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path: root/fs/bcachefs/btree_key_cache.c
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2023-10-22bcachefs: Fix a startup raceKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Be more careful about JOURNAL_RES_GET_RESERVEDKent Overstreet
JOURNAL_RES_GET_RESERVED should only be used for updatse that need to be done to free up space in the journal. In particular, when we're flushing keys from the key cache, if we're flushing them out of order we shouldn't be using it, since we're using up our remaining space in the journal without dropping a pin that will let us make forward progress. With this patch, BTREE_INSERT_JOURNAL_RECLAIM without BTREE_INSERT_JOURNAL_RESERVED may return -EAGAIN - we can't wait on journal reclaim if we're already in journal reclaim. This means we need to propagate these errors up to journal reclaim, indicating that flushing a journal pin should be retried in the future. This is prep work for a patch to change the way journal reclaim works, to split out flushing key cache keys because the btree key cache is too dirty from journal reclaim because we need space in the journal. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Split out bpos_cmp() and bkey_cmp()Kent Overstreet
With snapshots, we're going to need to differentiate between comparisons that should and shouldn't include the snapshot field. bpos_cmp is now the comparison function that does include the snapshot field, used by core btree code. Upper level filesystem code generally does _not_ want to compare against the snapshot field - that code wants keys to compare as equal even when one of them is in an ancestor snapshot. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: btree key cache locking improvementsKent Overstreet
The btree key cache mutex was becoming a significant bottleneck - it was mainly used to protect the lists of dirty, clean and freed cached keys. This patch eliminates the dirty and clean lists - instead, when we need to scan for keys to drop from the cache we iterate over the rhashtable, and thus we're able to remove most uses of that lock. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: btree_iter_set_dontneed()Kent Overstreet
This is a bit clearer than using bch2_btree_iter_free(). Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Fix locking in bch2_btree_iter_traverse_cached()Kent Overstreet
bch2_btree_iter_traverse() is supposed to ensure we have the correct type of lock - it was downgrading if necessary, but if we entered with a read lock it wasn't upgrading to an intent lock, oops. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Don't use BTREE_INSERT_USE_RESERVE so muchKent Overstreet
Previously, we were using BTREE_INSERT_RESERVE in a lot of places where it no longer makes sense. - we now have more open_buckets than we used to, and the reserves work better, so we shouldn't need to use BTREE_INSERT_RESERVE just because we're holding open_buckets pinned anymore. - We have the btree key cache for updates to the alloc btree, meaning we no longer need the btree reserve to ensure the allocator can make forward progress. This means that we should only need a reserve for btree updates to ensure that copygc can make forward progress. Since it's now just for copygc, we can also fold RESERVE_BTREE into RESERVE_MOVINGGC (the allocator's freelist reserve). Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Add some cond_rescheds() in shutdown pathKent Overstreet
Particularly on emergency shutdown we can end up having to clean up a lot of dirty cached btree keys here. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Fix some spurious gcc warningsKent Overstreet
These only come up when building in userspace, for some reason. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: bch2_trans_get_iter() no longer returns errorsKent Overstreet
Since we now always preallocate the maximum number of iterators when we initialize a btree transaction, getting an iterator never fails - we can delete a fair amount of error path code. This patch also simplifies the iterator allocation code a bit. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Change a BUG_ON() to a fatal errorKent Overstreet
In the btree key cache code, failing to flush a dirty key is a serious error, but it doesn't need to be a BUG_ON(), we can stop the filesystem instead. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Fix error in filesystem initializationKent Overstreet
The rhashtable code doesn't like when we destroy an rhashtable that was never initialized Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Move journal reclaim to a kthreadKent Overstreet
This is to make tracing easier. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Ensure journal reclaim runs when btree key cache is too dirtyKent Overstreet
Ensuring the key cache isn't too dirty is critical for ensuring that the shrinker can reclaim memory. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Improve btree key cache shrinkerKent Overstreet
The shrinker should start scanning for entries that can be freed oldest to newest - this way, we can avoid scanning a lot of entries that are too new to be freed. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Add a kmem_cache for btree_key_cache objectsKent Overstreet
We allocate a lot of these, and we're seeing sporading OOMs - this will help with tracking those down. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Add a shrinker for the btree key cacheKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Fix btree key cache shutdownKent Overstreet
On emergency shutdown, we might still have dirty keys in the btree key cache that need to be cleaned up properly. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Add accounting for dirty btree nodes/keysKent Overstreet
This lets us improve journal reclaim, so that it now tries to make sure no more than 3/4s of the btree node cache and btree key cache are dirty - ensuring the shrinkers can free memory. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: More inlinining in the btree key cache codeKent Overstreet
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Improve tracing for transaction restartsKent Overstreet
We have a bug where we can get stuck with a process spinning in transaction restarts - need more information. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Use cached iterators for inode updatesKent Overstreet
This switches inode updates to use cached btree iterators - which should be a nice performance boost, since lock contention on the inodes btree can be a bottleneck on multithreaded workloads. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Fix lock ordering with new btree cache codeKent Overstreet
The code that checks lock ordering was recently changed to go off of the pos of the btree node, rather than the iterator, but the btree cache code didn't update to handle iterators that point to cached bkeys. Oops Also, update various debug code. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Btree key cacheKent Overstreet
This introduces a new kind of btree iterator, cached iterators, which point to keys cached in a hash table. The cache also acts as a write cache - in the update path, we journal the update but defer updating the btree until the cached entry is flushed by journal reclaim. Cache coherency is for now up to the users to handle, which isn't ideal but should be good enough for now. These new iterators will be used for updating inodes and alloc info (the alloc and stripes btrees). Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>