GC dcookies better.

diff --git a/linux-2.6-590-GC-dcookies.patch b/linux-2.6-590-GC-dcookies.patch
index bf9c6f2..fee1c31 100644 (file)
--- a/linux-2.6-590-GC-dcookies.patch
+++ b/linux-2.6-590-GC-dcookies.patch
@@ -1,139 +1,190 @@
---- linux-2.6.22.19-chopstix/fs/dcookies.c     2009-02-28 03:10:05.000000000 -0500
-+++ linux-2.6.22.19-chopstix/fs/dcookies.c.orig        2008-02-25 18:59:40.000000000 -0500
-@@ -38,19 +38,14 @@
+diff -Nurb linux-2.6.22.19/fs/dcookies.c linux-2.6.22.19-dcookies/fs/dcookies.c
+--- linux-2.6.22.19/fs/dcookies.c      2008-02-25 18:59:40.000000000 -0500
++++ linux-2.6.22.19-dcookies/fs/dcookies.c     2009-03-16 14:44:24.000000000 -0400
+@@ -38,14 +38,19 @@
  static LIST_HEAD(dcookie_users);
  static DEFINE_MUTEX(dcookie_mutex);
  static struct kmem_cache *dcookie_cache __read_mostly;
--static struct list_head *dcookie_hashtable[2] __read_mostly;
-+static struct list_head *dcookie_hashtable __read_mostly;
+-static struct list_head *dcookie_hashtable __read_mostly;
++static struct list_head *dcookie_hashtable[3] __read_mostly;
  static size_t hash_size __read_mostly;
--unsigned int current_hash = 0;
++unsigned int current_hash = 0, old_hash = -1;
  
  static inline int is_live(void)
  {
        return !(list_empty(&dcookie_users));
  }
  
--static inline int is_shared(void)
--{
--      return !(list_empty(&dcookie_users)) && !(list_empty(dcookie_users.next));
--}
++static inline int is_shared(void)
++{
++      return !(list_empty(&dcookie_users)) && !(list_empty(dcookie_users.next));
++}
  
  /* The dentry is locked, its address will do for the cookie */
  static inline unsigned long dcookie_value(struct dcookie_struct * dcs)
-@@ -72,7 +67,7 @@
+@@ -67,7 +72,7 @@
        struct list_head * pos;
        struct list_head * list;
  
--      list = dcookie_hashtable[current_hash] + dcookie_hash(dcookie);
-+      list = dcookie_hashtable + dcookie_hash(dcookie);
+-      list = dcookie_hashtable + dcookie_hash(dcookie);
++      list = dcookie_hashtable[current_hash] + dcookie_hash(dcookie);
  
        list_for_each(pos, list) {
                dcs = list_entry(pos, struct dcookie_struct, hash_list);
-@@ -88,7 +83,7 @@
+@@ -77,13 +82,26 @@
+               }
+       }
+ 
++    if (!found && (old_hash!=-1)) {
++        list = dcookie_hashtable[old_hash] + dcookie_hash(dcookie);
++
++        list_for_each(pos, list) {
++            dcs = list_entry(pos, struct dcookie_struct, hash_list);
++            if (dcookie_value(dcs) == dcookie) {
++                found = dcs;
++                break;
++            }
++        }
++
++    }
++
+       return found;
+ }
+ 
  
  static void hash_dcookie(struct dcookie_struct * dcs)
  {
--      struct list_head * list = dcookie_hashtable[current_hash] + dcookie_hash(dcookie_value(dcs));
-+      struct list_head * list = dcookie_hashtable + dcookie_hash(dcookie_value(dcs));
+-      struct list_head * list = dcookie_hashtable + dcookie_hash(dcookie_value(dcs));
++      struct list_head * list = dcookie_hashtable[current_hash] + dcookie_hash(dcookie_value(dcs));
        list_add(&dcs->hash_list, list);
  }
  
-@@ -96,7 +91,7 @@
+@@ -91,7 +109,7 @@
  static struct dcookie_struct * alloc_dcookie(struct dentry * dentry,
        struct vfsmount * vfsmnt)
  {
--      struct dcookie_struct * dcs = kmem_cache_alloc(dcookie_cache, GFP_ATOMIC);
-+      struct dcookie_struct * dcs = kmem_cache_alloc(dcookie_cache, GFP_KERNEL);
+-      struct dcookie_struct * dcs = kmem_cache_alloc(dcookie_cache, GFP_KERNEL);
++      struct dcookie_struct * dcs = kmem_cache_alloc(dcookie_cache, GFP_ATOMIC);
        if (!dcs)
                return NULL;
  
-@@ -215,12 +210,8 @@
+@@ -210,10 +228,19 @@
        if (!dcookie_cache)
                goto out;
  
--      dcookie_hashtable[0] = kmalloc(PAGE_SIZE, GFP_KERNEL);
--      if (!dcookie_hashtable[0])
--              goto out_kmem;
--    
--    dcookie_hashtable[1] = kmalloc(PAGE_SIZE, GFP_KERNEL);
--      if (!dcookie_hashtable[1])
-+      dcookie_hashtable = kmalloc(PAGE_SIZE, GFP_KERNEL);
-+      if (!dcookie_hashtable)
+-      dcookie_hashtable = kmalloc(PAGE_SIZE, GFP_KERNEL);
+-      if (!dcookie_hashtable)
++      dcookie_hashtable[0] = kmalloc(PAGE_SIZE, GFP_KERNEL);
++      if (!dcookie_hashtable[0])
++              goto out_kmem;
++    
++    dcookie_hashtable[1] = kmalloc(PAGE_SIZE, GFP_KERNEL);
++      if (!dcookie_hashtable[1])
                goto out_kmem;
  
++    dcookie_hashtable[2] = kmalloc(PAGE_SIZE, GFP_KERNEL);
++      if (!dcookie_hashtable[0])
++              goto out_kmem;
++    
++
        err = 0;
-@@ -244,15 +235,7 @@
+ 
+       /*
+@@ -235,7 +262,24 @@
        hash_size = 1UL << hash_bits;
  
        /* And initialize the newly allocated array */
--      d = dcookie_hashtable[0];
--      i = hash_size;
--      do {
--              INIT_LIST_HEAD(d);
--              d++;
--              i--;
--      } while (i);
--
--    d = dcookie_hashtable[1];
-+      d = dcookie_hashtable;
+-      d = dcookie_hashtable;
++
++      d = dcookie_hashtable[0];
++      i = hash_size;
++      do {
++              INIT_LIST_HEAD(d);
++              d++;
++              i--;
++      } while (i);
++
++    d = dcookie_hashtable[1];
++      i = hash_size;
++      do {
++              INIT_LIST_HEAD(d);
++              d++;
++              i--;
++      } while (i);
++
++    d = dcookie_hashtable[2];
        i = hash_size;
        do {
                INIT_LIST_HEAD(d);
-@@ -276,30 +259,6 @@
+@@ -259,6 +303,39 @@
        kmem_cache_free(dcookie_cache, dcs);
  }
  
--/* Switch to the second hash */
--int garbage_collect(void) {
--    struct list_head * list;
--      struct list_head * pos;
--      struct list_head * pos2;
--      struct dcookie_struct * dcs;
--      size_t i;
--
--    if (is_shared())
--        return -EAGAIN;
--
--      for (i = 0; i < hash_size; ++i) {
--              list = dcookie_hashtable[current_hash] + i;
--              list_for_each_safe(pos, pos2, list) {
--                      dcs = list_entry(pos, struct dcookie_struct, hash_list);
--                      list_del(&dcs->hash_list);
--                      free_dcookie(dcs);
--              }
--      }
--
--    current_hash = (current_hash & 1) ^ 1;
--
--    return 0;
--}
++int dcookie_swap(void) {
++    if (is_shared())
++        return -EAGAIN;
++
++    old_hash=current_hash;
++    current_hash = (current_hash + 1) % 3;
++    return 0;
++}
++
++/* Switch to the second hash */
++int dcookie_garbage_collect(void) {
++    struct list_head * list;
++      struct list_head * pos;
++      struct list_head * pos2;
++      struct dcookie_struct * dcs;
++      size_t i;
++    int next_hash=(current_hash + 1) % 3;
++
++    if (is_shared())
++        return -EAGAIN;
++
++    /* XXX consider the consequence of dcookie allocation concurring with this cleanup */
++      for (i = 0; i < hash_size; ++i) {
++              list = dcookie_hashtable[next_hash] + i;
++              list_for_each_safe(pos, pos2, list) {
++                      dcs = list_entry(pos, struct dcookie_struct, hash_list);
++                      list_del(&dcs->hash_list);
++                      free_dcookie(dcs);
++              }
++      }
++
++    return 0;
++}
  
  static void dcookie_exit(void)
  {
-@@ -310,14 +269,7 @@
+@@ -269,7 +346,14 @@
        size_t i;
  
        for (i = 0; i < hash_size; ++i) {
--              list = dcookie_hashtable[0] + i;
--              list_for_each_safe(pos, pos2, list) {
--                      dcs = list_entry(pos, struct dcookie_struct, hash_list);
--                      list_del(&dcs->hash_list);
--                      free_dcookie(dcs);
--              }
--
--        list = dcookie_hashtable[1] + i;
-+              list = dcookie_hashtable + i;
+-              list = dcookie_hashtable + i;
++              list = dcookie_hashtable[0] + i;
++              list_for_each_safe(pos, pos2, list) {
++                      dcs = list_entry(pos, struct dcookie_struct, hash_list);
++                      list_del(&dcs->hash_list);
++                      free_dcookie(dcs);
++              }
++
++        list = dcookie_hashtable[1] + i;
                list_for_each_safe(pos, pos2, list) {
                        dcs = list_entry(pos, struct dcookie_struct, hash_list);
                        list_del(&dcs->hash_list);
-@@ -325,8 +277,7 @@
+@@ -277,7 +361,8 @@
                }
        }
  
--      kfree(dcookie_hashtable[0]);
--      kfree(dcookie_hashtable[1]);
-+      kfree(dcookie_hashtable);
+-      kfree(dcookie_hashtable);
++      kfree(dcookie_hashtable[0]);
++      kfree(dcookie_hashtable[1]);
        kmem_cache_destroy(dcookie_cache);
  }
  
+@@ -327,3 +412,5 @@
+ EXPORT_SYMBOL_GPL(dcookie_register);
+ EXPORT_SYMBOL_GPL(dcookie_unregister);
+ EXPORT_SYMBOL_GPL(get_dcookie);
++EXPORT_SYMBOL_GPL(dcookie_garbage_collect);
++EXPORT_SYMBOL_GPL(dcookie_swap);