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Commit 37d1aeee authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Throttle tuning 



This avoids waiting for transactions with pages locked by breaking out
the code to wait for the current transaction to close into a function
called by btrfs_throttle.

It also lowers the limits for where we start throttling.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 47ac14fa

fs/btrfs/extent-tree.c

+3 −0
Original line number Diff line number Diff line
@@ -2526,6 +2526,9 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans, 
				*level = 0;

				break;

			}

			if (printk_ratelimit())

				printk("leaf ref miss for bytenr %llu\n",

				       (unsigned long long)bytenr);

		}

		next = btrfs_find_tree_block(root, bytenr, blocksize);

		if (!next || !btrfs_buffer_uptodate(next, ptr_gen)) {

fs/btrfs/file.c

+1 −1
Original line number Diff line number Diff line
@@ -253,7 +253,7 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans, 
	end_of_last_block = start_pos + num_bytes - 1;



	lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);

	trans = btrfs_start_transaction(root, 1);

	trans = btrfs_join_transaction(root, 1);

	if (!trans) {

		err = -ENOMEM;

		goto out_unlock;

fs/btrfs/transaction.c

+27 −11
Original line number Diff line number Diff line
@@ -124,17 +124,12 @@ static noinline int record_root_in_trans(struct btrfs_root *root) 
	return 0;

}



struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,

					     int num_blocks, int join)

static void wait_current_trans(struct btrfs_root *root)

{

	struct btrfs_trans_handle *h =

		kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);

	struct btrfs_transaction *cur_trans;

	int ret;



	mutex_lock(&root->fs_info->trans_mutex);

	cur_trans = root->fs_info->running_transaction;

	if (cur_trans && cur_trans->blocked && !join) {

	if (cur_trans && cur_trans->blocked) {

		DEFINE_WAIT(wait);

		cur_trans->use_count++;

		while(1) {
@@ -154,6 +149,18 @@ struct btrfs_trans_handle *start_transaction(struct btrfs_root *root, 
		}

		put_transaction(cur_trans);

	}

}



struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,

					     int num_blocks, int join)

{

	struct btrfs_trans_handle *h =

		kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);

	int ret;



	mutex_lock(&root->fs_info->trans_mutex);

	if (!join)

		wait_current_trans(root);

	ret = join_transaction(root);

	BUG_ON(ret);
@@ -200,7 +207,7 @@ static noinline int wait_for_commit(struct btrfs_root *root, 
	return 0;

}



void btrfs_throttle(struct btrfs_root *root)

static void throttle_on_drops(struct btrfs_root *root)

{

	struct btrfs_fs_info *info = root->fs_info;
@@ -223,19 +230,28 @@ void btrfs_throttle(struct btrfs_root *root) 
		} while (thr == atomic_read(&info->throttle_gen));



		if (harder_count < 5 &&

		    info->total_ref_cache_size > 5 * 1024 * 1024) {

		    info->total_ref_cache_size > 1 * 1024 * 1024) {

			harder_count++;

			goto harder;

		}



		if (harder_count < 10 &&

		    info->total_ref_cache_size > 10 * 1024 * 1024) {

		    info->total_ref_cache_size > 5 * 1024 * 1024) {

			harder_count++;

			goto harder;

		}

	}

}



void btrfs_throttle(struct btrfs_root *root)

{

	mutex_lock(&root->fs_info->trans_mutex);

	wait_current_trans(root);

	mutex_unlock(&root->fs_info->trans_mutex);



	throttle_on_drops(root);

}



static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,

			  struct btrfs_root *root, int throttle)

{
@@ -256,7 +272,7 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, 
	kmem_cache_free(btrfs_trans_handle_cachep, trans);



	if (throttle)

		btrfs_throttle(root);

		throttle_on_drops(root);



	return 0;

}