Add some tracepoints for the extent map shrinker to help debug and analyse
main events. These have proved useful during development of the shrinker.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Nowadays we have a lock used to synchronize mmap writes with reflink and
fsync operations (struct btrfs_inode::i_mmap_lock), so update the comment
for btrfs_set_inode_full_sync() to mention that it can also be called
while holding that mmap lock. Besides being a valid alternative to the
inode's VFS lock, we already have the extent map shrinker using that mmap
lock instead.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Extent maps are used either to represent existing file extent items, or to
represent new extents that are going to be written and the respective file
extent items are created when the ordered extent completes.
We currently don't have any limit for how many extent maps we can have,
neither per inode nor globally. Most of the time this not too noticeable
because extent maps are removed in the following situations:
1) When evicting an inode;
2) When releasing folios (pages) through the btrfs_release_folio() address
space operation callback.
However we won't release extent maps in the folio range if the folio is
either dirty or under writeback or if the inode's i_size is less than
or equals to 16M (see try_release_extent_mapping(). This 16M i_size
constraint was added back in 2008 with commit 70dec8079d ("Btrfs:
extent_io and extent_state optimizations"), but there's no explanation
about why we have it or why the 16M value.
This means that for buffered IO we can reach an OOM situation due to too
many extent maps if either of the following happens:
1) There's a set of tasks constantly doing IO on many files with a size
not larger than 16M, specially if they keep the files open for very
long periods, therefore preventing inode eviction.
This requires a really high number of such files, and having many non
mergeable extent maps (due to random 4K writes for example) and a
machine with very little memory;
2) There's a set tasks constantly doing random write IO (therefore
creating many non mergeable extent maps) on files and keeping them
open for long periods of time, so inode eviction doesn't happen and
there's always a lot of dirty pages or pages under writeback,
preventing btrfs_release_folio() from releasing the respective extent
maps.
This second case was actually reported in the thread pointed by the Link
tag below, and it requires a very large file under heavy IO and a machine
with very little amount of RAM, which is probably hard to happen in
practice in a real world use case.
However when using direct IO this is not so hard to happen, because the
page cache is not used, and therefore btrfs_release_folio() is never
called. Which means extent maps are dropped only when evicting the inode,
and that means that if we have tasks that keep a file descriptor open and
keep doing IO on a very large file (or files), we can exhaust memory due
to an unbounded amount of extent maps. This is especially easy to happen
if we have a huge file with millions of small extents and their extent
maps are not mergeable (non contiguous offsets and disk locations).
This was reported in that thread with the following fio test:
$ cat test.sh
#!/bin/bash
DEV=/dev/sdj
MNT=/mnt/sdj
MOUNT_OPTIONS="-o ssd"
MKFS_OPTIONS=""
cat <<EOF > /tmp/fio-job.ini
[global]
name=fio-rand-write
filename=$MNT/fio-rand-write
rw=randwrite
bs=4K
direct=1
numjobs=16
fallocate=none
time_based
runtime=90000
[file1]
size=300G
ioengine=libaio
iodepth=16
EOF
umount $MNT &> /dev/null
mkfs.btrfs -f $MKFS_OPTIONS $DEV
mount $MOUNT_OPTIONS $DEV $MNT
fio /tmp/fio-job.ini
umount $MNT
Monitoring the btrfs_extent_map slab while running the test with:
$ watch -d -n 1 'cat /sys/kernel/slab/btrfs_extent_map/objects \
/sys/kernel/slab/btrfs_extent_map/total_objects'
Shows the number of active and total extent maps skyrocketing to tens of
millions, and on systems with a short amount of memory it's easy and quick
to get into an OOM situation, as reported in that thread.
So to avoid this issue add a shrinker that will remove extents maps, as
long as they are not pinned, and takes proper care with any concurrent
fsync to avoid missing extents (setting the full sync flag while in the
middle of a fast fsync). This shrinker is triggered through the callbacks
nr_cached_objects and free_cached_objects of struct super_operations.
The shrinker will iterate over all roots and over all inodes of each
root, and keeps track of the last scanned root and inode, so that the
next time it runs, it starts from that root and from the next inode.
This is similar to what xfs does for its inode reclaim (implements those
callbacks, and cycles through inodes by starting from where it ended
last time).
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add a per cpu counter that tracks the total number of extent maps that are
in extent trees of inodes that belong to fs trees. This is going to be
used in an upcoming change that adds a shrinker for extent maps. Only
extent maps for fs trees are considered, because for special trees such as
the data relocation tree we don't want to evict their extent maps which
are critical for the relocation to work, and since those are limited, it's
not a concern to have them in memory during the relocation of a block
group. Another case are extent maps for free space cache inodes, which
must always remain in memory, but those are limited (there's only one per
free space cache inode, which means one per block group).
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Extent maps are always associated to an inode's extent map tree, so
there's no need to pass the extent map tree explicitly to try_merge_map().
In order to facilitate an upcoming change that adds a shrinker for extent
maps, change try_merge_map() to receive the inode instead of its extent
map tree.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Extent maps are always associated to an inode's extent map tree, so
there's no need to pass the extent map tree explicitly to
setup_extent_mapping().
In order to facilitate an upcoming change that adds a shrinker for extent
maps, change setup_extent_mapping() to receive the inode instead of its
extent map tree.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Extent maps are always associated to an inode's extent map tree, so
there's no need to pass the extent map tree explicitly to
replace_extent_mapping().
In order to facilitate an upcoming change that adds a shrinker for extent
maps, change replace_extent_mapping() to receive the inode instead of its
extent map tree.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Extent maps are always associated to an inode's extent map tree, so
there's no need to pass the extent map tree explicitly to
remove_extent_mapping().
In order to facilitate an upcoming change that adds a shrinker for extent
maps, change remove_extent_mapping() to receive the inode instead of its
extent map tree.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Extent maps are always associated to an inode's extent map tree, so
there's no need to pass the extent map tree explicitly to
clear_em_logging().
In order to facilitate an upcoming change that adds a shrinker for extent
maps, change clear_em_logging() to receive the inode instead of its extent
map tree.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Extent maps are always added to an inode's extent map tree, so there's no
need to pass the extent map tree explicitly to add_extent_mapping().
In order to facilitate an upcoming change that adds a shrinker for extent
maps, change add_extent_mapping() to receive the inode instead of its
extent map tree.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A comment from Filipe on one of my previous cleanups brought my
attention to a new helper we have for getting the root id of a root,
which makes it easier to read in the code.
The changes where made with the following Coccinelle semantic patch:
// <smpl>
@@
expression E,E1;
@@
(
E->root_key.objectid = E1
|
- E->root_key.objectid
+ btrfs_root_id(E)
)
// </smpl>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minor style fixups ]
Signed-off-by: David Sterba <dsterba@suse.com>
Our subpage testing started hanging on generic/560 and I bisected it
down to 1cab1375ba ("btrfs: reuse cloned extent buffer during
fiemap to avoid re-allocations"). This is subtle because we use
eb->start to figure out where in the folio we're copying to when we're
subpage, as our ->start may refer to an area inside of the folio.
For example, assume a 16K page size machine with a 4K node size, and
assume that we already have a cloned extent buffer when we cloned the
previous search.
copy_extent_buffer_full() will do the following when copying the extent
buffer path->nodes[0] (src) into cloned (dest):
src->start = 8k; // this is the new leaf we're cloning
cloned->start = 4k; // this is left over from the previous clone
src_addr = folio_address(src->folios[0]);
dest_addr = folio_address(dest->folios[0]);
memcpy(dest_addr + get_eb_offset_in_folio(dst, 0),
src_addr + get_eb_offset_in_folio(src, 0), src->len);
Now get_eb_offset_in_folio() is where the problems occur, because for
sub-pagesize blocksize we can have multiple eb's per folio, the code for
this is as follows
size_t get_eb_offset_in_folio(eb, offset) {
return (eb->start + offset & (folio_size(eb->folio[0]) - 1));
}
So in the above example we are copying into offset 4K inside the folio.
However once we update cloned->start to 8K to match the src the math for
get_eb_offset_in_folio() changes, and any subsequent reads (i.e.
btrfs_item_key_to_cpu()) will start reading from the offset 8K instead
of 4K where we copied to, giving us garbage.
Fix this by setting start before we co copy_extent_buffer_full() to make
sure that we're copying into the same offset inside of the folio that we
will read from later.
All other sites of copy_extent_buffer_full() are correct because we
either set ->start beforehand or we simply don't change it in the case
of the tree-log usage.
With this fix we now pass generic/560 on our subpage tests.
Fixes: 1cab1375ba ("btrfs: reuse cloned extent buffer during fiemap to avoid re-allocations")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that these two structs are the same, move the btrfs_data_ref and
btrfs_tree_ref up and use these in the btrfs_delayed_ref_node. Then
remove the btrfs_delayed_*_ref structs.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we don't use these helpers anywhere, remove them.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We only ever need to use this to get the level of the tree block ref, so
use the btrfs_delayed_ref_owner() helper, which returns the level for
the given reference.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that most of our elements are inside of btrfs_delayed_ref_node
directly and we have helpers for the delayed_data_ref bits, go ahead and
remove all direct usage of btrfs_delayed_data_ref and use the helpers
where needed.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We don't need to pass in all the elements for the backrefs as function
arguments, simply pass through the btrfs_delayed_ref_node and then
extract the values we need from that.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have all the information we need in our btrfs_delayed_ref_node, which
we already pass into __btrfs_free_extent. Drop the extra arguments and
just extract the values from btrfs_delayed_ref_node.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We're just extracting the values from btrfs_delayed_ref_node and passing
them through, simply pass the btrfs_delayed_ref_node into
__btrfs_inc_extent_ref and shrink the function arguments.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is how we refer to it in the rest of the extent reference related
code, make it consistent.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
These two members are shared by both the tree refs and data refs, so
move them into btrfs_delayed_ref_node proper. This allows us to greatly
simplify the comparison code, as the shared refs always only sort on
parent, and the non shared refs always sort first on ref_root, and then
only data refs sort on their specific fields.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We consistently use ->num_bytes everywhere through the delayed ref code,
except in btrfs_ref. Rename btrfs_ref to match all the other code.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that these helpers are identical, create a helper function that
handles everything properly and strip the individual helpers down to use
just the common helper. This cleans up a significant amount of
duplicated code.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that all of the delayed ref information is in the delayed ref node,
drastically simplify the delayed ref tracepoints by simply passing in
the btrfs_delayed_ref_node and populating the tracepoints with the
values from the structure itself.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that the btrfs_delayed_ref_node contains a union of the data and
metadata specific information we can move the initialization into
init_delayed_ref_common and just use the btrfs_ref to initialize the
correct fields of the reference.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We are calling init_delayed_ref_head with all of the elements from
btrfs_ref, clean this up to simply pass in the btrfs_ref and initialize
the btrfs_delayed_ref_head with the values from the btrfs_ref directly.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We're extracting all of these values from the btrfs_ref we passed in
already, just pass the btrfs_ref through to init_delayed_ref_common and
get the values directly from the struct.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have this in both btrfs_tree_ref and btrfs_data_ref, which is just
wasting space and making the code more complicated. Move this into
btrfs_ref proper and update all the call sites to do the assignment in
btrfs_ref.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_ref currently has ->owning_root, and ->ref_root is shared between
the tree ref and data ref, so in order to move that into btrfs_ref
proper I would need to add another root parameter to the initialization
function. This function has too many arguments, and adding another root
will make it easy to make mistakes about which root goes where.
Drop the generic ref init function and statically initialize the
btrfs_ref in every usage. This makes the code easier to read because we
can see what elements we're assigning, and will make the upcoming change
moving the ref_root into the btrfs_ref more clear and less error prone
than adding a new element to the initialization function.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have been embedding btrfs_delayed_ref_node in the
btrfs_delayed_data_ref and btrfs_delayed_tree_ref, and then we have two
sets of cachep's and a variety of handling that is awkward because of
this separation.
Instead union these two members inside of btrfs_delayed_ref_node and
make that the first class object. This allows us to go down to one
cachep for our delayed ref nodes instead of two.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have several different ways we refer to references throughout the
code and it's not consistent and there's a bit of duplication. In order
to clean this up I want to have one structure we use to define reference
information, and one structure we use for the delayed reference
information. Start this process by adding a helper to get from the
btrfs_delayed_data_ref/btrfs_delayed_tree_ref to the
btrfs_delayed_ref_node so that it'll make moving these structures around
simpler.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently btrfs_prune_dentries() has open code to find the first inode in
a root with a minimum inode number. Remove that code and make it use the
helper btrfs_find_first_inode() for that task.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Export the relocation private helper find_next_inode() to inode.c, as this
same logic is also used at btrfs_prune_dentries() and will be used by an
upcoming change that adds an extent map shrinker. The next patch will
change btrfs_prune_dentries() to use this helper.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The add_extent_mapping() function is short and trivial, there's no need to
have a label for a quick exit in case of an error, even because there's no
error handling needed, we just need to return the error. So remove that
label and return directly.
Also while at it remove the redundant initialization of 'ret', as that may
help avoid some warnings with clang tools such as the one reported/fixed
by commit 966de47ff0 ("btrfs: remove redundant initialization of
variables in log_new_ancestors").
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In the extent map self tests, when freeing all extent maps from a test
extent map tree we are not expecting to find any extent map with a
reference count different from 1 (the tree reference). If we find any,
we just log a message but we don't fail the test, which makes it very easy
to miss any bug/regression - no one reads the test messages unless a test
fails. So change the behaviour to make a test fail if we find an extent
map in the tree with a reference count different from 1. Make the failure
happen only after removing all extent maps, so that we don't leak memory.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Instead of passing fs_info and extent map tree arguments to
btrfs_add_extent_mapping(), we can pass an inode instead, as extent maps
are always inserted in the extent map tree of an inode, and the fs_info
can be extracted from the inode (inode->root->fs_info). The only exception
is in the self tests where we allocate an extent map tree and then use it
to insert/update/remove extent maps. However the tests can be changed to
use a test inode and then use the inode's extent map tree.
So change btrfs_add_extent_mapping() to have an inode as an argument
instead of a fs_info and an extent map tree. This reduces the number of
parameters and will also be needed for an upcoming change.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The csum_exist_in_range() function is now too trivial and is only used in
one place, so open code it in its single caller.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Before deciding if we can do a NOCOW write into a range, one of the things
we have to do is check if there are checksum items for that range. We do
that through the btrfs_lookup_csums_list() function, which searches for
checksums and adds them to a list supplied by the caller.
But all we need is to check if there is any checksum, we don't need to
look for all of them and collect them into a list, which requires more
search time in the checksums tree, allocating memory for checksums items
to add to the list, copy checksums from a leaf into those list items,
then free that memory, etc. This is all unnecessary overhead, wasting
mostly CPU time, and perhaps some occasional IO if we need to read from
disk any extent buffers.
So change btrfs_lookup_csums_list() to allow to return immediately in
case it finds any checksum, without the need to add it to a list and read
it from a leaf. This is accomplished by allowing a NULL list parameter and
making the function return 1 if it found any checksum, 0 if it didn't
found any, and a negative value in case of an error.
The following test with fio was used to measure performance:
$ cat test.sh
#!/bin/bash
DEV=/dev/nullb0
MNT=/mnt/nullb0
cat <<EOF > /tmp/fio-job.ini
[global]
name=fio-rand-write
filename=$MNT/fio-rand-write
rw=randwrite
bssplit=4k/20:8k/20:16k/20:32k/20:64k/20
direct=1
numjobs=16
fallocate=posix
time_based
runtime=300
[file1]
size=8G
ioengine=io_uring
iodepth=16
EOF
umount $MNT &> /dev/null
mkfs.btrfs -f $DEV
mount -o ssd $DEV $MNT
fio /tmp/fio-job.ini
umount $MNT
The test was run on a release kernel (Debian's default kernel config).
The results before this patch:
WRITE: bw=139MiB/s (146MB/s), 8204KiB/s-9504KiB/s (8401kB/s-9732kB/s), io=17.0GiB (18.3GB), run=125317-125344msec
The results after this patch:
WRITE: bw=153MiB/s (160MB/s), 9241KiB/s-10.0MiB/s (9463kB/s-10.5MB/s), io=17.0GiB (18.3GB), run=114054-114071msec
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In the error path we have this while loop that keeps iterating over the
csums of the list and then delete them from the list and free them,
testing for an error (ret < 0) and list emptyness as the conditions of
the while loop.
Simplify this by using list_for_each_entry_safe() so there's no need to
delete elements from the list and need to test the error condition on
each iteration.
Also rename the 'fail' label to 'out' since the label is not exclusive
to a failure path, as we also end up there when the function succeeds,
and it's also a more common label name.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There's no need to use a temporary list to add the checksums, we can just
add them to input list and then on error delete and free any checksums
that were added. So simplify and remove the temporary list.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
All the callers of btrfs_lookup_csums_list() pass a value of 0 as the
"search_commit" parameter. So remove it and make the function behave as
to always search from the regular root.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add a function comment to btrfs_lookup_csums_list() to document it.
With another upcoming change its parameter list and return value will be
less obvious. So add the documentation now so that it can be updated where
needed later.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_page_mkwrite() is a struct vm_operations_struct callback and we
define that structure in file.c. Currently the function is in inode.c and
has to be exported to be used in file.c, which makes no sense because it's
not used anywhere else. So move btrfs_page_mkwrite() from inode.c and into
file.c.
While at it do a few minor style changes:
1) Capitalize the first word of every comment and end each sentence with
punctuation;
2) Avoid splitting some statements into two lines when everything fits in
85 characters or less.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are no more users of btrfs_clone_chunk_map(), the last one (and
only one ever) was removed in commit 1ec17ef591 ("btrfs: zoned: fix
use-after-free in do_zone_finish()"). So remove btrfs_clone_chunk_map().
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At warn_about_uncommitted_trans(), there's no need to check if the list
is empty and return, because list_for_each_entry_safe() is safe to call
for an empty list, it simply does nothing. So remove the check.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At btrfs_finish_one_ordered() it's pointless to assign 0 to the 'ret'
variable because if it has a non-zero value (error), we have already
jumped to the 'out' label. So remove that redundant assignment.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The mod_start and mod_len fields of struct extent_map were introduced by
commit 4e2f84e63d ("Btrfs: improve fsync by filtering extents that we
want") in order to avoid too low performance when fsyncing a file that
keeps getting extent maps merge, because it resulted in each fsync logging
again csum ranges that were already merged before.
We don't need this anymore as extent maps in the list of modified extents
are never merged with other extent maps and once we log an extent map we
remove it from the list of modified extent maps, so it's never logged
twice.
So remove the mod_start and mod_len fields from struct extent_map and use
instead the start and len fields when logging checksums in the fast fsync
path. This also makes EXTENT_FLAG_FILLING unused so remove it as well.
Running the reproducer from the commit mentioned before, with a larger
number of extents and against a null block device, so that IO is fast
and we can better see any impact from searching checksums items and
logging them, gave the following results from dd:
Before this change:
409600000 bytes (410 MB, 391 MiB) copied, 22.948 s, 17.8 MB/s
After this change:
409600000 bytes (410 MB, 391 MiB) copied, 22.9997 s, 17.8 MB/s
So no changes in throughput.
The test was done in a release kernel (non-debug, Debian's default kernel
config) and its steps are the following:
$ mkfs.btrfs -f /dev/nullb0
$ mount /dev/sdb /mnt
$ dd if=/dev/zero of=/mnt/foobar bs=4k count=100000 oflag=sync
$ umount /mnt
This also reduces the size of struct extent_map from 128 bytes down to 112
bytes, so now we can have 36 extents maps per 4K page instead of 32.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Some of the operations after the free might convert more PERTRANS
metadata. Do the freeing as late as possible to eliminate a source of
leaked PERTRANS metadata.
This helps with the pass rate of generic/269 and generic/475.
Reviewed-by: Qu Wenruo <qwu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
For both compression and decompression paths, we always require a
"struct page **pages" and "unsigned long nr_pages", this involves quite
some part of the btrfs compression paths:
- All the compression entry points
- compressed_bio structure
This affects both compression and decompression.
- async_extent structure
Unfortunately with all those involved parts, there is no good way to
split the conversion into smaller patches while still passing compiling.
So do this in one big conversion in one go.
Please note this is direct page->folio conversion, no change on the page
sized folio requirement yet.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minor style fixups ]
Signed-off-by: David Sterba <dsterba@suse.com>
The new helper will do the same thing as btrfs_alloc_page_array(), but
with folios.
One extra difference is, there is no extra helper for bulk allocation,
thus it may not be as efficient as the page version.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
