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path: root/fs/bcachefs/btree_key_cache.h
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2023-10-22bcachefs: More style fixesKent Overstreet
Fixes for various checkpatch errors. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Btree key cache coherencyKent Overstreet
- Updates to non key cache iterators will now be transparently redirected to the key cache for cached btrees. - Except when creating new keys: then the update goes to underlying btree For for iterating over a cached btree to work, we need to ensure that if a key exists in the key cache, it also exists in the btree - otherwise the iterator code will skip past it and not check the key cache. Otherwise, for consistency, all updates should go to the same place - the key cache. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Simplify journal replayKent Overstreet
With BTREE_ITER_WITH_JOURNAL, there's no longer any restrictions on the order we have to replay keys from the journal in, and we can also start up journal reclaim right away - and delete a bunch of code. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
2023-10-22bcachefs: btree_pathKent Overstreet
This splits btree_iter into two components: btree_iter is now the externally visible componont, and it points to a btree_path which is now reference counted. This means we no longer have to clone iterators up front if they might be mutated - btree_path can be shared by multiple iterators, and cloned if an iterator would mutate a shared btree_path. This will help us use iterators more efficiently, as well as slimming down the main long lived state in btree_trans, and significantly cleans up the logic for iterator lifetimes. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Further reduce iter->trans usageKent Overstreet
This is prep work for splitting btree_path out from btree_iter - btree_path will not have a pointer to btree_trans. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
2023-10-22bcachefs: Don't flush btree writes more aggressively because of btree key cacheKent Overstreet
We need to flush the btree key cache when it's too dirty, because otherwise the shrinker won't be able to reclaim memory - this is done by journal reclaim. But journal reclaim also kicks btree node writes: this meant that btree node writes were getting kicked much too often just because we needed to flush btree key cache keys. This patch splits journal pins into two different lists, and teaches journal reclaim to not flush btree node writes when it only needs to flush key cache keys. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Have journal reclaim thread flush more aggressivelyKent Overstreet
This adds a new watermark for the journal reclaim when flushing btree key cache entries - it should try and stay ahead of where foreground threads doing transaction commits will enter direct journal reclaim. 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: Fix for spinning in journal reclaim on startupKent Overstreet
We normally avoid having too many dirty keys in the btree key cache, to ensure that we can always shrink our caches to reclaim memory if needed. But this check was causing us to go into an infinite loop on startup, in the btree insert path before journal reclaim was started. 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 dirty checksKent Overstreet
Had a type that meant we were triggering journal reclaim _much_ more aggressively than needed. Also, fix a potential integer overflow. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22bcachefs: Throttle updates when btree key cache is too dirtyKent Overstreet
This is needed to ensure we don't deadlock because journal reclaim and thus memory reclaim isn't making forward progress. 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: 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: 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>