From: Filipe Manana <fdmanana@gmail.com>
To: Josef Bacik <josef@toxicpanda.com>
Cc: linux-btrfs <linux-btrfs@vger.kernel.org>, kernel-team@fb.com
Subject: Re: [PATCH 02/14] btrfs: cleanup extent buffer readahead
Date: Fri, 6 Nov 2020 11:51:15 +0000 [thread overview]
Message-ID: <CAL3q7H4zxBmBAeFsMKvnCuQbRydMvjyGSYmTEJ-ydppPOkqm=w@mail.gmail.com> (raw)
In-Reply-To: <c064bd10eca6d335160fa3ab838816fbc87de7c1.1604591048.git.josef@toxicpanda.com>
On Thu, Nov 5, 2020 at 3:47 PM Josef Bacik <josef@toxicpanda.com> wrote:
>
> I'm going to need to start passing around a lot more information when we
> allocate extent buffers, in order to make that cleaner we need to
> cleanup how we do readahead. Most of the callers have the parent node
> that we're getting our blockptr from, with the sole exception of
> relocation which simply has the bytenr it wants to read. Add a helper
> that takes the current arguments that we need (bytenr and gen), and add
> another helper for simply reading the slot out of a node. In followup
> patches the helper that takes all the extra arguments will be expanded,
> and the simpler helper won't need to have it's arguments adjusted.
>
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
I couldn't get anymore the lockdep splat I reported before (after
applying the whole patchset of course), it used to happen very often
with btrfs/033.
Looks good, thanks.
> ---
> fs/btrfs/ctree.c | 45 ++++++++--------------------------------
> fs/btrfs/disk-io.c | 16 --------------
> fs/btrfs/disk-io.h | 1 -
> fs/btrfs/extent-tree.c | 2 +-
> fs/btrfs/extent_io.c | 47 ++++++++++++++++++++++++++++++++++++++++++
> fs/btrfs/extent_io.h | 3 +++
> fs/btrfs/relocation.c | 3 ++-
> fs/btrfs/volumes.c | 8 ++-----
> 8 files changed, 64 insertions(+), 61 deletions(-)
>
> diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
> index d2d5854d51a7..0ff866328a4f 100644
> --- a/fs/btrfs/ctree.c
> +++ b/fs/btrfs/ctree.c
> @@ -2226,7 +2226,7 @@ static void reada_for_search(struct btrfs_fs_info *fs_info,
> search = btrfs_node_blockptr(node, nr);
> if ((search <= target && target - search <= 65536) ||
> (search > target && search - target <= 65536)) {
> - readahead_tree_block(fs_info, search);
> + btrfs_readahead_node_child(node, nr);
> nread += blocksize;
> }
> nscan++;
> @@ -2235,16 +2235,11 @@ static void reada_for_search(struct btrfs_fs_info *fs_info,
> }
> }
>
> -static noinline void reada_for_balance(struct btrfs_fs_info *fs_info,
> - struct btrfs_path *path, int level)
> +static noinline void reada_for_balance(struct btrfs_path *path, int level)
> {
> + struct extent_buffer *parent;
> int slot;
> int nritems;
> - struct extent_buffer *parent;
> - struct extent_buffer *eb;
> - u64 gen;
> - u64 block1 = 0;
> - u64 block2 = 0;
>
> parent = path->nodes[level + 1];
> if (!parent)
> @@ -2253,32 +2248,10 @@ static noinline void reada_for_balance(struct btrfs_fs_info *fs_info,
> nritems = btrfs_header_nritems(parent);
> slot = path->slots[level + 1];
>
> - if (slot > 0) {
> - block1 = btrfs_node_blockptr(parent, slot - 1);
> - gen = btrfs_node_ptr_generation(parent, slot - 1);
> - eb = find_extent_buffer(fs_info, block1);
> - /*
> - * if we get -eagain from btrfs_buffer_uptodate, we
> - * don't want to return eagain here. That will loop
> - * forever
> - */
> - if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
> - block1 = 0;
> - free_extent_buffer(eb);
> - }
> - if (slot + 1 < nritems) {
> - block2 = btrfs_node_blockptr(parent, slot + 1);
> - gen = btrfs_node_ptr_generation(parent, slot + 1);
> - eb = find_extent_buffer(fs_info, block2);
> - if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
> - block2 = 0;
> - free_extent_buffer(eb);
> - }
> -
> - if (block1)
> - readahead_tree_block(fs_info, block1);
> - if (block2)
> - readahead_tree_block(fs_info, block2);
> + if (slot > 0)
> + btrfs_readahead_node_child(parent, slot - 1);
> + if (slot + 1 < nritems)
> + btrfs_readahead_node_child(parent, slot + 1);
> }
>
>
> @@ -2454,7 +2427,7 @@ setup_nodes_for_search(struct btrfs_trans_handle *trans,
> goto again;
> }
>
> - reada_for_balance(fs_info, p, level);
> + reada_for_balance(p, level);
> sret = split_node(trans, root, p, level);
>
> BUG_ON(sret > 0);
> @@ -2473,7 +2446,7 @@ setup_nodes_for_search(struct btrfs_trans_handle *trans,
> goto again;
> }
>
> - reada_for_balance(fs_info, p, level);
> + reada_for_balance(p, level);
> sret = balance_level(trans, root, p, level);
>
> if (sret) {
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 35b16fe3b05f..ec64e087520e 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -945,22 +945,6 @@ static const struct address_space_operations btree_aops = {
> .set_page_dirty = btree_set_page_dirty,
> };
>
> -void readahead_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr)
> -{
> - struct extent_buffer *buf = NULL;
> - int ret;
> -
> - buf = btrfs_find_create_tree_block(fs_info, bytenr);
> - if (IS_ERR(buf))
> - return;
> -
> - ret = read_extent_buffer_pages(buf, WAIT_NONE, 0);
> - if (ret < 0)
> - free_extent_buffer_stale(buf);
> - else
> - free_extent_buffer(buf);
> -}
> -
> struct extent_buffer *btrfs_find_create_tree_block(
> struct btrfs_fs_info *fs_info,
> u64 bytenr)
> diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
> index 238b45223f2e..009f505d6c97 100644
> --- a/fs/btrfs/disk-io.h
> +++ b/fs/btrfs/disk-io.h
> @@ -45,7 +45,6 @@ int btrfs_verify_level_key(struct extent_buffer *eb, int level,
> struct extent_buffer *read_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr,
> u64 parent_transid, int level,
> struct btrfs_key *first_key);
> -void readahead_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr);
> struct extent_buffer *btrfs_find_create_tree_block(
> struct btrfs_fs_info *fs_info,
> u64 bytenr);
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index d7a68203cda0..bf2f0af24e91 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -4854,7 +4854,7 @@ static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
> continue;
> }
> reada:
> - readahead_tree_block(fs_info, bytenr);
> + btrfs_readahead_node_child(eb, slot);
> nread++;
> }
> wc->reada_slot = slot;
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index 119ced4a501b..c9d652b0770a 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -6114,3 +6114,50 @@ int try_release_extent_buffer(struct page *page)
>
> return release_extent_buffer(eb);
> }
> +
> +/**
> + * btrfs_readahead_tree_block - attempt to readahead a child block.
> + * @fs_info - the fs_info for the fs.
> + * @bytenr - the bytenr to read.
> + * @gen - the generation for the uptodate check, can be 0.
> + *
> + * Attempt to readahead a tree block at @bytenr. If @gen is 0 then we do a
> + * normal uptodate check of the eb, without checking the generation. If we have
> + * to read the block we will not block on anything.
> + */
> +void btrfs_readahead_tree_block(struct btrfs_fs_info *fs_info,
> + u64 bytenr, u64 gen)
> +{
> + struct extent_buffer *eb;
> + int ret;
> +
> + eb = btrfs_find_create_tree_block(fs_info, bytenr);
> + if (IS_ERR(eb))
> + return;
> +
> + if (btrfs_buffer_uptodate(eb, gen, 1)) {
> + free_extent_buffer(eb);
> + return;
> + }
> +
> + ret = read_extent_buffer_pages(eb, WAIT_NONE, 0);
> + if (ret < 0)
> + free_extent_buffer_stale(eb);
> + else
> + free_extent_buffer(eb);
> +}
> +
> +/**
> + * btrfs_readahead_node_child - readahead a node's child block.
> + * @node - the parent node we're reading from.
> + * @slot - the slot in the parent node for the child we want to read.
> + *
> + * A helper for btrfs_readahead_tree_block, we simply read the bytenr pointed at
> + * the slot in the node provided.
> + */
> +void btrfs_readahead_node_child(struct extent_buffer *node, int slot)
> +{
> + btrfs_readahead_tree_block(node->fs_info,
> + btrfs_node_blockptr(node, slot),
> + btrfs_node_ptr_generation(node, slot));
> +}
> diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
> index 3c2bf21c54eb..a211e90292f8 100644
> --- a/fs/btrfs/extent_io.h
> +++ b/fs/btrfs/extent_io.h
> @@ -198,6 +198,9 @@ void free_extent_buffer_stale(struct extent_buffer *eb);
> int read_extent_buffer_pages(struct extent_buffer *eb, int wait,
> int mirror_num);
> void wait_on_extent_buffer_writeback(struct extent_buffer *eb);
> +void btrfs_readahead_tree_block(struct btrfs_fs_info *fs_info,
> + u64 bytenr, u64 gen);
> +void btrfs_readahead_node_child(struct extent_buffer *node, int slot);
>
> static inline int num_extent_pages(const struct extent_buffer *eb)
> {
> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
> index 0b3ccf464c3d..0e2dd7cf87f6 100644
> --- a/fs/btrfs/relocation.c
> +++ b/fs/btrfs/relocation.c
> @@ -2542,7 +2542,8 @@ int relocate_tree_blocks(struct btrfs_trans_handle *trans,
> /* Kick in readahead for tree blocks with missing keys */
> rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
> if (!block->key_ready)
> - readahead_tree_block(fs_info, block->bytenr);
> + btrfs_readahead_tree_block(fs_info,
> + block->bytenr, 0);
> }
>
> /* Get first keys */
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index c927dc597550..8beb91d3cd88 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -7065,12 +7065,8 @@ static void readahead_tree_node_children(struct extent_buffer *node)
> int i;
> const int nr_items = btrfs_header_nritems(node);
>
> - for (i = 0; i < nr_items; i++) {
> - u64 start;
> -
> - start = btrfs_node_blockptr(node, i);
> - readahead_tree_block(node->fs_info, start);
> - }
> + for (i = 0; i < nr_items; i++)
> + btrfs_readahead_node_child(node, i);
> }
>
> int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info)
> --
> 2.26.2
>
--
Filipe David Manana,
“Whether you think you can, or you think you can't — you're right.”
next prev parent reply other threads:[~2020-11-06 11:51 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-05 15:45 [PATCH 00/14][REBASED] Set the lockdep class on eb's at allocation time Josef Bacik
2020-11-05 15:45 ` [PATCH 01/14] btrfs: remove lockdep classes for the fs tree Josef Bacik
2020-11-06 11:50 ` Filipe Manana
2020-11-05 15:45 ` [PATCH 02/14] btrfs: cleanup extent buffer readahead Josef Bacik
2020-11-06 11:51 ` Filipe Manana [this message]
2020-11-09 15:09 ` David Sterba
2020-11-05 15:45 ` [PATCH 03/14] btrfs: use btrfs_read_node_slot in btrfs_realloc_node Josef Bacik
2020-11-06 11:51 ` Filipe Manana
2020-11-05 15:45 ` [PATCH 04/14] btrfs: use btrfs_read_node_slot in walk_down_reloc_tree Josef Bacik
2020-11-06 11:52 ` Filipe Manana
2020-11-05 15:45 ` [PATCH 05/14] btrfs: use btrfs_read_node_slot in do_relocation Josef Bacik
2020-11-06 11:52 ` Filipe Manana
2020-11-05 15:45 ` [PATCH 06/14] btrfs: use btrfs_read_node_slot in replace_path Josef Bacik
2020-11-06 11:53 ` Filipe Manana
2020-11-05 15:45 ` [PATCH 07/14] btrfs: use btrfs_read_node_slot in walk_down_tree Josef Bacik
2020-11-06 11:53 ` Filipe Manana
2020-11-05 15:45 ` [PATCH 08/14] btrfs: use btrfs_read_node_slot in qgroup_trace_extent_swap Josef Bacik
2020-11-06 11:53 ` Filipe Manana
2020-11-05 15:45 ` [PATCH 09/14] btrfs: use btrfs_read_node_slot in qgroup_trace_new_subtree_blocks Josef Bacik
2020-11-06 11:54 ` Filipe Manana
2020-11-05 15:45 ` [PATCH 10/14] btrfs: use btrfs_read_node_slot in btrfs_qgroup_trace_subtree Josef Bacik
2020-11-06 11:55 ` Filipe Manana
2020-11-05 15:45 ` [PATCH 11/14] btrfs: pass root owner to read_tree_block Josef Bacik
2020-11-06 11:55 ` Filipe Manana
2020-11-05 15:45 ` [PATCH 12/14] btrfs: pass the root owner and level around for reada Josef Bacik
2020-11-06 11:56 ` Filipe Manana
2020-11-05 15:45 ` [PATCH 13/14] btrfs: pass the owner_root and level to alloc_extent_buffer Josef Bacik
2020-11-06 11:54 ` Filipe Manana
2020-11-05 15:45 ` [PATCH 14/14] btrfs: set the lockdep class for ebs on creation Josef Bacik
2020-11-06 11:58 ` Filipe Manana
2020-11-09 16:50 ` [PATCH 00/14][REBASED] Set the lockdep class on eb's at allocation time David Sterba
-- strict thread matches above, loose matches on Subject: below --
2020-10-30 21:02 [PATCH 00/14] " Josef Bacik
2020-10-30 21:02 ` [PATCH 02/14] btrfs: cleanup extent buffer readahead Josef Bacik
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