m68k: mm: Extend table allocator for multiple sizes

In addition to the PGD/PMD table size (128*4) add a PTE table size
(64*4) to the table allocator. This completely removes the pte-table
overhead compared to the old code, even for dense tables.

Notes:

 - the allocator gained a list_empty() check to deal with there not
   being any pages at all.

 - the free mask is extended to cover more than the 8 bits required
   for the (512 byte) PGD/PMD tables.

 - NR_PAGETABLE accounting is restored.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20200131125403.882175409@infradead.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

1 files changed, 19 insertions, 12 deletions

diff --git a/arch/m68k/include/asm/motorola_pgalloc.h b/arch/m68k/include/asm/motorola_pgalloc.h
index c15e04277be7..c66e42917912 100644
--- a/arch/m68k/include/asm/motorola_pgalloc.h
+++ b/arch/m68k/include/asm/motorola_pgalloc.h
@@ -8,61 +8,68 @@
 extern void mmu_page_ctor(void *page);
 extern void mmu_page_dtor(void *page);
 
-extern pmd_t *get_pointer_table(void);
-extern int free_pointer_table(pmd_t *);
+enum m68k_table_types {
+	TABLE_PGD = 0,
+	TABLE_PMD = 0, /* same size as PGD */
+	TABLE_PTE = 1,
+};
+
+extern void init_pointer_table(void *table, int type);
+extern void *get_pointer_table(int type);
+extern int free_pointer_table(void *table, int type);
 
 static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
 {
-	return (pte_t *)get_pointer_table();
+	return get_pointer_table(TABLE_PTE);
 }
 
 static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 {
-	free_pointer_table((void *)pte);
+	free_pointer_table(pte, TABLE_PTE);
 }
 
 static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
 {
-	return (pte_t *)get_pointer_table();
+	return get_pointer_table(TABLE_PTE);
 }
 
 static inline void pte_free(struct mm_struct *mm, pgtable_t pgtable)
 {
-	free_pointer_table((void *)pgtable);
+	free_pointer_table(pgtable, TABLE_PTE);
 }
 
 static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pgtable,
 				  unsigned long address)
 {
-	free_pointer_table((void *)pgtable);
+	free_pointer_table(pgtable, TABLE_PTE);
 }
 
 
 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 {
-	return get_pointer_table();
+	return get_pointer_table(TABLE_PMD);
 }
 
 static inline int pmd_free(struct mm_struct *mm, pmd_t *pmd)
 {
-	return free_pointer_table(pmd);
+	return free_pointer_table(pmd, TABLE_PMD);
 }
 
 static inline int __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd,
 				 unsigned long address)
 {
-	return free_pointer_table(pmd);
+	return free_pointer_table(pmd, TABLE_PMD);
 }
 
 
 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 {
-	pmd_free(mm, (pmd_t *)pgd);
+	free_pointer_table(pgd, TABLE_PGD);
 }
 
 static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 {
-	return (pgd_t *)get_pointer_table();
+	return get_pointer_table(TABLE_PGD);
 }