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bcache: Allocation kthread fixes

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The alloc kthread should've been using try_to_freeze() - and also there
was the potential for the alloc kthread to get woken up after it had
shut down, which would have been bad.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
This commit is contained in:
Kent Overstreet 2013-07-10 18:31:58 -07:00
parent 29ebf465b9
commit 79826c35eb
3 changed files with 15 additions and 18 deletions
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18
drivers/md/bcache/alloc.c
View File

@ -63,6 +63,7 @@
#include "bcache.h"
#include "btree.h"
#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/random.h>
#include <trace/events/bcache.h>
@ -363,11 +364,10 @@ do { \
break; \
\
mutex_unlock(&(ca)->set->bucket_lock); \
if (test_bit(CACHE_SET_STOPPING_2, &ca->set->flags)) { \
closure_put(&ca->set->cl); \
if (kthread_should_stop()) \
return 0; \
} \
\
try_to_freeze(); \
schedule(); \
mutex_lock(&(ca)->set->bucket_lock); \
} \
@ -547,14 +547,12 @@ int bch_bucket_alloc_set(struct cache_set *c, unsigned watermark,
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);
struct task_struct *k = kthread_run(bch_allocator_thread,
ca, "bcache_allocator");
if (IS_ERR(k))
return PTR_ERR(k);
ca->alloc_thread = k;
return 0;
}

4
drivers/md/bcache/bcache.h
View File

@ -664,13 +664,9 @@ struct gc_stat {
* CACHE_SET_STOPPING always gets set first when we're closing down a cache set;
* we'll continue to run normally for awhile with CACHE_SET_STOPPING set (i.e.
* flushing dirty data).
*
* CACHE_SET_STOPPING_2 gets set at the last phase, when it's time to shut down
* the allocation thread.
*/
#define CACHE_SET_UNREGISTERING 0
#define CACHE_SET_STOPPING 1
#define CACHE_SET_STOPPING_2 2
struct cache_set {
struct closure cl;

11
drivers/md/bcache/super.c
View File

@ -16,6 +16,7 @@
#include <linux/buffer_head.h>
#include <linux/debugfs.h>
#include <linux/genhd.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/reboot.h>
@ -1329,11 +1330,9 @@ static void cache_set_free(struct closure *cl)
static void cache_set_flush(struct closure *cl)
{
struct cache_set *c = container_of(cl, struct cache_set, caching);
struct cache *ca;
struct btree *b;
/* Shut down allocator threads */
set_bit(CACHE_SET_STOPPING_2, &c->flags);
wake_up_allocators(c);
unsigned i;
bch_cache_accounting_destroy(&c->accounting);
@ -1348,6 +1347,10 @@ static void cache_set_flush(struct closure *cl)
if (btree_node_dirty(b))
bch_btree_node_write(b, NULL);
for_each_cache(ca, c, i)
if (ca->alloc_thread)
kthread_stop(ca->alloc_thread);
closure_return(cl);
}