Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
drm/gem: Add ww_acquire_ctx support to drm_gem_lru_scan()
If the callback is going to have to attempt to grab more locks, it is
useful to have an ww_acquire_ctx to avoid locking order problems.
Why not use the drm_exec helper instead? Mainly because (a) where
ww_acquire_init() is called is awkward, and (b) we don't really
need to retry after backoff, we can just move on to the next object.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>
Tested-by: Antonino Maniscalco <antomani103@gmail.com>
Reviewed-by: Antonino Maniscalco <antomani103@gmail.com>
Patchwork: https://patchwork.freedesktop.org/patch/661463/
+30
-18
+11
-3
drivers/gpu/drm/drm_gem.c
+11
-3
drivers/gpu/drm/drm_gem.c
···
1429
1429
* @nr_to_scan: The number of pages to try to reclaim
1430
1430
* @remaining: The number of pages left to reclaim, should be initialized by caller
1431
1431
* @shrink: Callback to try to shrink/reclaim the object.
1432
+
* @ticket: Optional ww_acquire_ctx context to use for locking
1432
1433
*/
1433
1434
unsigned long
1434
1435
drm_gem_lru_scan(struct drm_gem_lru *lru,
1435
1436
unsigned int nr_to_scan,
1436
1437
unsigned long *remaining,
1437
-
bool (*shrink)(struct drm_gem_object *obj))
1438
+
bool (*shrink)(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket),
1439
+
struct ww_acquire_ctx *ticket)
1438
1440
{
1439
1441
struct drm_gem_lru still_in_lru;
1440
1442
struct drm_gem_object *obj;
···
1469
1467
*/
1470
1468
mutex_unlock(lru->lock);
1471
1469
1470
+
if (ticket)
1471
+
ww_acquire_init(ticket, &reservation_ww_class);
1472
+
1472
1473
/*
1473
1474
* Note that this still needs to be trylock, since we can
1474
1475
* hit shrinker in response to trying to get backing pages
1475
1476
* for this obj (ie. while it's lock is already held)
1476
1477
*/
1477
-
if (!dma_resv_trylock(obj->resv)) {
1478
+
if (!ww_mutex_trylock(&obj->resv->lock, ticket)) {
1478
1479
*remaining += obj->size >> PAGE_SHIFT;
1479
1480
goto tail;
1480
1481
}
1481
1482
1482
-
if (shrink(obj)) {
1483
+
if (shrink(obj, ticket)) {
1483
1484
freed += obj->size >> PAGE_SHIFT;
1484
1485
1485
1486
/*
···
1495
1490
}
1496
1491
1497
1492
dma_resv_unlock(obj->resv);
1493
+
1494
+
if (ticket)
1495
+
ww_acquire_fini(ticket);
1498
1496
1499
1497
tail:
1500
1498
drm_gem_object_put(obj);
+13
-11
drivers/gpu/drm/msm/msm_gem_shrinker.c
+13
-11
drivers/gpu/drm/msm/msm_gem_shrinker.c
···
44
44
}
45
45
46
46
static bool
47
-
purge(struct drm_gem_object *obj)
47
+
purge(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
48
48
{
49
49
if (!is_purgeable(to_msm_bo(obj)))
50
50
return false;
···
58
58
}
59
59
60
60
static bool
61
-
evict(struct drm_gem_object *obj)
61
+
evict(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
62
62
{
63
63
if (is_unevictable(to_msm_bo(obj)))
64
64
return false;
···
79
79
}
80
80
81
81
static bool
82
-
active_purge(struct drm_gem_object *obj)
82
+
active_purge(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
83
83
{
84
84
if (!wait_for_idle(obj))
85
85
return false;
86
86
87
-
return purge(obj);
87
+
return purge(obj, ticket);
88
88
}
89
89
90
90
static bool
91
-
active_evict(struct drm_gem_object *obj)
91
+
active_evict(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
92
92
{
93
93
if (!wait_for_idle(obj))
94
94
return false;
95
95
96
-
return evict(obj);
96
+
return evict(obj, ticket);
97
97
}
98
98
99
99
static unsigned long
···
102
102
struct msm_drm_private *priv = shrinker->private_data;
103
103
struct {
104
104
struct drm_gem_lru *lru;
105
-
bool (*shrink)(struct drm_gem_object *obj);
105
+
bool (*shrink)(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket);
106
106
bool cond;
107
107
unsigned long freed;
108
108
unsigned long remaining;
···
122
122
continue;
123
123
stages[i].freed =
124
124
drm_gem_lru_scan(stages[i].lru, nr,
125
-
&stages[i].remaining,
126
-
stages[i].shrink);
125
+
&stages[i].remaining,
126
+
stages[i].shrink,
127
+
NULL);
127
128
nr -= stages[i].freed;
128
129
freed += stages[i].freed;
129
130
remaining += stages[i].remaining;
···
165
164
static const int vmap_shrink_limit = 15;
166
165
167
166
static bool
168
-
vmap_shrink(struct drm_gem_object *obj)
167
+
vmap_shrink(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
169
168
{
170
169
if (!is_vunmapable(to_msm_bo(obj)))
171
170
return false;
···
193
192
unmapped += drm_gem_lru_scan(lrus[idx],
194
193
vmap_shrink_limit - unmapped,
195
194
&remaining,
196
-
vmap_shrink);
195
+
vmap_shrink,
196
+
NULL);
197
197
}
198
198
199
199
*(unsigned long *)ptr += unmapped;
+6
-4
include/drm/drm_gem.h
+6
-4
include/drm/drm_gem.h
···
560
560
void drm_gem_lru_remove(struct drm_gem_object *obj);
561
561
void drm_gem_lru_move_tail_locked(struct drm_gem_lru *lru, struct drm_gem_object *obj);
562
562
void drm_gem_lru_move_tail(struct drm_gem_lru *lru, struct drm_gem_object *obj);
563
-
unsigned long drm_gem_lru_scan(struct drm_gem_lru *lru,
564
-
unsigned int nr_to_scan,
565
-
unsigned long *remaining,
566
-
bool (*shrink)(struct drm_gem_object *obj));
563
+
unsigned long
564
+
drm_gem_lru_scan(struct drm_gem_lru *lru,
565
+
unsigned int nr_to_scan,
566
+
unsigned long *remaining,
567
+
bool (*shrink)(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket),
568
+
struct ww_acquire_ctx *ticket);
567
569
568
570
int drm_gem_evict_locked(struct drm_gem_object *obj);
569
571