On Thu, Oct 31, 2002 at 04:18:26PM -0800, Andrew Morton wrote:
> This is Al's implementation of the Orlov block allocator for ext2.
>
> At least doubles the throughput for the traverse-a-kernel-tree
> test and is well tested.
>
> I still need to do the ext3 version.
Here's the ext3 version. :-)
- Ted
fs/ext3/ialloc.c | 336 ++++++++++++++++++++++++++++++++++-----------
fs/ext3/super.c | 11 +
include/linux/ext3_fs.h | 7
include/linux/ext3_fs_sb.h | 2
4 files changed, 277 insertions(+), 79 deletions(-)
diff -Nru a/fs/ext3/ialloc.c b/fs/ext3/ialloc.c
--- a/fs/ext3/ialloc.c Sat Nov 2 01:32:18 2002
+++ b/fs/ext3/ialloc.c Sat Nov 2 01:32:18 2002
@@ -21,6 +21,7 @@
#include <linux/string.h>
#include <linux/quotaops.h>
#include <linux/buffer_head.h>
+#include <linux/random.h>
#include <asm/bitops.h>
#include <asm/byteorder.h>
@@ -198,6 +199,230 @@
* the groups with above-average free space, that group with the fewest
* directories already is chosen.
*
+ * For other inodes, search forward from the parent directory\'s block
+ * group to find a free inode.
+ */
+static int find_group_dir(struct super_block *sb, struct inode *parent)
+{
+ struct ext3_super_block * es = EXT3_SB(sb)->s_es;
+ int ngroups = EXT3_SB(sb)->s_groups_count;
+ int avefreei = le32_to_cpu(es->s_free_inodes_count) / ngroups;
+ struct ext3_group_desc *desc, *best_desc = NULL;
+ struct buffer_head *bh, *best_bh = NULL;
+ int group, best_group = -1;
+
+ for (group = 0; group < ngroups; group++) {
+ desc = ext3_get_group_desc (sb, group, &bh);
+ if (!desc || !desc->bg_free_inodes_count)
+ continue;
+ if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
+ continue;
+ if (!best_desc ||
+ (le16_to_cpu(desc->bg_free_blocks_count) >
+ le16_to_cpu(best_desc->bg_free_blocks_count))) {
+ best_group = group;
+ best_desc = desc;
+ best_bh = bh;
+ }
+ }
+ if (!best_desc)
+ return -1;
+ best_desc->bg_free_inodes_count =
+ cpu_to_le16(le16_to_cpu(best_desc->bg_free_inodes_count) - 1);
+ best_desc->bg_used_dirs_count =
+ cpu_to_le16(le16_to_cpu(best_desc->bg_used_dirs_count) + 1);
+ mark_buffer_dirty(best_bh);
+ return best_group;
+}
+
+/*
+ * Orlov's allocator for directories.
+ *
+ * We always try to spread first-level directories.
+ *
+ * If there are blockgroups with both free inodes and free blocks counts
+ * not worse than average we return one with smallest directory count.
+ * Otherwise we simply return a random group.
+ *
+ * For the rest rules look so:
+ *
+ * It's OK to put directory into a group unless
+ * it has too many directories already (max_dirs) or
+ * it has too few free inodes left (min_inodes) or
+ * it has too few free blocks left (min_blocks) or
+ * it's already running too large debt (max_debt).
+ * Parent's group is prefered, if it doesn't satisfy these
+ * conditions we search cyclically through the rest. If none
+ * of the groups look good we just look for a group with more
+ * free inodes than average (starting at parent's group).
+ *
+ * Debt is incremented each time we allocate a directory and decremented
+ * when we allocate an inode, within 0--255.
+ */
+
+#define INODE_COST 64
+#define BLOCK_COST 256
+
+static int find_group_orlov(struct super_block *sb, struct inode *parent)
+{
+ int parent_group = EXT3_I(parent)->i_block_group;
+ struct ext3_sb_info *sbi = EXT3_SB(sb);
+ struct ext3_super_block *es = sbi->s_es;
+ int ngroups = sbi->s_groups_count;
+ int inodes_per_group = EXT3_INODES_PER_GROUP(sb);
+ int avefreei = le32_to_cpu(es->s_free_inodes_count) / ngroups;
+ int avefreeb = le32_to_cpu(es->s_free_blocks_count) / ngroups;
+ int blocks_per_dir;
+ int ndirs = sbi->s_dir_count;
+ int max_debt, max_dirs, min_blocks, min_inodes;
+ int group = -1, i;
+ struct ext3_group_desc *desc;
+ struct buffer_head *bh;
+
+ if ((parent == sb->s_root->d_inode) ||
+ (parent->i_flags & EXT3_TOPDIR_FL)) {
+ struct ext3_group_desc *best_desc = NULL;
+ struct buffer_head *best_bh = NULL;
+ int best_ndir = inodes_per_group;
+ int best_group = -1;
+
+ get_random_bytes(&group, sizeof(group));
+ parent_group = (unsigned)group % ngroups;
+ for (i = 0; i < ngroups; i++) {
+ group = (parent_group + i) % ngroups;
+ desc = ext3_get_group_desc (sb, group, &bh);
+ if (!desc || !desc->bg_free_inodes_count)
+ continue;
+ if (le16_to_cpu(desc->bg_used_dirs_count) >= best_ndir)
+ continue;
+ if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
+ continue;
+ if (le16_to_cpu(desc->bg_free_blocks_count) < avefreeb)
+ continue;
+ best_group = group;
+ best_ndir = le16_to_cpu(desc->bg_used_dirs_count);
+ best_desc = desc;
+ best_bh = bh;
+ }
+ if (best_group >= 0) {
+ desc = best_desc;
+ bh = best_bh;
+ group = best_group;
+ goto found;
+ }
+ goto fallback;
+ }
+
+ blocks_per_dir = (le32_to_cpu(es->s_blocks_count) -
+ le32_to_cpu(es->s_free_blocks_count)) / ndirs;
+
+ max_dirs = ndirs / ngroups + inodes_per_group / 16;
+ min_inodes = avefreei - inodes_per_group / 4;
+ min_blocks = avefreeb - EXT3_BLOCKS_PER_GROUP(sb) / 4;
+
+ max_debt = EXT3_BLOCKS_PER_GROUP(sb) / max(blocks_per_dir, BLOCK_COST);
+ if (max_debt * INODE_COST > inodes_per_group)
+ max_debt = inodes_per_group / INODE_COST;
+ if (max_debt > 255)
+ max_debt = 255;
+ if (max_debt == 0)
+ max_debt = 1;
+
+ for (i = 0; i < ngroups; i++) {
+ group = (parent_group + i) % ngroups;
+ desc = ext3_get_group_desc (sb, group, &bh);
+ if (!desc || !desc->bg_free_inodes_count)
+ continue;
+ if (sbi->s_debts[group] >= max_debt)
+ continue;
+ if (le16_to_cpu(desc->bg_used_dirs_count) >= max_dirs)
+ continue;
+ if (le16_to_cpu(desc->bg_free_inodes_count) < min_inodes)
+ continue;
+ if (le16_to_cpu(desc->bg_free_blocks_count) < min_blocks)
+ continue;
+ goto found;
+ }
+
+fallback:
+ for (i = 0; i < ngroups; i++) {
+ group = (parent_group + i) % ngroups;
+ desc = ext3_get_group_desc (sb, group, &bh);
+ if (!desc || !desc->bg_free_inodes_count)
+ continue;
+ if (le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
+ goto found;
+ }
+
+ return -1;
+
+found:
+ desc->bg_free_inodes_count =
+ cpu_to_le16(le16_to_cpu(desc->bg_free_inodes_count) - 1);
+ desc->bg_used_dirs_count =
+ cpu_to_le16(le16_to_cpu(desc->bg_used_dirs_count) + 1);
+ sbi->s_dir_count++;
+ mark_buffer_dirty(bh);
+ return group;
+}
+
+static int find_group_other(struct super_block *sb, struct inode *parent)
+{
+ int parent_group = EXT3_I(parent)->i_block_group;
+ int ngroups = EXT3_SB(sb)->s_groups_count;
+ struct ext3_group_desc *desc;
+ struct buffer_head *bh;
+ int group, i;
+
+ /*
+ * Try to place the inode in its parent directory
+ */
+ group = parent_group;
+ desc = ext3_get_group_desc (sb, group, &bh);
+ if (desc && le16_to_cpu(desc->bg_free_inodes_count))
+ goto found;
+
+ /*
+ * Use a quadratic hash to find a group with a
+ * free inode
+ */
+ for (i = 1; i < ngroups; i <<= 1) {
+ group += i;
+ if (group >= ngroups)
+ group -= ngroups;
+ desc = ext3_get_group_desc (sb, group, &bh);
+ if (desc && le16_to_cpu(desc->bg_free_inodes_count))
+ goto found;
+ }
+
+ /*
+ * That failed: try linear search for a free inode
+ */
+ group = parent_group + 1;
+ for (i = 2; i < ngroups; i++) {
+ if (++group >= ngroups)
+ group = 0;
+ desc = ext3_get_group_desc (sb, group, &bh);
+ if (desc && le16_to_cpu(desc->bg_free_inodes_count))
+ goto found;
+ }
+
+ return -1;
+
+found:
+ desc->bg_free_inodes_count =
+ cpu_to_le16(le16_to_cpu(desc->bg_free_inodes_count) - 1);
+ mark_buffer_dirty(bh);
+ return group;
+}
+
+/*
+ * There are two policies for allocating an inode. If the new inode is
+ * a directory, then a forward search is made for a block group with both
+ * free space and a low directory-to-inode ratio; if that fails, then of
+ * the groups with above-average free space, that group with the fewest
+ * directories already is chosen.
+ *
* For other inodes, search forward from the parent directory's block
* group to find a free inode.
*/
@@ -206,10 +431,10 @@
struct super_block *sb;
struct buffer_head *bitmap_bh = NULL;
struct buffer_head *bh2;
- int i, j, avefreei;
+ int group;
+ ino_t ino;
struct inode * inode;
struct ext3_group_desc * gdp;
- struct ext3_group_desc * tmp;
struct ext3_super_block * es;
struct ext3_inode_info *ei;
int err = 0;
@@ -228,93 +453,35 @@
lock_super (sb);
es = EXT3_SB(sb)->s_es;
repeat:
- gdp = NULL;
- i = 0;
-
if (S_ISDIR(mode)) {
- avefreei = le32_to_cpu(es->s_free_inodes_count) /
- EXT3_SB(sb)->s_groups_count;
- if (!gdp) {
- for (j = 0; j < EXT3_SB(sb)->s_groups_count; j++) {
- struct buffer_head *temp_buffer;
- tmp = ext3_get_group_desc (sb, j, &temp_buffer);
- if (tmp &&
- le16_to_cpu(tmp->bg_free_inodes_count) &&
- le16_to_cpu(tmp->bg_free_inodes_count) >=
- avefreei) {
- if (!gdp || (le16_to_cpu(tmp->bg_free_blocks_count) >
- le16_to_cpu(gdp->bg_free_blocks_count))) {
- i = j;
- gdp = tmp;
- bh2 = temp_buffer;
- }
- }
- }
- }
- } else {
- /*
- * Try to place the inode in its parent directory
- */
- i = EXT3_I(dir)->i_block_group;
- tmp = ext3_get_group_desc (sb, i, &bh2);
- if (tmp && le16_to_cpu(tmp->bg_free_inodes_count))
- gdp = tmp;
+ if (test_opt (sb, OLDALLOC))
+ group = find_group_dir(sb, dir);
else
- {
- /*
- * Use a quadratic hash to find a group with a
- * free inode
- */
- for (j = 1; j < EXT3_SB(sb)->s_groups_count; j <<= 1) {
- i += j;
- if (i >= EXT3_SB(sb)->s_groups_count)
- i -= EXT3_SB(sb)->s_groups_count;
- tmp = ext3_get_group_desc (sb, i, &bh2);
- if (tmp &&
- le16_to_cpu(tmp->bg_free_inodes_count)) {
- gdp = tmp;
- break;
- }
- }
- }
- if (!gdp) {
- /*
- * That failed: try linear search for a free inode
- */
- i = EXT3_I(dir)->i_block_group + 1;
- for (j = 2; j < EXT3_SB(sb)->s_groups_count; j++) {
- if (++i >= EXT3_SB(sb)->s_groups_count)
- i = 0;
- tmp = ext3_get_group_desc (sb, i, &bh2);
- if (tmp &&
- le16_to_cpu(tmp->bg_free_inodes_count)) {
- gdp = tmp;
- break;
- }
- }
- }
- }
+ group = find_group_orlov(sb, dir);
+ } else
+ group = find_group_other(sb, dir);
err = -ENOSPC;
- if (!gdp)
+ if (group == -1)
goto out;
err = -EIO;
brelse(bitmap_bh);
- bitmap_bh = read_inode_bitmap(sb, i);
+ bitmap_bh = read_inode_bitmap(sb, group);
if (!bitmap_bh)
goto fail;
+ gdp = ext3_get_group_desc (sb, group, &bh2);
- if ((j = ext3_find_first_zero_bit((unsigned long *)bitmap_bh->b_data,
+ if ((ino = ext3_find_first_zero_bit((unsigned long *)bitmap_bh->b_data,
EXT3_INODES_PER_GROUP(sb))) <
EXT3_INODES_PER_GROUP(sb)) {
BUFFER_TRACE(bitmap_bh, "get_write_access");
err = ext3_journal_get_write_access(handle, bitmap_bh);
if (err) goto fail;
- if (ext3_set_bit(j, bitmap_bh->b_data)) {
+ if (ext3_set_bit(ino, bitmap_bh->b_data)) {
ext3_error (sb, "ext3_new_inode",
- "bit already set for inode %d", j);
+ "bit already set for inode %lu", ino);
goto repeat;
}
BUFFER_TRACE(bitmap_bh, "call ext3_journal_dirty_metadata");
@@ -324,7 +491,7 @@
if (le16_to_cpu(gdp->bg_free_inodes_count) != 0) {
ext3_error (sb, "ext3_new_inode",
"Free inodes count corrupted in group %d",
- i);
+ group);
/* Is it really ENOSPC? */
err = -ENOSPC;
if (sb->s_flags & MS_RDONLY)
@@ -340,11 +507,11 @@
}
goto repeat;
}
- j += i * EXT3_INODES_PER_GROUP(sb) + 1;
- if (j < EXT3_FIRST_INO(sb) || j > le32_to_cpu(es->s_inodes_count)) {
+ ino += group * EXT3_INODES_PER_GROUP(sb) + 1;
+ if (ino < EXT3_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
ext3_error (sb, "ext3_new_inode",
"reserved inode or inode > inodes count - "
- "block_group = %d,inode=%d", i, j);
+ "block_group = %d, inode=%lu", group, ino);
err = -EIO;
goto fail;
}
@@ -382,7 +549,7 @@
inode->i_gid = current->fsgid;
inode->i_mode = mode;
- inode->i_ino = j;
+ inode->i_ino = ino;
/* This is the optimal IO size (for stat), not the fs block size */
inode->i_blksize = PAGE_SIZE;
inode->i_blocks = 0;
@@ -412,7 +579,7 @@
ei->i_prealloc_block = 0;
ei->i_prealloc_count = 0;
#endif
- ei->i_block_group = i;
+ ei->i_block_group = group;
if (ei->i_flags & EXT3_SYNC_FL)
inode->i_flags |= S_SYNC;
@@ -560,6 +727,21 @@
#else
return le32_to_cpu(EXT3_SB(sb)->s_es->s_free_inodes_count);
#endif
+}
+
+/* Called at mount-time, super-block is locked */
+unsigned long ext3_count_dirs (struct super_block * sb)
+{
+ unsigned long count = 0;
+ int i;
+
+ for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
+ struct ext3_group_desc *gdp = ext3_get_group_desc (sb, i, NULL);
+ if (!gdp)
+ continue;
+ count += le16_to_cpu(gdp->bg_used_dirs_count);
+ }
+ return count;
}
#ifdef CONFIG_EXT3_CHECK
diff -Nru a/fs/ext3/super.c b/fs/ext3/super.c
--- a/fs/ext3/super.c Sat Nov 2 01:32:18 2002
+++ b/fs/ext3/super.c Sat Nov 2 01:32:18 2002
@@ -390,6 +390,7 @@
for (i = 0; i < sbi->s_gdb_count; i++)
brelse(sbi->s_group_desc[i]);
kfree(sbi->s_group_desc);
+ kfree(sbi->s_debts);
brelse(sbi->s_sbh);
/* Debugging code just in case the in-memory inode orphan list
@@ -1221,6 +1222,13 @@
printk (KERN_ERR "EXT3-fs: not enough memory\n");
goto failed_mount;
}
+ sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
+ GFP_KERNEL);
+ if (!sbi->s_debts) {
+ printk ("EXT3-fs: not enough memory\n");
+ goto failed_mount2;
+ }
+ memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
for (i = 0; i < db_count; i++) {
block = descriptor_loc(sb, logic_sb_block, i);
sbi->s_group_desc[i] = sb_bread(sb, block);
@@ -1236,6 +1244,7 @@
goto failed_mount2;
}
sbi->s_gdb_count = db_count;
+ sbi->s_dir_count = ext3_count_dirs(sb);
/*
* set up enough so that it can read an inode
*/
@@ -1339,6 +1348,8 @@
failed_mount3:
journal_destroy(sbi->s_journal);
failed_mount2:
+ if (sbi->s_debts)
+ kfree(sbi->s_debts);
for (i = 0; i < db_count; i++)
brelse(sbi->s_group_desc[i]);
kfree(sbi->s_group_desc);
diff -Nru a/include/linux/ext3_fs.h b/include/linux/ext3_fs.h
--- a/include/linux/ext3_fs.h Sat Nov 2 01:32:18 2002
+++ b/include/linux/ext3_fs.h Sat Nov 2 01:32:18 2002
@@ -186,10 +186,11 @@
#define EXT3_JOURNAL_DATA_FL 0x00004000 /* file data should be journaled */
#define EXT3_NOTAIL_FL 0x00008000 /* file tail should not be merged */
#define EXT3_DIRSYNC_FL 0x00010000 /* dirsync behaviour (directories only) */
+#define EXT3_TOPDIR_FL 0x00020000 /* Top of directory hierarchies*/
#define EXT3_RESERVED_FL 0x80000000 /* reserved for ext3 lib */
-#define EXT3_FL_USER_VISIBLE 0x00015FFF /* User visible flags */
-#define EXT3_FL_USER_MODIFIABLE 0x000100FF /* User modifiable flags */
+#define EXT3_FL_USER_VISIBLE 0x0003DFFF /* User visible flags */
+#define EXT3_FL_USER_MODIFIABLE 0x000380FF /* User modifiable flags */
/*
* Inode dynamic state flags
@@ -308,6 +309,7 @@
* Mount flags
*/
#define EXT3_MOUNT_CHECK 0x0001 /* Do mount-time checks */
+#define EXT3_MOUNT_OLDALLOC 0x0002 /* Don't use the new Orlov allocator */
#define EXT3_MOUNT_GRPID 0x0004 /* Create files with directory's group */
#define EXT3_MOUNT_DEBUG 0x0008 /* Some debugging messages */
#define EXT3_MOUNT_ERRORS_CONT 0x0010 /* Continue on errors */
@@ -704,6 +706,7 @@
extern void ext3_free_inode (handle_t *, struct inode *);
extern struct inode * ext3_orphan_get (struct super_block *, ino_t);
extern unsigned long ext3_count_free_inodes (struct super_block *);
+extern unsigned long ext3_count_dirs (struct super_block *);
extern void ext3_check_inodes_bitmap (struct super_block *);
extern unsigned long ext3_count_free (struct buffer_head *, unsigned);
diff -Nru a/include/linux/ext3_fs_sb.h b/include/linux/ext3_fs_sb.h
--- a/include/linux/ext3_fs_sb.h Sat Nov 2 01:32:18 2002
+++ b/include/linux/ext3_fs_sb.h Sat Nov 2 01:32:18 2002
@@ -50,6 +50,8 @@
u32 s_next_generation;
u32 s_hash_seed[4];
int s_def_hash_version;
+ unsigned long s_dir_count;
+ u8 *s_debts;
/* Journaling */
struct inode * s_journal_inode;
-
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This archive was generated by hypermail 2b29 : Thu Nov 07 2002 - 22:00:23 EST