diff options
| author | Kent Overstreet <kent.overstreet@gmail.com> | 2021-12-28 04:45:07 +0300 |
|---|---|---|
| committer | Kent Overstreet <kent.overstreet@linux.dev> | 2023-10-23 00:09:20 +0300 |
| commit | c7ce813fe49a58344ba11219c0bd3a2fdb2e8b9e (patch) | |
| tree | 7313f7c84a4578da61d9ac25836cf36fd5b13c93 /fs/bcachefs | |
| parent | d93cf6858fe67a84e90af76994a2fe4b390c0a0b (diff) | |
| download | linux-c7ce813fe49a58344ba11219c0bd3a2fdb2e8b9e.tar.xz | |
bcachefs: Add a tracepoint for the btree cache shrinker
This is to help with diagnosing why the btree node can doesn't seem to
be shrinking - we've had issues in the past with granularity/batch size,
since btree nodes are so big.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Diffstat (limited to 'fs/bcachefs')
| -rw-r--r-- | fs/bcachefs/btree_cache.c | 11 | ||||
| -rw-r--r-- | fs/bcachefs/trace.h | 28 |
2 files changed, 37 insertions, 2 deletions
diff --git a/fs/bcachefs/btree_cache.c b/fs/bcachefs/btree_cache.c index 5bf493a315ca..40061887f5d8 100644 --- a/fs/bcachefs/btree_cache.c +++ b/fs/bcachefs/btree_cache.c @@ -275,6 +275,7 @@ static unsigned long bch2_btree_cache_scan(struct shrinker *shrink, unsigned long touched = 0; unsigned long freed = 0; unsigned i, flags; + unsigned long ret = SHRINK_STOP; if (bch2_btree_shrinker_disabled) return SHRINK_STOP; @@ -283,7 +284,7 @@ static unsigned long bch2_btree_cache_scan(struct shrinker *shrink, if (sc->gfp_mask & __GFP_FS) mutex_lock(&bc->lock); else if (!mutex_trylock(&bc->lock)) - return -1; + goto out_norestore; flags = memalloc_nofs_save(); @@ -358,8 +359,14 @@ restart: mutex_unlock(&bc->lock); out: + ret = (unsigned long) freed * btree_pages(c); memalloc_nofs_restore(flags); - return (unsigned long) freed * btree_pages(c); +out_norestore: + trace_btree_cache_scan(sc->nr_to_scan, + sc->nr_to_scan / btree_pages(c), + btree_cache_can_free(bc), + ret); + return ret; } static unsigned long bch2_btree_cache_count(struct shrinker *shrink, diff --git a/fs/bcachefs/trace.h b/fs/bcachefs/trace.h index 21d026277540..a1122fa3ccc6 100644 --- a/fs/bcachefs/trace.h +++ b/fs/bcachefs/trace.h @@ -318,6 +318,34 @@ DEFINE_EVENT(btree_node, btree_set_root, TP_ARGS(c, b) ); +TRACE_EVENT(btree_cache_scan, + TP_PROTO(unsigned long nr_to_scan_pages, + unsigned long nr_to_scan_nodes, + unsigned long can_free_nodes, + long ret), + TP_ARGS(nr_to_scan_pages, nr_to_scan_nodes, can_free_nodes, ret), + + TP_STRUCT__entry( + __field(unsigned long, nr_to_scan_pages ) + __field(unsigned long, nr_to_scan_nodes ) + __field(unsigned long, can_free_nodes ) + __field(long, ret ) + ), + + TP_fast_assign( + __entry->nr_to_scan_pages = nr_to_scan_pages; + __entry->nr_to_scan_nodes = nr_to_scan_nodes; + __entry->can_free_nodes = can_free_nodes; + __entry->ret = ret; + ), + + TP_printk("scanned for %lu pages, %lu nodes, can free %lu nodes, ret %li", + __entry->nr_to_scan_pages, + __entry->nr_to_scan_nodes, + __entry->can_free_nodes, + __entry->ret) +); + /* Garbage collection */ DEFINE_EVENT(btree_node, btree_gc_rewrite_node, |