| Message ID | 20230224-track_gt-v1-1-0222096fcdc6@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915: track gt->wakerefs | expand |
On Fri, 24 Feb 2023, Andrzej Hajda <andrzej.hajda@intel.com> wrote: > From: Chris Wilson <chris.p.wilson@intel.com> > > Extract the callstack tracking of intel_runtime_pm.c into its own > utility so that that we can reuse it for other online debugging of > scoped wakerefs. > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > Signed-off-by: Andrzej Hajda <andrzej.hajda@intel.com> > --- > drivers/gpu/drm/i915/Kconfig.debug | 9 + > drivers/gpu/drm/i915/Makefile | 4 + > drivers/gpu/drm/i915/intel_runtime_pm.c | 244 +++------------------------ > drivers/gpu/drm/i915/intel_runtime_pm.h | 10 +- > drivers/gpu/drm/i915/intel_wakeref.h | 6 +- > drivers/gpu/drm/i915/intel_wakeref_tracker.c | 234 +++++++++++++++++++++++++ > drivers/gpu/drm/i915/intel_wakeref_tracker.h | 76 +++++++++ > 7 files changed, 355 insertions(+), 228 deletions(-) > > diff --git a/drivers/gpu/drm/i915/Kconfig.debug b/drivers/gpu/drm/i915/Kconfig.debug > index 93dfb7ed970547..5fde52107e3b44 100644 > --- a/drivers/gpu/drm/i915/Kconfig.debug > +++ b/drivers/gpu/drm/i915/Kconfig.debug > @@ -25,6 +25,7 @@ config DRM_I915_DEBUG > select PREEMPT_COUNT > select I2C_CHARDEV > select STACKDEPOT > + select STACKTRACE > select DRM_DP_AUX_CHARDEV > select X86_MSR # used by igt/pm_rpm > select DRM_VGEM # used by igt/prime_vgem (dmabuf interop checks) > @@ -37,6 +38,7 @@ config DRM_I915_DEBUG > select DRM_I915_DEBUG_GEM > select DRM_I915_DEBUG_GEM_ONCE > select DRM_I915_DEBUG_MMIO > + select DRM_I915_TRACK_WAKEREF > select DRM_I915_DEBUG_RUNTIME_PM > select DRM_I915_SW_FENCE_DEBUG_OBJECTS > select DRM_I915_SELFTEST > @@ -227,11 +229,18 @@ config DRM_I915_DEBUG_VBLANK_EVADE > > If in doubt, say "N". > > +config DRM_I915_TRACK_WAKEREF > + depends on STACKDEPOT > + depends on STACKTRACE > + bool > + > config DRM_I915_DEBUG_RUNTIME_PM > bool "Enable extra state checking for runtime PM" > depends on DRM_I915 > default n > select STACKDEPOT > + select STACKTRACE > + select DRM_I915_TRACK_WAKEREF > help > Choose this option to turn on extra state checking for the > runtime PM functionality. This may introduce overhead during > diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile > index b2f91a1f826858..42daff6d575a82 100644 > --- a/drivers/gpu/drm/i915/Makefile > +++ b/drivers/gpu/drm/i915/Makefile > @@ -81,6 +81,10 @@ i915-$(CONFIG_DEBUG_FS) += \ > i915_debugfs_params.o \ > display/intel_display_debugfs.o \ > display/intel_pipe_crc.o > + > +i915-$(CONFIG_DRM_I915_TRACK_WAKEREF) += \ > + intel_wakeref_tracker.o > + > i915-$(CONFIG_PERF_EVENTS) += i915_pmu.o > > # "Graphics Technology" (aka we talk to the gpu) > diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c > index 129746713d072f..72887e2bb03c21 100644 > --- a/drivers/gpu/drm/i915/intel_runtime_pm.c > +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c > @@ -52,182 +52,37 @@ > > #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM) > > -#include <linux/sort.h> > - > -#define STACKDEPTH 8 > - > -static noinline depot_stack_handle_t __save_depot_stack(void) > -{ > - unsigned long entries[STACKDEPTH]; > - unsigned int n; > - > - n = stack_trace_save(entries, ARRAY_SIZE(entries), 1); > - return stack_depot_save(entries, n, GFP_NOWAIT | __GFP_NOWARN); > -} > - > static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm) > { > - spin_lock_init(&rpm->debug.lock); > - stack_depot_init(); > + intel_wakeref_tracker_init(&rpm->debug); > } > > -static noinline depot_stack_handle_t > +static intel_wakeref_t > track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm) > { > - depot_stack_handle_t stack, *stacks; > - unsigned long flags; > - > - if (rpm->no_wakeref_tracking) > - return -1; > - > - stack = __save_depot_stack(); > - if (!stack) > + if (!rpm->available) > return -1; > > - spin_lock_irqsave(&rpm->debug.lock, flags); > - > - if (!rpm->debug.count) > - rpm->debug.last_acquire = stack; > - > - stacks = krealloc(rpm->debug.owners, > - (rpm->debug.count + 1) * sizeof(*stacks), > - GFP_NOWAIT | __GFP_NOWARN); > - if (stacks) { > - stacks[rpm->debug.count++] = stack; > - rpm->debug.owners = stacks; > - } else { > - stack = -1; > - } > - > - spin_unlock_irqrestore(&rpm->debug.lock, flags); > - > - return stack; > + return intel_wakeref_tracker_add(&rpm->debug); > } > > static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm, > - depot_stack_handle_t stack) > + intel_wakeref_t wakeref) > { > - struct drm_i915_private *i915 = container_of(rpm, > - struct drm_i915_private, > - runtime_pm); > - unsigned long flags, n; > - bool found = false; > - > - if (unlikely(stack == -1)) > - return; > - > - spin_lock_irqsave(&rpm->debug.lock, flags); > - for (n = rpm->debug.count; n--; ) { > - if (rpm->debug.owners[n] == stack) { > - memmove(rpm->debug.owners + n, > - rpm->debug.owners + n + 1, > - (--rpm->debug.count - n) * sizeof(stack)); > - found = true; > - break; > - } > - } > - spin_unlock_irqrestore(&rpm->debug.lock, flags); > - > - if (drm_WARN(&i915->drm, !found, > - "Unmatched wakeref (tracking %lu), count %u\n", > - rpm->debug.count, atomic_read(&rpm->wakeref_count))) { > - char *buf; > - > - buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN); > - if (!buf) > - return; > - > - stack_depot_snprint(stack, buf, PAGE_SIZE, 2); > - DRM_DEBUG_DRIVER("wakeref %x from\n%s", stack, buf); > - > - stack = READ_ONCE(rpm->debug.last_release); > - if (stack) { > - stack_depot_snprint(stack, buf, PAGE_SIZE, 2); > - DRM_DEBUG_DRIVER("wakeref last released at\n%s", buf); > - } > - > - kfree(buf); > - } > + intel_wakeref_tracker_remove(&rpm->debug, wakeref); > } > > -static int cmphandle(const void *_a, const void *_b) > +static void untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm) > { > - const depot_stack_handle_t * const a = _a, * const b = _b; > + struct drm_printer p = drm_debug_printer("i915"); > > - if (*a < *b) > - return -1; > - else if (*a > *b) > - return 1; > - else > - return 0; > -} > - > -static void > -__print_intel_runtime_pm_wakeref(struct drm_printer *p, > - const struct intel_runtime_pm_debug *dbg) > -{ > - unsigned long i; > - char *buf; > - > - buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN); > - if (!buf) > - return; > - > - if (dbg->last_acquire) { > - stack_depot_snprint(dbg->last_acquire, buf, PAGE_SIZE, 2); > - drm_printf(p, "Wakeref last acquired:\n%s", buf); > - } > - > - if (dbg->last_release) { > - stack_depot_snprint(dbg->last_release, buf, PAGE_SIZE, 2); > - drm_printf(p, "Wakeref last released:\n%s", buf); > - } > - > - drm_printf(p, "Wakeref count: %lu\n", dbg->count); > - > - sort(dbg->owners, dbg->count, sizeof(*dbg->owners), cmphandle, NULL); > - > - for (i = 0; i < dbg->count; i++) { > - depot_stack_handle_t stack = dbg->owners[i]; > - unsigned long rep; > - > - rep = 1; > - while (i + 1 < dbg->count && dbg->owners[i + 1] == stack) > - rep++, i++; > - stack_depot_snprint(stack, buf, PAGE_SIZE, 2); > - drm_printf(p, "Wakeref x%lu taken at:\n%s", rep, buf); > - } > - > - kfree(buf); > -} > - > -static noinline void > -__untrack_all_wakerefs(struct intel_runtime_pm_debug *debug, > - struct intel_runtime_pm_debug *saved) > -{ > - *saved = *debug; > - > - debug->owners = NULL; > - debug->count = 0; > - debug->last_release = __save_depot_stack(); > -} > - > -static void > -dump_and_free_wakeref_tracking(struct intel_runtime_pm_debug *debug) > -{ > - if (debug->count) { > - struct drm_printer p = drm_debug_printer("i915"); > - > - __print_intel_runtime_pm_wakeref(&p, debug); > - } > - > - kfree(debug->owners); > + intel_wakeref_tracker_reset(&rpm->debug, &p); > } > > static noinline void > __intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm) > { > - struct intel_runtime_pm_debug dbg = {}; > + struct intel_wakeref_tracker saved; > unsigned long flags; > > if (!atomic_dec_and_lock_irqsave(&rpm->wakeref_count, > @@ -235,60 +90,21 @@ __intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm) > flags)) > return; > > - __untrack_all_wakerefs(&rpm->debug, &dbg); > + saved = __intel_wakeref_tracker_reset(&rpm->debug); > spin_unlock_irqrestore(&rpm->debug.lock, flags); > > - dump_and_free_wakeref_tracking(&dbg); > -} > - > -static noinline void > -untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm) > -{ > - struct intel_runtime_pm_debug dbg = {}; > - unsigned long flags; > - > - spin_lock_irqsave(&rpm->debug.lock, flags); > - __untrack_all_wakerefs(&rpm->debug, &dbg); > - spin_unlock_irqrestore(&rpm->debug.lock, flags); > + if (saved.count) { > + struct drm_printer p = drm_debug_printer("i915"); > > - dump_and_free_wakeref_tracking(&dbg); > + __intel_wakeref_tracker_show(&saved, &p); > + intel_wakeref_tracker_fini(&saved); > + } > } > > void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm, > struct drm_printer *p) > { > - struct intel_runtime_pm_debug dbg = {}; > - > - do { > - unsigned long alloc = dbg.count; > - depot_stack_handle_t *s; > - > - spin_lock_irq(&rpm->debug.lock); > - dbg.count = rpm->debug.count; > - if (dbg.count <= alloc) { > - memcpy(dbg.owners, > - rpm->debug.owners, > - dbg.count * sizeof(*s)); > - } > - dbg.last_acquire = rpm->debug.last_acquire; > - dbg.last_release = rpm->debug.last_release; > - spin_unlock_irq(&rpm->debug.lock); > - if (dbg.count <= alloc) > - break; > - > - s = krealloc(dbg.owners, > - dbg.count * sizeof(*s), > - GFP_NOWAIT | __GFP_NOWARN); > - if (!s) > - goto out; > - > - dbg.owners = s; > - } while (1); > - > - __print_intel_runtime_pm_wakeref(p, &dbg); > - > -out: > - kfree(dbg.owners); > + intel_wakeref_tracker_show(&rpm->debug, p); > } > > #else > @@ -297,14 +113,14 @@ static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm) > { > } > > -static depot_stack_handle_t > +static intel_wakeref_t > track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm) > { > return -1; > } > > static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm, > - intel_wakeref_t wref) > + intel_wakeref_t wakeref) > { > } > > @@ -349,9 +165,8 @@ intel_runtime_pm_release(struct intel_runtime_pm *rpm, int wakelock) > static intel_wakeref_t __intel_runtime_pm_get(struct intel_runtime_pm *rpm, > bool wakelock) > { > - struct drm_i915_private *i915 = container_of(rpm, > - struct drm_i915_private, > - runtime_pm); > + struct drm_i915_private *i915 = > + container_of(rpm, struct drm_i915_private, runtime_pm); > int ret; > > ret = pm_runtime_get_sync(rpm->kdev); > @@ -556,9 +371,8 @@ void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref) > */ > void intel_runtime_pm_enable(struct intel_runtime_pm *rpm) > { > - struct drm_i915_private *i915 = container_of(rpm, > - struct drm_i915_private, > - runtime_pm); > + struct drm_i915_private *i915 = > + container_of(rpm, struct drm_i915_private, runtime_pm); > struct device *kdev = rpm->kdev; > > /* > @@ -611,9 +425,8 @@ void intel_runtime_pm_enable(struct intel_runtime_pm *rpm) > > void intel_runtime_pm_disable(struct intel_runtime_pm *rpm) > { > - struct drm_i915_private *i915 = container_of(rpm, > - struct drm_i915_private, > - runtime_pm); > + struct drm_i915_private *i915 = > + container_of(rpm, struct drm_i915_private, runtime_pm); > struct device *kdev = rpm->kdev; > > /* Transfer rpm ownership back to core */ > @@ -628,9 +441,8 @@ void intel_runtime_pm_disable(struct intel_runtime_pm *rpm) > > void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm) > { > - struct drm_i915_private *i915 = container_of(rpm, > - struct drm_i915_private, > - runtime_pm); > + struct drm_i915_private *i915 = > + container_of(rpm, struct drm_i915_private, runtime_pm); > int count = atomic_read(&rpm->wakeref_count); > > intel_wakeref_auto_fini(&rpm->userfault_wakeref); > @@ -646,7 +458,7 @@ void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm) > void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm) > { > struct drm_i915_private *i915 = > - container_of(rpm, struct drm_i915_private, runtime_pm); > + container_of(rpm, struct drm_i915_private, runtime_pm); Lots of unrelated changes above that should be separate patches. > struct pci_dev *pdev = to_pci_dev(i915->drm.dev); > struct device *kdev = &pdev->dev; > > diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.h b/drivers/gpu/drm/i915/intel_runtime_pm.h > index e592e8d6499a1f..a8dc2baf79844f 100644 > --- a/drivers/gpu/drm/i915/intel_runtime_pm.h > +++ b/drivers/gpu/drm/i915/intel_runtime_pm.h > @@ -83,15 +83,7 @@ struct intel_runtime_pm { > * paired rpm_put) we can remove corresponding pairs of and keep > * the array trimmed to active wakerefs. > */ > - struct intel_runtime_pm_debug { > - spinlock_t lock; > - > - depot_stack_handle_t last_acquire; > - depot_stack_handle_t last_release; > - > - depot_stack_handle_t *owners; > - unsigned long count; > - } debug; > + struct intel_wakeref_tracker debug; There's a lot going on in the patch all around. Adding the struct to a separate file could maybe be an individual patch to simplify the actual changes. This doesn't include the file that defines struct intel_wakeref_tracker; it's included via intel_wakeref.h. But only if > #endif > }; > > diff --git a/drivers/gpu/drm/i915/intel_wakeref.h b/drivers/gpu/drm/i915/intel_wakeref.h > index 71b8a63f6f104d..20720fbcc28d46 100644 > --- a/drivers/gpu/drm/i915/intel_wakeref.h > +++ b/drivers/gpu/drm/i915/intel_wakeref.h > @@ -17,7 +17,9 @@ > #include <linux/timer.h> > #include <linux/workqueue.h> > > -#if IS_ENABLED(CONFIG_DRM_I915_DEBUG) > +#include "intel_wakeref_tracker.h" > + > +#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF) > #define INTEL_WAKEREF_BUG_ON(expr) BUG_ON(expr) > #else > #define INTEL_WAKEREF_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr) > @@ -26,8 +28,6 @@ > struct intel_runtime_pm; > struct intel_wakeref; > > -typedef depot_stack_handle_t intel_wakeref_t; > - > struct intel_wakeref_ops { > int (*get)(struct intel_wakeref *wf); > int (*put)(struct intel_wakeref *wf); > diff --git a/drivers/gpu/drm/i915/intel_wakeref_tracker.c b/drivers/gpu/drm/i915/intel_wakeref_tracker.c > new file mode 100644 > index 00000000000000..a0bcef13a1085a > --- /dev/null > +++ b/drivers/gpu/drm/i915/intel_wakeref_tracker.c > @@ -0,0 +1,234 @@ > +// SPDX-License-Identifier: MIT > +/* > + * Copyright © 2021 Intel Corporation > + */ > + > +#include <linux/slab.h> > +#include <linux/stackdepot.h> > +#include <linux/stacktrace.h> > +#include <linux/sort.h> > + > +#include <drm/drm_print.h> > + > +#include "intel_wakeref.h" This should really include the corresponding .h i.e. intel_wakeref_tracker.h too. Now it gets included via intel_wakeref.h but I'm not sure why. > + > +#define STACKDEPTH 8 > + > +static noinline depot_stack_handle_t __save_depot_stack(void) > +{ > + unsigned long entries[STACKDEPTH]; > + unsigned int n; > + > + n = stack_trace_save(entries, ARRAY_SIZE(entries), 1); > + return stack_depot_save(entries, n, GFP_NOWAIT | __GFP_NOWARN); > +} > + > +static void __print_depot_stack(depot_stack_handle_t stack, > + char *buf, int sz, int indent) > +{ > + unsigned long *entries; > + unsigned int nr_entries; > + > + nr_entries = stack_depot_fetch(stack, &entries); > + stack_trace_snprint(buf, sz, entries, nr_entries, indent); > +} > + > +static int cmphandle(const void *_a, const void *_b) > +{ > + const depot_stack_handle_t * const a = _a, * const b = _b; > + > + if (*a < *b) > + return -1; > + else if (*a > *b) > + return 1; > + else > + return 0; > +} > + > +void > +__intel_wakeref_tracker_show(const struct intel_wakeref_tracker *w, > + struct drm_printer *p) > +{ > + unsigned long i; > + char *buf; > + > + buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN); > + if (!buf) > + return; > + > + if (w->last_acquire) { > + __print_depot_stack(w->last_acquire, buf, PAGE_SIZE, 2); > + drm_printf(p, "Wakeref last acquired:\n%s", buf); > + } > + > + if (w->last_release) { > + __print_depot_stack(w->last_release, buf, PAGE_SIZE, 2); > + drm_printf(p, "Wakeref last released:\n%s", buf); > + } > + > + drm_printf(p, "Wakeref count: %lu\n", w->count); > + > + sort(w->owners, w->count, sizeof(*w->owners), cmphandle, NULL); > + > + for (i = 0; i < w->count; i++) { > + depot_stack_handle_t stack = w->owners[i]; > + unsigned long rep; > + > + rep = 1; > + while (i + 1 < w->count && w->owners[i + 1] == stack) > + rep++, i++; > + __print_depot_stack(stack, buf, PAGE_SIZE, 2); > + drm_printf(p, "Wakeref x%lu taken at:\n%s", rep, buf); > + } > + > + kfree(buf); > +} > + > +void intel_wakeref_tracker_show(struct intel_wakeref_tracker *w, > + struct drm_printer *p) > +{ > + struct intel_wakeref_tracker tmp = {}; > + > + do { > + unsigned long alloc = tmp.count; > + depot_stack_handle_t *s; > + > + spin_lock_irq(&w->lock); > + tmp.count = w->count; > + if (tmp.count <= alloc) > + memcpy(tmp.owners, w->owners, tmp.count * sizeof(*s)); > + tmp.last_acquire = w->last_acquire; > + tmp.last_release = w->last_release; > + spin_unlock_irq(&w->lock); > + if (tmp.count <= alloc) > + break; > + > + s = krealloc(tmp.owners, > + tmp.count * sizeof(*s), > + GFP_NOWAIT | __GFP_NOWARN); > + if (!s) > + goto out; > + > + tmp.owners = s; > + } while (1); > + > + __intel_wakeref_tracker_show(&tmp, p); > + > +out: > + intel_wakeref_tracker_fini(&tmp); > +} > + > +intel_wakeref_t intel_wakeref_tracker_add(struct intel_wakeref_tracker *w) > +{ > + depot_stack_handle_t stack, *stacks; > + unsigned long flags; > + > + stack = __save_depot_stack(); > + if (!stack) > + return -1; > + > + spin_lock_irqsave(&w->lock, flags); > + > + if (!w->count) > + w->last_acquire = stack; > + > + stacks = krealloc(w->owners, > + (w->count + 1) * sizeof(*stacks), > + GFP_NOWAIT | __GFP_NOWARN); > + if (stacks) { > + stacks[w->count++] = stack; > + w->owners = stacks; > + } else { > + stack = -1; > + } > + > + spin_unlock_irqrestore(&w->lock, flags); > + > + return stack; > +} > + > +void intel_wakeref_tracker_remove(struct intel_wakeref_tracker *w, > + intel_wakeref_t stack) > +{ > + unsigned long flags, n; > + bool found = false; > + > + if (unlikely(stack == -1)) > + return; > + > + spin_lock_irqsave(&w->lock, flags); > + for (n = w->count; n--; ) { > + if (w->owners[n] == stack) { > + memmove(w->owners + n, > + w->owners + n + 1, > + (--w->count - n) * sizeof(stack)); > + found = true; > + break; > + } > + } > + spin_unlock_irqrestore(&w->lock, flags); > + > + if (WARN(!found, > + "Unmatched wakeref %x, tracking %lu\n", > + stack, w->count)) { > + char *buf; > + > + buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN); > + if (!buf) > + return; > + > + __print_depot_stack(stack, buf, PAGE_SIZE, 2); > + pr_err("wakeref %x from\n%s", stack, buf); > + > + stack = READ_ONCE(w->last_release); > + if (stack && !w->count) { > + __print_depot_stack(stack, buf, PAGE_SIZE, 2); > + pr_err("wakeref last released at\n%s", buf); > + } > + > + kfree(buf); > + } > +} > + > +struct intel_wakeref_tracker > +__intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w) > +{ > + struct intel_wakeref_tracker saved; > + > + lockdep_assert_held(&w->lock); > + > + saved = *w; > + > + w->owners = NULL; > + w->count = 0; > + w->last_release = __save_depot_stack(); > + > + return saved; > +} > + > +void intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w, > + struct drm_printer *p) > +{ > + struct intel_wakeref_tracker tmp; > + > + spin_lock_irq(&w->lock); > + tmp = __intel_wakeref_tracker_reset(w); > + spin_unlock_irq(&w->lock); > + > + if (tmp.count) > + __intel_wakeref_tracker_show(&tmp, p); > + > + intel_wakeref_tracker_fini(&tmp); > +} > + > +void intel_wakeref_tracker_init(struct intel_wakeref_tracker *w) > +{ > + memset(w, 0, sizeof(*w)); > + spin_lock_init(&w->lock); > + stack_depot_init(); > +} > + > +void intel_wakeref_tracker_fini(struct intel_wakeref_tracker *w) > +{ > + kfree(w->owners); > +} > diff --git a/drivers/gpu/drm/i915/intel_wakeref_tracker.h b/drivers/gpu/drm/i915/intel_wakeref_tracker.h > new file mode 100644 > index 00000000000000..61df68e28c0fbf > --- /dev/null > +++ b/drivers/gpu/drm/i915/intel_wakeref_tracker.h > @@ -0,0 +1,76 @@ > +/* SPDX-License-Identifier: MIT */ > +/* > + * Copyright © 2019 Intel Corporation > + */ > + > +#ifndef INTEL_WAKEREF_TRACKER_H > +#define INTEL_WAKEREF_TRACKER_H > + > +#include <linux/kconfig.h> > +#include <linux/spinlock.h> > +#include <linux/stackdepot.h> > + > +typedef depot_stack_handle_t intel_wakeref_t; > + > +struct drm_printer; > + > +struct intel_wakeref_tracker { > + spinlock_t lock; > + > + depot_stack_handle_t last_acquire; > + depot_stack_handle_t last_release; > + > + depot_stack_handle_t *owners; > + unsigned long count; > +}; > + > +#if IS_ENABLED(CONFIG_DRM_I915_TRACK_WAKEREF) > + > +void intel_wakeref_tracker_init(struct intel_wakeref_tracker *w); > +void intel_wakeref_tracker_fini(struct intel_wakeref_tracker *w); > + > +intel_wakeref_t intel_wakeref_tracker_add(struct intel_wakeref_tracker *w); > +void intel_wakeref_tracker_remove(struct intel_wakeref_tracker *w, > + intel_wakeref_t handle); > + > +struct intel_wakeref_tracker > +__intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w); > +void intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w, > + struct drm_printer *p); > + > +void __intel_wakeref_tracker_show(const struct intel_wakeref_tracker *w, > + struct drm_printer *p); > +void intel_wakeref_tracker_show(struct intel_wakeref_tracker *w, > + struct drm_printer *p); > + > +#else > + > +static inline void intel_wakeref_tracker_init(struct intel_wakeref_tracker *w) {} > +static inline void intel_wakeref_tracker_fini(struct intel_wakeref_tracker *w) {} > + > +static inline intel_wakeref_t > +intel_wakeref_tracker_add(struct intel_wakeref_tracker *w) > +{ > + return -1; > +} > + > +static inline void > +intel_wakeref_untrack_remove(struct intel_wakeref_tracker *w, intel_wakeref_t handle) {} > + > +static inline struct intel_wakeref_tracker > +__intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w) > +{ > + return (struct intel_wakeref_tracker){}; > +} > + > +static inline void intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w, > + struct drm_printer *p) > +{ > +} > + > +static inline void __intel_wakeref_tracker_show(const struct intel_wakeref_tracker *w, struct drm_printer *p) {} > +static inline void intel_wakeref_tracker_show(struct intel_wakeref_tracker *w, struct drm_printer *p) {} > + > +#endif > + > +#endif /* INTEL_WAKEREF_TRACKER_H */
On 27.02.2023 12:50, Jani Nikula wrote: > On Fri, 24 Feb 2023, Andrzej Hajda <andrzej.hajda@intel.com> wrote: >> From: Chris Wilson <chris.p.wilson@intel.com> >> >> Extract the callstack tracking of intel_runtime_pm.c into its own >> utility so that that we can reuse it for other online debugging of >> scoped wakerefs. >> >> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> >> Signed-off-by: Andrzej Hajda <andrzej.hajda@intel.com> >> --- >> drivers/gpu/drm/i915/Kconfig.debug | 9 + >> drivers/gpu/drm/i915/Makefile | 4 + >> drivers/gpu/drm/i915/intel_runtime_pm.c | 244 +++------------------------ >> drivers/gpu/drm/i915/intel_runtime_pm.h | 10 +- >> drivers/gpu/drm/i915/intel_wakeref.h | 6 +- >> drivers/gpu/drm/i915/intel_wakeref_tracker.c | 234 +++++++++++++++++++++++++ >> drivers/gpu/drm/i915/intel_wakeref_tracker.h | 76 +++++++++ >> 7 files changed, 355 insertions(+), 228 deletions(-) >> >> diff --git a/drivers/gpu/drm/i915/Kconfig.debug b/drivers/gpu/drm/i915/Kconfig.debug >> index 93dfb7ed970547..5fde52107e3b44 100644 >> --- a/drivers/gpu/drm/i915/Kconfig.debug >> +++ b/drivers/gpu/drm/i915/Kconfig.debug >> @@ -25,6 +25,7 @@ config DRM_I915_DEBUG >> select PREEMPT_COUNT >> select I2C_CHARDEV >> select STACKDEPOT >> + select STACKTRACE >> select DRM_DP_AUX_CHARDEV >> select X86_MSR # used by igt/pm_rpm >> select DRM_VGEM # used by igt/prime_vgem (dmabuf interop checks) >> @@ -37,6 +38,7 @@ config DRM_I915_DEBUG >> select DRM_I915_DEBUG_GEM >> select DRM_I915_DEBUG_GEM_ONCE >> select DRM_I915_DEBUG_MMIO >> + select DRM_I915_TRACK_WAKEREF >> select DRM_I915_DEBUG_RUNTIME_PM >> select DRM_I915_SW_FENCE_DEBUG_OBJECTS >> select DRM_I915_SELFTEST >> @@ -227,11 +229,18 @@ config DRM_I915_DEBUG_VBLANK_EVADE >> >> If in doubt, say "N". >> >> +config DRM_I915_TRACK_WAKEREF >> + depends on STACKDEPOT >> + depends on STACKTRACE >> + bool >> + >> config DRM_I915_DEBUG_RUNTIME_PM >> bool "Enable extra state checking for runtime PM" >> depends on DRM_I915 >> default n >> select STACKDEPOT >> + select STACKTRACE >> + select DRM_I915_TRACK_WAKEREF >> help >> Choose this option to turn on extra state checking for the >> runtime PM functionality. This may introduce overhead during >> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile >> index b2f91a1f826858..42daff6d575a82 100644 >> --- a/drivers/gpu/drm/i915/Makefile >> +++ b/drivers/gpu/drm/i915/Makefile >> @@ -81,6 +81,10 @@ i915-$(CONFIG_DEBUG_FS) += \ >> i915_debugfs_params.o \ >> display/intel_display_debugfs.o \ >> display/intel_pipe_crc.o >> + >> +i915-$(CONFIG_DRM_I915_TRACK_WAKEREF) += \ >> + intel_wakeref_tracker.o >> + >> i915-$(CONFIG_PERF_EVENTS) += i915_pmu.o >> >> # "Graphics Technology" (aka we talk to the gpu) >> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c >> index 129746713d072f..72887e2bb03c21 100644 >> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c >> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c >> @@ -52,182 +52,37 @@ >> >> #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM) >> >> -#include <linux/sort.h> >> - >> -#define STACKDEPTH 8 >> - >> -static noinline depot_stack_handle_t __save_depot_stack(void) >> -{ >> - unsigned long entries[STACKDEPTH]; >> - unsigned int n; >> - >> - n = stack_trace_save(entries, ARRAY_SIZE(entries), 1); >> - return stack_depot_save(entries, n, GFP_NOWAIT | __GFP_NOWARN); >> -} >> - >> static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm) >> { >> - spin_lock_init(&rpm->debug.lock); >> - stack_depot_init(); >> + intel_wakeref_tracker_init(&rpm->debug); >> } >> >> -static noinline depot_stack_handle_t >> +static intel_wakeref_t >> track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm) >> { >> - depot_stack_handle_t stack, *stacks; >> - unsigned long flags; >> - >> - if (rpm->no_wakeref_tracking) >> - return -1; >> - >> - stack = __save_depot_stack(); >> - if (!stack) >> + if (!rpm->available) >> return -1; >> >> - spin_lock_irqsave(&rpm->debug.lock, flags); >> - >> - if (!rpm->debug.count) >> - rpm->debug.last_acquire = stack; >> - >> - stacks = krealloc(rpm->debug.owners, >> - (rpm->debug.count + 1) * sizeof(*stacks), >> - GFP_NOWAIT | __GFP_NOWARN); >> - if (stacks) { >> - stacks[rpm->debug.count++] = stack; >> - rpm->debug.owners = stacks; >> - } else { >> - stack = -1; >> - } >> - >> - spin_unlock_irqrestore(&rpm->debug.lock, flags); >> - >> - return stack; >> + return intel_wakeref_tracker_add(&rpm->debug); >> } >> >> static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm, >> - depot_stack_handle_t stack) >> + intel_wakeref_t wakeref) >> { >> - struct drm_i915_private *i915 = container_of(rpm, >> - struct drm_i915_private, >> - runtime_pm); >> - unsigned long flags, n; >> - bool found = false; >> - >> - if (unlikely(stack == -1)) >> - return; >> - >> - spin_lock_irqsave(&rpm->debug.lock, flags); >> - for (n = rpm->debug.count; n--; ) { >> - if (rpm->debug.owners[n] == stack) { >> - memmove(rpm->debug.owners + n, >> - rpm->debug.owners + n + 1, >> - (--rpm->debug.count - n) * sizeof(stack)); >> - found = true; >> - break; >> - } >> - } >> - spin_unlock_irqrestore(&rpm->debug.lock, flags); >> - >> - if (drm_WARN(&i915->drm, !found, >> - "Unmatched wakeref (tracking %lu), count %u\n", >> - rpm->debug.count, atomic_read(&rpm->wakeref_count))) { >> - char *buf; >> - >> - buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN); >> - if (!buf) >> - return; >> - >> - stack_depot_snprint(stack, buf, PAGE_SIZE, 2); >> - DRM_DEBUG_DRIVER("wakeref %x from\n%s", stack, buf); >> - >> - stack = READ_ONCE(rpm->debug.last_release); >> - if (stack) { >> - stack_depot_snprint(stack, buf, PAGE_SIZE, 2); >> - DRM_DEBUG_DRIVER("wakeref last released at\n%s", buf); >> - } >> - >> - kfree(buf); >> - } >> + intel_wakeref_tracker_remove(&rpm->debug, wakeref); >> } >> >> -static int cmphandle(const void *_a, const void *_b) >> +static void untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm) >> { >> - const depot_stack_handle_t * const a = _a, * const b = _b; >> + struct drm_printer p = drm_debug_printer("i915"); >> >> - if (*a < *b) >> - return -1; >> - else if (*a > *b) >> - return 1; >> - else >> - return 0; >> -} >> - >> -static void >> -__print_intel_runtime_pm_wakeref(struct drm_printer *p, >> - const struct intel_runtime_pm_debug *dbg) >> -{ >> - unsigned long i; >> - char *buf; >> - >> - buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN); >> - if (!buf) >> - return; >> - >> - if (dbg->last_acquire) { >> - stack_depot_snprint(dbg->last_acquire, buf, PAGE_SIZE, 2); >> - drm_printf(p, "Wakeref last acquired:\n%s", buf); >> - } >> - >> - if (dbg->last_release) { >> - stack_depot_snprint(dbg->last_release, buf, PAGE_SIZE, 2); >> - drm_printf(p, "Wakeref last released:\n%s", buf); >> - } >> - >> - drm_printf(p, "Wakeref count: %lu\n", dbg->count); >> - >> - sort(dbg->owners, dbg->count, sizeof(*dbg->owners), cmphandle, NULL); >> - >> - for (i = 0; i < dbg->count; i++) { >> - depot_stack_handle_t stack = dbg->owners[i]; >> - unsigned long rep; >> - >> - rep = 1; >> - while (i + 1 < dbg->count && dbg->owners[i + 1] == stack) >> - rep++, i++; >> - stack_depot_snprint(stack, buf, PAGE_SIZE, 2); >> - drm_printf(p, "Wakeref x%lu taken at:\n%s", rep, buf); >> - } >> - >> - kfree(buf); >> -} >> - >> -static noinline void >> -__untrack_all_wakerefs(struct intel_runtime_pm_debug *debug, >> - struct intel_runtime_pm_debug *saved) >> -{ >> - *saved = *debug; >> - >> - debug->owners = NULL; >> - debug->count = 0; >> - debug->last_release = __save_depot_stack(); >> -} >> - >> -static void >> -dump_and_free_wakeref_tracking(struct intel_runtime_pm_debug *debug) >> -{ >> - if (debug->count) { >> - struct drm_printer p = drm_debug_printer("i915"); >> - >> - __print_intel_runtime_pm_wakeref(&p, debug); >> - } >> - >> - kfree(debug->owners); >> + intel_wakeref_tracker_reset(&rpm->debug, &p); >> } >> >> static noinline void >> __intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm) >> { >> - struct intel_runtime_pm_debug dbg = {}; >> + struct intel_wakeref_tracker saved; >> unsigned long flags; >> >> if (!atomic_dec_and_lock_irqsave(&rpm->wakeref_count, >> @@ -235,60 +90,21 @@ __intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm) >> flags)) >> return; >> >> - __untrack_all_wakerefs(&rpm->debug, &dbg); >> + saved = __intel_wakeref_tracker_reset(&rpm->debug); >> spin_unlock_irqrestore(&rpm->debug.lock, flags); >> >> - dump_and_free_wakeref_tracking(&dbg); >> -} >> - >> -static noinline void >> -untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm) >> -{ >> - struct intel_runtime_pm_debug dbg = {}; >> - unsigned long flags; >> - >> - spin_lock_irqsave(&rpm->debug.lock, flags); >> - __untrack_all_wakerefs(&rpm->debug, &dbg); >> - spin_unlock_irqrestore(&rpm->debug.lock, flags); >> + if (saved.count) { >> + struct drm_printer p = drm_debug_printer("i915"); >> >> - dump_and_free_wakeref_tracking(&dbg); >> + __intel_wakeref_tracker_show(&saved, &p); >> + intel_wakeref_tracker_fini(&saved); >> + } >> } >> >> void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm, >> struct drm_printer *p) >> { >> - struct intel_runtime_pm_debug dbg = {}; >> - >> - do { >> - unsigned long alloc = dbg.count; >> - depot_stack_handle_t *s; >> - >> - spin_lock_irq(&rpm->debug.lock); >> - dbg.count = rpm->debug.count; >> - if (dbg.count <= alloc) { >> - memcpy(dbg.owners, >> - rpm->debug.owners, >> - dbg.count * sizeof(*s)); >> - } >> - dbg.last_acquire = rpm->debug.last_acquire; >> - dbg.last_release = rpm->debug.last_release; >> - spin_unlock_irq(&rpm->debug.lock); >> - if (dbg.count <= alloc) >> - break; >> - >> - s = krealloc(dbg.owners, >> - dbg.count * sizeof(*s), >> - GFP_NOWAIT | __GFP_NOWARN); >> - if (!s) >> - goto out; >> - >> - dbg.owners = s; >> - } while (1); >> - >> - __print_intel_runtime_pm_wakeref(p, &dbg); >> - >> -out: >> - kfree(dbg.owners); >> + intel_wakeref_tracker_show(&rpm->debug, p); >> } >> >> #else >> @@ -297,14 +113,14 @@ static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm) >> { >> } >> >> -static depot_stack_handle_t >> +static intel_wakeref_t >> track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm) >> { >> return -1; >> } >> >> static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm, >> - intel_wakeref_t wref) >> + intel_wakeref_t wakeref) >> { >> } >> >> @@ -349,9 +165,8 @@ intel_runtime_pm_release(struct intel_runtime_pm *rpm, int wakelock) >> static intel_wakeref_t __intel_runtime_pm_get(struct intel_runtime_pm *rpm, >> bool wakelock) >> { >> - struct drm_i915_private *i915 = container_of(rpm, >> - struct drm_i915_private, >> - runtime_pm); >> + struct drm_i915_private *i915 = >> + container_of(rpm, struct drm_i915_private, runtime_pm); >> int ret; >> >> ret = pm_runtime_get_sync(rpm->kdev); >> @@ -556,9 +371,8 @@ void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref) >> */ >> void intel_runtime_pm_enable(struct intel_runtime_pm *rpm) >> { >> - struct drm_i915_private *i915 = container_of(rpm, >> - struct drm_i915_private, >> - runtime_pm); >> + struct drm_i915_private *i915 = >> + container_of(rpm, struct drm_i915_private, runtime_pm); >> struct device *kdev = rpm->kdev; >> >> /* >> @@ -611,9 +425,8 @@ void intel_runtime_pm_enable(struct intel_runtime_pm *rpm) >> >> void intel_runtime_pm_disable(struct intel_runtime_pm *rpm) >> { >> - struct drm_i915_private *i915 = container_of(rpm, >> - struct drm_i915_private, >> - runtime_pm); >> + struct drm_i915_private *i915 = >> + container_of(rpm, struct drm_i915_private, runtime_pm); >> struct device *kdev = rpm->kdev; >> >> /* Transfer rpm ownership back to core */ >> @@ -628,9 +441,8 @@ void intel_runtime_pm_disable(struct intel_runtime_pm *rpm) >> >> void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm) >> { >> - struct drm_i915_private *i915 = container_of(rpm, >> - struct drm_i915_private, >> - runtime_pm); >> + struct drm_i915_private *i915 = >> + container_of(rpm, struct drm_i915_private, runtime_pm); >> int count = atomic_read(&rpm->wakeref_count); >> >> intel_wakeref_auto_fini(&rpm->userfault_wakeref); >> @@ -646,7 +458,7 @@ void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm) >> void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm) >> { >> struct drm_i915_private *i915 = >> - container_of(rpm, struct drm_i915_private, runtime_pm); >> + container_of(rpm, struct drm_i915_private, runtime_pm); > > Lots of unrelated changes above that should be separate patches. OK > >> struct pci_dev *pdev = to_pci_dev(i915->drm.dev); >> struct device *kdev = &pdev->dev; >> >> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.h b/drivers/gpu/drm/i915/intel_runtime_pm.h >> index e592e8d6499a1f..a8dc2baf79844f 100644 >> --- a/drivers/gpu/drm/i915/intel_runtime_pm.h >> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.h >> @@ -83,15 +83,7 @@ struct intel_runtime_pm { >> * paired rpm_put) we can remove corresponding pairs of and keep >> * the array trimmed to active wakerefs. >> */ >> - struct intel_runtime_pm_debug { >> - spinlock_t lock; >> - >> - depot_stack_handle_t last_acquire; >> - depot_stack_handle_t last_release; >> - >> - depot_stack_handle_t *owners; >> - unsigned long count; >> - } debug; >> + struct intel_wakeref_tracker debug; > > There's a lot going on in the patch all around. Adding the struct to a > separate file could maybe be an individual patch to simplify the actual > changes. Hmm, the patch abstracts out wakeref_tracker from rpm to separate 'library'. In this context the change above looks quite natural and atomic for me. > > This doesn't include the file that defines struct intel_wakeref_tracker; > it's included via intel_wakeref.h. But only if > >> #endif >> }; >> >> diff --git a/drivers/gpu/drm/i915/intel_wakeref.h b/drivers/gpu/drm/i915/intel_wakeref.h >> index 71b8a63f6f104d..20720fbcc28d46 100644 >> --- a/drivers/gpu/drm/i915/intel_wakeref.h >> +++ b/drivers/gpu/drm/i915/intel_wakeref.h >> @@ -17,7 +17,9 @@ >> #include <linux/timer.h> >> #include <linux/workqueue.h> >> >> -#if IS_ENABLED(CONFIG_DRM_I915_DEBUG) >> +#include "intel_wakeref_tracker.h" >> + >> +#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF) >> #define INTEL_WAKEREF_BUG_ON(expr) BUG_ON(expr) >> #else >> #define INTEL_WAKEREF_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr) >> @@ -26,8 +28,6 @@ >> struct intel_runtime_pm; >> struct intel_wakeref; >> >> -typedef depot_stack_handle_t intel_wakeref_t; >> - >> struct intel_wakeref_ops { >> int (*get)(struct intel_wakeref *wf); >> int (*put)(struct intel_wakeref *wf); >> diff --git a/drivers/gpu/drm/i915/intel_wakeref_tracker.c b/drivers/gpu/drm/i915/intel_wakeref_tracker.c >> new file mode 100644 >> index 00000000000000..a0bcef13a1085a >> --- /dev/null >> +++ b/drivers/gpu/drm/i915/intel_wakeref_tracker.c >> @@ -0,0 +1,234 @@ >> +// SPDX-License-Identifier: MIT >> +/* >> + * Copyright © 2021 Intel Corporation >> + */ >> + >> +#include <linux/slab.h> >> +#include <linux/stackdepot.h> >> +#include <linux/stacktrace.h> >> +#include <linux/sort.h> >> + >> +#include <drm/drm_print.h> >> + >> +#include "intel_wakeref.h" > > This should really include the corresponding .h > i.e. intel_wakeref_tracker.h too. Now it gets included via > intel_wakeref.h but I'm not sure why. Apparently some leftover, will fix it. Regards Andrzej > >> + >> +#define STACKDEPTH 8 >> + >> +static noinline depot_stack_handle_t __save_depot_stack(void) >> +{ >> + unsigned long entries[STACKDEPTH]; >> + unsigned int n; >> + >> + n = stack_trace_save(entries, ARRAY_SIZE(entries), 1); >> + return stack_depot_save(entries, n, GFP_NOWAIT | __GFP_NOWARN); >> +} >> + >> +static void __print_depot_stack(depot_stack_handle_t stack, >> + char *buf, int sz, int indent) >> +{ >> + unsigned long *entries; >> + unsigned int nr_entries; >> + >> + nr_entries = stack_depot_fetch(stack, &entries); >> + stack_trace_snprint(buf, sz, entries, nr_entries, indent); >> +} >> + >> +static int cmphandle(const void *_a, const void *_b) >> +{ >> + const depot_stack_handle_t * const a = _a, * const b = _b; >> + >> + if (*a < *b) >> + return -1; >> + else if (*a > *b) >> + return 1; >> + else >> + return 0; >> +} >> + >> +void >> +__intel_wakeref_tracker_show(const struct intel_wakeref_tracker *w, >> + struct drm_printer *p) >> +{ >> + unsigned long i; >> + char *buf; >> + >> + buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN); >> + if (!buf) >> + return; >> + >> + if (w->last_acquire) { >> + __print_depot_stack(w->last_acquire, buf, PAGE_SIZE, 2); >> + drm_printf(p, "Wakeref last acquired:\n%s", buf); >> + } >> + >> + if (w->last_release) { >> + __print_depot_stack(w->last_release, buf, PAGE_SIZE, 2); >> + drm_printf(p, "Wakeref last released:\n%s", buf); >> + } >> + >> + drm_printf(p, "Wakeref count: %lu\n", w->count); >> + >> + sort(w->owners, w->count, sizeof(*w->owners), cmphandle, NULL); >> + >> + for (i = 0; i < w->count; i++) { >> + depot_stack_handle_t stack = w->owners[i]; >> + unsigned long rep; >> + >> + rep = 1; >> + while (i + 1 < w->count && w->owners[i + 1] == stack) >> + rep++, i++; >> + __print_depot_stack(stack, buf, PAGE_SIZE, 2); >> + drm_printf(p, "Wakeref x%lu taken at:\n%s", rep, buf); >> + } >> + >> + kfree(buf); >> +} >> + >> +void intel_wakeref_tracker_show(struct intel_wakeref_tracker *w, >> + struct drm_printer *p) >> +{ >> + struct intel_wakeref_tracker tmp = {}; >> + >> + do { >> + unsigned long alloc = tmp.count; >> + depot_stack_handle_t *s; >> + >> + spin_lock_irq(&w->lock); >> + tmp.count = w->count; >> + if (tmp.count <= alloc) >> + memcpy(tmp.owners, w->owners, tmp.count * sizeof(*s)); >> + tmp.last_acquire = w->last_acquire; >> + tmp.last_release = w->last_release; >> + spin_unlock_irq(&w->lock); >> + if (tmp.count <= alloc) >> + break; >> + >> + s = krealloc(tmp.owners, >> + tmp.count * sizeof(*s), >> + GFP_NOWAIT | __GFP_NOWARN); >> + if (!s) >> + goto out; >> + >> + tmp.owners = s; >> + } while (1); >> + >> + __intel_wakeref_tracker_show(&tmp, p); >> + >> +out: >> + intel_wakeref_tracker_fini(&tmp); >> +} >> + >> +intel_wakeref_t intel_wakeref_tracker_add(struct intel_wakeref_tracker *w) >> +{ >> + depot_stack_handle_t stack, *stacks; >> + unsigned long flags; >> + >> + stack = __save_depot_stack(); >> + if (!stack) >> + return -1; >> + >> + spin_lock_irqsave(&w->lock, flags); >> + >> + if (!w->count) >> + w->last_acquire = stack; >> + >> + stacks = krealloc(w->owners, >> + (w->count + 1) * sizeof(*stacks), >> + GFP_NOWAIT | __GFP_NOWARN); >> + if (stacks) { >> + stacks[w->count++] = stack; >> + w->owners = stacks; >> + } else { >> + stack = -1; >> + } >> + >> + spin_unlock_irqrestore(&w->lock, flags); >> + >> + return stack; >> +} >> + >> +void intel_wakeref_tracker_remove(struct intel_wakeref_tracker *w, >> + intel_wakeref_t stack) >> +{ >> + unsigned long flags, n; >> + bool found = false; >> + >> + if (unlikely(stack == -1)) >> + return; >> + >> + spin_lock_irqsave(&w->lock, flags); >> + for (n = w->count; n--; ) { >> + if (w->owners[n] == stack) { >> + memmove(w->owners + n, >> + w->owners + n + 1, >> + (--w->count - n) * sizeof(stack)); >> + found = true; >> + break; >> + } >> + } >> + spin_unlock_irqrestore(&w->lock, flags); >> + >> + if (WARN(!found, >> + "Unmatched wakeref %x, tracking %lu\n", >> + stack, w->count)) { >> + char *buf; >> + >> + buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN); >> + if (!buf) >> + return; >> + >> + __print_depot_stack(stack, buf, PAGE_SIZE, 2); >> + pr_err("wakeref %x from\n%s", stack, buf); >> + >> + stack = READ_ONCE(w->last_release); >> + if (stack && !w->count) { >> + __print_depot_stack(stack, buf, PAGE_SIZE, 2); >> + pr_err("wakeref last released at\n%s", buf); >> + } >> + >> + kfree(buf); >> + } >> +} >> + >> +struct intel_wakeref_tracker >> +__intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w) >> +{ >> + struct intel_wakeref_tracker saved; >> + >> + lockdep_assert_held(&w->lock); >> + >> + saved = *w; >> + >> + w->owners = NULL; >> + w->count = 0; >> + w->last_release = __save_depot_stack(); >> + >> + return saved; >> +} >> + >> +void intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w, >> + struct drm_printer *p) >> +{ >> + struct intel_wakeref_tracker tmp; >> + >> + spin_lock_irq(&w->lock); >> + tmp = __intel_wakeref_tracker_reset(w); >> + spin_unlock_irq(&w->lock); >> + >> + if (tmp.count) >> + __intel_wakeref_tracker_show(&tmp, p); >> + >> + intel_wakeref_tracker_fini(&tmp); >> +} >> + >> +void intel_wakeref_tracker_init(struct intel_wakeref_tracker *w) >> +{ >> + memset(w, 0, sizeof(*w)); >> + spin_lock_init(&w->lock); >> + stack_depot_init(); >> +} >> + >> +void intel_wakeref_tracker_fini(struct intel_wakeref_tracker *w) >> +{ >> + kfree(w->owners); >> +} >> diff --git a/drivers/gpu/drm/i915/intel_wakeref_tracker.h b/drivers/gpu/drm/i915/intel_wakeref_tracker.h >> new file mode 100644 >> index 00000000000000..61df68e28c0fbf >> --- /dev/null >> +++ b/drivers/gpu/drm/i915/intel_wakeref_tracker.h >> @@ -0,0 +1,76 @@ >> +/* SPDX-License-Identifier: MIT */ >> +/* >> + * Copyright © 2019 Intel Corporation >> + */ >> + >> +#ifndef INTEL_WAKEREF_TRACKER_H >> +#define INTEL_WAKEREF_TRACKER_H >> + >> +#include <linux/kconfig.h> >> +#include <linux/spinlock.h> >> +#include <linux/stackdepot.h> >> + >> +typedef depot_stack_handle_t intel_wakeref_t; >> + >> +struct drm_printer; >> + >> +struct intel_wakeref_tracker { >> + spinlock_t lock; >> + >> + depot_stack_handle_t last_acquire; >> + depot_stack_handle_t last_release; >> + >> + depot_stack_handle_t *owners; >> + unsigned long count; >> +}; >> + >> +#if IS_ENABLED(CONFIG_DRM_I915_TRACK_WAKEREF) >> + >> +void intel_wakeref_tracker_init(struct intel_wakeref_tracker *w); >> +void intel_wakeref_tracker_fini(struct intel_wakeref_tracker *w); >> + >> +intel_wakeref_t intel_wakeref_tracker_add(struct intel_wakeref_tracker *w); >> +void intel_wakeref_tracker_remove(struct intel_wakeref_tracker *w, >> + intel_wakeref_t handle); >> + >> +struct intel_wakeref_tracker >> +__intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w); >> +void intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w, >> + struct drm_printer *p); >> + >> +void __intel_wakeref_tracker_show(const struct intel_wakeref_tracker *w, >> + struct drm_printer *p); >> +void intel_wakeref_tracker_show(struct intel_wakeref_tracker *w, >> + struct drm_printer *p); >> + >> +#else >> + >> +static inline void intel_wakeref_tracker_init(struct intel_wakeref_tracker *w) {} >> +static inline void intel_wakeref_tracker_fini(struct intel_wakeref_tracker *w) {} >> + >> +static inline intel_wakeref_t >> +intel_wakeref_tracker_add(struct intel_wakeref_tracker *w) >> +{ >> + return -1; >> +} >> + >> +static inline void >> +intel_wakeref_untrack_remove(struct intel_wakeref_tracker *w, intel_wakeref_t handle) {} >> + >> +static inline struct intel_wakeref_tracker >> +__intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w) >> +{ >> + return (struct intel_wakeref_tracker){}; >> +} >> + >> +static inline void intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w, >> + struct drm_printer *p) >> +{ >> +} >> + >> +static inline void __intel_wakeref_tracker_show(const struct intel_wakeref_tracker *w, struct drm_printer *p) {} >> +static inline void intel_wakeref_tracker_show(struct intel_wakeref_tracker *w, struct drm_printer *p) {} >> + >> +#endif >> + >> +#endif /* INTEL_WAKEREF_TRACKER_H */ >
diff --git a/drivers/gpu/drm/i915/Kconfig.debug b/drivers/gpu/drm/i915/Kconfig.debug index 93dfb7ed970547..5fde52107e3b44 100644 --- a/drivers/gpu/drm/i915/Kconfig.debug +++ b/drivers/gpu/drm/i915/Kconfig.debug @@ -25,6 +25,7 @@ config DRM_I915_DEBUG select PREEMPT_COUNT select I2C_CHARDEV select STACKDEPOT + select STACKTRACE select DRM_DP_AUX_CHARDEV select X86_MSR # used by igt/pm_rpm select DRM_VGEM # used by igt/prime_vgem (dmabuf interop checks) @@ -37,6 +38,7 @@ config DRM_I915_DEBUG select DRM_I915_DEBUG_GEM select DRM_I915_DEBUG_GEM_ONCE select DRM_I915_DEBUG_MMIO + select DRM_I915_TRACK_WAKEREF select DRM_I915_DEBUG_RUNTIME_PM select DRM_I915_SW_FENCE_DEBUG_OBJECTS select DRM_I915_SELFTEST @@ -227,11 +229,18 @@ config DRM_I915_DEBUG_VBLANK_EVADE If in doubt, say "N". +config DRM_I915_TRACK_WAKEREF + depends on STACKDEPOT + depends on STACKTRACE + bool + config DRM_I915_DEBUG_RUNTIME_PM bool "Enable extra state checking for runtime PM" depends on DRM_I915 default n select STACKDEPOT + select STACKTRACE + select DRM_I915_TRACK_WAKEREF help Choose this option to turn on extra state checking for the runtime PM functionality. This may introduce overhead during diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile index b2f91a1f826858..42daff6d575a82 100644 --- a/drivers/gpu/drm/i915/Makefile +++ b/drivers/gpu/drm/i915/Makefile @@ -81,6 +81,10 @@ i915-$(CONFIG_DEBUG_FS) += \ i915_debugfs_params.o \ display/intel_display_debugfs.o \ display/intel_pipe_crc.o + +i915-$(CONFIG_DRM_I915_TRACK_WAKEREF) += \ + intel_wakeref_tracker.o + i915-$(CONFIG_PERF_EVENTS) += i915_pmu.o # "Graphics Technology" (aka we talk to the gpu) diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c index 129746713d072f..72887e2bb03c21 100644 --- a/drivers/gpu/drm/i915/intel_runtime_pm.c +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c @@ -52,182 +52,37 @@ #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM) -#include <linux/sort.h> - -#define STACKDEPTH 8 - -static noinline depot_stack_handle_t __save_depot_stack(void) -{ - unsigned long entries[STACKDEPTH]; - unsigned int n; - - n = stack_trace_save(entries, ARRAY_SIZE(entries), 1); - return stack_depot_save(entries, n, GFP_NOWAIT | __GFP_NOWARN); -} - static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm) { - spin_lock_init(&rpm->debug.lock); - stack_depot_init(); + intel_wakeref_tracker_init(&rpm->debug); } -static noinline depot_stack_handle_t +static intel_wakeref_t track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm) { - depot_stack_handle_t stack, *stacks; - unsigned long flags; - - if (rpm->no_wakeref_tracking) - return -1; - - stack = __save_depot_stack(); - if (!stack) + if (!rpm->available) return -1; - spin_lock_irqsave(&rpm->debug.lock, flags); - - if (!rpm->debug.count) - rpm->debug.last_acquire = stack; - - stacks = krealloc(rpm->debug.owners, - (rpm->debug.count + 1) * sizeof(*stacks), - GFP_NOWAIT | __GFP_NOWARN); - if (stacks) { - stacks[rpm->debug.count++] = stack; - rpm->debug.owners = stacks; - } else { - stack = -1; - } - - spin_unlock_irqrestore(&rpm->debug.lock, flags); - - return stack; + return intel_wakeref_tracker_add(&rpm->debug); } static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm, - depot_stack_handle_t stack) + intel_wakeref_t wakeref) { - struct drm_i915_private *i915 = container_of(rpm, - struct drm_i915_private, - runtime_pm); - unsigned long flags, n; - bool found = false; - - if (unlikely(stack == -1)) - return; - - spin_lock_irqsave(&rpm->debug.lock, flags); - for (n = rpm->debug.count; n--; ) { - if (rpm->debug.owners[n] == stack) { - memmove(rpm->debug.owners + n, - rpm->debug.owners + n + 1, - (--rpm->debug.count - n) * sizeof(stack)); - found = true; - break; - } - } - spin_unlock_irqrestore(&rpm->debug.lock, flags); - - if (drm_WARN(&i915->drm, !found, - "Unmatched wakeref (tracking %lu), count %u\n", - rpm->debug.count, atomic_read(&rpm->wakeref_count))) { - char *buf; - - buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN); - if (!buf) - return; - - stack_depot_snprint(stack, buf, PAGE_SIZE, 2); - DRM_DEBUG_DRIVER("wakeref %x from\n%s", stack, buf); - - stack = READ_ONCE(rpm->debug.last_release); - if (stack) { - stack_depot_snprint(stack, buf, PAGE_SIZE, 2); - DRM_DEBUG_DRIVER("wakeref last released at\n%s", buf); - } - - kfree(buf); - } + intel_wakeref_tracker_remove(&rpm->debug, wakeref); } -static int cmphandle(const void *_a, const void *_b) +static void untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm) { - const depot_stack_handle_t * const a = _a, * const b = _b; + struct drm_printer p = drm_debug_printer("i915"); - if (*a < *b) - return -1; - else if (*a > *b) - return 1; - else - return 0; -} - -static void -__print_intel_runtime_pm_wakeref(struct drm_printer *p, - const struct intel_runtime_pm_debug *dbg) -{ - unsigned long i; - char *buf; - - buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN); - if (!buf) - return; - - if (dbg->last_acquire) { - stack_depot_snprint(dbg->last_acquire, buf, PAGE_SIZE, 2); - drm_printf(p, "Wakeref last acquired:\n%s", buf); - } - - if (dbg->last_release) { - stack_depot_snprint(dbg->last_release, buf, PAGE_SIZE, 2); - drm_printf(p, "Wakeref last released:\n%s", buf); - } - - drm_printf(p, "Wakeref count: %lu\n", dbg->count); - - sort(dbg->owners, dbg->count, sizeof(*dbg->owners), cmphandle, NULL); - - for (i = 0; i < dbg->count; i++) { - depot_stack_handle_t stack = dbg->owners[i]; - unsigned long rep; - - rep = 1; - while (i + 1 < dbg->count && dbg->owners[i + 1] == stack) - rep++, i++; - stack_depot_snprint(stack, buf, PAGE_SIZE, 2); - drm_printf(p, "Wakeref x%lu taken at:\n%s", rep, buf); - } - - kfree(buf); -} - -static noinline void -__untrack_all_wakerefs(struct intel_runtime_pm_debug *debug, - struct intel_runtime_pm_debug *saved) -{ - *saved = *debug; - - debug->owners = NULL; - debug->count = 0; - debug->last_release = __save_depot_stack(); -} - -static void -dump_and_free_wakeref_tracking(struct intel_runtime_pm_debug *debug) -{ - if (debug->count) { - struct drm_printer p = drm_debug_printer("i915"); - - __print_intel_runtime_pm_wakeref(&p, debug); - } - - kfree(debug->owners); + intel_wakeref_tracker_reset(&rpm->debug, &p); } static noinline void __intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm) { - struct intel_runtime_pm_debug dbg = {}; + struct intel_wakeref_tracker saved; unsigned long flags; if (!atomic_dec_and_lock_irqsave(&rpm->wakeref_count, @@ -235,60 +90,21 @@ __intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm) flags)) return; - __untrack_all_wakerefs(&rpm->debug, &dbg); + saved = __intel_wakeref_tracker_reset(&rpm->debug); spin_unlock_irqrestore(&rpm->debug.lock, flags); - dump_and_free_wakeref_tracking(&dbg); -} - -static noinline void -untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm) -{ - struct intel_runtime_pm_debug dbg = {}; - unsigned long flags; - - spin_lock_irqsave(&rpm->debug.lock, flags); - __untrack_all_wakerefs(&rpm->debug, &dbg); - spin_unlock_irqrestore(&rpm->debug.lock, flags); + if (saved.count) { + struct drm_printer p = drm_debug_printer("i915"); - dump_and_free_wakeref_tracking(&dbg); + __intel_wakeref_tracker_show(&saved, &p); + intel_wakeref_tracker_fini(&saved); + } } void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm, struct drm_printer *p) { - struct intel_runtime_pm_debug dbg = {}; - - do { - unsigned long alloc = dbg.count; - depot_stack_handle_t *s; - - spin_lock_irq(&rpm->debug.lock); - dbg.count = rpm->debug.count; - if (dbg.count <= alloc) { - memcpy(dbg.owners, - rpm->debug.owners, - dbg.count * sizeof(*s)); - } - dbg.last_acquire = rpm->debug.last_acquire; - dbg.last_release = rpm->debug.last_release; - spin_unlock_irq(&rpm->debug.lock); - if (dbg.count <= alloc) - break; - - s = krealloc(dbg.owners, - dbg.count * sizeof(*s), - GFP_NOWAIT | __GFP_NOWARN); - if (!s) - goto out; - - dbg.owners = s; - } while (1); - - __print_intel_runtime_pm_wakeref(p, &dbg); - -out: - kfree(dbg.owners); + intel_wakeref_tracker_show(&rpm->debug, p); } #else @@ -297,14 +113,14 @@ static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm) { } -static depot_stack_handle_t +static intel_wakeref_t track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm) { return -1; } static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm, - intel_wakeref_t wref) + intel_wakeref_t wakeref) { } @@ -349,9 +165,8 @@ intel_runtime_pm_release(struct intel_runtime_pm *rpm, int wakelock) static intel_wakeref_t __intel_runtime_pm_get(struct intel_runtime_pm *rpm, bool wakelock) { - struct drm_i915_private *i915 = container_of(rpm, - struct drm_i915_private, - runtime_pm); + struct drm_i915_private *i915 = + container_of(rpm, struct drm_i915_private, runtime_pm); int ret; ret = pm_runtime_get_sync(rpm->kdev); @@ -556,9 +371,8 @@ void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref) */ void intel_runtime_pm_enable(struct intel_runtime_pm *rpm) { - struct drm_i915_private *i915 = container_of(rpm, - struct drm_i915_private, - runtime_pm); + struct drm_i915_private *i915 = + container_of(rpm, struct drm_i915_private, runtime_pm); struct device *kdev = rpm->kdev; /* @@ -611,9 +425,8 @@ void intel_runtime_pm_enable(struct intel_runtime_pm *rpm) void intel_runtime_pm_disable(struct intel_runtime_pm *rpm) { - struct drm_i915_private *i915 = container_of(rpm, - struct drm_i915_private, - runtime_pm); + struct drm_i915_private *i915 = + container_of(rpm, struct drm_i915_private, runtime_pm); struct device *kdev = rpm->kdev; /* Transfer rpm ownership back to core */ @@ -628,9 +441,8 @@ void intel_runtime_pm_disable(struct intel_runtime_pm *rpm) void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm) { - struct drm_i915_private *i915 = container_of(rpm, - struct drm_i915_private, - runtime_pm); + struct drm_i915_private *i915 = + container_of(rpm, struct drm_i915_private, runtime_pm); int count = atomic_read(&rpm->wakeref_count); intel_wakeref_auto_fini(&rpm->userfault_wakeref); @@ -646,7 +458,7 @@ void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm) void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm) { struct drm_i915_private *i915 = - container_of(rpm, struct drm_i915_private, runtime_pm); + container_of(rpm, struct drm_i915_private, runtime_pm); struct pci_dev *pdev = to_pci_dev(i915->drm.dev); struct device *kdev = &pdev->dev; diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.h b/drivers/gpu/drm/i915/intel_runtime_pm.h index e592e8d6499a1f..a8dc2baf79844f 100644 --- a/drivers/gpu/drm/i915/intel_runtime_pm.h +++ b/drivers/gpu/drm/i915/intel_runtime_pm.h @@ -83,15 +83,7 @@ struct intel_runtime_pm { * paired rpm_put) we can remove corresponding pairs of and keep * the array trimmed to active wakerefs. */ - struct intel_runtime_pm_debug { - spinlock_t lock; - - depot_stack_handle_t last_acquire; - depot_stack_handle_t last_release; - - depot_stack_handle_t *owners; - unsigned long count; - } debug; + struct intel_wakeref_tracker debug; #endif }; diff --git a/drivers/gpu/drm/i915/intel_wakeref.h b/drivers/gpu/drm/i915/intel_wakeref.h index 71b8a63f6f104d..20720fbcc28d46 100644 --- a/drivers/gpu/drm/i915/intel_wakeref.h +++ b/drivers/gpu/drm/i915/intel_wakeref.h @@ -17,7 +17,9 @@ #include <linux/timer.h> #include <linux/workqueue.h> -#if IS_ENABLED(CONFIG_DRM_I915_DEBUG) +#include "intel_wakeref_tracker.h" + +#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF) #define INTEL_WAKEREF_BUG_ON(expr) BUG_ON(expr) #else #define INTEL_WAKEREF_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr) @@ -26,8 +28,6 @@ struct intel_runtime_pm; struct intel_wakeref; -typedef depot_stack_handle_t intel_wakeref_t; - struct intel_wakeref_ops { int (*get)(struct intel_wakeref *wf); int (*put)(struct intel_wakeref *wf); diff --git a/drivers/gpu/drm/i915/intel_wakeref_tracker.c b/drivers/gpu/drm/i915/intel_wakeref_tracker.c new file mode 100644 index 00000000000000..a0bcef13a1085a --- /dev/null +++ b/drivers/gpu/drm/i915/intel_wakeref_tracker.c @@ -0,0 +1,234 @@ +// SPDX-License-Identifier: MIT +/* + * Copyright © 2021 Intel Corporation + */ + +#include <linux/slab.h> +#include <linux/stackdepot.h> +#include <linux/stacktrace.h> +#include <linux/sort.h> + +#include <drm/drm_print.h> + +#include "intel_wakeref.h" + +#define STACKDEPTH 8 + +static noinline depot_stack_handle_t __save_depot_stack(void) +{ + unsigned long entries[STACKDEPTH]; + unsigned int n; + + n = stack_trace_save(entries, ARRAY_SIZE(entries), 1); + return stack_depot_save(entries, n, GFP_NOWAIT | __GFP_NOWARN); +} + +static void __print_depot_stack(depot_stack_handle_t stack, + char *buf, int sz, int indent) +{ + unsigned long *entries; + unsigned int nr_entries; + + nr_entries = stack_depot_fetch(stack, &entries); + stack_trace_snprint(buf, sz, entries, nr_entries, indent); +} + +static int cmphandle(const void *_a, const void *_b) +{ + const depot_stack_handle_t * const a = _a, * const b = _b; + + if (*a < *b) + return -1; + else if (*a > *b) + return 1; + else + return 0; +} + +void +__intel_wakeref_tracker_show(const struct intel_wakeref_tracker *w, + struct drm_printer *p) +{ + unsigned long i; + char *buf; + + buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN); + if (!buf) + return; + + if (w->last_acquire) { + __print_depot_stack(w->last_acquire, buf, PAGE_SIZE, 2); + drm_printf(p, "Wakeref last acquired:\n%s", buf); + } + + if (w->last_release) { + __print_depot_stack(w->last_release, buf, PAGE_SIZE, 2); + drm_printf(p, "Wakeref last released:\n%s", buf); + } + + drm_printf(p, "Wakeref count: %lu\n", w->count); + + sort(w->owners, w->count, sizeof(*w->owners), cmphandle, NULL); + + for (i = 0; i < w->count; i++) { + depot_stack_handle_t stack = w->owners[i]; + unsigned long rep; + + rep = 1; + while (i + 1 < w->count && w->owners[i + 1] == stack) + rep++, i++; + __print_depot_stack(stack, buf, PAGE_SIZE, 2); + drm_printf(p, "Wakeref x%lu taken at:\n%s", rep, buf); + } + + kfree(buf); +} + +void intel_wakeref_tracker_show(struct intel_wakeref_tracker *w, + struct drm_printer *p) +{ + struct intel_wakeref_tracker tmp = {}; + + do { + unsigned long alloc = tmp.count; + depot_stack_handle_t *s; + + spin_lock_irq(&w->lock); + tmp.count = w->count; + if (tmp.count <= alloc) + memcpy(tmp.owners, w->owners, tmp.count * sizeof(*s)); + tmp.last_acquire = w->last_acquire; + tmp.last_release = w->last_release; + spin_unlock_irq(&w->lock); + if (tmp.count <= alloc) + break; + + s = krealloc(tmp.owners, + tmp.count * sizeof(*s), + GFP_NOWAIT | __GFP_NOWARN); + if (!s) + goto out; + + tmp.owners = s; + } while (1); + + __intel_wakeref_tracker_show(&tmp, p); + +out: + intel_wakeref_tracker_fini(&tmp); +} + +intel_wakeref_t intel_wakeref_tracker_add(struct intel_wakeref_tracker *w) +{ + depot_stack_handle_t stack, *stacks; + unsigned long flags; + + stack = __save_depot_stack(); + if (!stack) + return -1; + + spin_lock_irqsave(&w->lock, flags); + + if (!w->count) + w->last_acquire = stack; + + stacks = krealloc(w->owners, + (w->count + 1) * sizeof(*stacks), + GFP_NOWAIT | __GFP_NOWARN); + if (stacks) { + stacks[w->count++] = stack; + w->owners = stacks; + } else { + stack = -1; + } + + spin_unlock_irqrestore(&w->lock, flags); + + return stack; +} + +void intel_wakeref_tracker_remove(struct intel_wakeref_tracker *w, + intel_wakeref_t stack) +{ + unsigned long flags, n; + bool found = false; + + if (unlikely(stack == -1)) + return; + + spin_lock_irqsave(&w->lock, flags); + for (n = w->count; n--; ) { + if (w->owners[n] == stack) { + memmove(w->owners + n, + w->owners + n + 1, + (--w->count - n) * sizeof(stack)); + found = true; + break; + } + } + spin_unlock_irqrestore(&w->lock, flags); + + if (WARN(!found, + "Unmatched wakeref %x, tracking %lu\n", + stack, w->count)) { + char *buf; + + buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN); + if (!buf) + return; + + __print_depot_stack(stack, buf, PAGE_SIZE, 2); + pr_err("wakeref %x from\n%s", stack, buf); + + stack = READ_ONCE(w->last_release); + if (stack && !w->count) { + __print_depot_stack(stack, buf, PAGE_SIZE, 2); + pr_err("wakeref last released at\n%s", buf); + } + + kfree(buf); + } +} + +struct intel_wakeref_tracker +__intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w) +{ + struct intel_wakeref_tracker saved; + + lockdep_assert_held(&w->lock); + + saved = *w; + + w->owners = NULL; + w->count = 0; + w->last_release = __save_depot_stack(); + + return saved; +} + +void intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w, + struct drm_printer *p) +{ + struct intel_wakeref_tracker tmp; + + spin_lock_irq(&w->lock); + tmp = __intel_wakeref_tracker_reset(w); + spin_unlock_irq(&w->lock); + + if (tmp.count) + __intel_wakeref_tracker_show(&tmp, p); + + intel_wakeref_tracker_fini(&tmp); +} + +void intel_wakeref_tracker_init(struct intel_wakeref_tracker *w) +{ + memset(w, 0, sizeof(*w)); + spin_lock_init(&w->lock); + stack_depot_init(); +} + +void intel_wakeref_tracker_fini(struct intel_wakeref_tracker *w) +{ + kfree(w->owners); +} diff --git a/drivers/gpu/drm/i915/intel_wakeref_tracker.h b/drivers/gpu/drm/i915/intel_wakeref_tracker.h new file mode 100644 index 00000000000000..61df68e28c0fbf --- /dev/null +++ b/drivers/gpu/drm/i915/intel_wakeref_tracker.h @@ -0,0 +1,76 @@ +/* SPDX-License-Identifier: MIT */ +/* + * Copyright © 2019 Intel Corporation + */ + +#ifndef INTEL_WAKEREF_TRACKER_H +#define INTEL_WAKEREF_TRACKER_H + +#include <linux/kconfig.h> +#include <linux/spinlock.h> +#include <linux/stackdepot.h> + +typedef depot_stack_handle_t intel_wakeref_t; + +struct drm_printer; + +struct intel_wakeref_tracker { + spinlock_t lock; + + depot_stack_handle_t last_acquire; + depot_stack_handle_t last_release; + + depot_stack_handle_t *owners; + unsigned long count; +}; + +#if IS_ENABLED(CONFIG_DRM_I915_TRACK_WAKEREF) + +void intel_wakeref_tracker_init(struct intel_wakeref_tracker *w); +void intel_wakeref_tracker_fini(struct intel_wakeref_tracker *w); + +intel_wakeref_t intel_wakeref_tracker_add(struct intel_wakeref_tracker *w); +void intel_wakeref_tracker_remove(struct intel_wakeref_tracker *w, + intel_wakeref_t handle); + +struct intel_wakeref_tracker +__intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w); +void intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w, + struct drm_printer *p); + +void __intel_wakeref_tracker_show(const struct intel_wakeref_tracker *w, + struct drm_printer *p); +void intel_wakeref_tracker_show(struct intel_wakeref_tracker *w, + struct drm_printer *p); + +#else + +static inline void intel_wakeref_tracker_init(struct intel_wakeref_tracker *w) {} +static inline void intel_wakeref_tracker_fini(struct intel_wakeref_tracker *w) {} + +static inline intel_wakeref_t +intel_wakeref_tracker_add(struct intel_wakeref_tracker *w) +{ + return -1; +} + +static inline void +intel_wakeref_untrack_remove(struct intel_wakeref_tracker *w, intel_wakeref_t handle) {} + +static inline struct intel_wakeref_tracker +__intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w) +{ + return (struct intel_wakeref_tracker){}; +} + +static inline void intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w, + struct drm_printer *p) +{ +} + +static inline void __intel_wakeref_tracker_show(const struct intel_wakeref_tracker *w, struct drm_printer *p) {} +static inline void intel_wakeref_tracker_show(struct intel_wakeref_tracker *w, struct drm_printer *p) {} + +#endif + +#endif /* INTEL_WAKEREF_TRACKER_H */