parisc: Optimize per-pagetable spinlocks

[sfrench/cifs-2.6.git] / arch / parisc / include / asm / pgalloc.h

diff --git a/arch/parisc/include/asm/pgalloc.h b/arch/parisc/include/asm/pgalloc.h
index a6482b2ce0eab35eeec1c574a4ea8f0de50a477e..dda55708531166b5f47b19c10404ac0c4f89512c 100644 (file)
--- a/arch/parisc/include/asm/pgalloc.h
+++ b/arch/parisc/include/asm/pgalloc.h
@@ -15,47 +15,23 @@
 #define __HAVE_ARCH_PGD_FREE
 #include <asm-generic/pgalloc.h>
 
-/* Allocate the top level pgd (page directory)
- *
- * Here (for 64 bit kernels) we implement a Hybrid L2/L3 scheme: we
- * allocate the first pmd adjacent to the pgd.  This means that we can
- * subtract a constant offset to get to it.  The pmd and pgd sizes are
- * arranged so that a single pmd covers 4GB (giving a full 64-bit
- * process access to 8TB) so our lookups are effectively L2 for the
- * first 4GB of the kernel (i.e. for all ILP32 processes and all the
- * kernel for machines with under 4GB of memory) */
+/* Allocate the top level pgd (page directory) */
 static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 {
-       pgd_t *pgd = (pgd_t *)__get_free_pages(GFP_KERNEL,
-                                              PGD_ALLOC_ORDER);
-       pgd_t *actual_pgd = pgd;
+       pgd_t *pgd;
 
-       if (likely(pgd != NULL)) {
-               memset(pgd, 0, PAGE_SIZE<<PGD_ALLOC_ORDER);
-#if CONFIG_PGTABLE_LEVELS == 3
-               actual_pgd += PTRS_PER_PGD;
-               /* Populate first pmd with allocated memory.  We mark it
-                * with PxD_FLAG_ATTACHED as a signal to the system that this
-                * pmd entry may not be cleared. */
-               set_pgd(actual_pgd, __pgd((PxD_FLAG_PRESENT |
-                                       PxD_FLAG_VALID |
-                                       PxD_FLAG_ATTACHED)
-                       + (__u32)(__pa((unsigned long)pgd) >> PxD_VALUE_SHIFT)));
-               /* The first pmd entry also is marked with PxD_FLAG_ATTACHED as
-                * a signal that this pmd may not be freed */
-               set_pgd(pgd, __pgd(PxD_FLAG_ATTACHED));
-#endif
-       }
-       spin_lock_init(pgd_spinlock(actual_pgd));
-       return actual_pgd;
+       pgd = (pgd_t *) __get_free_pages(GFP_KERNEL, PGD_ORDER);
+       if (unlikely(pgd == NULL))
+               return NULL;
+
+       memset(pgd, 0, PAGE_SIZE << PGD_ORDER);
+
+       return pgd;
 }
 
 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 {
-#if CONFIG_PGTABLE_LEVELS == 3
-       pgd -= PTRS_PER_PGD;
-#endif
-       free_pages((unsigned long)pgd, PGD_ALLOC_ORDER);
+       free_pages((unsigned long)pgd, PGD_ORDER);
 }
 
 #if CONFIG_PGTABLE_LEVELS == 3
@@ -70,41 +46,25 @@ static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
 
 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 {
-       return (pmd_t *)__get_free_pages(GFP_PGTABLE_KERNEL, PMD_ORDER);
+       pmd_t *pmd;
+
+       pmd = (pmd_t *)__get_free_pages(GFP_PGTABLE_KERNEL, PMD_ORDER);
+       if (likely(pmd))
+               memset ((void *)pmd, 0, PAGE_SIZE << PMD_ORDER);
+       return pmd;
 }
 
 static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
 {
-       if (pmd_flag(*pmd) & PxD_FLAG_ATTACHED) {
-               /*
-                * This is the permanent pmd attached to the pgd;
-                * cannot free it.
-                * Increment the counter to compensate for the decrement
-                * done by generic mm code.
-                */
-               mm_inc_nr_pmds(mm);
-               return;
-       }
        free_pages((unsigned long)pmd, PMD_ORDER);
 }
-
 #endif
 
 static inline void
 pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
 {
-#if CONFIG_PGTABLE_LEVELS == 3
-       /* preserve the gateway marker if this is the beginning of
-        * the permanent pmd */
-       if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED)
-               set_pmd(pmd, __pmd((PxD_FLAG_PRESENT |
-                               PxD_FLAG_VALID |
-                               PxD_FLAG_ATTACHED)
-                       + (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT)));
-       else
-#endif
-               set_pmd(pmd, __pmd((PxD_FLAG_PRESENT | PxD_FLAG_VALID)
-                       + (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT)));
+       set_pmd(pmd, __pmd((PxD_FLAG_PRESENT | PxD_FLAG_VALID)
+               + (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT)));
 }
 
 #define pmd_populate(mm, pmd, pte_page) \