[PATCH v13 11/13] drm/i915/guc: Pre-allocate output nodes for extraction

In the rare but possible scenario where we are in the midst of multiple GuC error-capture (and engine reset) events and the user also triggers a forced full GT reset or the internal watchdog triggers the same, intel_guc_submission_reset_prepare's call to flush_work(&guc->ct.requests.worker) can cause the G2H message handler to trigger intel_guc_capture_store_snapshot upon receiving new G2H error-capture notifications. This can happen despite the prior call to disable_submission(guc);. However, there's no race-free way for intel_guc_capture_store_snapshot to know that we are in the midst of a reset. That said, we can never dynamically allocate the output nodes in this handler. Thus, we shall pre-allocate a fixed number of empty nodes up front (at the time of ADS registration) that we can consume from or return to an internal cached list of nodes.

Signed-off-by: Alan Previn alan.previn.teres.alexis@intel.com Reviewed-by: Umesh Nerlige Ramappa umesh.nerlige.ramappa@intel.com --- drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h | 19 +- .../gpu/drm/i915/gt/uc/intel_guc_capture.c | 177 ++++++++++++++---- 2 files changed, 161 insertions(+), 35 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h b/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h index 5d959e62d146..3624abfd22d1 100644 --- a/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h +++ b/drivers/gpu/drm/i915/gt/uc/guc_capture_fwif.h @@ -31,7 +31,7 @@ struct __guc_capture_bufstate { * * A single unit of extracted error-capture output data grouped together * at an engine-instance level. We keep these nodes in a linked list. - * See outlist below. + * See cachelist and outlist below. */ struct __guc_capture_parsed_output { /* @@ -190,7 +190,22 @@ struct intel_guc_state_capture { void *ads_null_cache;

/** - * @outlist: allocated nodes with parsed engine-instance error capture data + * @cachelist: Pool of pre-allocated nodes for error capture output + * + * We need this pool of pre-allocated nodes because we cannot + * dynamically allocate new nodes when receiving the G2H notification + * because the event handlers for all G2H event-processing is called + * by the ct processing worker queue and when that queue is being + * processed, there is no absoluate guarantee that we are not in the + * midst of a GT reset operation (which doesn't allow allocations). + */ + struct list_head cachelist; +#define PREALLOC_NODES_MAX_COUNT (3 * GUC_MAX_ENGINE_CLASSES * GUC_MAX_INSTANCES_PER_CLASS) +#define PREALLOC_NODES_DEFAULT_NUMREGS 64 + int max_mmio_per_node; + + /** + * @outlist: Pool of pre-allocated nodes for error capture output * * A linked list of parsed GuC error-capture output data before * reporting with formatting via i915_gpu_coredump. Each node in this linked list shall diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_capture.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_capture.c index af82f6ff3534..b279d80e4772 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_capture.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_capture.c @@ -581,6 +581,8 @@ intel_guc_capture_getlistsize(struct intel_guc *guc, u32 owner, u32 type, u32 cl return 0; }

+static void guc_capture_create_prealloc_nodes(struct intel_guc *guc); + int intel_guc_capture_getlist(struct intel_guc *guc, u32 owner, u32 type, u32 classid, void **outptr) @@ -601,6 +603,12 @@ intel_guc_capture_getlist(struct intel_guc *guc, u32 owner, u32 type, u32 classi return cache->status; }

+ /* + * ADS population of input registers is a good + * time to pre-allocate cachelist output nodes + */ + guc_capture_create_prealloc_nodes(guc); + ret = intel_guc_capture_getlistsize(guc, owner, type, classid, &size); if (ret) { cache->is_valid = true; @@ -741,7 +749,8 @@ intel_guc_capture_output_min_size_est(struct intel_guc *guc) * err-state-captured register-list we find, we alloc 'C': * --> alloc C: A capture-output-node structure that includes misc capture info along * with 3 register list dumps (global, engine-class and engine-instance) - * This node is dynamically allocated and populated with the error-capture + * This node is created from a pre-allocated list of blank nodes in + * guc->capture->cachelist and populated with the error-capture * data from GuC and then it's added into guc->capture->outlist linked * list. This list is used for matchup and printout by i915_gpu_coredump * and err_print_gt, (when user invokes the error capture sysfs). @@ -901,19 +910,20 @@ guc_capture_delete_one_node(struct intel_guc *guc, struct __guc_capture_parsed_o }

static void -guc_capture_delete_nodes(struct intel_guc *guc) +guc_capture_delete_prealloc_nodes(struct intel_guc *guc) { + struct __guc_capture_parsed_output *n, *ntmp; + /* * NOTE: At the end of driver operation, we must assume that we - * have nodes in outlist from unclaimed error capture events - * that occurred prior to shutdown. + * have prealloc nodes in both the cachelist as well as outlist + * if unclaimed error capture events occurred prior to shutdown. */ - if (!list_empty(&guc->capture->outlist)) { - struct __guc_capture_parsed_output *n, *ntmp; + list_for_each_entry_safe(n, ntmp, &guc->capture->outlist, link) + guc_capture_delete_one_node(guc, n);

- list_for_each_entry_safe(n, ntmp, &guc->capture->outlist, link) - guc_capture_delete_one_node(guc, n); - } + list_for_each_entry_safe(n, ntmp, &guc->capture->cachelist, link) + guc_capture_delete_one_node(guc, n); }

static void @@ -930,21 +940,80 @@ guc_capture_add_node_to_outlist(struct intel_guc_state_capture *gc, guc_capture_add_node_to_list(node, &gc->outlist); }

+static void +guc_capture_add_node_to_cachelist(struct intel_guc_state_capture *gc, + struct __guc_capture_parsed_output *node) +{ + guc_capture_add_node_to_list(node, &gc->cachelist); +} + static void guc_capture_init_node(struct intel_guc *guc, struct __guc_capture_parsed_output *node) { + struct guc_mmio_reg *tmp[GUC_CAPTURE_LIST_TYPE_MAX]; + int i; + + for (i = 0; i < GUC_CAPTURE_LIST_TYPE_MAX; ++i) { + tmp[i] = node->reginfo[i].regs; + memset(tmp[i], 0, sizeof(struct guc_mmio_reg) * + guc->capture->max_mmio_per_node); + } + memset(node, 0, sizeof(*node)); + for (i = 0; i < GUC_CAPTURE_LIST_TYPE_MAX; ++i) + node->reginfo[i].regs = tmp[i]; + INIT_LIST_HEAD(&node->link); }

+static struct __guc_capture_parsed_output * +guc_capture_get_prealloc_node(struct intel_guc *guc) +{ + struct __guc_capture_parsed_output *found = NULL; + + if (!list_empty(&guc->capture->cachelist)) { + struct __guc_capture_parsed_output *n, *ntmp; + + /* get first avail node from the cache list */ + list_for_each_entry_safe(n, ntmp, &guc->capture->cachelist, link) { + found = n; + list_del(&n->link); + break; + } + } else { + struct __guc_capture_parsed_output *n, *ntmp; + + /* traverse down and steal back the oldest node already allocated */ + list_for_each_entry_safe(n, ntmp, &guc->capture->outlist, link) { + found = n; + } + if (found) + list_del(&found->link); + } + if (found) + guc_capture_init_node(guc, found); + + return found; +} + static struct __guc_capture_parsed_output * guc_capture_alloc_one_node(struct intel_guc *guc) { struct __guc_capture_parsed_output *new; + int i;

new = kzalloc(sizeof(*new), GFP_KERNEL); if (!new) return NULL;

+ for (i = 0; i < GUC_CAPTURE_LIST_TYPE_MAX; ++i) { + new->reginfo[i].regs = kcalloc(guc->capture->max_mmio_per_node, + sizeof(struct guc_mmio_reg), GFP_KERNEL); + if (!new->reginfo[i].regs) { + while (i) + kfree(new->reginfo[--i].regs); + return NULL; + } + } guc_capture_init_node(guc, new);

return new; @@ -957,7 +1026,7 @@ guc_capture_clone_node(struct intel_guc *guc, struct __guc_capture_parsed_output struct __guc_capture_parsed_output *new; int i;

- new = guc_capture_alloc_one_node(guc); + new = guc_capture_get_prealloc_node(guc); if (!new) return NULL; if (!original) @@ -968,13 +1037,12 @@ guc_capture_clone_node(struct intel_guc *guc, struct __guc_capture_parsed_output /* copy reg-lists that we want to clone */ for (i = 0; i < GUC_CAPTURE_LIST_TYPE_MAX; ++i) { if (keep_reglist_mask & BIT(i)) { - new->reginfo[i].regs = kcalloc(original->reginfo[i].num_regs, - sizeof(struct guc_mmio_reg), GFP_KERNEL); - if (!new->reginfo[i].regs) - goto bail_clone; + GEM_BUG_ON(original->reginfo[i].num_regs > + guc->capture->max_mmio_per_node);

memcpy(new->reginfo[i].regs, original->reginfo[i].regs, original->reginfo[i].num_regs * sizeof(struct guc_mmio_reg)); + new->reginfo[i].num_regs = original->reginfo[i].num_regs; new->reginfo[i].vfid = original->reginfo[i].vfid;

@@ -989,12 +1057,58 @@ guc_capture_clone_node(struct intel_guc *guc, struct __guc_capture_parsed_output }

return new; +}

-bail_clone: - for (i = 0; i < GUC_CAPTURE_LIST_TYPE_MAX; ++i) - kfree(new->reginfo[i].regs); - kfree(new); - return NULL; +static void +__guc_capture_create_prealloc_nodes(struct intel_guc *guc) +{ + struct __guc_capture_parsed_output *node = NULL; + struct drm_i915_private *i915 = guc_to_gt(guc)->i915; + int i; + + for (i = 0; i < PREALLOC_NODES_MAX_COUNT; ++i) { + node = guc_capture_alloc_one_node(guc); + if (!node) { + drm_warn(&i915->drm, "GuC Capture pre-alloc-cache failure\n"); + /* dont free the priors, use what we got and cleanup at shutdown */ + return; + } + guc_capture_add_node_to_cachelist(guc->capture, node); + } +} + +static int +guc_get_max_reglist_count(struct intel_guc *guc) +{ + int i, j, k, tmp, maxregcount = 0; + + for (i = 0; i < GUC_CAPTURE_LIST_INDEX_MAX; ++i) { + for (j = 0; j < GUC_CAPTURE_LIST_TYPE_MAX; ++j) { + for (k = 0; k < GUC_MAX_ENGINE_CLASSES; ++k) { + if (j == GUC_CAPTURE_LIST_TYPE_GLOBAL && k > 0) + continue; + + tmp = guc_cap_list_num_regs(guc->capture, i, j, k); + if (tmp > maxregcount) + maxregcount = tmp; + } + } + } + if (!maxregcount) + maxregcount = PREALLOC_NODES_DEFAULT_NUMREGS; + + return maxregcount; +} + +static void +guc_capture_create_prealloc_nodes(struct intel_guc *guc) +{ + /* skip if we've already done the pre-alloc */ + if (guc->capture->max_mmio_per_node) + return; + + guc->capture->max_mmio_per_node = guc_get_max_reglist_count(guc); + __guc_capture_create_prealloc_nodes(guc); }

static int @@ -1110,13 +1224,13 @@ guc_capture_extract_reglists(struct intel_guc *guc, struct __guc_capture_bufstat guc_capture_add_node_to_outlist(guc->capture, node); node = NULL; } else if (datatype == GUC_CAPTURE_LIST_TYPE_ENGINE_CLASS && - node->reginfo[GUC_CAPTURE_LIST_TYPE_ENGINE_CLASS].regs) { + node->reginfo[GUC_CAPTURE_LIST_TYPE_ENGINE_CLASS].num_regs) { /* Add to list, clone node and duplicate global list */ guc_capture_add_node_to_outlist(guc->capture, node); node = guc_capture_clone_node(guc, node, GCAP_PARSED_REGLIST_INDEX_GLOBAL); } else if (datatype == GUC_CAPTURE_LIST_TYPE_ENGINE_INSTANCE && - node->reginfo[GUC_CAPTURE_LIST_TYPE_ENGINE_INSTANCE].regs) { + node->reginfo[GUC_CAPTURE_LIST_TYPE_ENGINE_INSTANCE].num_regs) { /* Add to list, clone node and duplicate global + class lists */ guc_capture_add_node_to_outlist(guc->capture, node); node = guc_capture_clone_node(guc, node, @@ -1126,7 +1240,7 @@ guc_capture_extract_reglists(struct intel_guc *guc, struct __guc_capture_bufstat }

if (!node) { - node = guc_capture_alloc_one_node(guc); + node = guc_capture_get_prealloc_node(guc); if (!node) { ret = -ENOMEM; break; @@ -1151,17 +1265,13 @@ guc_capture_extract_reglists(struct intel_guc *guc, struct __guc_capture_bufstat break; }

- regs = NULL; numregs = FIELD_GET(CAP_HDR_NUM_MMIOS, hdr.num_mmios); - if (numregs) { - regs = kcalloc(numregs, sizeof(struct guc_mmio_reg), GFP_KERNEL); - if (!regs) { - ret = -ENOMEM; - break; - } + if (numregs > guc->capture->max_mmio_per_node) { + drm_dbg(&i915->drm, "GuC Capture list extraction clipped by prealloc!\n"); + numregs = guc->capture->max_mmio_per_node; } node->reginfo[datatype].num_regs = numregs; - node->reginfo[datatype].regs = regs; + regs = node->reginfo[datatype].regs; i = 0; while (numregs--) { if (guc_capture_log_get_register(guc, buf, &regs[i++])) { @@ -1181,8 +1291,8 @@ guc_capture_extract_reglists(struct intel_guc *guc, struct __guc_capture_bufstat break; } } - /* else free it */ - kfree(node); + if (node) /* else return it back to cache list */ + guc_capture_add_node_to_cachelist(guc->capture, node); } return ret; } @@ -1290,7 +1400,7 @@ void intel_guc_capture_destroy(struct intel_guc *guc)

guc_capture_free_ads_cache(guc->capture);

- guc_capture_delete_nodes(guc); + guc_capture_delete_prealloc_nodes(guc);

guc_capture_free_extlists(guc->capture->extlists); kfree(guc->capture->extlists); @@ -1308,6 +1418,7 @@ int intel_guc_capture_init(struct intel_guc *guc) guc->capture->reglists = guc_capture_get_device_reglist(guc);

INIT_LIST_HEAD(&guc->capture->outlist); + INIT_LIST_HEAD(&guc->capture->cachelist);

return 0; }