| Message ID | 20230724094354.90817-29-zhengqi.arch@bytedance.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | use refcount+RCU method to implement lockless slab shrink | expand |
On 2023/7/24 17:43, Qi Zheng wrote: > In preparation for implementing lockless slab shrink, use new APIs to > dynamically allocate the md-bcache shrinker, so that it can be freed > asynchronously using kfree_rcu(). Then it doesn't need to wait for RCU > read-side critical section when releasing the struct cache_set. > > Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> > --- > drivers/md/bcache/bcache.h | 2 +- > drivers/md/bcache/btree.c | 27 ++++++++++++++++----------- > drivers/md/bcache/sysfs.c | 3 ++- > 3 files changed, 19 insertions(+), 13 deletions(-) > > diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h > index 5a79bb3c272f..c622bc50f81b 100644 > --- a/drivers/md/bcache/bcache.h > +++ b/drivers/md/bcache/bcache.h > @@ -541,7 +541,7 @@ struct cache_set { > struct bio_set bio_split; > > /* For the btree cache */ > - struct shrinker shrink; > + struct shrinker *shrink; > > /* For the btree cache and anything allocation related */ > struct mutex bucket_lock; > diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c > index fd121a61f17c..c176c7fc77d9 100644 > --- a/drivers/md/bcache/btree.c > +++ b/drivers/md/bcache/btree.c > @@ -667,7 +667,7 @@ static int mca_reap(struct btree *b, unsigned int min_order, bool flush) > static unsigned long bch_mca_scan(struct shrinker *shrink, > struct shrink_control *sc) > { > - struct cache_set *c = container_of(shrink, struct cache_set, shrink); > + struct cache_set *c = shrink->private_data; > struct btree *b, *t; > unsigned long i, nr = sc->nr_to_scan; > unsigned long freed = 0; > @@ -734,7 +734,7 @@ static unsigned long bch_mca_scan(struct shrinker *shrink, > static unsigned long bch_mca_count(struct shrinker *shrink, > struct shrink_control *sc) > { > - struct cache_set *c = container_of(shrink, struct cache_set, shrink); > + struct cache_set *c = shrink->private_data; > > if (c->shrinker_disabled) > return 0; > @@ -752,8 +752,8 @@ void bch_btree_cache_free(struct cache_set *c) > > closure_init_stack(&cl); > > - if (c->shrink.list.next) > - unregister_shrinker(&c->shrink); > + if (c->shrink) > + shrinker_unregister(c->shrink); > > mutex_lock(&c->bucket_lock); > > @@ -828,14 +828,19 @@ int bch_btree_cache_alloc(struct cache_set *c) > c->verify_data = NULL; > #endif > > - c->shrink.count_objects = bch_mca_count; > - c->shrink.scan_objects = bch_mca_scan; > - c->shrink.seeks = 4; > - c->shrink.batch = c->btree_pages * 2; > + c->shrink = shrinker_alloc(0, "md-bcache:%pU", c->set_uuid); > + if (!c->shrink) { > + pr_warn("bcache: %s: could not allocate shrinker\n", __func__); > + return -ENOMEM; Seems you have cheanged the semantic of this. In the past, it is better to have a shrinker, but now it becomes a mandatory. Right? I don't know if it is acceptable. From my point of view, just do the cleanup, don't change any behaviour. > + } > + > + c->shrink->count_objects = bch_mca_count; > + c->shrink->scan_objects = bch_mca_scan; > + c->shrink->seeks = 4; > + c->shrink->batch = c->btree_pages * 2; > + c->shrink->private_data = c; > > - if (register_shrinker(&c->shrink, "md-bcache:%pU", c->set_uuid)) > - pr_warn("bcache: %s: could not register shrinker\n", > - __func__); > + shrinker_register(c->shrink); > > return 0; > } > diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c > index 0e2c1880f60b..45d8af755de6 100644 > --- a/drivers/md/bcache/sysfs.c > +++ b/drivers/md/bcache/sysfs.c > @@ -866,7 +866,8 @@ STORE(__bch_cache_set) > > sc.gfp_mask = GFP_KERNEL; > sc.nr_to_scan = strtoul_or_return(buf); > - c->shrink.scan_objects(&c->shrink, &sc); > + if (c->shrink) > + c->shrink->scan_objects(c->shrink, &sc); > } > > sysfs_strtoul_clamp(congested_read_threshold_us,
On 2023/7/26 15:32, Muchun Song wrote: > > > On 2023/7/24 17:43, Qi Zheng wrote: >> In preparation for implementing lockless slab shrink, use new APIs to >> dynamically allocate the md-bcache shrinker, so that it can be freed >> asynchronously using kfree_rcu(). Then it doesn't need to wait for RCU >> read-side critical section when releasing the struct cache_set. >> >> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> >> --- >> drivers/md/bcache/bcache.h | 2 +- >> drivers/md/bcache/btree.c | 27 ++++++++++++++++----------- >> drivers/md/bcache/sysfs.c | 3 ++- >> 3 files changed, 19 insertions(+), 13 deletions(-) >> >> diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h >> index 5a79bb3c272f..c622bc50f81b 100644 >> --- a/drivers/md/bcache/bcache.h >> +++ b/drivers/md/bcache/bcache.h >> @@ -541,7 +541,7 @@ struct cache_set { >> struct bio_set bio_split; >> /* For the btree cache */ >> - struct shrinker shrink; >> + struct shrinker *shrink; >> /* For the btree cache and anything allocation related */ >> struct mutex bucket_lock; >> diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c >> index fd121a61f17c..c176c7fc77d9 100644 >> --- a/drivers/md/bcache/btree.c >> +++ b/drivers/md/bcache/btree.c >> @@ -667,7 +667,7 @@ static int mca_reap(struct btree *b, unsigned int >> min_order, bool flush) >> static unsigned long bch_mca_scan(struct shrinker *shrink, >> struct shrink_control *sc) >> { >> - struct cache_set *c = container_of(shrink, struct cache_set, >> shrink); >> + struct cache_set *c = shrink->private_data; >> struct btree *b, *t; >> unsigned long i, nr = sc->nr_to_scan; >> unsigned long freed = 0; >> @@ -734,7 +734,7 @@ static unsigned long bch_mca_scan(struct shrinker >> *shrink, >> static unsigned long bch_mca_count(struct shrinker *shrink, >> struct shrink_control *sc) >> { >> - struct cache_set *c = container_of(shrink, struct cache_set, >> shrink); >> + struct cache_set *c = shrink->private_data; >> if (c->shrinker_disabled) >> return 0; >> @@ -752,8 +752,8 @@ void bch_btree_cache_free(struct cache_set *c) >> closure_init_stack(&cl); >> - if (c->shrink.list.next) >> - unregister_shrinker(&c->shrink); >> + if (c->shrink) >> + shrinker_unregister(c->shrink); >> mutex_lock(&c->bucket_lock); >> @@ -828,14 +828,19 @@ int bch_btree_cache_alloc(struct cache_set *c) >> c->verify_data = NULL; >> #endif >> - c->shrink.count_objects = bch_mca_count; >> - c->shrink.scan_objects = bch_mca_scan; >> - c->shrink.seeks = 4; >> - c->shrink.batch = c->btree_pages * 2; >> + c->shrink = shrinker_alloc(0, "md-bcache:%pU", c->set_uuid); >> + if (!c->shrink) { >> + pr_warn("bcache: %s: could not allocate shrinker\n", __func__); >> + return -ENOMEM; > > Seems you have cheanged the semantic of this. In the past, > it is better to have a shrinker, but now it becomes a mandatory. > Right? I don't know if it is acceptable. From my point of view, > just do the cleanup, don't change any behaviour. Oh, should return 0 here, will do. > >> + } >> + >> + c->shrink->count_objects = bch_mca_count; >> + c->shrink->scan_objects = bch_mca_scan; >> + c->shrink->seeks = 4; >> + c->shrink->batch = c->btree_pages * 2; >> + c->shrink->private_data = c; >> - if (register_shrinker(&c->shrink, "md-bcache:%pU", c->set_uuid)) >> - pr_warn("bcache: %s: could not register shrinker\n", >> - __func__); >> + shrinker_register(c->shrink); >> return 0; >> } >> diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c >> index 0e2c1880f60b..45d8af755de6 100644 >> --- a/drivers/md/bcache/sysfs.c >> +++ b/drivers/md/bcache/sysfs.c >> @@ -866,7 +866,8 @@ STORE(__bch_cache_set) >> sc.gfp_mask = GFP_KERNEL; >> sc.nr_to_scan = strtoul_or_return(buf); >> - c->shrink.scan_objects(&c->shrink, &sc); >> + if (c->shrink) >> + c->shrink->scan_objects(c->shrink, &sc); >> } >> sysfs_strtoul_clamp(congested_read_threshold_us, >
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h index 5a79bb3c272f..c622bc50f81b 100644 --- a/drivers/md/bcache/bcache.h +++ b/drivers/md/bcache/bcache.h @@ -541,7 +541,7 @@ struct cache_set { struct bio_set bio_split; /* For the btree cache */ - struct shrinker shrink; + struct shrinker *shrink; /* For the btree cache and anything allocation related */ struct mutex bucket_lock; diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c index fd121a61f17c..c176c7fc77d9 100644 --- a/drivers/md/bcache/btree.c +++ b/drivers/md/bcache/btree.c @@ -667,7 +667,7 @@ static int mca_reap(struct btree *b, unsigned int min_order, bool flush) static unsigned long bch_mca_scan(struct shrinker *shrink, struct shrink_control *sc) { - struct cache_set *c = container_of(shrink, struct cache_set, shrink); + struct cache_set *c = shrink->private_data; struct btree *b, *t; unsigned long i, nr = sc->nr_to_scan; unsigned long freed = 0; @@ -734,7 +734,7 @@ static unsigned long bch_mca_scan(struct shrinker *shrink, static unsigned long bch_mca_count(struct shrinker *shrink, struct shrink_control *sc) { - struct cache_set *c = container_of(shrink, struct cache_set, shrink); + struct cache_set *c = shrink->private_data; if (c->shrinker_disabled) return 0; @@ -752,8 +752,8 @@ void bch_btree_cache_free(struct cache_set *c) closure_init_stack(&cl); - if (c->shrink.list.next) - unregister_shrinker(&c->shrink); + if (c->shrink) + shrinker_unregister(c->shrink); mutex_lock(&c->bucket_lock); @@ -828,14 +828,19 @@ int bch_btree_cache_alloc(struct cache_set *c) c->verify_data = NULL; #endif - c->shrink.count_objects = bch_mca_count; - c->shrink.scan_objects = bch_mca_scan; - c->shrink.seeks = 4; - c->shrink.batch = c->btree_pages * 2; + c->shrink = shrinker_alloc(0, "md-bcache:%pU", c->set_uuid); + if (!c->shrink) { + pr_warn("bcache: %s: could not allocate shrinker\n", __func__); + return -ENOMEM; + } + + c->shrink->count_objects = bch_mca_count; + c->shrink->scan_objects = bch_mca_scan; + c->shrink->seeks = 4; + c->shrink->batch = c->btree_pages * 2; + c->shrink->private_data = c; - if (register_shrinker(&c->shrink, "md-bcache:%pU", c->set_uuid)) - pr_warn("bcache: %s: could not register shrinker\n", - __func__); + shrinker_register(c->shrink); return 0; } diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c index 0e2c1880f60b..45d8af755de6 100644 --- a/drivers/md/bcache/sysfs.c +++ b/drivers/md/bcache/sysfs.c @@ -866,7 +866,8 @@ STORE(__bch_cache_set) sc.gfp_mask = GFP_KERNEL; sc.nr_to_scan = strtoul_or_return(buf); - c->shrink.scan_objects(&c->shrink, &sc); + if (c->shrink) + c->shrink->scan_objects(c->shrink, &sc); } sysfs_strtoul_clamp(congested_read_threshold_us,
In preparation for implementing lockless slab shrink, use new APIs to dynamically allocate the md-bcache shrinker, so that it can be freed asynchronously using kfree_rcu(). Then it doesn't need to wait for RCU read-side critical section when releasing the struct cache_set. Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> --- drivers/md/bcache/bcache.h | 2 +- drivers/md/bcache/btree.c | 27 ++++++++++++++++----------- drivers/md/bcache/sysfs.c | 3 ++- 3 files changed, 19 insertions(+), 13 deletions(-)