On 2025-10-17 04:42, Zhu Lingshan wrote:
This commit introduces a new id field for
struct kfd process, which helps identify
a kfd process among multiple contexts that
all belong to a single user space program.
The sysfs entry of a secondary kfd process
is placed under the sysfs entry folder of
its primary kfd process.
The naming format of the sysfs entry of a secondary
kfd process is "context_%u" where %u is the process id.
Signed-off-by: Zhu Lingshan <[email protected]>
---
drivers/gpu/drm/amd/amdkfd/kfd_priv.h | 6 ++
drivers/gpu/drm/amd/amdkfd/kfd_process.c | 78 +++++++++++++++++++++++-
2 files changed, 81 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
index 919510f18249..9de658119cd9 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
@@ -1021,10 +1021,16 @@ struct kfd_process {
/*kfd context id */
u16 context_id;
+
+ /* The primary kfd_process allocating IDs for its secondary
kfd_process, 0 for primary kfd_process */
+ struct ida id_table;
+
};
#define KFD_PROCESS_TABLE_SIZE 8 /* bits: 256 entries */
#define KFD_CONTEXT_ID_PRIMARY 0xFFFF
+#define KFD_CONTEXT_ID_MIN 0
+#define KFD_CONTEXT_ID_WIDTH 16
extern DECLARE_HASHTABLE(kfd_processes_table, KFD_PROCESS_TABLE_SIZE);
extern struct srcu_struct kfd_processes_srcu;
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
index 995d27be06e3..157145c94314 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
@@ -827,6 +827,7 @@ static void kfd_process_device_destroy_ib_mem(struct
kfd_process_device *pdd)
int kfd_create_process_sysfs(struct kfd_process *process)
{
+ struct kfd_process *primary_process;
int ret;
if (process->kobj) {
@@ -839,9 +840,22 @@ int kfd_create_process_sysfs(struct kfd_process *process)
pr_warn("Creating procfs kobject failed");
return -ENOMEM;
}
- ret = kobject_init_and_add(process->kobj, &procfs_type,
- procfs.kobj, "%d",
- (int)process->lead_thread->pid);
+
+ if (process->context_id == KFD_CONTEXT_ID_PRIMARY)
+ ret = kobject_init_and_add(process->kobj, &procfs_type,
+ procfs.kobj, "%d",
+ (int)process->lead_thread->pid);
+ else {
+ primary_process =
kfd_lookup_process_by_mm(process->lead_thread->mm);
+ if (!primary_process)
+ return -ESRCH;
+
+ ret = kobject_init_and_add(process->kobj, &procfs_type,
+ primary_process->kobj, "context_%u",
+ process->context_id);
+ kfd_unref_process(primary_process);
+ }
+
if (ret) {
pr_warn("Creating procfs pid directory failed");
kobject_put(process->kobj);
@@ -863,6 +877,50 @@ int kfd_create_process_sysfs(struct kfd_process *process)
return 0;
}
+static int kfd_process_alloc_id(struct kfd_process *process)
+{
+ int ret;
+ struct kfd_process *primary_process;
+
+ /* already assign 0xFFFF when create */
+ if (process->context_id == KFD_CONTEXT_ID_PRIMARY)
+ return 0;
+
+ primary_process = kfd_lookup_process_by_mm(process->lead_thread->mm);
+ if (!primary_process)
+ return -ESRCH;
+
+ /* id range: KFD_CONTEXT_ID_MIN to 0xFFFE */
+ ret = ida_alloc_range(&primary_process->id_table, KFD_CONTEXT_ID_MIN,
+ (1 << KFD_CONTEXT_ID_WIDTH) - 2, GFP_KERNEL);
This would be safer and more obvious if you just set the upper limit as
KFD_CONTEXT_ID_PRIMARY - 1. Then you don't need KFD_CONTEXT_ID_WIDTH at all.
Regards,
Felix
+ if (ret < 0)
+ goto out;
+
+ process->context_id = ret;
+ ret = 0;
+
+out:
+ kfd_unref_process(primary_process);
+
+ return ret;
+}
+
+static void kfd_process_free_id(struct kfd_process *process)
+{
+ struct kfd_process *primary_process;
+
+ if (process->context_id != KFD_CONTEXT_ID_PRIMARY)
+ return;
+
+ primary_process = kfd_lookup_process_by_mm(process->lead_thread->mm);
+ if (!primary_process)
+ return;
+
+ ida_free(&primary_process->id_table, process->context_id);
+
+ kfd_unref_process(primary_process);
+}
+
struct kfd_process *kfd_create_process(struct task_struct *thread)
{
struct kfd_process *process;
@@ -1195,6 +1253,11 @@ static void kfd_process_wq_release(struct work_struct
*work)
if (ef)
dma_fence_signal(ef);
+ if (p->context_id != KFD_CONTEXT_ID_PRIMARY)
+ kfd_process_free_id(p);
+ else
+ ida_destroy(&p->id_table);
+
kfd_process_remove_sysfs(p);
kfd_debugfs_remove_process(p);
@@ -1601,6 +1664,13 @@ static struct kfd_process *create_process(const struct task_struct *thread, bool
goto err_register_notifier;
}
BUG_ON(mn != &process->mmu_notifier);
+ ida_init(&process->id_table);
+ }
+
+ err = kfd_process_alloc_id(process);
+ if (err) {
+ pr_err("Creating kfd process: failed to alloc an id\n");
+ goto err_alloc_id;
}
kfd_unref_process(process);
@@ -1610,6 +1680,8 @@ static struct kfd_process *create_process(const struct
task_struct *thread, bool
return process;
+err_alloc_id:
+ kfd_process_free_id(process);
err_register_notifier:
hash_del_rcu(&process->kfd_processes);
svm_range_list_fini(process);
