[PATCH 01/25] drm/amdkfd: Reliably prevent reclaim-FS while holding DQM lock
Felix Kuehling
Felix.Kuehling at amd.com
Thu Jul 12 02:32:44 UTC 2018
This is needed to prevent deadlocks when MMU notifiers run in
reclaim-FS context and take the DQM lock for userptr evictions.
Previously this was done by making all memory allocations under
DQM locks GFP_NOIO. This is error prone. Using
memalloc_nofs_save/restore will reliably affect all memory
allocations anywhere in the kernel while the DQM lock is held.
Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
---
.../gpu/drm/amd/amdkfd/kfd_device_queue_manager.c | 85 +++++++++++-----------
.../gpu/drm/amd/amdkfd/kfd_device_queue_manager.h | 20 ++++-
2 files changed, 62 insertions(+), 43 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
index 668ad07..f2f81d2 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
@@ -240,7 +240,7 @@ static int create_queue_nocpsch(struct device_queue_manager *dqm,
print_queue(q);
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
if (dqm->total_queue_count >= max_num_of_queues_per_device) {
pr_warn("Can't create new usermode queue because %d queues were already created\n",
@@ -297,7 +297,7 @@ static int create_queue_nocpsch(struct device_queue_manager *dqm,
dqm->total_queue_count);
out_unlock:
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return retval;
}
@@ -457,9 +457,9 @@ static int destroy_queue_nocpsch(struct device_queue_manager *dqm,
{
int retval;
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
retval = destroy_queue_nocpsch_locked(dqm, qpd, q);
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return retval;
}
@@ -471,7 +471,7 @@ static int update_queue(struct device_queue_manager *dqm, struct queue *q)
struct kfd_process_device *pdd;
bool prev_active = false;
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
pdd = kfd_get_process_device_data(q->device, q->process);
if (!pdd) {
retval = -ENODEV;
@@ -537,7 +537,7 @@ static int update_queue(struct device_queue_manager *dqm, struct queue *q)
&q->properties, q->process->mm);
out_unlock:
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return retval;
}
@@ -570,7 +570,7 @@ static int evict_process_queues_nocpsch(struct device_queue_manager *dqm,
struct kfd_process_device *pdd;
int retval = 0;
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
if (qpd->evicted++ > 0) /* already evicted, do nothing */
goto out;
@@ -600,7 +600,7 @@ static int evict_process_queues_nocpsch(struct device_queue_manager *dqm,
}
out:
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return retval;
}
@@ -611,7 +611,7 @@ static int evict_process_queues_cpsch(struct device_queue_manager *dqm,
struct kfd_process_device *pdd;
int retval = 0;
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
if (qpd->evicted++ > 0) /* already evicted, do nothing */
goto out;
@@ -633,7 +633,7 @@ static int evict_process_queues_cpsch(struct device_queue_manager *dqm,
KFD_UNMAP_QUEUES_FILTER_DYNAMIC_QUEUES, 0);
out:
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return retval;
}
@@ -650,7 +650,7 @@ static int restore_process_queues_nocpsch(struct device_queue_manager *dqm,
/* Retrieve PD base */
pd_base = dqm->dev->kfd2kgd->get_process_page_dir(pdd->vm);
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
if (WARN_ON_ONCE(!qpd->evicted)) /* already restored, do nothing */
goto out;
if (qpd->evicted > 1) { /* ref count still > 0, decrement & quit */
@@ -695,7 +695,7 @@ static int restore_process_queues_nocpsch(struct device_queue_manager *dqm,
}
qpd->evicted = 0;
out:
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return retval;
}
@@ -711,7 +711,7 @@ static int restore_process_queues_cpsch(struct device_queue_manager *dqm,
/* Retrieve PD base */
pd_base = dqm->dev->kfd2kgd->get_process_page_dir(pdd->vm);
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
if (WARN_ON_ONCE(!qpd->evicted)) /* already restored, do nothing */
goto out;
if (qpd->evicted > 1) { /* ref count still > 0, decrement & quit */
@@ -739,7 +739,7 @@ static int restore_process_queues_cpsch(struct device_queue_manager *dqm,
if (!retval)
qpd->evicted = 0;
out:
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return retval;
}
@@ -761,7 +761,7 @@ static int register_process(struct device_queue_manager *dqm,
/* Retrieve PD base */
pd_base = dqm->dev->kfd2kgd->get_process_page_dir(pdd->vm);
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
list_add(&n->list, &dqm->queues);
/* Update PD Base in QPD */
@@ -771,7 +771,7 @@ static int register_process(struct device_queue_manager *dqm,
dqm->processes_count++;
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return retval;
}
@@ -786,7 +786,7 @@ static int unregister_process(struct device_queue_manager *dqm,
list_empty(&qpd->queues_list) ? "empty" : "not empty");
retval = 0;
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
list_for_each_entry_safe(cur, next, &dqm->queues, list) {
if (qpd == cur->qpd) {
@@ -799,7 +799,7 @@ static int unregister_process(struct device_queue_manager *dqm,
/* qpd not found in dqm list */
retval = 1;
out:
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return retval;
}
@@ -838,7 +838,7 @@ static int initialize_nocpsch(struct device_queue_manager *dqm)
if (!dqm->allocated_queues)
return -ENOMEM;
- mutex_init(&dqm->lock);
+ mutex_init(&dqm->lock_hidden);
INIT_LIST_HEAD(&dqm->queues);
dqm->queue_count = dqm->next_pipe_to_allocate = 0;
dqm->sdma_queue_count = 0;
@@ -867,7 +867,7 @@ static void uninitialize(struct device_queue_manager *dqm)
kfree(dqm->allocated_queues);
for (i = 0 ; i < KFD_MQD_TYPE_MAX ; i++)
kfree(dqm->mqds[i]);
- mutex_destroy(&dqm->lock);
+ mutex_destroy(&dqm->lock_hidden);
kfd_gtt_sa_free(dqm->dev, dqm->pipeline_mem);
}
@@ -1003,7 +1003,7 @@ static int initialize_cpsch(struct device_queue_manager *dqm)
{
pr_debug("num of pipes: %d\n", get_pipes_per_mec(dqm));
- mutex_init(&dqm->lock);
+ mutex_init(&dqm->lock_hidden);
INIT_LIST_HEAD(&dqm->queues);
dqm->queue_count = dqm->processes_count = 0;
dqm->sdma_queue_count = 0;
@@ -1041,9 +1041,9 @@ static int start_cpsch(struct device_queue_manager *dqm)
init_interrupts(dqm);
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
execute_queues_cpsch(dqm, KFD_UNMAP_QUEUES_FILTER_DYNAMIC_QUEUES, 0);
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return 0;
fail_allocate_vidmem:
@@ -1055,9 +1055,9 @@ static int start_cpsch(struct device_queue_manager *dqm)
static int stop_cpsch(struct device_queue_manager *dqm)
{
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
unmap_queues_cpsch(dqm, KFD_UNMAP_QUEUES_FILTER_ALL_QUEUES, 0);
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
kfd_gtt_sa_free(dqm->dev, dqm->fence_mem);
pm_uninit(&dqm->packets);
@@ -1069,11 +1069,11 @@ static int create_kernel_queue_cpsch(struct device_queue_manager *dqm,
struct kernel_queue *kq,
struct qcm_process_device *qpd)
{
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
if (dqm->total_queue_count >= max_num_of_queues_per_device) {
pr_warn("Can't create new kernel queue because %d queues were already created\n",
dqm->total_queue_count);
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return -EPERM;
}
@@ -1089,7 +1089,7 @@ static int create_kernel_queue_cpsch(struct device_queue_manager *dqm,
dqm->queue_count++;
qpd->is_debug = true;
execute_queues_cpsch(dqm, KFD_UNMAP_QUEUES_FILTER_DYNAMIC_QUEUES, 0);
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return 0;
}
@@ -1098,7 +1098,7 @@ static void destroy_kernel_queue_cpsch(struct device_queue_manager *dqm,
struct kernel_queue *kq,
struct qcm_process_device *qpd)
{
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
list_del(&kq->list);
dqm->queue_count--;
qpd->is_debug = false;
@@ -1110,7 +1110,7 @@ static void destroy_kernel_queue_cpsch(struct device_queue_manager *dqm,
dqm->total_queue_count--;
pr_debug("Total of %d queues are accountable so far\n",
dqm->total_queue_count);
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
}
static int create_queue_cpsch(struct device_queue_manager *dqm, struct queue *q,
@@ -1121,7 +1121,7 @@ static int create_queue_cpsch(struct device_queue_manager *dqm, struct queue *q,
retval = 0;
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
if (dqm->total_queue_count >= max_num_of_queues_per_device) {
pr_warn("Can't create new usermode queue because %d queues were already created\n",
@@ -1188,7 +1188,7 @@ static int create_queue_cpsch(struct device_queue_manager *dqm, struct queue *q,
pr_debug("Total of %d queues are accountable so far\n",
dqm->total_queue_count);
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return retval;
out_deallocate_doorbell:
@@ -1197,7 +1197,8 @@ static int create_queue_cpsch(struct device_queue_manager *dqm, struct queue *q,
if (q->properties.type == KFD_QUEUE_TYPE_SDMA)
deallocate_sdma_queue(dqm, q->sdma_id);
out_unlock:
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
+
return retval;
}
@@ -1314,7 +1315,7 @@ static int destroy_queue_cpsch(struct device_queue_manager *dqm,
retval = 0;
/* remove queue from list to prevent rescheduling after preemption */
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
if (qpd->is_debug) {
/*
@@ -1360,14 +1361,14 @@ static int destroy_queue_cpsch(struct device_queue_manager *dqm,
pr_debug("Total of %d queues are accountable so far\n",
dqm->total_queue_count);
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return retval;
failed:
failed_try_destroy_debugged_queue:
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return retval;
}
@@ -1391,7 +1392,7 @@ static bool set_cache_memory_policy(struct device_queue_manager *dqm,
if (!dqm->asic_ops.set_cache_memory_policy)
return retval;
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
if (alternate_aperture_size == 0) {
/* base > limit disables APE1 */
@@ -1437,7 +1438,7 @@ static bool set_cache_memory_policy(struct device_queue_manager *dqm,
qpd->sh_mem_ape1_limit);
out:
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return retval;
}
@@ -1468,7 +1469,7 @@ static int process_termination_nocpsch(struct device_queue_manager *dqm,
struct device_process_node *cur, *next_dpn;
int retval = 0;
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
/* Clear all user mode queues */
list_for_each_entry_safe(q, next, &qpd->queues_list, list) {
@@ -1489,7 +1490,7 @@ static int process_termination_nocpsch(struct device_queue_manager *dqm,
}
}
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return retval;
}
@@ -1507,7 +1508,7 @@ static int process_termination_cpsch(struct device_queue_manager *dqm,
retval = 0;
- mutex_lock(&dqm->lock);
+ dqm_lock(dqm);
/* Clean all kernel queues */
list_for_each_entry_safe(kq, kq_next, &qpd->priv_queue_list, list) {
@@ -1562,7 +1563,7 @@ static int process_termination_cpsch(struct device_queue_manager *dqm,
}
out:
- mutex_unlock(&dqm->lock);
+ dqm_unlock(dqm);
return retval;
}
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
index 59a6b19..0a23dda 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
@@ -26,6 +26,8 @@
#include <linux/rwsem.h>
#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/sched/mm.h>
#include "kfd_priv.h"
#include "kfd_mqd_manager.h"
@@ -173,8 +175,9 @@ struct device_queue_manager {
struct mqd_manager *mqds[KFD_MQD_TYPE_MAX];
struct packet_manager packets;
struct kfd_dev *dev;
- struct mutex lock;
+ struct mutex lock_hidden; /* use dqm_lock/unlock(dqm) */
struct list_head queues;
+ unsigned int saved_flags;
unsigned int processes_count;
unsigned int queue_count;
unsigned int sdma_queue_count;
@@ -219,4 +222,19 @@ get_sh_mem_bases_nybble_64(struct kfd_process_device *pdd)
return (pdd->lds_base >> 60) & 0x0E;
}
+/* The DQM lock can be taken in MMU notifiers. Make sure no reclaim-FS
+ * happens while holding this lock anywhere to prevent deadlocks when
+ * an MMU notifier runs in reclaim-FS context.
+ */
+static inline void dqm_lock(struct device_queue_manager *dqm)
+{
+ mutex_lock(&dqm->lock_hidden);
+ dqm->saved_flags = memalloc_nofs_save();
+}
+static inline void dqm_unlock(struct device_queue_manager *dqm)
+{
+ memalloc_nofs_restore(dqm->saved_flags);
+ mutex_unlock(&dqm->lock_hidden);
+}
+
#endif /* KFD_DEVICE_QUEUE_MANAGER_H_ */
--
2.7.4
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