[RFC,01/17] btrfs: priority alloc: prepare of priority aware allocator
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Message ID 20181128031148.357-2-suy.fnst@cn.fujitsu.com
State New
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Series
  • btrfs: implementation of priority aware allocator
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Commit Message

Su Yue Nov. 28, 2018, 3:11 a.m. UTC
To implement priority aware allocator, this patch:
Introduces struct btrfs_priority_tree which contains block groups
in same level.
Adds member priority to struct btrfs_block_group_cache and pointer
points to the priority tree it's located.

Adds member priority_trees to struct btrfs_space_info to represents
priority trees in different raid types.

Signed-off-by: Su Yue <suy.fnst@cn.fujitsu.com>
---
 fs/btrfs/ctree.h | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

Comments

Nikolay Borisov Nov. 28, 2018, 8:24 a.m. UTC | #1
On 28.11.18 г. 5:11 ч., Su Yue wrote:
> To implement priority aware allocator, this patch:
> Introduces struct btrfs_priority_tree which contains block groups
> in same level.
> Adds member priority to struct btrfs_block_group_cache and pointer
> points to the priority tree it's located.
> 
> Adds member priority_trees to struct btrfs_space_info to represents
> priority trees in different raid types.
> 
> Signed-off-by: Su Yue <suy.fnst@cn.fujitsu.com>
> ---
>  fs/btrfs/ctree.h | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index e62824cae00a..5c4651d8a524 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -437,6 +437,8 @@ struct btrfs_space_info {
>  	struct rw_semaphore groups_sem;
>  	/* for block groups in our same type */
>  	struct list_head block_groups[BTRFS_NR_RAID_TYPES];
> +	/* for priority trees in our same type */
> +	struct rb_root priority_trees[BTRFS_NR_RAID_TYPES];
>  	wait_queue_head_t wait;
>  
>  	struct kobject kobj;
> @@ -558,6 +560,21 @@ struct btrfs_full_stripe_locks_tree {
>  	struct mutex lock;
>  };
>  
> +/*
> + * Tree to record all block_groups in same priority level.
> + * Only used in priority aware allocator.
> + */
> +struct btrfs_priority_tree {
> +	/* protected by groups_sem */
> +	struct rb_root block_groups;
> +	struct rw_semaphore groups_sem;
> +
> +	/* for different level priority trees in same index*/
> +	struct rb_node node;
> +
> +	int level;

Do you ever expect the level to be a negative number? If not then use
u8/u32 depending on the range of levels you expect.

> +};
> +
>  struct btrfs_block_group_cache {
>  	struct btrfs_key key;
>  	struct btrfs_block_group_item item;
> @@ -571,6 +588,8 @@ struct btrfs_block_group_cache {
>  	u64 flags;
>  	u64 cache_generation;
>  
> +	/* It's used only when priority aware allocator is enabled. */
> +	long priority;

What's the range of priorities you are expecting, wouldn't an u8 be
sufficient, that gives us 256 priorities?

>  	/*
>  	 * If the free space extent count exceeds this number, convert the block
>  	 * group to bitmaps.
> @@ -616,6 +635,9 @@ struct btrfs_block_group_cache {
>  	/* for block groups in the same raid type */
>  	struct list_head list;
>  
> +	/* for block groups in the same priority level */
> +	struct rb_node node;
> +
>  	/* usage count */
>  	atomic_t count;
>  
> @@ -670,6 +692,8 @@ struct btrfs_block_group_cache {
>  
>  	/* Record locked full stripes for RAID5/6 block group */
>  	struct btrfs_full_stripe_locks_tree full_stripe_locks_root;
> +
> +	struct btrfs_priority_tree *priority_tree;
>  };
>  
>  /* delayed seq elem */
>
Su Yue Nov. 28, 2018, 9:24 a.m. UTC | #2
On 11/28/18 4:24 PM, Nikolay Borisov wrote:
> 
> 
> On 28.11.18 г. 5:11 ч., Su Yue wrote:
>> To implement priority aware allocator, this patch:
>> Introduces struct btrfs_priority_tree which contains block groups
>> in same level.
>> Adds member priority to struct btrfs_block_group_cache and pointer
>> points to the priority tree it's located.
>>
>> Adds member priority_trees to struct btrfs_space_info to represents
>> priority trees in different raid types.
>>
>> Signed-off-by: Su Yue <suy.fnst@cn.fujitsu.com>
>> ---
>>   fs/btrfs/ctree.h | 24 ++++++++++++++++++++++++
>>   1 file changed, 24 insertions(+)
>>
>> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
>> index e62824cae00a..5c4651d8a524 100644
>> --- a/fs/btrfs/ctree.h
>> +++ b/fs/btrfs/ctree.h
>> @@ -437,6 +437,8 @@ struct btrfs_space_info {
>>   	struct rw_semaphore groups_sem;
>>   	/* for block groups in our same type */
>>   	struct list_head block_groups[BTRFS_NR_RAID_TYPES];
>> +	/* for priority trees in our same type */
>> +	struct rb_root priority_trees[BTRFS_NR_RAID_TYPES];
>>   	wait_queue_head_t wait;
>>   
>>   	struct kobject kobj;
>> @@ -558,6 +560,21 @@ struct btrfs_full_stripe_locks_tree {
>>   	struct mutex lock;
>>   };
>>   
>> +/*
>> + * Tree to record all block_groups in same priority level.
>> + * Only used in priority aware allocator.
>> + */
>> +struct btrfs_priority_tree {
>> +	/* protected by groups_sem */
>> +	struct rb_root block_groups;
>> +	struct rw_semaphore groups_sem;
>> +
>> +	/* for different level priority trees in same index*/
>> +	struct rb_node node;
>> +
>> +	int level;
> 
> Do you ever expect the level to be a negative number? If not then use
> u8/u32 depending on the range of levels you expect.
> 

Indeed, level is not expected to be negative. u8 is more proper.

>> +};
>> +
>>   struct btrfs_block_group_cache {
>>   	struct btrfs_key key;
>>   	struct btrfs_block_group_item item;
>> @@ -571,6 +588,8 @@ struct btrfs_block_group_cache {
>>   	u64 flags;
>>   	u64 cache_generation;
>>   
>> +	/* It's used only when priority aware allocator is enabled. */
>> +	long priority;
> 
> What's the range of priorities you are expecting, wouldn't an u8 be
> sufficient, that gives us 256 priorities?
> 

The 6th patch introduces three special priorities. That's what I called
dirty codes.

Thanks,
Su

>>   	/*
>>   	 * If the free space extent count exceeds this number, convert the block
>>   	 * group to bitmaps.
>> @@ -616,6 +635,9 @@ struct btrfs_block_group_cache {
>>   	/* for block groups in the same raid type */
>>   	struct list_head list;
>>   
>> +	/* for block groups in the same priority level */
>> +	struct rb_node node;
>> +
>>   	/* usage count */
>>   	atomic_t count;
>>   
>> @@ -670,6 +692,8 @@ struct btrfs_block_group_cache {
>>   
>>   	/* Record locked full stripes for RAID5/6 block group */
>>   	struct btrfs_full_stripe_locks_tree full_stripe_locks_root;
>> +
>> +	struct btrfs_priority_tree *priority_tree;
>>   };
>>   
>>   /* delayed seq elem */
>>
> 
>

Patch
diff mbox series

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index e62824cae00a..5c4651d8a524 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -437,6 +437,8 @@  struct btrfs_space_info {
 	struct rw_semaphore groups_sem;
 	/* for block groups in our same type */
 	struct list_head block_groups[BTRFS_NR_RAID_TYPES];
+	/* for priority trees in our same type */
+	struct rb_root priority_trees[BTRFS_NR_RAID_TYPES];
 	wait_queue_head_t wait;
 
 	struct kobject kobj;
@@ -558,6 +560,21 @@  struct btrfs_full_stripe_locks_tree {
 	struct mutex lock;
 };
 
+/*
+ * Tree to record all block_groups in same priority level.
+ * Only used in priority aware allocator.
+ */
+struct btrfs_priority_tree {
+	/* protected by groups_sem */
+	struct rb_root block_groups;
+	struct rw_semaphore groups_sem;
+
+	/* for different level priority trees in same index*/
+	struct rb_node node;
+
+	int level;
+};
+
 struct btrfs_block_group_cache {
 	struct btrfs_key key;
 	struct btrfs_block_group_item item;
@@ -571,6 +588,8 @@  struct btrfs_block_group_cache {
 	u64 flags;
 	u64 cache_generation;
 
+	/* It's used only when priority aware allocator is enabled. */
+	long priority;
 	/*
 	 * If the free space extent count exceeds this number, convert the block
 	 * group to bitmaps.
@@ -616,6 +635,9 @@  struct btrfs_block_group_cache {
 	/* for block groups in the same raid type */
 	struct list_head list;
 
+	/* for block groups in the same priority level */
+	struct rb_node node;
+
 	/* usage count */
 	atomic_t count;
 
@@ -670,6 +692,8 @@  struct btrfs_block_group_cache {
 
 	/* Record locked full stripes for RAID5/6 block group */
 	struct btrfs_full_stripe_locks_tree full_stripe_locks_root;
+
+	struct btrfs_priority_tree *priority_tree;
 };
 
 /* delayed seq elem */