mm: thp: set the accessed flag for old pages on access fault

[pandora-kernel.git] / lib / flex_array.c

diff --git a/lib/flex_array.c b/lib/flex_array.c
index 854b57b..9b8b894 100644 (file)
--- a/lib/flex_array.c
+++ b/lib/flex_array.c
@@ -24,6 +24,7 @@
 #include <linux/slab.h>
 #include <linux/stddef.h>
 #include <linux/module.h>
+#include <linux/reciprocal_div.h>
 
 struct flex_array_part {
        char elements[FLEX_ARRAY_PART_SIZE];
@@ -70,15 +71,15 @@ static inline int elements_fit_in_base(struct flex_array *fa)
  * Element size | Objects | Objects |
  * PAGE_SIZE=4k |  32-bit |  64-bit |
  * ---------------------------------|
- *      1 bytes | 4186112 | 2093056 |
- *      2 bytes | 2093056 | 1046528 |
- *      3 bytes | 1395030 |  697515 |
- *      4 bytes | 1046528 |  523264 |
- *     32 bytes |  130816 |   65408 |
- *     33 bytes |  126728 |   63364 |
- *   2048 bytes |    2044 |    1022 |
- *   2049 bytes |    1022 |     511 |
- *       void * | 1046528 |  261632 |
+ *      1 bytes | 4177920 | 2088960 |
+ *      2 bytes | 2088960 | 1044480 |
+ *      3 bytes | 1392300 |  696150 |
+ *      4 bytes | 1044480 |  522240 |
+ *     32 bytes |  130560 |   65408 |
+ *     33 bytes |  126480 |   63240 |
+ *   2048 bytes |    2040 |    1020 |
+ *   2049 bytes |    1020 |     510 |
+ *       void * | 1044480 |  261120 |
  *
  * Since 64-bit pointers are twice the size, we lose half the
  * capacity in the base structure.  Also note that no effort is made
@@ -88,8 +89,15 @@ struct flex_array *flex_array_alloc(int element_size, unsigned int total,
                                        gfp_t flags)
 {
        struct flex_array *ret;
-       int max_size = FLEX_ARRAY_NR_BASE_PTRS *
-                               FLEX_ARRAY_ELEMENTS_PER_PART(element_size);
+       int elems_per_part = 0;
+       int reciprocal_elems = 0;
+       int max_size = 0;
+
+       if (element_size) {
+               elems_per_part = FLEX_ARRAY_ELEMENTS_PER_PART(element_size);
+               reciprocal_elems = reciprocal_value(elems_per_part);
+               max_size = FLEX_ARRAY_NR_BASE_PTRS * elems_per_part;
+       }
 
        /* max_size will end up 0 if element_size > PAGE_SIZE */
        if (total > max_size)
@@ -99,6 +107,8 @@ struct flex_array *flex_array_alloc(int element_size, unsigned int total,
                return NULL;
        ret->element_size = element_size;
        ret->total_nr_elements = total;
+       ret->elems_per_part = elems_per_part;
+       ret->reciprocal_elems = reciprocal_elems;
        if (elements_fit_in_base(ret) && !(flags & __GFP_ZERO))
                memset(&ret->parts[0], FLEX_ARRAY_FREE,
                                                FLEX_ARRAY_BASE_BYTES_LEFT);
@@ -109,7 +119,7 @@ EXPORT_SYMBOL(flex_array_alloc);
 static int fa_element_to_part_nr(struct flex_array *fa,
                                        unsigned int element_nr)
 {
-       return element_nr / FLEX_ARRAY_ELEMENTS_PER_PART(fa->element_size);
+       return reciprocal_divide(element_nr, fa->reciprocal_elems);
 }
 
 /**
@@ -138,12 +148,12 @@ void flex_array_free(struct flex_array *fa)
 EXPORT_SYMBOL(flex_array_free);
 
 static unsigned int index_inside_part(struct flex_array *fa,
-                                       unsigned int element_nr)
+                                       unsigned int element_nr,
+                                       unsigned int part_nr)
 {
        unsigned int part_offset;
 
-       part_offset = element_nr %
-                               FLEX_ARRAY_ELEMENTS_PER_PART(fa->element_size);
+       part_offset = element_nr - part_nr * fa->elems_per_part;
        return part_offset * fa->element_size;
 }
 
@@ -183,20 +193,23 @@ __fa_get_part(struct flex_array *fa, int part_nr, gfp_t flags)
 int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src,
                        gfp_t flags)
 {
-       int part_nr = fa_element_to_part_nr(fa, element_nr);
+       int part_nr = 0;
        struct flex_array_part *part;
        void *dst;
 
        if (element_nr >= fa->total_nr_elements)
                return -ENOSPC;
+       if (!fa->element_size)
+               return 0;
        if (elements_fit_in_base(fa))
                part = (struct flex_array_part *)&fa->parts[0];
        else {
+               part_nr = fa_element_to_part_nr(fa, element_nr);
                part = __fa_get_part(fa, part_nr, flags);
                if (!part)
                        return -ENOMEM;
        }
-       dst = &part->elements[index_inside_part(fa, element_nr)];
+       dst = &part->elements[index_inside_part(fa, element_nr, part_nr)];
        memcpy(dst, src, fa->element_size);
        return 0;
 }
@@ -211,20 +224,23 @@ EXPORT_SYMBOL(flex_array_put);
  */
 int flex_array_clear(struct flex_array *fa, unsigned int element_nr)
 {
-       int part_nr = fa_element_to_part_nr(fa, element_nr);
+       int part_nr = 0;
        struct flex_array_part *part;
        void *dst;
 
        if (element_nr >= fa->total_nr_elements)
                return -ENOSPC;
+       if (!fa->element_size)
+               return 0;
        if (elements_fit_in_base(fa))
                part = (struct flex_array_part *)&fa->parts[0];
        else {
+               part_nr = fa_element_to_part_nr(fa, element_nr);
                part = fa->parts[part_nr];
                if (!part)
                        return -EINVAL;
        }
-       dst = &part->elements[index_inside_part(fa, element_nr)];
+       dst = &part->elements[index_inside_part(fa, element_nr, part_nr)];
        memset(dst, FLEX_ARRAY_FREE, fa->element_size);
        return 0;
 }
@@ -264,6 +280,8 @@ int flex_array_prealloc(struct flex_array *fa, unsigned int start,
 
        if (end >= fa->total_nr_elements)
                return -ENOSPC;
+       if (!fa->element_size)
+               return 0;
        if (elements_fit_in_base(fa))
                return 0;
        start_part = fa_element_to_part_nr(fa, start);
@@ -291,19 +309,22 @@ EXPORT_SYMBOL(flex_array_prealloc);
  */
 void *flex_array_get(struct flex_array *fa, unsigned int element_nr)
 {
-       int part_nr = fa_element_to_part_nr(fa, element_nr);
+       int part_nr = 0;
        struct flex_array_part *part;
 
+       if (!fa->element_size)
+               return NULL;
        if (element_nr >= fa->total_nr_elements)
                return NULL;
        if (elements_fit_in_base(fa))
                part = (struct flex_array_part *)&fa->parts[0];
        else {
+               part_nr = fa_element_to_part_nr(fa, element_nr);
                part = fa->parts[part_nr];
                if (!part)
                        return NULL;
        }
-       return &part->elements[index_inside_part(fa, element_nr)];
+       return &part->elements[index_inside_part(fa, element_nr, part_nr)];
 }
 EXPORT_SYMBOL(flex_array_get);
 
@@ -353,7 +374,7 @@ int flex_array_shrink(struct flex_array *fa)
        int part_nr;
        int ret = 0;
 
-       if (!fa->total_nr_elements)
+       if (!fa->total_nr_elements || !fa->element_size)
                return 0;
        if (elements_fit_in_base(fa))
                return ret;