On Sat, 23 Apr 2005, Rik van Riel wrote:
> The next part of my cunning plan is to get rid of the object
> generation number,
Here's the change, incremental to the previous patch. This should
simplify things for the caller and work with both the swap cache
and filesystem backed inodes - assuming filesystems are smart about
recycling inode numbers, otherwise I may need to use another field
too ...
Signed-off-by: Rik van Riel <[email protected]>
--- linux-2.6.11/include/linux/nonresident.h.nr2 2005-04-23 14:10:00.000000000 -0400
+++ linux-2.6.11/include/linux/nonresident.h 2005-04-23 14:10:18.000000000 -0400
@@ -7,6 +7,6 @@
* Keeps track of whether a non-resident page was recently evicted
* and should be immediately promoted to the active list.
*/
-extern int recently_evicted(void *, unsigned long, unsigned long);
-extern int remember_page(void *, unsigned long, unsigned long);
+extern int recently_evicted(void *, unsigned long);
+extern int remember_page(void *, unsigned long);
void init_nonresident(unsigned long);
--- linux-2.6.11/mm/nonresident.c.nr2 2005-04-23 14:10:07.000000000 -0400
+++ linux-2.6.11/mm/nonresident.c 2005-04-23 14:52:31.000000000 -0400
@@ -26,14 +26,6 @@
static unsigned long nr_buckets;
-/*
- * We fold the object generation number into the offset field, since
- * that one has the most "free" bits on a 32 bit system.
- */
-#define NR_GEN_SHIFT (BITS_PER_LONG * 7 / 8)
-#define NR_OFFSET_MASK ((1 << NR_GEN_SHIFT) - 1)
-#define make_nr_oag(x,y) (((x) & NR_OFFSET_MASK) + ((y) << NR_GEN_SHIFT))
-
struct nr_page {
void * mapping;
unsigned long offset_and_gen;
@@ -51,19 +43,31 @@ struct nr_bucket
/* The non-resident page hash table. */
static struct nr_bucket * nr_hashtable;
-struct nr_bucket * nr_hash(void * mapping, unsigned long offset_and_gen)
+struct nr_bucket * nr_hash(void * mapping, unsigned long offset)
{
unsigned long bucket;
unsigned long hash;
- hash = 17;
- hash = 37 * hash + hash_ptr_mul(mapping);
- hash = 37 * hash + hash_long_mul(offset_and_gen);
+ hash = hash_ptr_mul(mapping);
+ hash = 37 * hash + hash_long_mul(offset);
bucket = hash % nr_buckets;
return nr_hashtable + bucket;
}
+static unsigned long nr_cookie(struct address_space * mapping, unsigned long offset)
+{
+ unsigned long cookie = offset;
+
+ if (mapping->host) {
+ cookie = hash_mul_long(offset);
+ cookie = 37 * cookie + hash_ptr_mul(mapping->host->i_ino);
+ cookie = 37 * cookie + hash_ptr_mul(mapping->host->i_sb);
+ }
+
+ return cookie;
+}
+
static int nr_same(struct nr_page * first, struct nr_page * second)
{
/* Chances are this nr_page belongs to a different mapping ... */
@@ -77,10 +81,10 @@ static int nr_same(struct nr_page * firs
return 0;
}
-int recently_evicted(void * mapping, unsigned long offset, unsigned long gen)
+int recently_evicted(struct address_space * mapping, unsigned long offset)
{
- unsigned long offset_and_gen = make_nr_oag(offset, gen);
- struct nr_bucket * nr_bucket = nr_hash(mapping, offset_and_gen);
+ unsigned long offset_and_gen = nr_cookie(mapping, offset);
+ struct nr_bucket * nr_bucket = nr_hash(mapping, offset);
struct nr_page wanted;
int state = -1;
int i;
@@ -102,10 +106,10 @@ int recently_evicted(void * mapping, uns
return state;
}
-int remember_page(void * mapping, unsigned long offset, unsigned long gen)
+int remember_page(struct address_space * mapping, unsigned long offset)
{
- unsigned long offset_and_gen = make_nr_oag(offset, gen);
- struct nr_bucket * nr_bucket = nr_hash(mapping, offset_and_gen);
+ unsigned long offset_and_gen = nr_cookie(mapping, offset);
+ struct nr_bucket * nr_bucket = nr_hash(mapping, offset);
struct nr_page * victim;
int recycled = 0;
int i;
-
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