amdkfd: identify a secondary kfd process by its id

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 context id.

Signed-off-by: Zhu Lingshan <lingshan.zhu@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
index 48dc6e737d0da4ad18d602359911abedae5904db..6388650fd6e6659f69bb0daf32c9203dc109d735 100644 (file)
--- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
@@ -1020,10 +1020,15 @@ 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
 
 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 622a0dc9d3c7bd993a0f67fcc7e82ee2c6b2e47c..c3bbcb28390f48acca36e1ec7c7a2336b89f4952 100644 (file)
--- 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,
+             KFD_CONTEXT_ID_PRIMARY - 1, GFP_KERNEL);
+       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;
@@ -1191,6 +1249,11 @@ 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);
 
@@ -1605,6 +1668,13 @@ 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);
@@ -1614,6 +1684,8 @@ 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);