowns.
         */
-       big_page_start = PMD_SIZE;
-
-       if (start < big_page_start) {
-               start_pfn = start >> PAGE_SHIFT;
-               end_pfn = min(big_page_start>>PAGE_SHIFT, end>>PAGE_SHIFT);
-       } else {
-               /* head is not big page alignment ? */
-               start_pfn = start >> PAGE_SHIFT;
-               end_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
+       /* head could not be big page alignment ? */
+       start_pfn = start >> PAGE_SHIFT;
+       pos = start_pfn << PAGE_SHIFT;
+       if (pos == 0)
+               end_pfn = 1<<(PMD_SHIFT - PAGE_SHIFT);
+       else
+               end_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
                                 << (PMD_SHIFT - PAGE_SHIFT);
+       if (end_pfn > (end>>PAGE_SHIFT))
+               end_pfn = end>>PAGE_SHIFT;
+       if (start_pfn < end_pfn) {
+               nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
+               pos = end_pfn << PAGE_SHIFT;
        }
-       if (start_pfn < end_pfn)
-               kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn, 0);
 
        /* big page range */
-       start_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
+       start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
                         << (PMD_SHIFT - PAGE_SHIFT);
-       if (start_pfn < (big_page_start >> PAGE_SHIFT))
-               start_pfn =  big_page_start >> PAGE_SHIFT;
        end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
-       if (start_pfn < end_pfn)
-               kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn,
-                                            use_pse);
+       if (start_pfn < end_pfn) {
+               nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
+                               page_size_mask & (1<<PG_LEVEL_2M));
+               pos = end_pfn << PAGE_SHIFT;
+       }
 
        /* tail is not big page alignment ? */
-       start_pfn = end_pfn;
-       if (start_pfn > (big_page_start>>PAGE_SHIFT)) {
-               end_pfn = end >> PAGE_SHIFT;
-               if (start_pfn < end_pfn)
-                       kernel_physical_mapping_init(pgd_base, start_pfn,
-                                                        end_pfn, 0);
+       start_pfn = pos>>PAGE_SHIFT;
+       end_pfn = end>>PAGE_SHIFT;
+       if (start_pfn < end_pfn)
+               nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
+
+       /* try to merge same page size and continuous */
+       for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
+               unsigned long old_start;
+               if (mr[i].end != mr[i+1].start ||
+                   mr[i].page_size_mask != mr[i+1].page_size_mask)
+                       continue;
+               /* move it */
+               old_start = mr[i].start;
+               memmove(&mr[i], &mr[i+1],
+                       (nr_range - 1 - i) * sizeof(struct map_range));
+               mr[i--].start = old_start;
+               nr_range--;
        }
 
+       for (i = 0; i < nr_range; i++)
+               printk(KERN_DEBUG " %08lx - %08lx page %s\n",
+                       mr[i].start, mr[i].end,
+                       (mr[i].page_size_mask & (1<<PG_LEVEL_2M)) ?
+                                 "big page" : "4k");
+
+       /*
+        * Find space for the kernel direct mapping tables.
+        */
+       if (!after_init_bootmem)
+               find_early_table_space(end, use_pse);
+
+       for (i = 0; i < nr_range; i++)
+               kernel_physical_mapping_init(pgd_base,
+                               mr[i].start >> PAGE_SHIFT,
+                               mr[i].end >> PAGE_SHIFT,
+                               mr[i].page_size_mask == (1<<PG_LEVEL_2M));
+
        early_ioremap_page_table_range_init(pgd_base);
 
        load_cr3(swapper_pg_dir);