@@ -42,8 +42,14 @@ struct __btrfs_workqueue {
/* Thresholding related variants */
atomic_t pending;
- int max_active;
- int current_max;
+
+ /* Up limit of concurrency workers */
+ int limit_active;
+
+ /* Current number of concurrency workers */
+ int current_active;
+
+ /* Threshold to change current_active */
int thresh;
unsigned int count;
spinlock_t thres_lock;
@@ -88,7 +94,7 @@ BTRFS_WORK_HELPER(scrubnc_helper);
BTRFS_WORK_HELPER(scrubparity_helper);
static struct __btrfs_workqueue *
-__btrfs_alloc_workqueue(const char *name, unsigned int flags, int max_active,
+__btrfs_alloc_workqueue(const char *name, unsigned int flags, int limit_active,
int thresh)
{
struct __btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS);
@@ -96,26 +102,31 @@ __btrfs_alloc_workqueue(const char *name, unsigned int flags, int max_active,
if (!ret)
return NULL;
- ret->max_active = max_active;
+ ret->limit_active = limit_active;
atomic_set(&ret->pending, 0);
if (thresh == 0)
thresh = DFT_THRESHOLD;
/* For low threshold, disabling threshold is a better choice */
if (thresh < DFT_THRESHOLD) {
- ret->current_max = max_active;
+ ret->current_active = limit_active;
ret->thresh = NO_THRESHOLD;
} else {
- ret->current_max = 1;
+ /*
+ * For threshold-able wq, let its concurrency grow on demand.
+ * Use minimal max_active at alloc time to reduce resource
+ * usage.
+ */
+ ret->current_active = 1;
ret->thresh = thresh;
}
if (flags & WQ_HIGHPRI)
ret->normal_wq = alloc_workqueue("%s-%s-high", flags,
- ret->max_active,
- "btrfs", name);
+ ret->current_active, "btrfs",
+ name);
else
ret->normal_wq = alloc_workqueue("%s-%s", flags,
- ret->max_active, "btrfs",
+ ret->current_active, "btrfs",
name);
if (!ret->normal_wq) {
kfree(ret);
@@ -134,7 +145,7 @@ __btrfs_destroy_workqueue(struct __btrfs_workqueue *wq);
struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name,
unsigned int flags,
- int max_active,
+ int limit_active,
int thresh)
{
struct btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS);
@@ -143,14 +154,14 @@ struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name,
return NULL;
ret->normal = __btrfs_alloc_workqueue(name, flags & ~WQ_HIGHPRI,
- max_active, thresh);
+ limit_active, thresh);
if (!ret->normal) {
kfree(ret);
return NULL;
}
if (flags & WQ_HIGHPRI) {
- ret->high = __btrfs_alloc_workqueue(name, flags, max_active,
+ ret->high = __btrfs_alloc_workqueue(name, flags, limit_active,
thresh);
if (!ret->high) {
__btrfs_destroy_workqueue(ret->normal);
@@ -180,7 +191,7 @@ static inline void thresh_queue_hook(struct __btrfs_workqueue *wq)
*/
static inline void thresh_exec_hook(struct __btrfs_workqueue *wq)
{
- int new_max_active;
+ int new_current_active;
long pending;
int need_change = 0;
@@ -197,7 +208,7 @@ static inline void thresh_exec_hook(struct __btrfs_workqueue *wq)
wq->count %= (wq->thresh / 4);
if (!wq->count)
goto out;
- new_max_active = wq->current_max;
+ new_current_active = wq->current_active;
/*
* pending may be changed later, but it's OK since we really
@@ -205,19 +216,19 @@ static inline void thresh_exec_hook(struct __btrfs_workqueue *wq)
*/
pending = atomic_read(&wq->pending);
if (pending > wq->thresh)
- new_max_active++;
+ new_current_active++;
if (pending < wq->thresh / 2)
- new_max_active--;
- new_max_active = clamp_val(new_max_active, 1, wq->max_active);
- if (new_max_active != wq->current_max) {
+ new_current_active--;
+ new_current_active = clamp_val(new_current_active, 1, wq->limit_active);
+ if (new_current_active != wq->current_active) {
need_change = 1;
- wq->current_max = new_max_active;
+ wq->current_active = new_current_active;
}
out:
spin_unlock(&wq->thres_lock);
if (need_change) {
- workqueue_set_max_active(wq->normal_wq, wq->current_max);
+ workqueue_set_max_active(wq->normal_wq, wq->current_active);
}
}
@@ -351,13 +362,13 @@ void btrfs_destroy_workqueue(struct btrfs_workqueue *wq)
kfree(wq);
}
-void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int max)
+void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int limit_active)
{
if (!wq)
return;
- wq->normal->max_active = max;
+ wq->normal->limit_active = limit_active;
if (wq->high)
- wq->high->max_active = max;
+ wq->high->limit_active = limit_active;
}
void btrfs_set_work_high_priority(struct btrfs_work *work)
@@ -69,7 +69,7 @@ BTRFS_WORK_HELPER_PROTO(scrubparity_helper);
struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name,
unsigned int flags,
- int max_active,
+ int limit_active,
int thresh);
void btrfs_init_work(struct btrfs_work *work, btrfs_work_func_t helper,
btrfs_func_t func,
At initializing time, for threshold-able workqueue, it's max_active of kernel workqueue should be 1 and grow if it hits threshold. But due to the bad naming, there is both 'max_active' for kernel workqueue and btrfs workqueue. So wrong value is given at workqueue initialization. This patch fixes it, and to avoid further misunderstanding, change the member name of btrfs_workqueue to 'current_active' and 'limit_active'. Also corresponding comment is added for readability. Reported-by: Alex Lyakas <alex.btrfs@zadarastorage.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> --- fs/btrfs/async-thread.c | 57 +++++++++++++++++++++++++++++-------------------- fs/btrfs/async-thread.h | 2 +- 2 files changed, 35 insertions(+), 24 deletions(-)