Commit 119ba0f8 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcache: Convert allocator thread to kthread 



Using a workqueue when we just want a single thread is a bit silly.

Signed-off-by: default avatarKent Overstreet <koverstreet@google.com>
parent a9dd53ad

drivers/md/bcache/alloc.c

+22 −12
Original line number Diff line number Diff line
@@ -63,6 +63,7 @@ 
#include "bcache.h"

#include "btree.h"



#include <linux/kthread.h>

#include <linux/random.h>



#define MAX_IN_FLIGHT_DISCARDS		8U
@@ -151,7 +152,7 @@ static void discard_finish(struct work_struct *w) 
	mutex_unlock(&ca->set->bucket_lock);



	closure_wake_up(&ca->set->bucket_wait);

	wake_up(&ca->set->alloc_wait);

	wake_up_process(ca->alloc_thread);



	closure_put(&ca->set->cl);

}
@@ -358,30 +359,26 @@ static void invalidate_buckets(struct cache *ca) 


#define allocator_wait(ca, cond)					\

do {									\

	DEFINE_WAIT(__wait);						\

									\

	while (1) {							\

		prepare_to_wait(&ca->set->alloc_wait,			\

				&__wait, TASK_INTERRUPTIBLE);		\

		set_current_state(TASK_INTERRUPTIBLE);			\

		if (cond)						\

			break;						\

									\

		mutex_unlock(&(ca)->set->bucket_lock);			\

		if (test_bit(CACHE_SET_STOPPING_2, &ca->set->flags)) {	\

			finish_wait(&ca->set->alloc_wait, &__wait);	\

			closure_return(cl);				\

			closure_put(&ca->set->cl);			\

			return 0;					\

		}							\

									\

		schedule();						\

		mutex_lock(&(ca)->set->bucket_lock);			\

	}								\

									\

	finish_wait(&ca->set->alloc_wait, &__wait);			\

	__set_current_state(TASK_RUNNING);				\

} while (0)



void bch_allocator_thread(struct closure *cl)

static int bch_allocator_thread(void *arg)

{

	struct cache *ca = container_of(cl, struct cache, alloc);

	struct cache *ca = arg;



	mutex_lock(&ca->set->bucket_lock);
@@ -442,7 +439,7 @@ long bch_bucket_alloc(struct cache *ca, unsigned watermark, struct closure *cl) 
{

	long r = -1;

again:

	wake_up(&ca->set->alloc_wait);

	wake_up_process(ca->alloc_thread);



	if (fifo_used(&ca->free) > ca->watermark[watermark] &&

	    fifo_pop(&ca->free, r)) {
@@ -552,6 +549,19 @@ int bch_bucket_alloc_set(struct cache_set *c, unsigned watermark, 


/* Init */



int bch_cache_allocator_start(struct cache *ca)

{

	ca->alloc_thread = kthread_create(bch_allocator_thread,

					  ca, "bcache_allocator");

	if (IS_ERR(ca->alloc_thread))

		return PTR_ERR(ca->alloc_thread);



	closure_get(&ca->set->cl);

	wake_up_process(ca->alloc_thread);



	return 0;

}



void bch_cache_allocator_exit(struct cache *ca)

{

	struct discard *d;

drivers/md/bcache/bcache.h

+11 −6
Original line number Diff line number Diff line
@@ -565,8 +565,7 @@ struct cache { 


	unsigned		watermark[WATERMARK_MAX];



	struct closure		alloc;

	struct workqueue_struct	*alloc_workqueue;

	struct task_struct	*alloc_thread;



	struct closure		prio;

	struct prio_set		*disk_buckets;
@@ -703,9 +702,6 @@ struct cache_set { 
	/* For the btree cache */

	struct shrinker		shrink;



	/* For the allocator itself */

	wait_queue_head_t	alloc_wait;



	/* For the btree cache and anything allocation related */

	struct mutex		bucket_lock;
@@ -1173,6 +1169,15 @@ static inline uint8_t bucket_disk_gen(struct bucket *b) 
	static struct kobj_attribute ksysfs_##n =			\

		__ATTR(n, S_IWUSR|S_IRUSR, show, store)



static inline void wake_up_allocators(struct cache_set *c)

{

	struct cache *ca;

	unsigned i;



	for_each_cache(ca, c, i)

		wake_up_process(ca->alloc_thread);

}



/* Forward declarations */



void bch_writeback_queue(struct cached_dev *);
@@ -1193,7 +1198,6 @@ void bch_submit_bbio(struct bio *, struct cache_set *, struct bkey *, unsigned); 
uint8_t bch_inc_gen(struct cache *, struct bucket *);

void bch_rescale_priorities(struct cache_set *, int);

bool bch_bucket_add_unused(struct cache *, struct bucket *);

void bch_allocator_thread(struct closure *);



long bch_bucket_alloc(struct cache *, unsigned, struct closure *);

void bch_bucket_free(struct cache_set *, struct bkey *);
@@ -1244,6 +1248,7 @@ int bch_btree_cache_alloc(struct cache_set *); 
void bch_cached_dev_writeback_init(struct cached_dev *);

void bch_moving_init_cache_set(struct cache_set *);



int bch_cache_allocator_start(struct cache *ca);

void bch_cache_allocator_exit(struct cache *ca);

int bch_cache_allocator_init(struct cache *ca);

drivers/md/bcache/btree.c

+3 −3
Original line number Diff line number Diff line
@@ -273,7 +273,7 @@ static void btree_complete_write(struct btree *b, struct btree_write *w) 
{

	if (w->prio_blocked &&

	    !atomic_sub_return(w->prio_blocked, &b->c->prio_blocked))

		wake_up(&b->c->alloc_wait);

		wake_up_allocators(b->c);



	if (w->journal) {

		atomic_dec_bug(w->journal);
@@ -984,7 +984,7 @@ static void btree_node_free(struct btree *b, struct btree_op *op) 


	if (b->prio_blocked &&

	    !atomic_sub_return(b->prio_blocked, &b->c->prio_blocked))

		wake_up(&b->c->alloc_wait);

		wake_up_allocators(b->c);



	b->prio_blocked = 0;
@@ -1547,7 +1547,7 @@ static void bch_btree_gc(struct closure *cl) 
	blktrace_msg_all(c, "Finished gc");



	trace_bcache_gc_end(c->sb.set_uuid);

	wake_up(&c->alloc_wait);

	wake_up_allocators(c);



	continue_at(cl, bch_moving_gc, bch_gc_wq);

}

drivers/md/bcache/super.c

+7 −12
Original line number Diff line number Diff line
@@ -1282,7 +1282,7 @@ static void cache_set_flush(struct closure *cl) 


	/* Shut down allocator threads */

	set_bit(CACHE_SET_STOPPING_2, &c->flags);

	wake_up(&c->alloc_wait);

	wake_up_allocators(c);



	bch_cache_accounting_destroy(&c->accounting);
@@ -1373,7 +1373,6 @@ struct cache_set *bch_cache_set_alloc(struct cache_sb *sb) 
		c->btree_pages = max_t(int, c->btree_pages / 4,

				       BTREE_MAX_PAGES);



	init_waitqueue_head(&c->alloc_wait);

	mutex_init(&c->bucket_lock);

	mutex_init(&c->fill_lock);

	mutex_init(&c->sort_lock);
@@ -1496,9 +1495,10 @@ static void run_cache_set(struct cache_set *c) 
		 */

		bch_journal_next(&c->journal);



		err = "error starting allocator thread";

		for_each_cache(ca, c, i)

			closure_call(&ca->alloc, bch_allocator_thread,

				     system_wq, &c->cl);

			if (bch_cache_allocator_start(ca))

				goto err;



		/*

		 * First place it's safe to allocate: btree_check() and
@@ -1531,17 +1531,16 @@ static void run_cache_set(struct cache_set *c) 


		bch_btree_gc_finish(c);



		err = "error starting allocator thread";

		for_each_cache(ca, c, i)

			closure_call(&ca->alloc, bch_allocator_thread,

				     ca->alloc_workqueue, &c->cl);

			if (bch_cache_allocator_start(ca))

				goto err;



		mutex_lock(&c->bucket_lock);

		for_each_cache(ca, c, i)

			bch_prio_write(ca);

		mutex_unlock(&c->bucket_lock);



		wake_up(&c->alloc_wait);



		err = "cannot allocate new UUID bucket";

		if (__uuid_write(c))

			goto err_unlock_gc;
@@ -1673,9 +1672,6 @@ void bch_cache_release(struct kobject *kobj) 


	bio_split_pool_free(&ca->bio_split_hook);



	if (ca->alloc_workqueue)

		destroy_workqueue(ca->alloc_workqueue);



	free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca)));

	kfree(ca->prio_buckets);

	vfree(ca->buckets);
@@ -1723,7 +1719,6 @@ static int cache_alloc(struct cache_sb *sb, struct cache *ca) 
	    !(ca->prio_buckets	= kzalloc(sizeof(uint64_t) * prio_buckets(ca) *

					  2, GFP_KERNEL)) ||

	    !(ca->disk_buckets	= alloc_bucket_pages(GFP_KERNEL, ca)) ||

	    !(ca->alloc_workqueue = alloc_workqueue("bch_allocator", 0, 1)) ||

	    bio_split_pool_init(&ca->bio_split_hook))

		return -ENOMEM;