[PATCH 4/4] drm/xe: Introduce the wedged_mode debugfs
Lucas De Marchi
lucas.demarchi at intel.com
Wed Apr 17 19:51:05 UTC 2024
On Tue, Apr 09, 2024 at 06:15:07PM GMT, Rodrigo Vivi wrote:
>So, the wedged mode can be selected per device at runtime,
>before the tests or before reproducing the issue.
>
>v2: - s/busted/wedged
> - some locking consistency
>
>Cc: Lucas De Marchi <lucas.demarchi at intel.com>
>Cc: Alan Previn <alan.previn.teres.alexis at intel.com>
>Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
>---
> drivers/gpu/drm/xe/xe_debugfs.c | 56 ++++++++++++++++++++++++++++
> drivers/gpu/drm/xe/xe_device.c | 41 ++++++++++++++------
> drivers/gpu/drm/xe/xe_device.h | 4 +-
> drivers/gpu/drm/xe/xe_device_types.h | 11 +++++-
> drivers/gpu/drm/xe/xe_gt.c | 2 +-
> drivers/gpu/drm/xe/xe_guc.c | 2 +-
> drivers/gpu/drm/xe/xe_guc_ads.c | 52 +++++++++++++++++++++++++-
> drivers/gpu/drm/xe/xe_guc_ads.h | 1 +
> drivers/gpu/drm/xe/xe_guc_submit.c | 28 +++++++-------
> 9 files changed, 163 insertions(+), 34 deletions(-)
>
>diff --git a/drivers/gpu/drm/xe/xe_debugfs.c b/drivers/gpu/drm/xe/xe_debugfs.c
>index 86150cafe0ff..6ff067ea5a8f 100644
>--- a/drivers/gpu/drm/xe/xe_debugfs.c
>+++ b/drivers/gpu/drm/xe/xe_debugfs.c
>@@ -12,6 +12,7 @@
> #include "xe_bo.h"
> #include "xe_device.h"
> #include "xe_gt_debugfs.h"
>+#include "xe_guc_ads.h"
> #include "xe_pm.h"
> #include "xe_step.h"
>
>@@ -106,6 +107,58 @@ static const struct file_operations forcewake_all_fops = {
> .release = forcewake_release,
> };
>
>+static ssize_t wedged_mode_show(struct file *f, char __user *ubuf,
>+ size_t size, loff_t *pos)
>+{
>+ struct xe_device *xe = file_inode(f)->i_private;
>+ char buf[32];
>+ int len = 0;
>+
>+ mutex_lock(&xe->wedged.lock);
what are we trying to synchronize here? multiple threads writing to
debugfs to change the wedged mode?
>+ len = scnprintf(buf, sizeof(buf), "%d\n", xe->wedged.mode);
>+ mutex_unlock(&xe->wedged.lock);
>+
>+ return simple_read_from_buffer(ubuf, size, pos, buf, len);
>+}
>+
>+static ssize_t wedged_mode_set(struct file *f, const char __user *ubuf,
>+ size_t size, loff_t *pos)
>+{
>+ struct xe_device *xe = file_inode(f)->i_private;
>+ struct xe_gt *gt;
>+ u32 wedged_mode;
>+ ssize_t ret;
>+ u8 id;
>+
>+ ret = kstrtouint_from_user(ubuf, size, 0, &wedged_mode);
>+ if (ret)
>+ return ret;
>+
>+ if (wedged_mode > 2)
>+ return -EINVAL;
>+
>+ mutex_lock(&xe->wedged.lock);
>+ xe->wedged.mode = wedged_mode;
should we return if xe->wedged.mode == wedged_mode already?
>+ if (wedged_mode == 2) {
this doesn't seem correct.
echo 2 > wedged_mode
echo 1 > wedged_mode
Second call doesn't fail, driver starts handling it as wedged_mode == 1,
guc still has the policy to disable reset. Or am I missing anything?
If we are not handling going back to 1, then we should just error
out above.
>+ for_each_gt(gt, xe, id) {
>+ ret = xe_guc_ads_scheduler_policy_disable_reset(>->uc.guc.ads);
>+ if (ret) {
>+ drm_err(&xe->drm, "Failed to update GuC ADS scheduler policy. GPU might still reset even on the wedged_mode=2\n");
humn... wouldn't it be better to keep xe->wedged.mode as is and error
out like:
drm_err(&xe->drm, "Failed to update GuC ADS scheduler policy, can't change wedged_mode\n");
also, we should return error here. dunno which one is appropriate, but
maybe -ECOMM. Also, maybe unwind the first GTs on error? May not be
needed and just make matters worse, but may deserve a comment about that
conscious decision here.
Lucas De Marchi
>+ break;
>+ }
>+ }
>+ }
>+ mutex_unlock(&xe->wedged.lock);
>+
>+ return size;
>+}
>+
>+static const struct file_operations wedged_mode_fops = {
>+ .owner = THIS_MODULE,
>+ .read = wedged_mode_show,
>+ .write = wedged_mode_set,
>+};
>+
> void xe_debugfs_register(struct xe_device *xe)
> {
> struct ttm_device *bdev = &xe->ttm;
>@@ -123,6 +176,9 @@ void xe_debugfs_register(struct xe_device *xe)
> debugfs_create_file("forcewake_all", 0400, root, xe,
> &forcewake_all_fops);
>
>+ debugfs_create_file("wedged_mode", 0400, root, xe,
>+ &wedged_mode_fops);
>+
> for (mem_type = XE_PL_VRAM0; mem_type <= XE_PL_VRAM1; ++mem_type) {
> man = ttm_manager_type(bdev, mem_type);
>
>diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
>index 7928a5470cee..949fca2f0400 100644
>--- a/drivers/gpu/drm/xe/xe_device.c
>+++ b/drivers/gpu/drm/xe/xe_device.c
>@@ -445,6 +445,9 @@ int xe_device_probe_early(struct xe_device *xe)
> if (err)
> return err;
>
>+ mutex_init(&xe->wedged.lock);
>+ xe->wedged.mode = xe_modparam.wedged_mode;
>+
> return 0;
> }
>
>@@ -787,26 +790,37 @@ u64 xe_device_uncanonicalize_addr(struct xe_device *xe, u64 address)
> }
>
> /**
>- * xe_device_declare_wedged - Declare device wedged
>+ * xe_device_hint_wedged - Get a hint and possibly declare device as wedged
> * @xe: xe device instance
>+ * @in_timeout_path: hint coming from a timeout path
> *
>- * This is a final state that can only be cleared with a module
>+ * The wedged state is a final on that can only be cleared with a module
> * re-probe (unbind + bind).
> * In this state every IOCTL will be blocked so the GT cannot be used.
>- * In general it will be called upon any critical error such as gt reset
>- * failure or guc loading failure.
>- * If xe.wedged module parameter is set to 2, this function will be called
>- * on every single execution timeout (a.k.a. GPU hang) right after devcoredump
>- * snapshot capture. In this mode, GT reset won't be attempted so the state of
>- * the issue is preserved for further debugging.
>+ * In general device will be declared wedged only at critical
>+ * error paths such as gt reset failure or guc loading failure.
>+ * Hints are also expected from every single execution timeout (a.k.a. GPU hang)
>+ * right after devcoredump snapshot capture. Then, device can be declared wedged
>+ * if wedged_mode is set to 2. In this mode, GT reset won't be attempted so the
>+ * state of the issue is preserved for further debugging.
>+ *
>+ * Return: True if device has been just declared wedged. False otherwise.
> */
>-void xe_device_declare_wedged(struct xe_device *xe)
>+bool xe_device_hint_wedged(struct xe_device *xe, bool in_timeout_path)
> {
>- if (xe_modparam.wedged_mode == 0)
>- return;
>+ bool ret = false;
>+
>+ mutex_lock(&xe->wedged.lock);
>
>- if (!atomic_xchg(&xe->wedged, 1)) {
>+ if (xe->wedged.mode == 0)
>+ goto out;
>+
>+ if (in_timeout_path && xe->wedged.mode != 2)
>+ goto out;
>+
>+ if (!atomic_xchg(&xe->wedged.flag, 1)) {
> xe->needs_flr_on_fini = true;
>+ ret = true;
> drm_err(&xe->drm,
> "CRITICAL: Xe has declared device %s as wedged.\n"
> "IOCTLs and executions are blocked until device is probed again with unbind and bind operations:\n"
>@@ -816,4 +830,7 @@ void xe_device_declare_wedged(struct xe_device *xe)
> dev_name(xe->drm.dev), dev_name(xe->drm.dev),
> dev_name(xe->drm.dev));
> }
>+out:
>+ mutex_unlock(&xe->wedged.lock);
>+ return ret;
> }
>diff --git a/drivers/gpu/drm/xe/xe_device.h b/drivers/gpu/drm/xe/xe_device.h
>index 0fea5c18f76d..e3ea8a43e7f9 100644
>--- a/drivers/gpu/drm/xe/xe_device.h
>+++ b/drivers/gpu/drm/xe/xe_device.h
>@@ -178,9 +178,9 @@ u64 xe_device_uncanonicalize_addr(struct xe_device *xe, u64 address);
>
> static inline bool xe_device_wedged(struct xe_device *xe)
> {
>- return atomic_read(&xe->wedged);
>+ return atomic_read(&xe->wedged.flag);
> }
>
>-void xe_device_declare_wedged(struct xe_device *xe);
>+bool xe_device_hint_wedged(struct xe_device *xe, bool in_timeout_path);
>
> #endif
>diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
>index b9ef60f21750..0da4787f1087 100644
>--- a/drivers/gpu/drm/xe/xe_device_types.h
>+++ b/drivers/gpu/drm/xe/xe_device_types.h
>@@ -458,8 +458,15 @@ struct xe_device {
> /** @needs_flr_on_fini: requests function-reset on fini */
> bool needs_flr_on_fini;
>
>- /** @wedged: Xe device faced a critical error and is now blocked. */
>- atomic_t wedged;
>+ /** @wedged: Struct to control Wedged States and mode */
>+ struct {
>+ /** @wedged.flag: Xe device faced a critical error and is now blocked. */
>+ atomic_t flag;
>+ /** @wedged.mode: Mode controlled by kernel parameter and debugfs */
>+ int mode;
>+ /** @wedged.lock: To protect @wedged.mode */
>+ struct mutex lock;
>+ } wedged;
>
> /* private: */
>
>diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c
>index 0844081b88ef..da16f4273877 100644
>--- a/drivers/gpu/drm/xe/xe_gt.c
>+++ b/drivers/gpu/drm/xe/xe_gt.c
>@@ -688,7 +688,7 @@ static int gt_reset(struct xe_gt *gt)
> err_fail:
> xe_gt_err(gt, "reset failed (%pe)\n", ERR_PTR(err));
>
>- xe_device_declare_wedged(gt_to_xe(gt));
>+ xe_device_hint_wedged(gt_to_xe(gt), false);
>
> return err;
> }
>diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
>index f1c3e338301d..ee7e0fa4815d 100644
>--- a/drivers/gpu/drm/xe/xe_guc.c
>+++ b/drivers/gpu/drm/xe/xe_guc.c
>@@ -495,7 +495,7 @@ static void guc_wait_ucode(struct xe_guc *guc)
> xe_gt_err(gt, "GuC firmware exception. EIP: %#x\n",
> xe_mmio_read32(gt, SOFT_SCRATCH(13)));
>
>- xe_device_declare_wedged(gt_to_xe(gt));
>+ xe_device_hint_wedged(gt_to_xe(gt), false);
> } else {
> xe_gt_dbg(gt, "GuC successfully loaded\n");
> }
>diff --git a/drivers/gpu/drm/xe/xe_guc_ads.c b/drivers/gpu/drm/xe/xe_guc_ads.c
>index dbd88ae20aa3..ad64d5a31239 100644
>--- a/drivers/gpu/drm/xe/xe_guc_ads.c
>+++ b/drivers/gpu/drm/xe/xe_guc_ads.c
>@@ -9,6 +9,7 @@
>
> #include <generated/xe_wa_oob.h>
>
>+#include "abi/guc_actions_abi.h"
> #include "regs/xe_engine_regs.h"
> #include "regs/xe_gt_regs.h"
> #include "regs/xe_guc_regs.h"
>@@ -16,11 +17,11 @@
> #include "xe_gt.h"
> #include "xe_gt_ccs_mode.h"
> #include "xe_guc.h"
>+#include "xe_guc_ct.h"
> #include "xe_hw_engine.h"
> #include "xe_lrc.h"
> #include "xe_map.h"
> #include "xe_mmio.h"
>-#include "xe_module.h"
> #include "xe_platform_types.h"
> #include "xe_wa.h"
>
>@@ -395,6 +396,7 @@ int xe_guc_ads_init_post_hwconfig(struct xe_guc_ads *ads)
>
> static void guc_policies_init(struct xe_guc_ads *ads)
> {
>+ struct xe_device *xe = ads_to_xe(ads);
> u32 global_flags = 0;
>
> ads_blob_write(ads, policies.dpc_promote_time,
>@@ -402,8 +404,10 @@ static void guc_policies_init(struct xe_guc_ads *ads)
> ads_blob_write(ads, policies.max_num_work_items,
> GLOBAL_POLICY_MAX_NUM_WI);
>
>- if (xe_modparam.wedged_mode == 2)
>+ mutex_lock(&xe->wedged.lock);
>+ if (xe->wedged.mode == 2)
> global_flags |= GLOBAL_POLICY_DISABLE_ENGINE_RESET;
>+ mutex_unlock(&xe->wedged.lock);
>
> ads_blob_write(ads, policies.global_flags, global_flags);
> ads_blob_write(ads, policies.is_valid, 1);
>@@ -760,3 +764,47 @@ void xe_guc_ads_populate_post_load(struct xe_guc_ads *ads)
> {
> guc_populate_golden_lrc(ads);
> }
>+
>+static int guc_ads_action_update_policies(struct xe_guc_ads *ads, u32 policy_offset)
>+{
>+ struct xe_guc_ct *ct = &ads_to_guc(ads)->ct;
>+ u32 action[] = {
>+ XE_GUC_ACTION_GLOBAL_SCHED_POLICY_CHANGE,
>+ policy_offset
>+ };
>+
>+ return xe_guc_ct_send(ct, action, ARRAY_SIZE(action), 0, 0);
>+}
>+
>+int xe_guc_ads_scheduler_policy_disable_reset(struct xe_guc_ads *ads)
>+{
>+ struct xe_device *xe = ads_to_xe(ads);
>+ struct xe_gt *gt = ads_to_gt(ads);
>+ struct xe_tile *tile = gt_to_tile(gt);
>+ struct guc_policies *policies;
>+ struct xe_bo *bo;
>+ int ret = 0;
>+
>+ policies = kmalloc(sizeof(*policies), GFP_KERNEL);
>+ if (!policies)
>+ return -ENOMEM;
>+
>+ policies->dpc_promote_time = ads_blob_read(ads, policies.dpc_promote_time);
>+ policies->max_num_work_items = ads_blob_read(ads, policies.max_num_work_items);
>+ policies->is_valid = 1;
>+ if (xe->wedged.mode == 2)
>+ policies->global_flags |= GLOBAL_POLICY_DISABLE_ENGINE_RESET;
>+
>+ bo = xe_managed_bo_create_from_data(xe, tile, policies, sizeof(struct guc_policies),
>+ XE_BO_FLAG_VRAM_IF_DGFX(tile) |
>+ XE_BO_FLAG_GGTT);
>+ if (IS_ERR(bo)) {
>+ ret = PTR_ERR(bo);
>+ goto out;
>+ }
>+
>+ ret = guc_ads_action_update_policies(ads, xe_bo_ggtt_addr(bo));
>+out:
>+ kfree(policies);
>+ return ret;
>+}
>diff --git a/drivers/gpu/drm/xe/xe_guc_ads.h b/drivers/gpu/drm/xe/xe_guc_ads.h
>index 138ef6267671..7c45c40fab34 100644
>--- a/drivers/gpu/drm/xe/xe_guc_ads.h
>+++ b/drivers/gpu/drm/xe/xe_guc_ads.h
>@@ -13,5 +13,6 @@ int xe_guc_ads_init_post_hwconfig(struct xe_guc_ads *ads);
> void xe_guc_ads_populate(struct xe_guc_ads *ads);
> void xe_guc_ads_populate_minimal(struct xe_guc_ads *ads);
> void xe_guc_ads_populate_post_load(struct xe_guc_ads *ads);
>+int xe_guc_ads_scheduler_policy_disable_reset(struct xe_guc_ads *ads);
>
> #endif
>diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
>index 0bea17536659..7de97b90ad00 100644
>--- a/drivers/gpu/drm/xe/xe_guc_submit.c
>+++ b/drivers/gpu/drm/xe/xe_guc_submit.c
>@@ -35,7 +35,6 @@
> #include "xe_macros.h"
> #include "xe_map.h"
> #include "xe_mocs.h"
>-#include "xe_module.h"
> #include "xe_ring_ops_types.h"
> #include "xe_sched_job.h"
> #include "xe_trace.h"
>@@ -868,26 +867,33 @@ static void xe_guc_exec_queue_trigger_cleanup(struct xe_exec_queue *q)
> xe_sched_tdr_queue_imm(&q->guc->sched);
> }
>
>-static void guc_submit_wedged(struct xe_guc *guc)
>+static bool guc_submit_hint_wedged(struct xe_guc *guc)
> {
> struct xe_exec_queue *q;
> unsigned long index;
> int err;
>
>- xe_device_declare_wedged(guc_to_xe(guc));
>+ if (xe_device_wedged(guc_to_xe(guc)))
>+ return true;
>+
>+ if (!xe_device_hint_wedged(guc_to_xe(guc), true))
>+ return false;
>+
> xe_guc_submit_reset_prepare(guc);
> xe_guc_ct_stop(&guc->ct);
>
> err = drmm_add_action_or_reset(&guc_to_xe(guc)->drm,
> guc_submit_wedged_fini, guc);
> if (err)
>- return;
>+ return true; /* Device is wedged anyway */
>
> mutex_lock(&guc->submission_state.lock);
> xa_for_each(&guc->submission_state.exec_queue_lookup, index, q)
> if (xe_exec_queue_get_unless_zero(q))
> set_exec_queue_wedged(q);
> mutex_unlock(&guc->submission_state.lock);
>+
>+ return true;
> }
>
> static void xe_guc_exec_queue_lr_cleanup(struct work_struct *w)
>@@ -898,15 +904,12 @@ static void xe_guc_exec_queue_lr_cleanup(struct work_struct *w)
> struct xe_guc *guc = exec_queue_to_guc(q);
> struct xe_device *xe = guc_to_xe(guc);
> struct xe_gpu_scheduler *sched = &ge->sched;
>- bool wedged = xe_device_wedged(xe);
>+ bool wedged;
>
> xe_assert(xe, xe_exec_queue_is_lr(q));
> trace_xe_exec_queue_lr_cleanup(q);
>
>- if (!wedged && xe_modparam.wedged_mode == 2) {
>- guc_submit_wedged(exec_queue_to_guc(q));
>- wedged = true;
>- }
>+ wedged = guc_submit_hint_wedged(exec_queue_to_guc(q));
>
> /* Kill the run_job / process_msg entry points */
> xe_sched_submission_stop(sched);
>@@ -957,7 +960,7 @@ guc_exec_queue_timedout_job(struct drm_sched_job *drm_job)
> struct xe_device *xe = guc_to_xe(exec_queue_to_guc(q));
> int err = -ETIME;
> int i = 0;
>- bool wedged = xe_device_wedged(xe);
>+ bool wedged;
>
> /*
> * TDR has fired before free job worker. Common if exec queue
>@@ -981,10 +984,7 @@ guc_exec_queue_timedout_job(struct drm_sched_job *drm_job)
>
> trace_xe_sched_job_timedout(job);
>
>- if (!wedged && xe_modparam.wedged_mode == 2) {
>- guc_submit_wedged(exec_queue_to_guc(q));
>- wedged = true;
>- }
>+ wedged = guc_submit_hint_wedged(exec_queue_to_guc(q));
>
> /* Kill the run_job entry point */
> xe_sched_submission_stop(sched);
>--
>2.44.0
>
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