mempolicy: document {set|get}_policy() vm_ops APIs

[safe/jmp/linux-2.6] / include / linux / mm.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 24659ed..8b7f4a5 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -107,6 +107,7 @@ extern unsigned int kobjsize(const void *objp);
 #define VM_ALWAYSDUMP  0x04000000      /* Always include in core dumps */
 
 #define VM_CAN_NONLINEAR 0x08000000    /* Has ->fault & does nonlinear pages */
+#define VM_MIXEDMAP    0x10000000      /* Can contain "struct page" and pure PFN pages */
 
 #ifndef VM_STACK_DEFAULT_FLAGS         /* arch can override this */
 #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
@@ -171,7 +172,25 @@ struct vm_operations_struct {
         * writable, if an error is returned it will cause a SIGBUS */
        int (*page_mkwrite)(struct vm_area_struct *vma, struct page *page);
 #ifdef CONFIG_NUMA
+       /*
+        * set_policy() op must add a reference to any non-NULL @new mempolicy
+        * to hold the policy upon return.  Caller should pass NULL @new to
+        * remove a policy and fall back to surrounding context--i.e. do not
+        * install a MPOL_DEFAULT policy, nor the task or system default
+        * mempolicy.
+        */
        int (*set_policy)(struct vm_area_struct *vma, struct mempolicy *new);
+
+       /*
+        * get_policy() op must add reference [mpol_get()] to any policy at
+        * (vma,addr) marked as MPOL_SHARED.  The shared policy infrastructure
+        * in mm/mempolicy.c will do this automatically.
+        * get_policy() must NOT add a ref if the policy at (vma,addr) is not
+        * marked as MPOL_SHARED. vma policies are protected by the mmap_sem.
+        * If no [shared/vma] mempolicy exists at the addr, get_policy() op
+        * must return NULL--i.e., do not "fallback" to task or system default
+        * policy.
+        */
        struct mempolicy *(*get_policy)(struct vm_area_struct *vma,
                                        unsigned long addr);
        int (*migrate)(struct vm_area_struct *vma, const nodemask_t *from,
@@ -407,7 +426,7 @@ static inline void set_compound_order(struct page *page, unsigned long order)
 
 #define ZONES_WIDTH            ZONES_SHIFT
 
-#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT <= FLAGS_RESERVED
+#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
 #define NODES_WIDTH            NODES_SHIFT
 #else
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
@@ -455,8 +474,8 @@ static inline void set_compound_order(struct page *page, unsigned long order)
 
 #define ZONEID_PGSHIFT         (ZONEID_PGOFF * (ZONEID_SHIFT != 0))
 
-#if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > FLAGS_RESERVED
-#error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > FLAGS_RESERVED
+#if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
+#error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
 #endif
 
 #define ZONES_MASK             ((1UL << ZONES_WIDTH) - 1)
@@ -605,9 +624,12 @@ static inline struct address_space *page_mapping(struct page *page)
        struct address_space *mapping = page->mapping;
 
        VM_BUG_ON(PageSlab(page));
+#ifdef CONFIG_SWAP
        if (unlikely(PageSwapCache(page)))
                mapping = &swapper_space;
-       else if (unlikely((unsigned long)mapping & PAGE_MAPPING_ANON))
+       else
+#endif
+       if (unlikely((unsigned long)mapping & PAGE_MAPPING_ANON))
                mapping = NULL;
        return mapping;
 }
@@ -717,7 +739,9 @@ struct zap_details {
        unsigned long truncate_count;           /* Compare vm_truncate_count */
 };
 
-struct page *vm_normal_page(struct vm_area_struct *, unsigned long, pte_t);
+struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
+               pte_t pte);
+
 unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
                unsigned long size, struct zap_details *);
 unsigned long unmap_vmas(struct mmu_gather **tlb,
@@ -1146,6 +1170,8 @@ int remap_pfn_range(struct vm_area_struct *, unsigned long addr,
 int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *);
 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
                        unsigned long pfn);
+int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
+                       unsigned long pfn);
 
 struct page *follow_page(struct vm_area_struct *, unsigned long address,
                        unsigned int foll_flags);