Hi Junhui--- I have applied the patch [with a small whitespace edit] to my tree. I will try to get some test mileage on it.
Reviewed-by: Michael Lyle <[email protected]> Thanks-- Mike On 10/24/2017 07:26 PM, [email protected] wrote: > From: Tang Junhui <[email protected]> > > bucket_in_use is updated in gc thread which triggered by invalidating or > writing sectors_to_gc dirty data, It's a long interval. Therefore, when we > use it to compare with the threshold, it is often not timely, which leads > to inaccurate judgment and often results in bucket depletion. > > We have send a patch before, by the means of updating bucket_in_use > periodically In gc thread, which Coly thought that would lead high > latency, In this patch, we add avail_nbuckets to record the count of > available buckets, and we calculate bucket_in_use when alloc or free > bucket in real time. > > Signed-off-by: Tang Junhui <[email protected]> > --- > drivers/md/bcache/alloc.c | 10 ++++++++++ > drivers/md/bcache/bcache.h | 1 + > drivers/md/bcache/btree.c | 17 ++++++++++------- > drivers/md/bcache/btree.h | 2 +- > 4 files changed, 22 insertions(+), 8 deletions(-) > mode change 100644 => 100755 drivers/md/bcache/alloc.c > mode change 100644 => 100755 drivers/md/bcache/bcache.h > mode change 100644 => 100755 drivers/md/bcache/btree.c > mode change 100644 => 100755 drivers/md/bcache/btree.h > > diff --git a/drivers/md/bcache/alloc.c b/drivers/md/bcache/alloc.c > old mode 100644 > new mode 100755 > index ca4abe1..6e036ff > --- a/drivers/md/bcache/alloc.c > +++ b/drivers/md/bcache/alloc.c > @@ -439,6 +439,11 @@ long bch_bucket_alloc(struct cache *ca, unsigned > reserve, bool wait) > b->prio = INITIAL_PRIO; > } > > + if(ca->set->avail_nbuckets > 0) { > + ca->set->avail_nbuckets--; > + bch_update_bucket_in_use(ca->set, &ca->set->gc_stats); > + } > + > return r; > } > > @@ -446,6 +451,11 @@ void __bch_bucket_free(struct cache *ca, struct bucket > *b) > { > SET_GC_MARK(b, 0); > SET_GC_SECTORS_USED(b, 0); > + > + if(ca->set->avail_nbuckets < ca->set->nbuckets) { > + ca->set->avail_nbuckets++; > + bch_update_bucket_in_use(ca->set, &ca->set->gc_stats); > + } > } > > void bch_bucket_free(struct cache_set *c, struct bkey *k) > diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h > old mode 100644 > new mode 100755 > index dee542f..275b29c > --- a/drivers/md/bcache/bcache.h > +++ b/drivers/md/bcache/bcache.h > @@ -580,6 +580,7 @@ struct cache_set { > uint8_t need_gc; > struct gc_stat gc_stats; > size_t nbuckets; > + size_t avail_nbuckets; > > struct task_struct *gc_thread; > /* Where in the btree gc currently is */ > diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c > old mode 100644 > new mode 100755 > index 866dcf7..d8865e6 > --- a/drivers/md/bcache/btree.c > +++ b/drivers/md/bcache/btree.c > @@ -1240,6 +1240,11 @@ void bch_initial_mark_key(struct cache_set *c, int > level, struct bkey *k) > __bch_btree_mark_key(c, level, k); > } > > +void bch_update_bucket_in_use(struct cache_set *c, struct gc_stat *stats) > +{ > + stats->in_use = (c->nbuckets - c->avail_nbuckets) * 100 / c->nbuckets; > +} > + > static bool btree_gc_mark_node(struct btree *b, struct gc_stat *gc) > { > uint8_t stale = 0; > @@ -1651,9 +1656,8 @@ static void btree_gc_start(struct cache_set *c) > mutex_unlock(&c->bucket_lock); > } > > -static size_t bch_btree_gc_finish(struct cache_set *c) > +static void bch_btree_gc_finish(struct cache_set *c) > { > - size_t available = 0; > struct bucket *b; > struct cache *ca; > unsigned i; > @@ -1690,6 +1694,7 @@ static size_t bch_btree_gc_finish(struct cache_set *c) > } > rcu_read_unlock(); > > + c->avail_nbuckets = 0; > for_each_cache(ca, c, i) { > uint64_t *i; > > @@ -1711,18 +1716,16 @@ static size_t bch_btree_gc_finish(struct cache_set *c) > BUG_ON(!GC_MARK(b) && GC_SECTORS_USED(b)); > > if (!GC_MARK(b) || GC_MARK(b) == GC_MARK_RECLAIMABLE) > - available++; > + c->avail_nbuckets++; > } > } > > mutex_unlock(&c->bucket_lock); > - return available; > } > > static void bch_btree_gc(struct cache_set *c) > { > int ret; > - unsigned long available; > struct gc_stat stats; > struct closure writes; > struct btree_op op; > @@ -1745,14 +1748,14 @@ static void bch_btree_gc(struct cache_set *c) > pr_warn("gc failed!"); > } while (ret); > > - available = bch_btree_gc_finish(c); > + bch_btree_gc_finish(c); > wake_up_allocators(c); > > bch_time_stats_update(&c->btree_gc_time, start_time); > > stats.key_bytes *= sizeof(uint64_t); > stats.data <<= 9; > - stats.in_use = (c->nbuckets - available) * 100 / c->nbuckets; > + bch_update_bucket_in_use(c, &stats); > memcpy(&c->gc_stats, &stats, sizeof(struct gc_stat)); > > trace_bcache_gc_end(c); > diff --git a/drivers/md/bcache/btree.h b/drivers/md/bcache/btree.h > old mode 100644 > new mode 100755 > index 73da1f5..4073aca > --- a/drivers/md/bcache/btree.h > +++ b/drivers/md/bcache/btree.h > @@ -305,5 +305,5 @@ bool bch_keybuf_check_overlapping(struct keybuf *, struct > bkey *, > struct keybuf_key *bch_keybuf_next(struct keybuf *); > struct keybuf_key *bch_keybuf_next_rescan(struct cache_set *, struct keybuf > *, > struct bkey *, keybuf_pred_fn *); > - > +void bch_update_bucket_in_use(struct cache_set *c, struct gc_stat *stats); > #endif >
