[PATCH] jbd: JBD slab allocation cleanups

[Mingming Cao <cmm@us.ibm.com>]

JBD: JBD slab allocation cleanups

From: Mingming Cao <cmm@us.ibm.com>

JBD: Replace slab allocations with page allocations

JBD allocate memory for committed_data and frozen_data from slab. However
JBD should not pass slab pages down to the block layer. Use page allocator pages instead. This will also prepare JBD for the large blocksize patchset.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
---

 fs/jbd/commit.c      |    6 +--
 fs/jbd/journal.c     |   88 ++-------------------------------------------------
 fs/jbd/transaction.c |    8 ++--
 include/linux/jbd.h  |   13 +++++--
 4 files changed, 21 insertions(+), 94 deletions(-)


Index: linux-2.6.23-rc9/fs/jbd/commit.c
===================================================================
--- linux-2.6.23-rc9.orig/fs/jbd/commit.c	2007-10-05 12:03:43.000000000 -0700
+++ linux-2.6.23-rc9/fs/jbd/commit.c	2007-10-05 12:08:08.000000000 -0700
@@ -375,7 +375,7 @@ void journal_commit_transaction(journal_
 			struct buffer_head *bh = jh2bh(jh);
 
 			jbd_lock_bh_state(bh);
-			jbd_slab_free(jh->b_committed_data, bh->b_size);
+			jbd_free(jh->b_committed_data, bh->b_size);
 			jh->b_committed_data = NULL;
 			jbd_unlock_bh_state(bh);
 		}
@@ -792,14 +792,14 @@ restart_loop:
 		 * Otherwise, we can just throw away the frozen data now.
 		 */
 		if (jh->b_committed_data) {
-			jbd_slab_free(jh->b_committed_data, bh->b_size);
+			jbd_free(jh->b_committed_data, bh->b_size);
 			jh->b_committed_data = NULL;
 			if (jh->b_frozen_data) {
 				jh->b_committed_data = jh->b_frozen_data;
 				jh->b_frozen_data = NULL;
 			}
 		} else if (jh->b_frozen_data) {
-			jbd_slab_free(jh->b_frozen_data, bh->b_size);
+			jbd_free(jh->b_frozen_data, bh->b_size);
 			jh->b_frozen_data = NULL;
 		}
 
Index: linux-2.6.23-rc9/fs/jbd/journal.c
===================================================================
--- linux-2.6.23-rc9.orig/fs/jbd/journal.c	2007-10-05 12:03:43.000000000 -0700
+++ linux-2.6.23-rc9/fs/jbd/journal.c	2007-10-05 12:08:08.000000000 -0700
@@ -83,7 +83,6 @@ EXPORT_SYMBOL(journal_force_commit);
 
 static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *);
 static void __journal_abort_soft (journal_t *journal, int errno);
-static int journal_create_jbd_slab(size_t slab_size);
 
 /*
  * Helper function used to manage commit timeouts
@@ -334,10 +333,10 @@ repeat:
 		char *tmp;
 
 		jbd_unlock_bh_state(bh_in);
-		tmp = jbd_slab_alloc(bh_in->b_size, GFP_NOFS);
+		tmp = jbd_alloc(bh_in->b_size, GFP_NOFS);
 		jbd_lock_bh_state(bh_in);
 		if (jh_in->b_frozen_data) {
-			jbd_slab_free(tmp, bh_in->b_size);
+			jbd_free(tmp, bh_in->b_size);
 			goto repeat;
 		}
 
@@ -1095,13 +1094,6 @@ int journal_load(journal_t *journal)
 		}
 	}
 
-	/*
-	 * Create a slab for this blocksize
-	 */
-	err = journal_create_jbd_slab(be32_to_cpu(sb->s_blocksize));
-	if (err)
-		return err;
-
 	/* Let the recovery code check whether it needs to recover any
 	 * data from the journal. */
 	if (journal_recover(journal))
@@ -1624,77 +1616,6 @@ void * __jbd_kmalloc (const char *where,
 }
 
 /*
- * jbd slab management: create 1k, 2k, 4k, 8k slabs as needed
- * and allocate frozen and commit buffers from these slabs.
- *
- * Reason for doing this is to avoid, SLAB_DEBUG - since it could
- * cause bh to cross page boundary.
- */
-
-#define JBD_MAX_SLABS 5
-#define JBD_SLAB_INDEX(size)  (size >> 11)
-
-static struct kmem_cache *jbd_slab[JBD_MAX_SLABS];
-static const char *jbd_slab_names[JBD_MAX_SLABS] = {
-	"jbd_1k", "jbd_2k", "jbd_4k", NULL, "jbd_8k"
-};
-
-static void journal_destroy_jbd_slabs(void)
-{
-	int i;
-
-	for (i = 0; i < JBD_MAX_SLABS; i++) {
-		if (jbd_slab[i])
-			kmem_cache_destroy(jbd_slab[i]);
-		jbd_slab[i] = NULL;
-	}
-}
-
-static int journal_create_jbd_slab(size_t slab_size)
-{
-	int i = JBD_SLAB_INDEX(slab_size);
-
-	BUG_ON(i >= JBD_MAX_SLABS);
-
-	/*
-	 * Check if we already have a slab created for this size
-	 */
-	if (jbd_slab[i])
-		return 0;
-
-	/*
-	 * Create a slab and force alignment to be same as slabsize -
-	 * this will make sure that allocations won't cross the page
-	 * boundary.
-	 */
-	jbd_slab[i] = kmem_cache_create(jbd_slab_names[i],
-				slab_size, slab_size, 0, NULL);
-	if (!jbd_slab[i]) {
-		printk(KERN_EMERG "JBD: no memory for jbd_slab cache\n");
-		return -ENOMEM;
-	}
-	return 0;
-}
-
-void * jbd_slab_alloc(size_t size, gfp_t flags)
-{
-	int idx;
-
-	idx = JBD_SLAB_INDEX(size);
-	BUG_ON(jbd_slab[idx] == NULL);
-	return kmem_cache_alloc(jbd_slab[idx], flags | __GFP_NOFAIL);
-}
-
-void jbd_slab_free(void *ptr,  size_t size)
-{
-	int idx;
-
-	idx = JBD_SLAB_INDEX(size);
-	BUG_ON(jbd_slab[idx] == NULL);
-	kmem_cache_free(jbd_slab[idx], ptr);
-}
-
-/*
  * Journal_head storage management
  */
 static struct kmem_cache *journal_head_cache;
@@ -1881,13 +1802,13 @@ static void __journal_remove_journal_hea
 				printk(KERN_WARNING "%s: freeing "
 						"b_frozen_data\n",
 						__FUNCTION__);
-				jbd_slab_free(jh->b_frozen_data, bh->b_size);
+				jbd_free(jh->b_frozen_data, bh->b_size);
 			}
 			if (jh->b_committed_data) {
 				printk(KERN_WARNING "%s: freeing "
 						"b_committed_data\n",
 						__FUNCTION__);
-				jbd_slab_free(jh->b_committed_data, bh->b_size);
+				jbd_free(jh->b_committed_data, bh->b_size);
 			}
 			bh->b_private = NULL;
 			jh->b_bh = NULL;	/* debug, really */
@@ -2042,7 +1963,6 @@ static void journal_destroy_caches(void)
 	journal_destroy_revoke_caches();
 	journal_destroy_journal_head_cache();
 	journal_destroy_handle_cache();
-	journal_destroy_jbd_slabs();
 }
 
 static int __init journal_init(void)
Index: linux-2.6.23-rc9/fs/jbd/transaction.c
===================================================================
--- linux-2.6.23-rc9.orig/fs/jbd/transaction.c	2007-10-05 12:03:43.000000000 -0700
+++ linux-2.6.23-rc9/fs/jbd/transaction.c	2007-10-05 12:08:08.000000000 -0700
@@ -668,7 +668,7 @@ repeat:
 				JBUFFER_TRACE(jh, "allocate memory for buffer");
 				jbd_unlock_bh_state(bh);
 				frozen_buffer =
-					jbd_slab_alloc(jh2bh(jh)->b_size,
+					jbd_alloc(jh2bh(jh)->b_size,
 							 GFP_NOFS);
 				if (!frozen_buffer) {
 					printk(KERN_EMERG
@@ -728,7 +728,7 @@ done:
 
 out:
 	if (unlikely(frozen_buffer))	/* It's usually NULL */
-		jbd_slab_free(frozen_buffer, bh->b_size);
+		jbd_free(frozen_buffer, bh->b_size);
 
 	JBUFFER_TRACE(jh, "exit");
 	return error;
@@ -881,7 +881,7 @@ int journal_get_undo_access(handle_t *ha
 
 repeat:
 	if (!jh->b_committed_data) {
-		committed_data = jbd_slab_alloc(jh2bh(jh)->b_size, GFP_NOFS);
+		committed_data = jbd_alloc(jh2bh(jh)->b_size, GFP_NOFS);
 		if (!committed_data) {
 			printk(KERN_EMERG "%s: No memory for committed data\n",
 				__FUNCTION__);
@@ -908,7 +908,7 @@ repeat:
 out:
 	journal_put_journal_head(jh);
 	if (unlikely(committed_data))
-		jbd_slab_free(committed_data, bh->b_size);
+		jbd_free(committed_data, bh->b_size);
 	return err;
 }
 
Index: linux-2.6.23-rc9/include/linux/jbd.h
===================================================================
--- linux-2.6.23-rc9.orig/include/linux/jbd.h	2007-10-05 12:03:43.000000000 -0700
+++ linux-2.6.23-rc9/include/linux/jbd.h	2007-10-05 12:08:08.000000000 -0700
@@ -72,14 +72,21 @@ extern int journal_enable_debug;
 #endif
 
 extern void * __jbd_kmalloc (const char *where, size_t size, gfp_t flags, int retry);
-extern void * jbd_slab_alloc(size_t size, gfp_t flags);
-extern void jbd_slab_free(void *ptr, size_t size);
-
 #define jbd_kmalloc(size, flags) \
 	__jbd_kmalloc(__FUNCTION__, (size), (flags), journal_oom_retry)
 #define jbd_rep_kmalloc(size, flags) \
 	__jbd_kmalloc(__FUNCTION__, (size), (flags), 1)
 
+static inline void *jbd_alloc(size_t size, gfp_t flags)
+{
+	return (void *)__get_free_pages(flags, get_order(size));
+}
+
+static inline void jbd_free(void *ptr, size_t size)
+{
+	free_pages((unsigned long)ptr, get_order(size));
+};
+
 #define JFS_MIN_JOURNAL_BLOCKS 1024
 
 #ifdef __KERNEL__