On Fri, Feb 27, 2009 at 12:08:12AM +0530, Aneesh Kumar K.V wrote:
> ....
>
> > static int find_group_orlov(struct super_block *sb, struct inode *parent,
> > - ext4_group_t *group)
> > + ext4_group_t *group, int mode)
> > {
> > ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
> > struct ext4_sb_info *sbi = EXT4_SB(sb);
> > - struct ext4_super_block *es = sbi->s_es;
> > ext4_group_t ngroups = sbi->s_groups_count;
> > int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
> > unsigned int freei, avefreei;
> > ext4_fsblk_t freeb, avefreeb;
> > - ext4_fsblk_t blocks_per_dir;
> > unsigned int ndirs;
> > - int max_debt, max_dirs, min_inodes;
> > + int max_dirs, min_inodes;
> > ext4_grpblk_t min_blocks;
> > - ext4_group_t i;
> > + ext4_group_t i, grp, g;
> > struct ext4_group_desc *desc;
> > + struct orlov_stats stats;
> > + int flex_size = ext4_flex_bg_size(sbi);
> > +
> > + if (flex_size > 1) {
> > + ngroups = (ngroups + flex_size - 1) >>
> > + sbi->s_log_groups_per_flex;
> > + parent_group >>= sbi->s_log_groups_per_flex;
> > + }
> >
> > freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
> > avefreei = freei / ngroups;
> > @@ -460,71 +496,97 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent,
> > do_div(avefreeb, ngroups);
> > ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
> >
> > - if ((parent == sb->s_root->d_inode) ||
> > - (EXT4_I(parent)->i_flags & EXT4_TOPDIR_FL)) {
> > + if (S_ISDIR(mode) &&
> > + ((parent == sb->s_root->d_inode) ||
> > + (EXT4_I(parent)->i_flags & EXT4_TOPDIR_FL))) {
> > int best_ndir = inodes_per_group;
> > - ext4_group_t grp;
> > int ret = -1;
> >
> > get_random_bytes(&grp, sizeof(grp));
> > parent_group = (unsigned)grp % ngroups;
> > for (i = 0; i < ngroups; i++) {
> > - grp = (parent_group + i) % ngroups;
> > - desc = ext4_get_group_desc(sb, grp, NULL);
> > - if (!desc || !ext4_free_inodes_count(sb, desc))
> > + g = (parent_group + i) % ngroups;
> > + get_orlov_stats(sb, g, flex_size, &stats);
> > + if (!stats.free_inodes)
> > continue;
> > - if (ext4_used_dirs_count(sb, desc) >= best_ndir)
> > + if (stats.used_dirs >= best_ndir)
> > continue;
> > - if (ext4_free_inodes_count(sb, desc) < avefreei)
> > + if (stats.free_inodes < avefreei)
> > continue;
> > - if (ext4_free_blks_count(sb, desc) < avefreeb)
> > + if (stats.free_blocks < avefreeb)
> > continue;
> > - *group = grp;
> > + grp = g;
> > ret = 0;
> > - best_ndir = ext4_used_dirs_count(sb, desc);
> > + best_ndir = stats.used_dirs;
> > + }
> > + if (ret)
> > + goto fallback;
> > + found_flex_bg:
> > + if (flex_size == 1) {
> > + *group = grp;
> > + return 0;
> > + }
> > +
> > + /*
> > + * We pack inodes at the beginning of the flexgroup's
> > + * inode tables. Block allocation decisions will do
> > + * something similar, although regular files will
> > + * start at 2nd block group of the flexgroup. See
> > + * ext4_ext_find_goal() and ext4_find_near().
> > + */
> > + grp *= flex_size;
> > + for (i = 0; i < flex_size; i++) {
> > + if (grp+i >= sbi->s_groups_count)
> > + break;
> > + desc = ext4_get_group_desc(sb, grp+i, NULL);
> > + if (desc && ext4_free_inodes_count(sb, desc)) {
> > + *group = grp+i;
> > + return 0;
> > + }
> > }
> > - if (ret == 0)
> > - return ret;
> > goto fallback;
> > }
> >
> > - blocks_per_dir = ext4_blocks_count(es) - freeb;
> > - do_div(blocks_per_dir, ndirs);
> > -
> > max_dirs = ndirs / ngroups + inodes_per_group / 16;
> > - min_inodes = avefreei - inodes_per_group / 4;
> > - min_blocks = avefreeb - EXT4_BLOCKS_PER_GROUP(sb) / 4;
> > -
> > - max_debt = EXT4_BLOCKS_PER_GROUP(sb);
> > - max_debt /= max_t(int, 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;
> > + min_inodes = avefreei - inodes_per_group*flex_size / 4;
> > + if (min_inodes < 1)
> > + min_inodes = 1;
> > + min_blocks = avefreeb - EXT4_BLOCKS_PER_GROUP(sb)*flex_size / 4;
> > +
> > + /*
> > + * Start looking in the flex group where we last allocated an
> > + * inode for this parent directory
> > + */
> > + if (EXT4_I(parent)->i_last_alloc_group != ~0) {
> > + parent_group = EXT4_I(parent)->i_last_alloc_group;
> > + if (flex_size > 1)
> > + parent_group >>= sbi->s_log_groups_per_flex;
> > + }
> >
> > for (i = 0; i < ngroups; i++) {
> > - *group = (parent_group + i) % ngroups;
> > - desc = ext4_get_group_desc(sb, *group, NULL);
> > - if (!desc || !ext4_free_inodes_count(sb, desc))
> > - continue;
> > - if (ext4_used_dirs_count(sb, desc) >= max_dirs)
> > + grp = (parent_group + i) % ngroups;
> > + get_orlov_stats(sb, grp, flex_size, &stats);
> > + if (stats.used_dirs >= max_dirs)
> > continue;
> > - if (ext4_free_inodes_count(sb, desc) < min_inodes)
> > + if (stats.free_inodes < min_inodes)
> > continue;
> > - if (ext4_free_blks_count(sb, desc) < min_blocks)
> > + if (stats.free_blocks < min_blocks)
> > continue;
> > - return 0;
> > + goto found_flex_bg;
> > }
> >
> > fallback:
> > + ngroups = sbi->s_groups_count;
> > + avefreei = freei / ngroups;
> > + parent_group = EXT4_I(parent)->i_block_group;
> > for (i = 0; i < ngroups; i++) {
> > - *group = (parent_group + i) % ngroups;
> > - desc = ext4_get_group_desc(sb, *group, NULL);
> > + grp = (parent_group + i) % ngroups;
> > + desc = ext4_get_group_desc(sb, grp, NULL);
> > if (desc && ext4_free_inodes_count(sb, desc) &&
> > - ext4_free_inodes_count(sb, desc) >= avefreei)
> > + ext4_free_inodes_count(sb, desc) >= avefreei) {
> > + *group = grp;
> > return 0;
> > + }
> > }
> >
> > if (avefreei) {
> > @@ -540,12 +602,51 @@ fallback:
> > }
> >
> > static int find_group_other(struct super_block *sb, struct inode *parent,
> > - ext4_group_t *group)
> > + ext4_group_t *group, int mode)
> > {
> > ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
> > ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
> > struct ext4_group_desc *desc;
> > - ext4_group_t i;
> > + ext4_group_t i, last;
> > + int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
> > +
> > + /*
> > + * Try to place the inode is the same flex group as its
> > + * parent. If we can't find space, use the Orlov algorithm to
> > + * find another flex group, and store that information in the
> > + * parent directory's inode information so that use that flex
> > + * group for future allocations.
> > + */
> > + if (flex_size > 1) {
> > + int retry = 0;
> > +
> > + try_again:
> > + parent_group &= ~(flex_size-1);
> > + last = parent_group + flex_size;
> > + if (last > ngroups)
> > + last = ngroups;
> > + for (i = parent_group; i < last; i++) {
> > + desc = ext4_get_group_desc(sb, i, NULL);
> > + if (desc && ext4_free_inodes_count(sb, desc)) {
> > + *group = i;
> > + return 0;
> > + }
> > + }
> > + if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
> > + retry = 1;
> > + parent_group = EXT4_I(parent)->i_last_alloc_group;
> > + goto try_again;
> > + }
>
>
> For directories we try first with i_last_alloc_group and then with the
> parent i_block_group. For file we are doing the other way round here.
> Does it make sense to try with i_last_alloc_group first ?
>
>
>
> > + /*
> > + * If this didn't work, use the Orlov search algorithm
> > + * to find a new flex group; we pass in the mode to
> > + * avoid the topdir algorithms.
> > + */
> > + *group = parent_group + flex_size;
> > + if (*group > ngroups)
> > + *group = 0;
> > + return find_group_orlov(sb, parent, group, mode);
> > + }
> >
> > /*
>
> If you want you can add
> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
>
How about the below update for the patch ?
commit 79561847d40ba84a8618f10445cb9f132c57bdd9
Author: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Date: Mon Mar 30 13:04:16 2009 +0530
update for orlov allocator
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 47b84e8..4dac65c 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -611,19 +611,26 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent,
static int find_group_other(struct super_block *sb, struct inode *parent,
ext4_group_t *group, int mode)
{
- ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
- ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
+ ext4_group_t parent_group;
struct ext4_group_desc *desc;
ext4_group_t i, last;
int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
-
+ ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
/*
* Try to place the inode is the same flex group as its
* parent. If we can't find space, use the Orlov algorithm to
* find another flex group, and store that information in the
* parent directory's inode information so that use that flex
* group for future allocations.
+ *
+ * Start looking in the flex group where we last allocated an
+ * for this parent directory.
*/
+ if (EXT4_I(parent)->i_last_alloc_group != ~0)
+ parent_group = EXT4_I(parent)->i_last_alloc_group;
+ else
+ parent_group = EXT4_I(parent)->i_block_group;
+
if (flex_size > 1) {
int retry = 0;
@@ -640,8 +647,13 @@ static int find_group_other(struct super_block *sb, struct inode *parent,
}
}
if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
+ /*
+ * with i_last_alloc_group we failed to find
+ * group with free inodes. So try with parent
+ * directory inode group.
+ */
+ parent_group = EXT4_I(parent)->i_block_group;
retry = 1;
- parent_group = EXT4_I(parent)->i_last_alloc_group;
goto try_again;
}
/*
--
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