[PATCH 4.4 14/15] bcache: Make gc wakeup sane, remove set_task_state()

Greg Kroah-Hartman
2017-02-21T13:12:42Z

From: Kent Overstreet <kent.overstreet@gmail.com>

commit be628be09563f8f6e81929efbd7cf3f45c344416 upstream.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/md/bcache/bcache.h | 4 ++--
drivers/md/bcache/btree.c | 40 ++++++++++++++++++++--------------------
drivers/md/bcache/btree.h | 3 +--
drivers/md/bcache/request.c | 4 +---
drivers/md/bcache/super.c | 2 ++
5 files changed, 26 insertions(+), 27 deletions(-)

--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -425,7 +425,7 @@ struct cache {
* until a gc finishes - otherwise we could pointlessly burn a ton of
* cpu
*/
- unsigned invalidate_needs_gc:1;
+ unsigned invalidate_needs_gc;

bool discard; /* Get rid of? */

@@ -593,8 +593,8 @@ struct cache_set {

/* Counts how many sectors bio_insert has added to the cache */
atomic_t sectors_to_gc;
+ wait_queue_head_t gc_wait;

- wait_queue_head_t moving_gc_wait;
struct keybuf moving_gc_keys;
/* Number of moving GC bios in flight */
struct semaphore moving_in_flight;
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -1762,33 +1762,34 @@ static void bch_btree_gc(struct cache_se
bch_moving_gc(c);
}

-static int bch_gc_thread(void *arg)
+static bool gc_should_run(struct cache_set *c)
{
- struct cache_set *c = arg;
struct cache *ca;
unsigned i;

- while (1) {
-again:
- bch_btree_gc(c);
+ for_each_cache(ca, c, i)
+ if (ca->invalidate_needs_gc)
+ return true;

- set_current_state(TASK_INTERRUPTIBLE);
- if (kthread_should_stop())
- break;
+ if (atomic_read(&c->sectors_to_gc) < 0)
+ return true;

- mutex_lock(&c->bucket_lock);
+ return false;
+}

- for_each_cache(ca, c, i)
- if (ca->invalidate_needs_gc) {
- mutex_unlock(&c->bucket_lock);
- set_current_state(TASK_RUNNING);
- goto again;
- }
+static int bch_gc_thread(void *arg)
+{
+ struct cache_set *c = arg;

- mutex_unlock(&c->bucket_lock);
+ while (1) {
+ wait_event_interruptible(c->gc_wait,
+ kthread_should_stop() || gc_should_run(c));

- try_to_freeze();
- schedule();
+ if (kthread_should_stop())
+ break;
+
+ set_gc_sectors(c);
+ bch_btree_gc(c);
}

return 0;
@@ -1796,11 +1797,10 @@ again:

int bch_gc_thread_start(struct cache_set *c)
{
- c->gc_thread = kthread_create(bch_gc_thread, c, "bcache_gc");
+ c->gc_thread = kthread_run(bch_gc_thread, c, "bcache_gc");
if (IS_ERR(c->gc_thread))
return PTR_ERR(c->gc_thread);

- set_task_state(c->gc_thread, TASK_INTERRUPTIBLE);
return 0;
}

--- a/drivers/md/bcache/btree.h
+++ b/drivers/md/bcache/btree.h
@@ -260,8 +260,7 @@ void bch_initial_mark_key(struct cache_s

static inline void wake_up_gc(struct cache_set *c)
{
- if (c->gc_thread)
- wake_up_process(c->gc_thread);
+ wake_up(&c->gc_wait);
}

#define MAP_DONE 0
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -196,10 +196,8 @@ static void bch_data_insert_start(struct
struct data_insert_op *op = container_of(cl, struct data_insert_op, cl);
struct bio *bio = op->bio, *n;

- if (atomic_sub_return(bio_sectors(bio), &op->c->sectors_to_gc) < 0) {
- set_gc_sectors(op->c);
+ if (atomic_sub_return(bio_sectors(bio), &op->c->sectors_to_gc) < 0)
wake_up_gc(op->c);
- }

if (op->bypass)
return bch_data_invalidate(cl);
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1489,6 +1489,7 @@ struct cache_set *bch_cache_set_alloc(st
mutex_init(&c->bucket_lock);
init_waitqueue_head(&c->btree_cache_wait);
init_waitqueue_head(&c->bucket_wait);
+ init_waitqueue_head(&c->gc_wait);
sema_init(&c->uuid_write_mutex, 1);

spin_lock_init(&c->btree_gc_time.lock);
@@ -1547,6 +1548,7 @@ static void run_cache_set(struct cache_s

for_each_cache(ca, c, i)
c->nbuckets += ca->sb.nbuckets;
+ set_gc_sectors(c);

if (CACHE_SYNC(&c->sb)) {
LIST_HEAD(journal);