| Message ID | 20181128031148.357-4-suy.fnst@cn.fujitsu.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs: implementation of priority aware allocator | expand |
On 28.11.18 г. 5:11 ч., Su Yue wrote: > Introduce compute_block_group_usage() and compute_block_group_usage(). > And call the latter in btrfs_make_block_group() and > btrfs_read_block_groups(). > > compute_priority_level use ilog2(free) to compute priority level. > > Signed-off-by: Su Yue <suy.fnst@cn.fujitsu.com> > --- > fs/btrfs/extent-tree.c | 60 ++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 60 insertions(+) > > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index d242a1174e50..0f4c5b1e0bcc 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -10091,6 +10091,7 @@ static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info) > return ret; > } > > +static long compute_block_group_priority(struct btrfs_block_group_cache *bg); That is ugly, just put the function above the first place where they are going to be used and don't introduce forward declarations for static functions. > int btrfs_read_block_groups(struct btrfs_fs_info *info) > { > struct btrfs_path *path; > @@ -10224,6 +10225,8 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info) > > link_block_group(cache); > > + cache->priority = compute_block_group_priority(cache); > + > set_avail_alloc_bits(info, cache->flags); > if (btrfs_chunk_readonly(info, cache->key.objectid)) { > inc_block_group_ro(cache, 1); > @@ -10373,6 +10376,8 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used, > > link_block_group(cache); > > + cache->priority = compute_block_group_priority(cache); > + > list_add_tail(&cache->bg_list, &trans->new_bgs); > > set_avail_alloc_bits(fs_info, type); > @@ -11190,3 +11195,58 @@ void btrfs_mark_bg_unused(struct btrfs_block_group_cache *bg) > } > spin_unlock(&fs_info->unused_bgs_lock); > } > + > +enum btrfs_priority_shift { > + PRIORITY_USAGE_SHIFT = 0 > +}; > + > +static inline u8 > +compute_block_group_usage(struct btrfs_block_group_cache *cache) > +{ > + u64 num_bytes; > + u8 usage; > + > + num_bytes = cache->reserved + cache->bytes_super + > + btrfs_block_group_used(&cache->item); > + > + usage = div_u64(num_bytes, div_factor_fine(cache->key.offset, 1)); Mention somewhere (either as a function description or in the patch description) that you use the % used. > + > + return usage; > +} > + > +static long compute_block_group_priority(struct btrfs_block_group_cache *bg) > +{ > + u8 usage; > + long priority = 0; > + > + if (btrfs_test_opt(bg->fs_info, PRIORITY_USAGE)) { > + usage = compute_block_group_usage(bg); > + priority |= usage << PRIORITY_USAGE_SHIFT; > + } Why is priority a signed type and not unsigned, I assume priority can never be negative? I briefly looked at the other patches and most of the time the argument passed is indeed na unsigned value. > + > + return priority; > +} > + > +static int compute_priority_level(struct btrfs_fs_info *fs_info, > + long priority) > +{ > + int level = 0; > + > + if (btrfs_test_opt(fs_info, PRIORITY_USAGE)) { > + u8 free; > + > + WARN_ON(priority < 0); I think this WARN_ON is redundant provided that the high-level interfaces are sane and don't allow negative value to trickle down. > + free = 100 - (priority >> PRIORITY_USAGE_SHIFT); > + > + if (free == 0) > + level = 0; > + else if (free == 100) > + level = ilog2(free) + 1; > + else > + level = ilog2(free); > + /* log2(1) == 0, leave level 0 for unused block_groups */ > + level = ilog2(100) + 1 - level; > + } > + > + return level; > +} >
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index d242a1174e50..0f4c5b1e0bcc 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -10091,6 +10091,7 @@ static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info) return ret; } +static long compute_block_group_priority(struct btrfs_block_group_cache *bg); int btrfs_read_block_groups(struct btrfs_fs_info *info) { struct btrfs_path *path; @@ -10224,6 +10225,8 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info) link_block_group(cache); + cache->priority = compute_block_group_priority(cache); + set_avail_alloc_bits(info, cache->flags); if (btrfs_chunk_readonly(info, cache->key.objectid)) { inc_block_group_ro(cache, 1); @@ -10373,6 +10376,8 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used, link_block_group(cache); + cache->priority = compute_block_group_priority(cache); + list_add_tail(&cache->bg_list, &trans->new_bgs); set_avail_alloc_bits(fs_info, type); @@ -11190,3 +11195,58 @@ void btrfs_mark_bg_unused(struct btrfs_block_group_cache *bg) } spin_unlock(&fs_info->unused_bgs_lock); } + +enum btrfs_priority_shift { + PRIORITY_USAGE_SHIFT = 0 +}; + +static inline u8 +compute_block_group_usage(struct btrfs_block_group_cache *cache) +{ + u64 num_bytes; + u8 usage; + + num_bytes = cache->reserved + cache->bytes_super + + btrfs_block_group_used(&cache->item); + + usage = div_u64(num_bytes, div_factor_fine(cache->key.offset, 1)); + + return usage; +} + +static long compute_block_group_priority(struct btrfs_block_group_cache *bg) +{ + u8 usage; + long priority = 0; + + if (btrfs_test_opt(bg->fs_info, PRIORITY_USAGE)) { + usage = compute_block_group_usage(bg); + priority |= usage << PRIORITY_USAGE_SHIFT; + } + + return priority; +} + +static int compute_priority_level(struct btrfs_fs_info *fs_info, + long priority) +{ + int level = 0; + + if (btrfs_test_opt(fs_info, PRIORITY_USAGE)) { + u8 free; + + WARN_ON(priority < 0); + free = 100 - (priority >> PRIORITY_USAGE_SHIFT); + + if (free == 0) + level = 0; + else if (free == 100) + level = ilog2(free) + 1; + else + level = ilog2(free); + /* log2(1) == 0, leave level 0 for unused block_groups */ + level = ilog2(100) + 1 - level; + } + + return level; +}
Introduce compute_block_group_usage() and compute_block_group_usage(). And call the latter in btrfs_make_block_group() and btrfs_read_block_groups(). compute_priority_level use ilog2(free) to compute priority level. Signed-off-by: Su Yue <suy.fnst@cn.fujitsu.com> --- fs/btrfs/extent-tree.c | 60 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+)