Commit c6dd6ea5 authored by Qu Wenruo's avatar Qu Wenruo Committed by Chris Mason

btrfs: async_thread: Fix workqueue 'max_active' value when initializing

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: default avatarAlex Lyakas <alex.btrfs@zadarastorage.com>
Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 943c6e99
...@@ -42,8 +42,14 @@ struct __btrfs_workqueue { ...@@ -42,8 +42,14 @@ struct __btrfs_workqueue {
/* Thresholding related variants */ /* Thresholding related variants */
atomic_t pending; 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; int thresh;
unsigned int count; unsigned int count;
spinlock_t thres_lock; spinlock_t thres_lock;
...@@ -88,7 +94,7 @@ BTRFS_WORK_HELPER(scrubnc_helper); ...@@ -88,7 +94,7 @@ BTRFS_WORK_HELPER(scrubnc_helper);
BTRFS_WORK_HELPER(scrubparity_helper); BTRFS_WORK_HELPER(scrubparity_helper);
static struct __btrfs_workqueue * 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) int thresh)
{ {
struct __btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS); 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, ...@@ -96,26 +102,31 @@ __btrfs_alloc_workqueue(const char *name, unsigned int flags, int max_active,
if (!ret) if (!ret)
return NULL; return NULL;
ret->max_active = max_active; ret->limit_active = limit_active;
atomic_set(&ret->pending, 0); atomic_set(&ret->pending, 0);
if (thresh == 0) if (thresh == 0)
thresh = DFT_THRESHOLD; thresh = DFT_THRESHOLD;
/* For low threshold, disabling threshold is a better choice */ /* For low threshold, disabling threshold is a better choice */
if (thresh < DFT_THRESHOLD) { if (thresh < DFT_THRESHOLD) {
ret->current_max = max_active; ret->current_active = limit_active;
ret->thresh = NO_THRESHOLD; ret->thresh = NO_THRESHOLD;
} else { } 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; ret->thresh = thresh;
} }
if (flags & WQ_HIGHPRI) if (flags & WQ_HIGHPRI)
ret->normal_wq = alloc_workqueue("%s-%s-high", flags, ret->normal_wq = alloc_workqueue("%s-%s-high", flags,
ret->max_active, ret->current_active, "btrfs",
"btrfs", name); name);
else else
ret->normal_wq = alloc_workqueue("%s-%s", flags, ret->normal_wq = alloc_workqueue("%s-%s", flags,
ret->max_active, "btrfs", ret->current_active, "btrfs",
name); name);
if (!ret->normal_wq) { if (!ret->normal_wq) {
kfree(ret); kfree(ret);
...@@ -134,7 +145,7 @@ __btrfs_destroy_workqueue(struct __btrfs_workqueue *wq); ...@@ -134,7 +145,7 @@ __btrfs_destroy_workqueue(struct __btrfs_workqueue *wq);
struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name, struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name,
unsigned int flags, unsigned int flags,
int max_active, int limit_active,
int thresh) int thresh)
{ {
struct btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS); struct btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS);
...@@ -143,14 +154,14 @@ struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name, ...@@ -143,14 +154,14 @@ struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name,
return NULL; return NULL;
ret->normal = __btrfs_alloc_workqueue(name, flags & ~WQ_HIGHPRI, ret->normal = __btrfs_alloc_workqueue(name, flags & ~WQ_HIGHPRI,
max_active, thresh); limit_active, thresh);
if (!ret->normal) { if (!ret->normal) {
kfree(ret); kfree(ret);
return NULL; return NULL;
} }
if (flags & WQ_HIGHPRI) { if (flags & WQ_HIGHPRI) {
ret->high = __btrfs_alloc_workqueue(name, flags, max_active, ret->high = __btrfs_alloc_workqueue(name, flags, limit_active,
thresh); thresh);
if (!ret->high) { if (!ret->high) {
__btrfs_destroy_workqueue(ret->normal); __btrfs_destroy_workqueue(ret->normal);
...@@ -180,7 +191,7 @@ static inline void thresh_queue_hook(struct __btrfs_workqueue *wq) ...@@ -180,7 +191,7 @@ static inline void thresh_queue_hook(struct __btrfs_workqueue *wq)
*/ */
static inline void thresh_exec_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; long pending;
int need_change = 0; int need_change = 0;
...@@ -197,7 +208,7 @@ static inline void thresh_exec_hook(struct __btrfs_workqueue *wq) ...@@ -197,7 +208,7 @@ static inline void thresh_exec_hook(struct __btrfs_workqueue *wq)
wq->count %= (wq->thresh / 4); wq->count %= (wq->thresh / 4);
if (!wq->count) if (!wq->count)
goto out; 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 * 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) ...@@ -205,19 +216,19 @@ static inline void thresh_exec_hook(struct __btrfs_workqueue *wq)
*/ */
pending = atomic_read(&wq->pending); pending = atomic_read(&wq->pending);
if (pending > wq->thresh) if (pending > wq->thresh)
new_max_active++; new_current_active++;
if (pending < wq->thresh / 2) if (pending < wq->thresh / 2)
new_max_active--; new_current_active--;
new_max_active = clamp_val(new_max_active, 1, wq->max_active); new_current_active = clamp_val(new_current_active, 1, wq->limit_active);
if (new_max_active != wq->current_max) { if (new_current_active != wq->current_active) {
need_change = 1; need_change = 1;
wq->current_max = new_max_active; wq->current_active = new_current_active;
} }
out: out:
spin_unlock(&wq->thres_lock); spin_unlock(&wq->thres_lock);
if (need_change) { 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) ...@@ -351,13 +362,13 @@ void btrfs_destroy_workqueue(struct btrfs_workqueue *wq)
kfree(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) if (!wq)
return; return;
wq->normal->max_active = max; wq->normal->limit_active = limit_active;
if (wq->high) if (wq->high)
wq->high->max_active = max; wq->high->limit_active = limit_active;
} }
void btrfs_set_work_high_priority(struct btrfs_work *work) void btrfs_set_work_high_priority(struct btrfs_work *work)
......
...@@ -69,7 +69,7 @@ BTRFS_WORK_HELPER_PROTO(scrubparity_helper); ...@@ -69,7 +69,7 @@ BTRFS_WORK_HELPER_PROTO(scrubparity_helper);
struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name, struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name,
unsigned int flags, unsigned int flags,
int max_active, int limit_active,
int thresh); int thresh);
void btrfs_init_work(struct btrfs_work *work, btrfs_work_func_t helper, void btrfs_init_work(struct btrfs_work *work, btrfs_work_func_t helper,
btrfs_func_t func, btrfs_func_t func,
......
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