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drm/amdkfd: change kfd process kref count at creation

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kfd process kref count(process->ref) is initialized to 1 by kref_init. After
it is created not need to increase its kref. Instad add kfd process kref at kfd
process mmu notifier allocation since we already decrease the kref at
free_notifier of mmu_notifier_ops, so pair them.

When user process opens kfd node multiple times the kfd process kref is
increased each time to balance with kfd node close operation.

Signed-off-by: Xiaogang Chen <xiaogang.chen@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Xiaogang Chen
2024-10-28 15:06:19 -05:00
committed by Alex Deucher
parent 408d208127
commit 6cb6d437b5
1 changed files with 6 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
drivers/gpu/drm/amd/amdkfd/kfd_process.c
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@@ -854,8 +854,10 @@ struct kfd_process *kfd_create_process(struct task_struct *thread)
goto out;
}
/* A prior open of /dev/kfd could have already created the process. */
process = find_process(thread, false);
/* A prior open of /dev/kfd could have already created the process.
* find_process will increase process kref in this case
*/
process = find_process(thread, true);
if (process) {
pr_debug("Process already found\n");
} else {
@@ -903,8 +905,6 @@ struct kfd_process *kfd_create_process(struct task_struct *thread)
init_waitqueue_head(&process->wait_irq_drain);
}
out:
if (!IS_ERR(process))
kref_get(&process->ref);
mutex_unlock(&kfd_processes_mutex);
mmput(thread->mm);
@@ -1190,10 +1190,8 @@ static void kfd_process_ref_release(struct kref *ref)
static struct mmu_notifier *kfd_process_alloc_notifier(struct mm_struct *mm)
{
int idx = srcu_read_lock(&kfd_processes_srcu);
struct kfd_process *p = find_process_by_mm(mm);
srcu_read_unlock(&kfd_processes_srcu, idx);
/* This increments p->ref counter if kfd process p exists */
struct kfd_process *p = kfd_lookup_process_by_mm(mm);
return p ? &p->mmu_notifier : ERR_PTR(-ESRCH);
}