bcachefs: Bucket invalidate path improvements

 - invalidate_one_bucket() now returns 1 when we don't have any buckets
   on this device to invalidate, ensuring we don't spin
 - the tracepoint invocation is moved to after the transaction commit,
   and we now include the number of cached sectors in the tracepoint

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

diff --git a/fs/bcachefs/alloc_background.c b/fs/bcachefs/alloc_background.c
index 933334fed960be36148cf3323ef0eb62e4ead9db..b784fe7c5b81bd0789a5f6487148940c5f218e41 100644 (file)
--- a/fs/bcachefs/alloc_background.c
+++ b/fs/bcachefs/alloc_background.c
@@ -1077,7 +1077,8 @@ void bch2_do_discards(struct bch_fs *c)
                percpu_ref_put(&c->writes);
 }
 
-static int invalidate_one_bucket(struct btree_trans *trans, struct bch_dev *ca)
+static int invalidate_one_bucket(struct btree_trans *trans, struct bch_dev *ca,
+                                struct bpos *bucket_pos, unsigned *cached_sectors)
 {
        struct bch_fs *c = trans->c;
        struct btree_iter lru_iter, alloc_iter = { NULL };
@@ -1095,8 +1096,10 @@ next_lru:
        if (ret)
                goto out;
 
-       if (!k.k || k.k->p.inode != ca->dev_idx)
+       if (!k.k || k.k->p.inode != ca->dev_idx) {
+               ret = 1;
                goto out;
+       }
 
        if (k.k->type != KEY_TYPE_lru) {
                prt_printf(&buf, "non lru key in lru btree:\n  ");
@@ -1116,8 +1119,9 @@ next_lru:
        idx     = k.k->p.offset;
        bucket  = le64_to_cpu(bkey_s_c_to_lru(k).v->idx);
 
-       a = bch2_trans_start_alloc_update(trans, &alloc_iter,
-                                         POS(ca->dev_idx, bucket));
+       *bucket_pos = POS(ca->dev_idx, bucket);
+
+       a = bch2_trans_start_alloc_update(trans, &alloc_iter, *bucket_pos);
        ret = PTR_ERR_OR_ZERO(a);
        if (ret)
                goto out;
@@ -1139,6 +1143,11 @@ next_lru:
                }
        }
 
+       if (!a->v.cached_sectors)
+               bch_err(c, "invalidating empty bucket, confused");
+
+       *cached_sectors = a->v.cached_sectors;
+
        SET_BCH_ALLOC_V4_NEED_INC_GEN(&a->v, false);
        a->v.gen++;
        a->v.data_type          = 0;
@@ -1151,8 +1160,6 @@ next_lru:
                                BTREE_TRIGGER_BUCKET_INVALIDATE);
        if (ret)
                goto out;
-
-       trace_invalidate_bucket(c, a->k.p.inode, a->k.p.offset);
 out:
        bch2_trans_iter_exit(trans, &alloc_iter);
        bch2_trans_iter_exit(trans, &lru_iter);
@@ -1165,7 +1172,8 @@ static void bch2_do_invalidates_work(struct work_struct *work)
        struct bch_fs *c = container_of(work, struct bch_fs, invalidate_work);
        struct bch_dev *ca;
        struct btree_trans trans;
-       unsigned i;
+       struct bpos bucket;
+       unsigned i, sectors;
        int ret = 0;
 
        bch2_trans_init(&trans, c, 0, 0);
@@ -1178,10 +1186,12 @@ static void bch2_do_invalidates_work(struct work_struct *work)
                        ret = __bch2_trans_do(&trans, NULL, NULL,
                                              BTREE_INSERT_USE_RESERVE|
                                              BTREE_INSERT_NOFAIL,
-                                       invalidate_one_bucket(&trans, ca));
+                                       invalidate_one_bucket(&trans, ca, &bucket,
+                                                             &sectors));
                        if (ret)
                                break;
 
+                       trace_invalidate_bucket(c, bucket.inode, bucket.offset, sectors);
                        this_cpu_inc(c->counters[BCH_COUNTER_bucket_invalidate]);
                }
        }

diff --git a/fs/bcachefs/trace.h b/fs/bcachefs/trace.h
index f5aa10762611656e48017421ceffa4b8c46fc068..b0ecf18fa1398a85f97cdfa1e85f5c95feaced70 100644 (file)
--- a/fs/bcachefs/trace.h
+++ b/fs/bcachefs/trace.h
@@ -542,24 +542,27 @@ TRACE_EVENT(discard_buckets,
 );
 
 TRACE_EVENT(invalidate_bucket,
-       TP_PROTO(struct bch_fs *c, unsigned dev, u64 bucket),
-       TP_ARGS(c, dev, bucket),
+       TP_PROTO(struct bch_fs *c, unsigned dev, u64 bucket, u32 sectors),
+       TP_ARGS(c, dev, bucket, sectors),
 
        TP_STRUCT__entry(
                __field(dev_t,          dev                     )
                __field(u32,            dev_idx                 )
+               __field(u32,            sectors                 )
                __field(u64,            bucket                  )
        ),
 
        TP_fast_assign(
                __entry->dev            = c->dev;
                __entry->dev_idx        = dev;
+               __entry->sectors        = sectors;
                __entry->bucket         = bucket;
        ),
 
-       TP_printk("%d:%d invalidated %u:%llu",
+       TP_printk("%d:%d invalidated %u:%llu cached sectors %u",
                  MAJOR(__entry->dev), MINOR(__entry->dev),
-                 __entry->dev_idx, __entry->bucket)
+                 __entry->dev_idx, __entry->bucket,
+                 __entry->sectors)
 );
 
 /* Moving IO */