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authorTejun Heo <tj@kernel.org>2010-07-20 22:09:01 +0200
committerTejun Heo <tj@kernel.org>2010-07-22 22:58:34 +0200
commit8b8edefa2fffbff97f9eec8b70e78ae23abad1a0 (patch)
tree7f0efac8adb9c9ed7be8af63e51510954f1c51dc /fs/fscache/object.c
parente120153ddf8620fd0a194d301e9c5a8b28483bb5 (diff)
fscache: convert object to use workqueue instead of slow-work
Make fscache object state transition callbacks use workqueue instead of slow-work. New dedicated unbound CPU workqueue fscache_object_wq is created. get/put callbacks are renamed and modified to take @object and called directly from the enqueue wrapper and the work function. While at it, make all open coded instances of get/put to use fscache_get/put_object(). * Unbound workqueue is used. * work_busy() output is printed instead of slow-work flags in object debugging outputs. They mean basically the same thing bit-for-bit. * sysctl fscache.object_max_active added to control concurrency. The default value is nr_cpus clamped between 4 and WQ_UNBOUND_MAX_ACTIVE. * slow_work_sleep_till_thread_needed() is replaced with fscache private implementation fscache_object_sleep_till_congested() which waits on fscache_object_wq congestion. * debugfs support is dropped for now. Tracing API based debug facility is planned to be added. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'fs/fscache/object.c')
-rw-r--r--fs/fscache/object.c106
1 files changed, 53 insertions, 53 deletions
diff --git a/fs/fscache/object.c b/fs/fscache/object.c
index 0b589a9b4ff..b6b897c550a 100644
--- a/fs/fscache/object.c
+++ b/fs/fscache/object.c
@@ -14,7 +14,6 @@
#define FSCACHE_DEBUG_LEVEL COOKIE
#include <linux/module.h>
-#include <linux/seq_file.h>
#include "internal.h"
const char *fscache_object_states[FSCACHE_OBJECT__NSTATES] = {
@@ -50,12 +49,8 @@ const char fscache_object_states_short[FSCACHE_OBJECT__NSTATES][5] = {
[FSCACHE_OBJECT_DEAD] = "DEAD",
};
-static void fscache_object_slow_work_put_ref(struct slow_work *);
-static int fscache_object_slow_work_get_ref(struct slow_work *);
-static void fscache_object_slow_work_execute(struct slow_work *);
-#ifdef CONFIG_SLOW_WORK_DEBUG
-static void fscache_object_slow_work_desc(struct slow_work *, struct seq_file *);
-#endif
+static int fscache_get_object(struct fscache_object *);
+static void fscache_put_object(struct fscache_object *);
static void fscache_initialise_object(struct fscache_object *);
static void fscache_lookup_object(struct fscache_object *);
static void fscache_object_available(struct fscache_object *);
@@ -64,17 +59,6 @@ static void fscache_withdraw_object(struct fscache_object *);
static void fscache_enqueue_dependents(struct fscache_object *);
static void fscache_dequeue_object(struct fscache_object *);
-const struct slow_work_ops fscache_object_slow_work_ops = {
- .owner = THIS_MODULE,
- .get_ref = fscache_object_slow_work_get_ref,
- .put_ref = fscache_object_slow_work_put_ref,
- .execute = fscache_object_slow_work_execute,
-#ifdef CONFIG_SLOW_WORK_DEBUG
- .desc = fscache_object_slow_work_desc,
-#endif
-};
-EXPORT_SYMBOL(fscache_object_slow_work_ops);
-
/*
* we need to notify the parent when an op completes that we had outstanding
* upon it
@@ -345,7 +329,7 @@ unsupported_event:
/*
* execute an object
*/
-static void fscache_object_slow_work_execute(struct slow_work *work)
+void fscache_object_work_func(struct work_struct *work)
{
struct fscache_object *object =
container_of(work, struct fscache_object, work);
@@ -359,23 +343,9 @@ static void fscache_object_slow_work_execute(struct slow_work *work)
if (object->events & object->event_mask)
fscache_enqueue_object(object);
clear_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
+ fscache_put_object(object);
}
-
-/*
- * describe an object for slow-work debugging
- */
-#ifdef CONFIG_SLOW_WORK_DEBUG
-static void fscache_object_slow_work_desc(struct slow_work *work,
- struct seq_file *m)
-{
- struct fscache_object *object =
- container_of(work, struct fscache_object, work);
-
- seq_printf(m, "FSC: OBJ%x: %s",
- object->debug_id,
- fscache_object_states_short[object->state]);
-}
-#endif
+EXPORT_SYMBOL(fscache_object_work_func);
/*
* initialise an object
@@ -393,7 +363,6 @@ static void fscache_initialise_object(struct fscache_object *object)
_enter("");
ASSERT(object->cookie != NULL);
ASSERT(object->cookie->parent != NULL);
- ASSERT(list_empty(&object->work.link));
if (object->events & ((1 << FSCACHE_OBJECT_EV_ERROR) |
(1 << FSCACHE_OBJECT_EV_RELEASE) |
@@ -671,10 +640,8 @@ static void fscache_drop_object(struct fscache_object *object)
object->parent = NULL;
}
- /* this just shifts the object release to the slow work processor */
- fscache_stat(&fscache_n_cop_put_object);
- object->cache->ops->put_object(object);
- fscache_stat_d(&fscache_n_cop_put_object);
+ /* this just shifts the object release to the work processor */
+ fscache_put_object(object);
_leave("");
}
@@ -758,12 +725,10 @@ void fscache_withdrawing_object(struct fscache_cache *cache,
}
/*
- * allow the slow work item processor to get a ref on an object
+ * get a ref on an object
*/
-static int fscache_object_slow_work_get_ref(struct slow_work *work)
+static int fscache_get_object(struct fscache_object *object)
{
- struct fscache_object *object =
- container_of(work, struct fscache_object, work);
int ret;
fscache_stat(&fscache_n_cop_grab_object);
@@ -773,13 +738,10 @@ static int fscache_object_slow_work_get_ref(struct slow_work *work)
}
/*
- * allow the slow work item processor to discard a ref on a work item
+ * discard a ref on a work item
*/
-static void fscache_object_slow_work_put_ref(struct slow_work *work)
+static void fscache_put_object(struct fscache_object *object)
{
- struct fscache_object *object =
- container_of(work, struct fscache_object, work);
-
fscache_stat(&fscache_n_cop_put_object);
object->cache->ops->put_object(object);
fscache_stat_d(&fscache_n_cop_put_object);
@@ -792,8 +754,48 @@ void fscache_enqueue_object(struct fscache_object *object)
{
_enter("{OBJ%x}", object->debug_id);
- slow_work_enqueue(&object->work);
+ if (fscache_get_object(object) >= 0) {
+ wait_queue_head_t *cong_wq =
+ &get_cpu_var(fscache_object_cong_wait);
+
+ if (queue_work(fscache_object_wq, &object->work)) {
+ if (fscache_object_congested())
+ wake_up(cong_wq);
+ } else
+ fscache_put_object(object);
+
+ put_cpu_var(fscache_object_cong_wait);
+ }
+}
+
+/**
+ * fscache_object_sleep_till_congested - Sleep until object wq is congested
+ * @timoutp: Scheduler sleep timeout
+ *
+ * Allow an object handler to sleep until the object workqueue is congested.
+ *
+ * The caller must set up a wake up event before calling this and must have set
+ * the appropriate sleep mode (such as TASK_UNINTERRUPTIBLE) and tested its own
+ * condition before calling this function as no test is made here.
+ *
+ * %true is returned if the object wq is congested, %false otherwise.
+ */
+bool fscache_object_sleep_till_congested(signed long *timeoutp)
+{
+ wait_queue_head_t *cong_wq = &__get_cpu_var(fscache_object_cong_wait);
+ DEFINE_WAIT(wait);
+
+ if (fscache_object_congested())
+ return true;
+
+ add_wait_queue_exclusive(cong_wq, &wait);
+ if (!fscache_object_congested())
+ *timeoutp = schedule_timeout(*timeoutp);
+ finish_wait(cong_wq, &wait);
+
+ return fscache_object_congested();
}
+EXPORT_SYMBOL_GPL(fscache_object_sleep_till_congested);
/*
* enqueue the dependents of an object for metadata-type processing
@@ -819,9 +821,7 @@ static void fscache_enqueue_dependents(struct fscache_object *object)
/* sort onto appropriate lists */
fscache_enqueue_object(dep);
- fscache_stat(&fscache_n_cop_put_object);
- dep->cache->ops->put_object(dep);
- fscache_stat_d(&fscache_n_cop_put_object);
+ fscache_put_object(dep);
if (!list_empty(&object->dependents))
cond_resched_lock(&object->lock);