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Simplify tracking of the range processed by using cur_alloc_size only to
store the reserved part that may fail to the allocated extent. Remove
the ram_size as well since it is always equal to cur_alloc_size in the
context. Advance the start in normal path until extent allocation
succeeds and keep the start unchanged in the error handling path.
Passed the fstest generic/475 test for a hundred times with quota
enabled. And a modified generic/475 test by removing the sleep time
for a hundred times. About one tenth of the tests do enter the error
handling path due to fail to reserve extent.
Suggested-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Haisu Wang <haisuwang@tencent.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Remove conditional path allocation from btrfs_read_locked_inode(). Add
an ASSERT(path) to indicate it should never be called with a NULL path.
Call btrfs_read_locked_inode() directly from btrfs_iget(). This causes
code duplication between btrfs_iget() and btrfs_iget_path(), but I
think this is justifiable as it removes the need for conditionally
allocating the path inside of btrfs_read_locked_inode(). This makes the
code easier to reason about and makes it clear who has the
responsibility of allocating and freeing the path.
Signed-off-by: Leo Martins <loemra.dev@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Move btrfs_add_inode_to_root() so it can be called from
btrfs_read_locked_inode(), no changes were made to the function.
Move cleanup code from btrfs_iget_path() to btrfs_read_locked_inode.
This improves readability and improves a leaky abstraction. Previously
btrfs_iget_path() had to handle a positive error case as a result of a
call to btrfs_search_slot(), but it makes more sense to handle this
closer to the source of the call.
Signed-off-by: Leo Martins <loemra.dev@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Add struct io_btrfs_cmd as a wrapper type for io_uring_cmd_to_pdu(),
rather than using a raw pointer.
Suggested-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Mark Harmstone <maharmstone@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Add an io_uring command for encoded reads, using the same interface as
the existing BTRFS_IOC_ENCODED_READ ioctl.
btrfs_uring_encoded_read() is an io_uring version of
btrfs_ioctl_encoded_read(), which validates the user input and calls
btrfs_encoded_read() to read the appropriate metadata. If we determine
that we need to read an extent from disk, we call
btrfs_encoded_read_regular_fill_pages() through
btrfs_uring_read_extent() to prepare the bio.
The existing btrfs_encoded_read_regular_fill_pages() is changed so that
if it is passed a valid uring_ctx, rather than waking up any waiting
threads it calls btrfs_uring_read_extent_endio(). This in turn copies
the read data back to userspace, and calls io_uring_cmd_done() to
complete the io_uring command.
Because we're potentially doing a non-blocking read,
btrfs_uring_read_extent() doesn't clean up after itself if it returns
-EIOCBQUEUED. Instead, it allocates a priv struct, populates the fields
there that we will need to unlock the inode and free our allocations,
and defers this to the btrfs_uring_read_finished() that gets called when
the bio completes.
Signed-off-by: Mark Harmstone <maharmstone@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Change btrfs_encoded_read_regular_fill_pages() so that the priv struct
is allocated rather than stored on the stack, in preparation for adding
an asynchronous mode to the function.
Signed-off-by: Mark Harmstone <maharmstone@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Change btrfs_encoded_read() so that it returns -EAGAIN rather than sleeps
if IOCB_NOWAIT is set in iocb->ki_flags. The conditions that require
sleeping are: inode lock, writeback, extent lock, ordered range.
Signed-off-by: Mark Harmstone <maharmstone@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Change the behaviour of btrfs_encoded_read() so that if it needs to read
an extent from disk, it leaves the extent and inode locked and returns
-EIOCBQUEUED. The caller is then responsible for doing the I/O via
btrfs_encoded_read_regular() and unlocking the extent and inode.
Signed-off-by: Mark Harmstone <maharmstone@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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iocb->ki_pos isn't used after this function, so there's no point in
changing its value.
Signed-off-by: Mark Harmstone <maharmstone@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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After the previous patch, which converted the rb-tree used to track
delayed ref heads into an xarray, the find_ref_head() function is now
used only by one caller which always passes false to the 'return_bigger'
argument. So remove the 'return_bigger' logic, simplifying the function,
and move all the function code to the single caller.
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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Currently we use a red black tree (rb-tree) to track the delayed ref
heads (in struct btrfs_delayed_ref_root::href_root). This however is not
very efficient when the number of delayed ref heads is large (and it's
very common to be at least in the order of thousands) since rb-trees are
binary trees. For example for 10K delayed ref heads, the tree has a depth
of 13. Besides that, inserting into the tree requires navigating through
it and pulling useless cache lines in the process since the red black tree
nodes are embedded within the delayed ref head structure - on the other
hand, by being embedded, it requires no extra memory allocations.
We can improve this by using an xarray instead which has a much higher
branching factor than a red black tree (binary balanced tree) and is more
cache friendly and behaves like a resizable array, with a much better
search and insertion complexity than a red black tree. This only has one
small disadvantage which is that insertion will sometimes require
allocating memory for the xarray - which may fail (not that often since
it uses a kmem_cache) - but on the other hand we can reduce the delayed
ref head structure size by 24 bytes (from 152 down to 128 bytes) after
removing the embedded red black tree node, meaning than we can now fit
32 delayed ref heads per 4K page instead of 26, and that gain compensates
for the occasional memory allocations needed for the xarray nodes. We
also end up using only 2 cache lines instead of 3 per delayed ref head.
Running the following fs_mark test showed some improvements:
$ cat test.sh
#!/bin/bash
DEV=/dev/nullb0
MNT=/mnt/nullb0
MOUNT_OPTIONS="-o ssd"
FILES=100000
THREADS=$(nproc --all)
echo "performance" | \
tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
mkfs.btrfs -f $DEV
mount $MOUNT_OPTIONS $DEV $MNT
OPTS="-S 0 -L 5 -n $FILES -s 0 -t $THREADS -k"
for ((i = 1; i <= $THREADS; i++)); do
OPTS="$OPTS -d $MNT/d$i"
done
fs_mark $OPTS
umount $MNT
Before this patch:
FSUse% Count Size Files/sec App Overhead
10 1200000 0 171845.7 12253839
16 2400000 0 230898.7 12308254
23 3600000 0 212292.9 12467768
30 4800000 0 195737.8 12627554
46 6000000 0 171055.2 12783329
After this patch:
FSUse% Count Size Files/sec App Overhead
10 1200000 0 173835.0 12246131
16 2400000 0 233537.8 12271746
23 3600000 0 220398.7 12307737
30 4800000 0 204483.6 12392318
40 6000000 0 182923.3 12771843
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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Add some comments to struct btrfs_delayed_ref_root's fields to mention
what its spinlock protects.
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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The delayed refs lock must be held when calling add_delayed_ref_head(),
so assert that it's being held.
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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The delayed refs lock must be held when calling find_first_ref_head(), so
assert that it's being held.
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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We have 3 callers for find_ref_head() so assert at find_ref_head() that we
have the delayed refs lock held, removing the assertion from one of its
callers (btrfs_find_delayed_ref_head()).
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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One of the following patches in the series will need to access fs_info at
btrfs_delete_ref_head(), so pass a fs_info argument to it.
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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One of the following patches in the series will need to access fs_info in
the function find_ref_head(), so pass a fs_info argument to it as well as
to the functions btrfs_select_ref_head() and btrfs_find_delayed_ref_head()
which call find_ref_head().
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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The unselect_delayed_ref_head() at extent-tree.c doesn't really belong in
that file as it's a delayed refs specific detail and therefore should be
at delayed-ref.c. Further its inverse, btrfs_select_ref_head(), is at
delayed-ref.c, so it only makes sense to have it there too.
So move unselect_delayed_ref_head() into delayed-ref.c and rename it to
btrfs_unselect_ref_head() so that its name closely matches its inverse
(btrfs_select_ref_head()).
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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Instead of doing it in two steps outside of delayed-ref.c, leaking low
level details such as locking, move the logic entirely to delayed-ref.c
under btrfs_select_ref_head(), reducing code and making things simpler
for the caller.
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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The function only returns 0, meaning it was able to lock the delayed ref
head, or -EAGAIN in case it wasn't able to lock it. So simplify this and
use a boolean return type instead, returning true if it was able to lock
and false otherwise.
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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The atomic counter 'num_entries' is not used anymore, we increment it
and decrement it but then we don't ever read it to use for any logic.
Its last use was removed with commit 61a56a992fcf ("btrfs: delayed refs
pre-flushing should only run the heads we have"). So remove it.
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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Instead of open coding it, use the find_first_ref_head() helper at
btrfs_destroy_delayed_refs(). This avoids duplicating the logic,
specially with the upcoming changes in subsequent patches.
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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When destroying delayed refs during a transaction abort, we have open
coded the removal of a delayed ref, which is also done by the static
helper function drop_delayed_ref(). So remove that duplicated code and
use drop_delayed_ref() instead.
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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The fs_info parameter is redundant because it can be extracted from the
transaction given as another parameter. So remove it and use the fs_info
accessible from the transaction.
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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The fs_info parameter is redundant because it can be extracted from the
transaction given as another parameter. So remove it and use the fs_info
accessible from the transaction.
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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It's better suited at delayed-ref.c since it's about delayed refs and
contains logic to iterate over them (using the red black tree, doing all
the locking, freeing, etc), so move it from disk-io.c, which is pretty
big, into delayed-ref.c, hiding implementation details of how delayed
refs are tracked and managed. This also facilitates the next patches in
the series.
This change moves the code between files but also does the following
simple cleanups:
1) Rename the 'cache' variable to 'bg', since it's a block group
(the 'cache' logic comes from old days where the block group
structure was named 'btrfs_block_group_cache');
2) Move the 'ref' variable declaration to the scope of the inner
while loop, since it's not used outside that loop.
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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At btrfs_destroy_delayed_refs() it's unexpected to not find the block
group to which a delayed reference's extent belongs to, so we have this
BUG_ON(), not just because it's highly unexpected but also because we
don't know what to do there.
Since we are in the transaction abort path, there's nothing we can do
other than proceed and cleanup all used resources we can. So remove
the BUG_ON() and deal with a missing block group by logging an error
message and continuing to cleanup all we can related to the current
delayed ref head and moving to other delayed refs.
Reviewed-by: Boris Burkov <boris@bur.io>
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>
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When inserting extent backref, in order to check whether refs other than
inline refs are used, we always use path keep locks for tree search, which
will increase the lock contention of extent tree.
We do not need the parent node every time to determine whether normal
refs are used. It is only needed when the extent item is the last item
in a leaf.
Therefore, we change it to first use keep_locks=0 for search. If the
extent item happens to be the last item in the leaf, we then change to
keep_locks=1 for the second search to reduce lock contention.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Robbie Ko <robbieko@synology.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Implement self-tests for partial deletion of RAID stripe-tree entries.
These two new tests cover both the deletion of the front of a RAID
stripe-tree stripe extent as well as truncation of an item to make it
smaller.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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In our CI system, the RAID stripe tree configuration sometimes fails with
the following ASSERT():
assertion failed: found_start >= start && found_end <= end, in fs/btrfs/raid-stripe-tree.c:64
This ASSERT()ion triggers, because for the initial design of RAID
stripe-tree, I had the "one ordered-extent equals one bio" rule of zoned
btrfs in mind.
But for a RAID stripe-tree based system, that is not hosted on a zoned
storage device, but on a regular device this rule doesn't apply.
So in case the range we want to delete starts in the middle of the
previous item, grab the item and "truncate" it's length. That is, clone
the item, subtract the deleted portion from the key's offset, delete the
old item and insert the new one.
In case the range to delete ends in the middle of an item, we have to
adjust both the item's key as well as the stripe extents and then
re-insert the modified clone into the tree after deleting the old stripe
extent.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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When fgp_flags and gfp_flags are zero, use filemap_get_folio(A, B)
instead of __filemap_get_folio(A, B, 0, 0)—no need for the extra
arguments 0, 0.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The buffered write path is still heavily utilizing the page interface.
Since we have converted it to do a page-by-page copying, it's much easier
to convert all involved functions to folio interface, this involves:
- btrfs_copy_from_user()
- btrfs_drop_folio()
- prepare_uptodate_page()
- prepare_one_page()
- lock_and_cleanup_extent_if_need()
- btrfs_dirty_page()
All function are changed to accept a folio parameter, and if the word
"page" is in the function name, change that to "folio" too.
The function btrfs_dirty_page() is exported for v1 space cache, convert
v1 cache call site to convert its page to folio for the new interface.
And there is a small enhancement for prepare_one_folio(), instead of
manually waiting for the page writeback, let __filemap_get_folio() to
handle that by using FGP_WRITEBEGIN, which implies
(FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE).
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Currently the btrfs_buffered_write() is preparing multiple page a time,
allowing a better performance.
But the current trend is to support larger folio as an optimization,
instead of implementing own multi-page optimization.
This is inspired by generic_perform_write(), which is copying one folio
a time.
Such change will prepare us to migrate to implement the write_begin()
and write_end() callbacks, and make every involved function a little
easier.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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btrfs_do_encoded_write() was converted to use folios in 400b172b8cdc,
but we're still allocating based on sizeof(struct page *) rather than
sizeof(struct folio *). There's no functional change.
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Mark Harmstone <maharmstone@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Remove hard-coded strings by using the str_yes_no() and str_no_yes()
helper functions.
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Since there is no user of reader locks, rename the writer locks into a
more generic name, by removing the "_writer" part from the name.
And also rename btrfs_subpage::writer into btrfs_subpage::locked.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Since commit d7172f52e993 ("btrfs: use per-buffer locking for
extent_buffer reading"), metadata read no longer relies on the subpage
reader locking.
This means we do not need to maintain a different metadata/data split
for locking, so we can convert the existing reader lock users by:
- add_ra_bio_pages()
Convert to btrfs_folio_set_writer_lock()
- end_folio_read()
Convert to btrfs_folio_end_writer_lock()
- begin_folio_read()
Convert to btrfs_folio_set_writer_lock()
- folio_range_has_eb()
Remove the subpage->readers checks, since it is always 0.
- Remove btrfs_subpage_start_reader() and btrfs_subpage_end_reader()
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This function is not really suitable to lock a folio, as it lacks the
proper mapping checks, thus the locked folio may not even belong to
btrfs.
And due to the above reason, the last user inside lock_delalloc_folios()
is already removed, and we can remove this function.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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If you follow the seed/sprout wiki, it suggests the following workflow:
btrfstune -S 1 seed_dev
mount seed_dev mnt
btrfs device add sprout_dev
mount -o remount,rw mnt
The first mount mounts the FS readonly, which results in not setting
BTRFS_FS_OPEN, and setting the readonly bit on the sb. The device add
somewhat surprisingly clears the readonly bit on the sb (though the
mount is still practically readonly, from the users perspective...).
Finally, the remount checks the readonly bit on the sb against the flag
and sees no change, so it does not run the code intended to run on
ro->rw transitions, leaving BTRFS_FS_OPEN unset.
As a result, when the cleaner_kthread runs, it sees no BTRFS_FS_OPEN and
does no work. This results in leaking deleted snapshots until we run out
of space.
I propose fixing it at the first departure from what feels reasonable:
when we clear the readonly bit on the sb during device add.
A new fstest I have written reproduces the bug and confirms the fix.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
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It's redundant to have the 'gen' variable since we already have the same
value in the local btrfs_tree_parent_check structure. So remove it and
instead use the structure's field.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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It's pointless to initialize the has_first_key field of the stack local
btrfs_tree_parent_check structure at btrfs_tree_parent_check() and at
btrfs_qgroup_trace_subtree() since all fields not explicitly initialized
are zeroed out. In the case of the first function it's a bit odd because
we are assigning 0 and the field is of type bool, however not incorrect
since a 0 is converted to false.
Just remove the explicit initializations due to their redundancy.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The only caller of btrfs_verify_level_key() is read_block_for_search() and
it's passing 3 arguments to it that can be extracted from its on stack
variable of type struct btrfs_tree_parent_check.
So change btrfs_verify_level_key() to accept an argument of type
struct btrfs_tree_parent_check instead of level, first key and parent
transid arguments.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The level parameter passed to read_block_for_search() always matches the
level of the extent buffer passed in the "eb_ret" parameter, which we are
also extracting into the "parent_level" local variable.
So remove the level parameter and instead use the "parent_level" variable
which in fact has a better name (it's the level of the parent node from
which we are reading a child node/leaf).
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Now that the extent map shrinker can only be run by a single task and runs
asynchronously as a work queue job, enable it as it can no longer cause
stalls on tasks allocating memory and entering the extent map shrinker
through the fs shrinker (implemented by btrfs_free_cached_objects()).
This is crucial to prevent exhaustion of memory due to unbounded extent
map creation, primarily with direct IO but also for buffered IO on files
with holes. This problem, for the direct IO case, was first reported in
the Link tag below. That report was added to a Link tag of the first patch
that introduced the extent map shrinker, commit 956a17d9d050 ("btrfs: add
a shrinker for extent maps"), however the Link tag disappeared somehow
from the committed patch (but was included in the submitted patch to the
mailing list), so adding it below for future reference.
Link: https://lore.kernel.org/linux-btrfs/13f94633dcf04d29aaf1f0a43d42c55e@amazon.com/
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The names for the members of struct btrfs_fs_info related to the extent
map shrinker are a bit too long, so rename them to be shorter by replacing
the "extent_map_" prefix with the "em_" prefix.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Now that the extent map shrinker can only be run by a single task (as a
work queue item) there is no need to keep the progress of the shrinker
protected by a spinlock and passing the progress to trace events as
parameters. So remove the lock and simplify the arguments for the trace
events.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Currently the extent map shrinker is run synchronously for kswapd tasks
that end up calling the fs shrinker (fs/super.c:super_cache_scan()).
This has some disadvantages and for some heavy workloads with memory
pressure it can cause some delays and stalls that make a machine
unresponsive for some periods. This happens because:
1) We can have several kswapd tasks on machines with multiple NUMA zones,
and running the extent map shrinker concurrently can cause high
contention on some spin locks, namely the spin locks that protect
the radix tree that tracks roots, the per root xarray that tracks
open inodes and the list of delayed iputs. This not only delays the
shrinker but also causes high CPU consumption and makes the task
running the shrinker monopolize a core, resulting in the symptoms
of an unresponsive system. This was noted in previous commits such as
commit ae1e766f623f ("btrfs: only run the extent map shrinker from
kswapd tasks");
2) The extent map shrinker's iteration over inodes can often be slow, even
after changing the data structure that tracks open inodes for a root
from a red black tree (up to kernel 6.10) to an xarray (kernel 6.10+).
The transition to the xarray while it made things a bit faster, it's
still somewhat slow - for example in a test scenario with 10000 inodes
that have no extent maps loaded, the extent map shrinker took between
5ms to 8ms, using a release, non-debug kernel. Iterating over the
extent maps of an inode can also be slow if have an inode with many
thousands of extent maps, since we use a red black tree to track and
search extent maps. So having the extent map shrinker run synchronously
adds extra delay for other things a kswapd task does.
So make the extent map shrinker run asynchronously as a job for the
system unbounded workqueue, just like what we do for data and metadata
space reclaim jobs.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Move the common code to remove an extent map from its inode's tree into a
helper function and use it, reducing duplicated code.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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When crawling btree, if an eb cache miss occurs, we change to use the eb
read lock and release all previous locks (including the parent lock) to
reduce lock contention.
If an eb cache miss occurs in a leaf and needs to execute IO, before this
change we released locks only from level 2 and up and we read a leaf's
content from disk while holding a lock on its parent (level 1), causing
the unnecessary lock contention on the parent, after this change we
release locks from level 1 and up, but we lock level 0, and read leaf's
content from disk.
Because we have prepared the check parameters and the read lock of eb we
hold, we can ensure that no race will occur during the check and cause
unexpected errors.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Robbie Ko <robbieko@synology.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The compression heuristic pass does not need a level, so we can drop the
parameter.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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