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/*
* Copyright 2016-2018 Advanced Micro Devices, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#include <linux/dma-fence.h>
#include <linux/spinlock.h>
#include <linux/atomic.h>
#include <linux/stacktrace.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/sched/mm.h>
#include "amdgpu_amdkfd.h"
static const struct dma_fence_ops amdkfd_fence_ops;
static atomic_t fence_seq = ATOMIC_INIT(0);
/* Eviction Fence
* Fence helper functions to deal with KFD memory eviction.
* Big Idea - Since KFD submissions are done by user queues, a BO cannot be
* evicted unless all the user queues for that process are evicted.
*
* All the BOs in a process share an eviction fence. When process X wants
* to map VRAM memory but TTM can't find enough space, TTM will attempt to
* evict BOs from its LRU list. TTM checks if the BO is valuable to evict
* by calling ttm_bo_driver->eviction_valuable().
*
* ttm_bo_driver->eviction_valuable() - will return false if the BO belongs
* to process X. Otherwise, it will return true to indicate BO can be
* evicted by TTM.
*
* If ttm_bo_driver->eviction_valuable returns true, then TTM will continue
* the evcition process for that BO by calling ttm_bo_evict --> amdgpu_bo_move
* --> amdgpu_copy_buffer(). This sets up job in GPU scheduler.
*
* GPU Scheduler (amd_sched_main) - sets up a cb (fence_add_callback) to
* nofity when the BO is free to move. fence_add_callback --> enable_signaling
* --> amdgpu_amdkfd_fence.enable_signaling
*
* amdgpu_amdkfd_fence.enable_signaling - Start a work item that will quiesce
* user queues and signal fence. The work item will also start another delayed
* work item to restore BOs
*/
struct amdgpu_amdkfd_fence *amdgpu_amdkfd_fence_create(u64 context,
struct mm_struct *mm)
{
struct amdgpu_amdkfd_fence *fence;
fence = kzalloc(sizeof(*fence), GFP_KERNEL);
if (fence == NULL)
return NULL;
/* This reference gets released in amdkfd_fence_release */
mmgrab(mm);
fence->mm = mm;
get_task_comm(fence->timeline_name, current);
spin_lock_init(&fence->lock);
dma_fence_init(&fence->base, &amdkfd_fence_ops, &fence->lock,
context, atomic_inc_return(&fence_seq));
return fence;
}
struct amdgpu_amdkfd_fence *to_amdgpu_amdkfd_fence(struct dma_fence *f)
{
struct amdgpu_amdkfd_fence *fence;
if (!f)
return NULL;
fence = container_of(f, struct amdgpu_amdkfd_fence, base);
if (f->ops == &amdkfd_fence_ops)
return fence;
return NULL;
}
static const char *amdkfd_fence_get_driver_name(struct dma_fence *f)
{
return "amdgpu_amdkfd_fence";
}
static const char *amdkfd_fence_get_timeline_name(struct dma_fence *f)
{
struct amdgpu_amdkfd_fence *fence = to_amdgpu_amdkfd_fence(f);
return fence->timeline_name;
}
/**
* amdkfd_fence_enable_signaling - This gets called when TTM wants to evict
* a KFD BO and schedules a job to move the BO.
* If fence is already signaled return true.
* If fence is not signaled schedule a evict KFD process work item.
*/
static bool amdkfd_fence_enable_signaling(struct dma_fence *f)
{
struct amdgpu_amdkfd_fence *fence = to_amdgpu_amdkfd_fence(f);
if (!fence)
return false;
if (dma_fence_is_signaled(f))
return true;
if (!kgd2kfd_schedule_evict_and_restore_process(fence->mm, f))
return true;
return false;
}
/**
* amdkfd_fence_release - callback that fence can be freed
*
* @fence: fence
*
* This function is called when the reference count becomes zero.
* Drops the mm_struct reference and RCU schedules freeing up the fence.
*/
static void amdkfd_fence_release(struct dma_fence *f)
{
struct amdgpu_amdkfd_fence *fence = to_amdgpu_amdkfd_fence(f);
/* Unconditionally signal the fence. The process is getting
* terminated.
*/
if (WARN_ON(!fence))
return; /* Not an amdgpu_amdkfd_fence */
mmdrop(fence->mm);
kfree_rcu(f, rcu);
}
/**
* amdkfd_fence_check_mm - Check if @mm is same as that of the fence @f
* if same return TRUE else return FALSE.
*
* @f: [IN] fence
* @mm: [IN] mm that needs to be verified
*/
bool amdkfd_fence_check_mm(struct dma_fence *f, struct mm_struct *mm)
{
struct amdgpu_amdkfd_fence *fence = to_amdgpu_amdkfd_fence(f);
if (!fence)
return false;
else if (fence->mm == mm)
return true;
return false;
}
static const struct dma_fence_ops amdkfd_fence_ops = {
.get_driver_name = amdkfd_fence_get_driver_name,
.get_timeline_name = amdkfd_fence_get_timeline_name,
.enable_signaling = amdkfd_fence_enable_signaling,
.release = amdkfd_fence_release,
};
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