On 2021-05-26 6:15 a.m., Christian König wrote:
> Am 26.05.21 um 02:40 schrieb Luben Tuikov:
>> On Context Query2 IOCTL return the correctable and
>> uncorrectable errors in O(1) fashion, from cached
>> values, and schedule a delayed work function to
>> calculate and cache them for the next such IOCTL.
>>
>> v2: Cancel pending delayed work at ras_fini().
>>
>> Cc: Alexander Deucher <Alexander.Deucher@xxxxxxx>
>> Cc: Christian König <christian.koenig@xxxxxxx>
>> Cc: John Clements <john.clements@xxxxxxx>
>> Cc: Hawking Zhang <Hawking.Zhang@xxxxxxx>
>> Signed-off-by: Luben Tuikov <luben.tuikov@xxxxxxx>
>> ---
>> drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c | 32 +++++++++++++++++--
>> drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c | 41 +++++++++++++++++++++++++
>> drivers/gpu/drm/amd/amdgpu/amdgpu_ras.h | 5 +++
>> 3 files changed, 76 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
>> index bb0cfe871aba..4e95d255960b 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
>> @@ -331,10 +331,13 @@ static int amdgpu_ctx_query(struct amdgpu_device *adev,
>> return 0;
>> }
>>
>> +#define AMDGPU_RAS_COUNTE_DELAY_MS 3000
>> +
>> static int amdgpu_ctx_query2(struct amdgpu_device *adev,
>> - struct amdgpu_fpriv *fpriv, uint32_t id,
>> - union drm_amdgpu_ctx_out *out)
>> + struct amdgpu_fpriv *fpriv, uint32_t id,
>> + union drm_amdgpu_ctx_out *out)
>> {
>> + struct amdgpu_ras *con = amdgpu_ras_get_context(adev);
>> struct amdgpu_ctx *ctx;
>> struct amdgpu_ctx_mgr *mgr;
>>
>> @@ -361,6 +364,31 @@ static int amdgpu_ctx_query2(struct amdgpu_device *adev,
>> if (atomic_read(&ctx->guilty))
>> out->state.flags |= AMDGPU_CTX_QUERY2_FLAGS_GUILTY;
>>
>> + if (adev->ras_enabled && con) {
>> + /* Return the cached values in O(1),
>> + * and schedule delayed work to cache
>> + * new vaues.
>> + */
>> + int ce_count, ue_count;
>> +
>> + ce_count = atomic_read(&con->ras_ce_count);
>> + ue_count = atomic_read(&con->ras_ue_count);
>> +
>> + if (ce_count != ctx->ras_counter_ce) {
>> + ctx->ras_counter_ce = ce_count;
>> + out->state.flags |= AMDGPU_CTX_QUERY2_FLAGS_RAS_CE;
>> + }
>> +
>> + if (ue_count != ctx->ras_counter_ue) {
>> + ctx->ras_counter_ue = ue_count;
>> + out->state.flags |= AMDGPU_CTX_QUERY2_FLAGS_RAS_UE;
>> + }
>> +
>> + if (!delayed_work_pending(&con->ras_counte_delay_work))
>> + schedule_delayed_work(&con->ras_counte_delay_work,
>> + msecs_to_jiffies(AMDGPU_RAS_COUNTE_DELAY_MS));
> You can skip the delayed_work_pending() check here, if I'm not totally
> mistaken that is already integrated in the schedule_delayed_work() logic.
I'll take a look and if so I'll remove the check. I've remembered this check from many
years ago--habit.
>
>> + }
>> +
>> mutex_unlock(&mgr->lock);
>> return 0;
>> }
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
>> index ed3c43e8b0b5..01114529040a 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
>> @@ -27,6 +27,7 @@
>> #include <linux/uaccess.h>
>> #include <linux/reboot.h>
>> #include <linux/syscalls.h>
>> +#include <linux/pm_runtime.h>
>>
>> #include "amdgpu.h"
>> #include "amdgpu_ras.h"
>> @@ -2116,6 +2117,30 @@ static void amdgpu_ras_check_supported(struct amdgpu_device *adev)
>> adev->ras_hw_enabled & amdgpu_ras_mask;
>> }
>>
>> +static void amdgpu_ras_counte_dw(struct work_struct *work)
>> +{
>> + struct amdgpu_ras *con = container_of(work, struct amdgpu_ras,
>> + ras_counte_delay_work.work);
>> + struct amdgpu_device *adev = con->adev;
>> + struct drm_device *dev = &adev->ddev;
>> + unsigned long ce_count, ue_count;
>> + int res;
>> +
>> + res = pm_runtime_get_sync(dev->dev);
>> + if (res < 0)
>> + goto Out;
>> +
>> + /* Cache new values.
>> + */
>> + amdgpu_ras_query_error_count(adev, &ce_count, &ue_count);
>> + atomic_set(&con->ras_ce_count, ce_count);
>> + atomic_set(&con->ras_ue_count, ue_count);
>> +
>> + pm_runtime_mark_last_busy(dev->dev);
>> +Out:
>> + pm_runtime_put_autosuspend(dev->dev);
>> +}
>> +
>> int amdgpu_ras_init(struct amdgpu_device *adev)
>> {
>> struct amdgpu_ras *con = amdgpu_ras_get_context(adev);
>> @@ -2130,6 +2155,11 @@ int amdgpu_ras_init(struct amdgpu_device *adev)
>> if (!con)
>> return -ENOMEM;
>>
>> + con->adev = adev;
>> + INIT_DELAYED_WORK(&con->ras_counte_delay_work, amdgpu_ras_counte_dw);
>> + atomic_set(&con->ras_ce_count, 0);
>> + atomic_set(&con->ras_ue_count, 0);
>> +
>> con->objs = (struct ras_manager *)(con + 1);
>>
>> amdgpu_ras_set_context(adev, con);
>> @@ -2233,6 +2263,8 @@ int amdgpu_ras_late_init(struct amdgpu_device *adev,
>> struct ras_fs_if *fs_info,
>> struct ras_ih_if *ih_info)
>> {
>> + struct amdgpu_ras *con = amdgpu_ras_get_context(adev);
>> + unsigned long ue_count, ce_count;
>> int r;
>>
>> /* disable RAS feature per IP block if it is not supported */
>> @@ -2273,6 +2305,12 @@ int amdgpu_ras_late_init(struct amdgpu_device *adev,
>> if (r)
>> goto sysfs;
>>
>> + /* Those are the cached values at init.
>> + */
>> + amdgpu_ras_query_error_count(adev, &ce_count, &ue_count);
>> + atomic_set(&con->ras_ce_count, ce_count);
>> + atomic_set(&con->ras_ue_count, ue_count);
>> +
>> return 0;
>> cleanup:
>> amdgpu_ras_sysfs_remove(adev, ras_block);
>> @@ -2390,6 +2428,9 @@ int amdgpu_ras_fini(struct amdgpu_device *adev)
>> if (con->features)
>> amdgpu_ras_disable_all_features(adev, 1);
>>
>> + if (delayed_work_pending(&con->ras_counte_delay_work))
>> + cancel_delayed_work_sync(&con->ras_counte_delay_work);
>> +
> Using delayed_work_pending() here causes a race problem, because the
> work might be running at the moment.
>
> Just calling cancel_delayed_work_sync() should fix that because the
> *_sync() variant also waits for running delayed work items to finish.
Yes, that's why I used the *_sync() version--we can't go on until the delayed work has
finished.
Yes, I agree that it is indeed a race, and I saw that, and I wonder why that interface exists
in the kernel in the first place.
Regards,
Luben
>
> Apart from that the patch looks good to me.
>
> Regards,
> Christian.
>
>> amdgpu_ras_set_context(adev, NULL);
>> kfree(con);
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.h
>> index 10fca0393106..256cea5d34f2 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.h
>> @@ -340,6 +340,11 @@ struct amdgpu_ras {
>>
>> /* disable ras error count harvest in recovery */
>> bool disable_ras_err_cnt_harvest;
>> +
>> + /* RAS count errors delayed work */
>> + struct delayed_work ras_counte_delay_work;
>> + atomic_t ras_ue_count;
>> + atomic_t ras_ce_count;
>> };
>>
>> struct ras_fs_data {
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