[PATCH] drm/xe/debugfs: Add support for gt synchronous force reset
Mika Kuoppala
mika.kuoppala at linux.intel.com
Tue Jan 2 15:26:32 UTC 2024
"Poosa, Karthik" <karthik.poosa at intel.com> writes:
> Hi Anshuman,
>
> Please find my comments inline below.
>
> Thanks,
>
> Karthik.
>
> On 01-01-2024 20:07, Gupta, Anshuman wrote:
>>
>>> -----Original Message-----
>>> From: Poosa, Karthik <karthik.poosa at intel.com>
>>> Sent: Sunday, December 31, 2023 8:18 PM
>>> To: intel-xe at lists.freedesktop.org
>>> Cc: Gupta, Anshuman <anshuman.gupta at intel.com>; Nilawar, Badal
>>> <badal.nilawar at intel.com>; Brost, Matthew <matthew.brost at intel.com>;
>>> Vivi, Rodrigo <rodrigo.vivi at intel.com>; Poosa, Karthik
>>> <karthik.poosa at intel.com>
>>> Subject: [PATCH] drm/xe/debugfs: Add support for gt synchronous force reset
>>>
>>> This support added as igt test freq_reset_multiple fails sporadically in case
>>> xe_guc_pc is not started.
>>> A completion is added in force_reset for this.
>>> Writing non-zero to force_reset debugfs entry does synchronous reset.
>> We need IGT patch as well for this patch.
>>> v2:
>>> - Changed wait for completion to interruptible (Anshuman).
>>> - Moved timeout to xe_gt.h (Anshuman).
>>> - Created a debugfs for updating timeout (Rodrigo).
>>>
>>> v3:
>>> - Update force_reset debugfs with write support.
>>> value 0 -> async reset, non-zero -> sync reset (Matthew Brost).
>>>
>>> Signed-off-by: Karthik Poosa <karthik.poosa at intel.com>
>>> ---
>>> drivers/gpu/drm/xe/xe_gt.c | 2 +
>>> drivers/gpu/drm/xe/xe_gt_debugfs.c | 72
>>> ++++++++++++++++++++++++++++-- drivers/gpu/drm/xe/xe_gt_debugfs.h
>>> | 3 ++
>>> drivers/gpu/drm/xe/xe_gt_types.h | 8 ++++
>>> 4 files changed, 82 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c index
>>> 3af2adec1295..c8d2c18b0c62 100644
>>> --- a/drivers/gpu/drm/xe/xe_gt.c
>>> +++ b/drivers/gpu/drm/xe/xe_gt.c
>>> @@ -65,6 +65,7 @@ struct xe_gt *xe_gt_alloc(struct xe_tile *tile)
>>>
>>> gt->tile = tile;
>>> gt->ordered_wq = alloc_ordered_workqueue("gt-ordered-wq", 0);
>>> + init_completion(>->reset.done);
>>>
>>> return gt;
>>> }
>>> @@ -633,6 +634,7 @@ static int gt_reset(struct xe_gt *gt)
>>> xe_device_mem_access_put(gt_to_xe(gt));
>>> XE_WARN_ON(err);
>>>
>>> + complete(>->reset.done);
>>> xe_gt_info(gt, "reset done\n");
>>>
>>> return 0;
>>> diff --git a/drivers/gpu/drm/xe/xe_gt_debugfs.c
>>> b/drivers/gpu/drm/xe/xe_gt_debugfs.c
>>> index c4b67cf09f8f..3518ab89ccfc 100644
>>> --- a/drivers/gpu/drm/xe/xe_gt_debugfs.c
>>> +++ b/drivers/gpu/drm/xe/xe_gt_debugfs.c
>>> @@ -55,15 +55,71 @@ static int hw_engines(struct seq_file *m, void *data)
>>> return 0;
>>> }
>>>
>>> -static int force_reset(struct seq_file *m, void *data)
>>> +static int force_reset(struct xe_gt *gt, bool is_sync)
>>> {
>>> - struct xe_gt *gt = node_to_gt(m->private);
>>> + struct xe_device *xe = gt_to_xe(gt);
>>> + long ret;
>>>
>>> xe_gt_reset_async(gt);
>>>
>>> + if (is_sync) {
>>> + drm_info(&xe->drm, "waiting for gt reset completion");
>>> + ret = wait_for_completion_interruptible_timeout(>-
>>>> reset.done,
>>> + msecs_to_jiffies(gt-
>>>> reset.timeout_ms));
>>> + if (ret <= 0) {
>>> + drm_err(&xe->drm, "gt reset timed out/interrputed,
>>> ret %ld\n", ret);
>>> + return -ETIMEDOUT;
>>> + }
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +ssize_t force_reset_write(struct file *f, const char __user *buf,
>>> +size_t len, loff_t *offset) {
>>> + struct xe_gt *gt = file_inode(f)->i_private;
>>> + struct xe_device *xe = gt_to_xe(gt);
>>> + char arg_str[5];
>>> + size_t size;
>>> + unsigned long arg;
>>> + int ret;
>>> +
>>> + size = min(sizeof(arg_str)-1, len);
>>> + arg = copy_from_user((void *)arg_str, buf, size);
>>> + if (arg < 0) {
>>> + drm_err(&xe->drm, "reading force_reset arg failed, ret %ld",
>>> arg);
>>> + return arg;
>>> + }
>>> + arg_str[size] = '\0';
>>> +
>>> + ret = kstrtoul(arg_str, 0, &arg);
>>> + if (ret) {
>>> + drm_err(&xe->drm, "force_reset arg parse failed, ret %d", ret);
>>> + return ret;
>>> + }
>>> +
>>> + ret = force_reset(gt, (arg && 1));
>> How about !!arg
> && will use a single instruction.
>
> but !! will happen with 2 instructions, so I think && would be better.
This is not in a hotpath, more readable is better.
-Mika
>
>> > + if (ret != 0) {
>>> + drm_err(&xe->drm, "force_reset failed, ret %d\n", ret);
>>> + return ret;
>>> + }
>>> + return len;
>>> +}
>>> +
>>> +ssize_t force_reset_read(struct file *f, char __user *buf, size_t len,
>>> +loff_t *offset) {
>>> + struct xe_gt *gt = file_inode(f)->i_private;
>>> +
>>> + force_reset(gt, 0);
>>> return 0;
>>> }
>>>
>>> +static const struct file_operations force_reset_fops = {
>>> + .owner = THIS_MODULE,
>>> + .write = force_reset_write,
>>> + .read = force_reset_read,
>>> +};
>>> +
>>> static int sa_info(struct seq_file *m, void *data) {
>>> struct xe_tile *tile = gt_to_tile(node_to_gt(m->private));
>>> @@ -192,7 +248,6 @@ static int vecs_default_lrc(struct seq_file *m, void
>>> *data)
>>>
>>> static const struct drm_info_list debugfs_list[] = {
>>> {"hw_engines", hw_engines, 0},
>>> - {"force_reset", force_reset, 0},
>>> {"sa_info", sa_info, 0},
>>> {"topology", topology, 0},
>>> {"steering", steering, 0},
>>> @@ -245,5 +300,16 @@ void xe_gt_debugfs_register(struct xe_gt *gt)
>>> ARRAY_SIZE(debugfs_list),
>>> root, minor);
>>>
>>> + gt->reset.fr_dentry = debugfs_create_file("force_reset", 0600, root,
>>> xe,
>>> + &force_reset_fops);
>> Please use DEFINE_SHOW_STORE_ATTRIBUTE here to create rw debugfs entry.
>> Use force_reset_show and force_reset_restore function name.
>>> + if (!gt->reset.fr_dentry)
>>> + drm_warn(&xe->drm, "force_reset debugfs file creation
>>> failed");
>>> + d_inode(gt->reset.fr_dentry)->i_private = gt;
>>> +
>>> + debugfs_create_u32("gt_reset_timeout_ms", 0600, root,
>>> + >->reset.timeout_ms);
>>> + /* set a default timeout value */
>>> + gt->reset.timeout_ms = 1000;
>> xe_gt_debugfs_register() should only do the job of debugfs registration.
>> This is odd here.
>
> Shall I move this to xe_gt_alloc (xe_gt.c), where gt is allocated and
> initialized.
>
>>> +
>>> xe_uc_debugfs_register(>->uc, root); } diff --git
>>> a/drivers/gpu/drm/xe/xe_gt_debugfs.h
>>> b/drivers/gpu/drm/xe/xe_gt_debugfs.h
>>> index 5a329f118a57..40adcf1822c6 100644
>>> --- a/drivers/gpu/drm/xe/xe_gt_debugfs.h
>>> +++ b/drivers/gpu/drm/xe/xe_gt_debugfs.h
>>> @@ -6,8 +6,11 @@
>>> #ifndef _XE_GT_DEBUGFS_H_
>>> #define _XE_GT_DEBUGFS_H_
>>>
>>> +#include <linux/fs.h>
>>> struct xe_gt;
>>>
>>> void xe_gt_debugfs_register(struct xe_gt *gt);
>>> +ssize_t force_reset_write(struct file *f, const char __user *buf,
>>> +size_t len, loff_t *offset); ssize_t force_reset_read(struct file *f,
>>> +char __user *buf, size_t len, loff_t *offset);
>>>
>>> #endif
>>> diff --git a/drivers/gpu/drm/xe/xe_gt_types.h
>>> b/drivers/gpu/drm/xe/xe_gt_types.h
>>> index f74684660475..d6134215094b 100644
>>> --- a/drivers/gpu/drm/xe/xe_gt_types.h
>>> +++ b/drivers/gpu/drm/xe/xe_gt_types.h
>>> @@ -148,6 +148,14 @@ struct xe_gt {
>>> * code to safely flush all code paths
>>> */
>>> struct work_struct worker;
>>> + /** @done : completion for GT reset */
>>> + struct completion done;
>>> + /** @timeout_ms : gt synchronous reset timeout in ms */
>>> + u32 timeout_ms;
>>> + /** @dentry: dentry for force_reset */
>>> + struct dentry *fr_dentry;
>>> + /** @is_sync_reset : gt reset is synchronous */
>>> + //bool is_sync_reset;
>> Remove thus unused var.
>>
>> Thanks,
>> Anshuman Gupta.
>>> } reset;
>>>
>>> /** @tlb_invalidation: TLB invalidation state */
>>> --
>>> 2.25.1
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