[PATCH] drm/amdgpu: use HMM mirror callback to replace mmu notifier v4
Felix Kuehling
felix.kuehling at amd.com
Fri Sep 14 20:21:57 UTC 2018
On 2018-09-14 01:52 PM, Christian König wrote:
> Am 14.09.2018 um 19:47 schrieb Philip Yang:
>> On 2018-09-14 03:51 AM, Christian König wrote:
>>> Am 13.09.2018 um 23:51 schrieb Felix Kuehling:
>>>> On 2018-09-13 04:52 PM, Philip Yang wrote:
>>>>> Replace our MMU notifier with
>>>>> hmm_mirror_ops.sync_cpu_device_pagetables
>>>>> callback. Enable CONFIG_HMM and CONFIG_HMM_MIRROR as a dependency in
>>>>> DRM_AMDGPU_USERPTR Kconfig.
>>>>>
>>>>> It supports both KFD userptr and gfx userptr paths.
>>>>>
>>>>> This depends on several HMM patchset from Jérôme Glisse queued for
>>>>> upstream.
>>>>>
>>>>> Change-Id: Ie62c3c5e3c5b8521ab3b438d1eff2aa2a003835e
>>>>> Signed-off-by: Philip Yang <Philip.Yang at amd.com>
>>>>> ---
>>>>> drivers/gpu/drm/amd/amdgpu/Kconfig | 6 +-
>>>>> drivers/gpu/drm/amd/amdgpu/Makefile | 2 +-
>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c | 121
>>>>> ++++++++++++++-------------------
>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h | 2 +-
>>>>> 4 files changed, 56 insertions(+), 75 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/Kconfig
>>>>> b/drivers/gpu/drm/amd/amdgpu/Kconfig
>>>>> index 9221e54..960a633 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/Kconfig
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/Kconfig
>>>>> @@ -26,10 +26,10 @@ config DRM_AMDGPU_CIK
>>>>> config DRM_AMDGPU_USERPTR
>>>>> bool "Always enable userptr write support"
>>>>> depends on DRM_AMDGPU
>>>>> - select MMU_NOTIFIER
>>>>> + select HMM_MIRROR
>>>>> help
>>>>> - This option selects CONFIG_MMU_NOTIFIER if it isn't already
>>>>> - selected to enabled full userptr support.
>>>>> + This option selects CONFIG_HMM and CONFIG_HMM_MIRROR if it
>>>>> + isn't already selected to enabled full userptr support.
>>>>> config DRM_AMDGPU_GART_DEBUGFS
>>>>> bool "Allow GART access through debugfs"
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/Makefile
>>>>> b/drivers/gpu/drm/amd/amdgpu/Makefile
>>>>> index 138cb78..c1e5d43 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/Makefile
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/Makefile
>>>>> @@ -171,7 +171,7 @@ endif
>>>>> amdgpu-$(CONFIG_COMPAT) += amdgpu_ioc32.o
>>>>> amdgpu-$(CONFIG_VGA_SWITCHEROO) += amdgpu_atpx_handler.o
>>>>> amdgpu-$(CONFIG_ACPI) += amdgpu_acpi.o
>>>>> -amdgpu-$(CONFIG_MMU_NOTIFIER) += amdgpu_mn.o
>>>>> +amdgpu-$(CONFIG_HMM) += amdgpu_mn.o
>>>>> include $(FULL_AMD_PATH)/powerplay/Makefile
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
>>>>> index e55508b..ad52f34 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
>>>>> @@ -45,7 +45,7 @@
>>>>> #include <linux/firmware.h>
>>>>> #include <linux/module.h>
>>>>> -#include <linux/mmu_notifier.h>
>>>>> +#include <linux/hmm.h>
>>>>> #include <linux/interval_tree.h>
>>>>> #include <drm/drmP.h>
>>>>> #include <drm/drm.h>
>>>>> @@ -66,6 +66,7 @@
>>>> Need to remove @mn documentation.
>>>>
>>>>> * @objects: interval tree containing amdgpu_mn_nodes
>>>>> * @read_lock: mutex for recursive locking of @lock
>>>>> * @recursion: depth of recursion
>>>>> + * @mirror: HMM mirror function support
>>>>> *
>>>>> * Data for each amdgpu device and process address space.
>>>>> */
>>>>> @@ -73,7 +74,6 @@ struct amdgpu_mn {
>>>>> /* constant after initialisation */
>>>>> struct amdgpu_device *adev;
>>>>> struct mm_struct *mm;
>>>>> - struct mmu_notifier mn;
>>>>> enum amdgpu_mn_type type;
>>>>> /* only used on destruction */
>>>>> @@ -87,6 +87,9 @@ struct amdgpu_mn {
>>>>> struct rb_root_cached objects;
>>>>> struct mutex read_lock;
>>>>> atomic_t recursion;
>>>>> +
>>>>> + /* HMM mirror */
>>>>> + struct hmm_mirror mirror;
>>>>> };
>>>>> /**
>>>>> @@ -103,7 +106,7 @@ struct amdgpu_mn_node {
>>>>> };
>>>>> /**
>>>>> - * amdgpu_mn_destroy - destroy the MMU notifier
>>>>> + * amdgpu_mn_destroy - destroy the HMM mirror
>>>>> *
>>>>> * @work: previously sheduled work item
>>>>> *
>>>>> @@ -129,28 +132,26 @@ static void amdgpu_mn_destroy(struct
>>>>> work_struct *work)
>>>>> }
>>>>> up_write(&amn->lock);
>>>>> mutex_unlock(&adev->mn_lock);
>>>>> - mmu_notifier_unregister_no_release(&amn->mn, amn->mm);
>>>>> + hmm_mirror_unregister(&amn->mirror);
>>>>> +
>>>>> kfree(amn);
>>>>> }
>>>>> /**
>>>>> * amdgpu_mn_release - callback to notify about mm destruction
>>>> Update the function name in the comment.
>>>>
>>>>> *
>>>>> - * @mn: our notifier
>>>>> - * @mm: the mm this callback is about
>>>>> + * @mirror: the HMM mirror (mm) this callback is about
>>>>> *
>>>>> - * Shedule a work item to lazy destroy our notifier.
>>>>> + * Shedule a work item to lazy destroy HMM mirror.
>>>>> */
>>>>> -static void amdgpu_mn_release(struct mmu_notifier *mn,
>>>>> - struct mm_struct *mm)
>>>>> +static void amdgpu_hmm_mirror_release(struct hmm_mirror *mirror)
>>>>> {
>>>>> - struct amdgpu_mn *amn = container_of(mn, struct amdgpu_mn, mn);
>>>>> + struct amdgpu_mn *amn = container_of(mirror, struct
>>>>> amdgpu_mn, mirror);
>>>>> INIT_WORK(&amn->work, amdgpu_mn_destroy);
>>>>> schedule_work(&amn->work);
>>>>> }
>>>>> -
>>>>> /**
>>>>> * amdgpu_mn_lock - take the write side lock for this notifier
>>>>> *
>>>>> @@ -237,21 +238,19 @@ static void amdgpu_mn_invalidate_node(struct
>>>>> amdgpu_mn_node *node,
>>>>> /**
>>>>> * amdgpu_mn_invalidate_range_start_gfx - callback to notify
>>>>> about mm change
>>>>> *
>>>>> - * @mn: our notifier
>>>>> - * @mm: the mm this callback is about
>>>>> - * @start: start of updated range
>>>>> - * @end: end of updated range
>>>>> + * @mirror: the hmm_mirror (mm) is about to update
>>>>> + * @update: the update start, end address
>>>>> *
>>>>> * Block for operations on BOs to finish and mark pages as
>>>>> accessed and
>>>>> * potentially dirty.
>>>>> */
>>>>> -static int amdgpu_mn_invalidate_range_start_gfx(struct
>>>>> mmu_notifier *mn,
>>>>> - struct mm_struct *mm,
>>>>> - unsigned long start,
>>>>> - unsigned long end,
>>>>> - bool blockable)
>>>>> +static int amdgpu_mn_invalidate_range_start_gfx(struct hmm_mirror
>>>>> *mirror,
>>>>> + const struct hmm_update *update)
>>>>> {
>>>>> - struct amdgpu_mn *amn = container_of(mn, struct amdgpu_mn, mn);
>>>>> + struct amdgpu_mn *amn = container_of(mirror, struct
>>>>> amdgpu_mn, mirror);
>>>>> + unsigned long start = update->start;
>>>>> + unsigned long end = update->end;
>>>>> + bool blockable = update->blockable;
>>>>> struct interval_tree_node *it;
>>>>> /* notification is exclusive, but interval is inclusive */
>>>>> @@ -278,28 +277,28 @@ static int
>>>>> amdgpu_mn_invalidate_range_start_gfx(struct mmu_notifier *mn,
>>>>> amdgpu_mn_invalidate_node(node, start, end);
>>>>> }
>>>>> + amdgpu_mn_read_unlock(amn);
>>>>> +
>>>> amdgpu_mn_read_lock/unlock support recursive locking for multiple
>>>> overlapping or nested invalidation ranges. But if you'r locking and
>>>> unlocking in the same function. Is that still a concern?
>>>
>> I don't understand the possible recursive case, but
>> amdgpu_mn_read_lock() still support recursive locking.
>>> Well the real problem is that unlocking them here won't work.
>>>
>>> We need to hold the lock until we are sure that the operation which
>>> updates the page tables is completed.
>>>
>> The reason for this change is because hmm mirror has invalidate_start
>> callback, no invalidate_end callback
>>
>> Check mmu_notifier.c and hmm.c again, below is entire logic to update
>> CPU page tables and callback:
>>
>> mn lock amn->lock is used to protect interval tree access because
>> user may submit/register new userptr anytime.
>> This is same for old and new way.
>>
>> step 2 guarantee the GPU operation is done before updating CPU page
>> table.
>>
>> So I think the change is safe. We don't need hold mn lock until the
>> CPU page tables update is completed.
>
> No, that isn't even remotely correct. The lock doesn't protects the
> interval tree.
>
>>
>> Old:
>> 1. down_read_non_owner(&amn->lock)
>> 2. loop to handle BOs from node->bos through interval tree
>> amn->object nodes
>> gfx: wait for pending BOs fence operation done, mark user
>> pages dirty
>> kfd: evict user queues of the process, wait for queue
>> unmap/map operation done
>> 3. update CPU page tables
>> 4. up_read(&amn->lock)
>>
>> New, switch step 3 and 4
>> 1. down_read_non_owner(&amn->lock)
>> 2. loop to handle BOs from node->bos through interval tree
>> amn->object nodes
>> gfx: wait for pending BOs fence operation done, mark user
>> pages dirty
>> kfd: evict user queues of the process, wait for queue
>> unmap/map operation done
>> 3. up_read(&amn->lock)
>> 4. update CPU page tables
>
> The lock is there to make sure that we serialize page table updates
> with command submission.
As I understand it, the idea is to prevent command submission (adding
new fences to BOs) while a page table invalidation is in progress. But
do we really need another lock for this? Wouldn't the re-validation of
userptr BOs (currently calling get_user_pages) force synchronization
with the ongoing page table invalidation through the mmap_sem or other
MM locks?
Regards,
Felix
>
> If HMM doesn't provide a callback for the end of the invalidating then
> it can't be used for this.
>
> Adding Jerome as well, since we are certainly missing something here.
>
> Regards,
> Christian.
>
>>
>> Regards,
>> Philip
>>> Christian.
>>>
>>>>
>>>>> return 0;
>>>>> }
>>>>> /**
>>>>> * amdgpu_mn_invalidate_range_start_hsa - callback to notify
>>>>> about mm change
>>>>> *
>>>>> - * @mn: our notifier
>>>>> - * @mm: the mm this callback is about
>>>>> - * @start: start of updated range
>>>>> - * @end: end of updated range
>>>>> + * @mirror: the hmm_mirror (mm) is about to update
>>>>> + * @update: the update start, end address
>>>>> *
>>>>> * We temporarily evict all BOs between start and end. This
>>>>> * necessitates evicting all user-mode queues of the process.
>>>>> The BOs
>>>>> * are restorted in amdgpu_mn_invalidate_range_end_hsa.
>>>>> */
>>>>> -static int amdgpu_mn_invalidate_range_start_hsa(struct
>>>>> mmu_notifier *mn,
>>>>> - struct mm_struct *mm,
>>>>> - unsigned long start,
>>>>> - unsigned long end,
>>>>> - bool blockable)
>>>>> +static int amdgpu_mn_invalidate_range_start_hsa(struct hmm_mirror
>>>>> *mirror,
>>>>> + const struct hmm_update *update)
>>>>> {
>>>>> - struct amdgpu_mn *amn = container_of(mn, struct amdgpu_mn, mn);
>>>>> + struct amdgpu_mn *amn = container_of(mirror, struct
>>>>> amdgpu_mn, mirror);
>>>>> + unsigned long start = update->start;
>>>>> + unsigned long end = update->end;
>>>>> + bool blockable = update->blockable;
>>>>> struct interval_tree_node *it;
>>>>> /* notification is exclusive, but interval is inclusive */
>>>>> @@ -326,59 +325,41 @@ static int
>>>>> amdgpu_mn_invalidate_range_start_hsa(struct mmu_notifier *mn,
>>>>> if (amdgpu_ttm_tt_affect_userptr(bo->tbo.ttm,
>>>>> start, end))
>>>>> - amdgpu_amdkfd_evict_userptr(mem, mm);
>>>>> + amdgpu_amdkfd_evict_userptr(mem, amn->mm);
>>>>> }
>>>>> }
>>>>> + amdgpu_mn_read_unlock(amn);
>>>>> +
>>>>> return 0;
>>>>> }
>>>>> -/**
>>>>> - * amdgpu_mn_invalidate_range_end - callback to notify about mm
>>>>> change
>>>>> - *
>>>>> - * @mn: our notifier
>>>>> - * @mm: the mm this callback is about
>>>>> - * @start: start of updated range
>>>>> - * @end: end of updated range
>>>>> - *
>>>>> - * Release the lock again to allow new command submissions.
>>>>> +/* Low bits of any reasonable mm pointer will be unused due to
>>>>> struct
>>>>> + * alignment. Use these bits to make a unique key from the mm
>>>>> pointer
>>>>> + * and notifier type.
>>>>> */
>>>>> -static void amdgpu_mn_invalidate_range_end(struct mmu_notifier *mn,
>>>>> - struct mm_struct *mm,
>>>>> - unsigned long start,
>>>>> - unsigned long end)
>>>>> -{
>>>>> - struct amdgpu_mn *amn = container_of(mn, struct amdgpu_mn, mn);
>>>>> -
>>>>> - amdgpu_mn_read_unlock(amn);
>>>>> -}
>>>>> +#define AMDGPU_MN_KEY(mm, type) ((unsigned long)(mm) + (type))
>>>>> -static const struct mmu_notifier_ops amdgpu_mn_ops[] = {
>>>>> +static struct hmm_mirror_ops amdgpu_hmm_mirror_ops[] = {
>>>>> [AMDGPU_MN_TYPE_GFX] = {
>>>>> - .release = amdgpu_mn_release,
>>>>> - .invalidate_range_start =
>>>>> amdgpu_mn_invalidate_range_start_gfx,
>>>>> - .invalidate_range_end = amdgpu_mn_invalidate_range_end,
>>>>> + .sync_cpu_device_pagetables =
>>>>> + amdgpu_mn_invalidate_range_start_gfx,
>>>>> + .release = amdgpu_hmm_mirror_release
>>>>> },
>>>>> [AMDGPU_MN_TYPE_HSA] = {
>>>>> - .release = amdgpu_mn_release,
>>>>> - .invalidate_range_start =
>>>>> amdgpu_mn_invalidate_range_start_hsa,
>>>>> - .invalidate_range_end = amdgpu_mn_invalidate_range_end,
>>>>> + .sync_cpu_device_pagetables =
>>>>> + amdgpu_mn_invalidate_range_start_hsa,
>>>>> + .release = amdgpu_hmm_mirror_release
>>>>> },
>>>>> };
>>>>> -/* Low bits of any reasonable mm pointer will be unused due to
>>>>> struct
>>>>> - * alignment. Use these bits to make a unique key from the mm
>>>>> pointer
>>>>> - * and notifier type.
>>>>> - */
>>>>> -#define AMDGPU_MN_KEY(mm, type) ((unsigned long)(mm) + (type))
>>>>> -
>>>>> /**
>>>>> - * amdgpu_mn_get - create notifier context
>>>>> + * amdgpu_mn_get - create HMM mirror context
>>>>> *
>>>>> * @adev: amdgpu device pointer
>>>>> * @type: type of MMU notifier context
>>>>> *
>>>>> - * Creates a notifier context for current->mm.
>>>>> + * Creates a HMM mirror context for current->mm.
>>>>> */
>>>>> struct amdgpu_mn *amdgpu_mn_get(struct amdgpu_device *adev,
>>>>> enum amdgpu_mn_type type)
>>>>> @@ -408,12 +389,12 @@ struct amdgpu_mn *amdgpu_mn_get(struct
>>>>> amdgpu_device *adev,
>>>>> amn->mm = mm;
>>>>> init_rwsem(&amn->lock);
>>>>> amn->type = type;
>>>>> - amn->mn.ops = &amdgpu_mn_ops[type];
>>>>> amn->objects = RB_ROOT_CACHED;
>>>>> mutex_init(&amn->read_lock);
>>>>> atomic_set(&amn->recursion, 0);
>>>>> - r = __mmu_notifier_register(&amn->mn, mm);
>>>>> + amn->mirror.ops = &amdgpu_hmm_mirror_ops[type];
>>>>> + r = hmm_mirror_register(&amn->mirror, mm);
>>>>> if (r)
>>>>> goto free_amn;
>>>>> @@ -439,7 +420,7 @@ struct amdgpu_mn *amdgpu_mn_get(struct
>>>>> amdgpu_device *adev,
>>>>> * @bo: amdgpu buffer object
>>>>> * @addr: userptr addr we should monitor
>>>>> *
>>>>> - * Registers an MMU notifier for the given BO at the specified
>>>>> address.
>>>>> + * Registers an HMM mirror for the given BO at the specified
>>>>> address.
>>>>> * Returns 0 on success, -ERRNO if anything goes wrong.
>>>>> */
>>>>> int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long addr)
>>>>> @@ -495,11 +476,11 @@ int amdgpu_mn_register(struct amdgpu_bo *bo,
>>>>> unsigned long addr)
>>>>> }
>>>>> /**
>>>>> - * amdgpu_mn_unregister - unregister a BO for notifier updates
>>>>> + * amdgpu_mn_unregister - unregister a BO for HMM mirror updates
>>>>> *
>>>>> * @bo: amdgpu buffer object
>>>>> *
>>>>> - * Remove any registration of MMU notifier updates from the
>>>>> buffer object.
>>>>> + * Remove any registration of HMM mirror updates from the buffer
>>>>> object.
>>>>> */
>>>>> void amdgpu_mn_unregister(struct amdgpu_bo *bo)
>>>>> {
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h
>>>>> index eb0f432..0e27526 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h
>>>>> @@ -34,7 +34,7 @@ enum amdgpu_mn_type {
>>>>> AMDGPU_MN_TYPE_HSA,
>>>>> };
>>>>> -#if defined(CONFIG_MMU_NOTIFIER)
>>>>> +#if defined(CONFIG_HMM)
>>>>> void amdgpu_mn_lock(struct amdgpu_mn *mn);
>>>>> void amdgpu_mn_unlock(struct amdgpu_mn *mn);
>>>>> struct amdgpu_mn *amdgpu_mn_get(struct amdgpu_device *adev,
>>>> _______________________________________________
>>>> amd-gfx mailing list
>>>> amd-gfx at lists.freedesktop.org
>>>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
>>>
>>
>
More information about the amd-gfx
mailing list