[Intel-gfx] [PATCH] drm/i915/gt: Keep a no-frills swappable copy of the default context state
Chris Wilson
chris at chris-wilson.co.uk
Tue Apr 28 21:24:53 UTC 2020
We need to keep the default context state around to instantiate new
contexts (aka golden rendercontext), and we also keep it pinned while
the engine is active so that we can quickly reset a hanging context.
However, the default contexts are large enough to merit keeping in
swappable memory as opposed to kernel memory, so we store them inside
shmemfs. Currently, we use the normal GEM objects to create the default
context image, but we can throw away all but the shmemfs file.
This greatly simplifies the tricky power management code which wants to
run underneath the normal GT locking, and we definitely do not want to
use any high level objects that may appear to recurse back into the GT.
Though perhaps the primary advantage of the complex GEM object is that
we aggressively cache the mapping, but here we are recreating the
vm_area everytime time we unpark. At the worst, we add a lightweight
cache, but first find a microbenchmark that is impacted.
Having started to create some utility functions to make working with
shmemfs objects easier, we can start putting them to wider use, where
GEM objects are overkill, such as storing persistent error state.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld at intel.com>
Cc: Ramalingam C <ramalingam.c at intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
drivers/gpu/drm/i915/Makefile | 1 +
drivers/gpu/drm/i915/gt/intel_engine_cs.c | 2 +-
drivers/gpu/drm/i915/gt/intel_engine_pm.c | 10 +-
drivers/gpu/drm/i915/gt/intel_engine_types.h | 2 +-
drivers/gpu/drm/i915/gt/intel_gt.c | 4 +-
drivers/gpu/drm/i915/gt/intel_lrc.c | 25 +--
.../gpu/drm/i915/gt/intel_ring_submission.c | 16 +-
drivers/gpu/drm/i915/gt/selftest_context.c | 2 +-
drivers/gpu/drm/i915/gt/selftest_lrc.c | 10 +-
drivers/gpu/drm/i915/gt/shmem_utils.c | 178 ++++++++++++++++++
drivers/gpu/drm/i915/gt/shmem_utils.h | 22 +++
drivers/gpu/drm/i915/i915_gpu_error.c | 26 ---
12 files changed, 226 insertions(+), 72 deletions(-)
create mode 100644 drivers/gpu/drm/i915/gt/shmem_utils.c
create mode 100644 drivers/gpu/drm/i915/gt/shmem_utils.h
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 21bb2fb5a6b8..caf00d92ea9d 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -111,6 +111,7 @@ gt-y += \
gt/intel_sseu.o \
gt/intel_timeline.o \
gt/intel_workarounds.o \
+ gt/shmem_utils.o \
gt/sysfs_engines.o
# autogenerated null render state
gt-y += \
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
index 7c3cb5aedfdf..80bf71636c0f 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -834,7 +834,7 @@ void intel_engine_cleanup_common(struct intel_engine_cs *engine)
intel_engine_cleanup_cmd_parser(engine);
if (engine->default_state)
- i915_gem_object_put(engine->default_state);
+ fput(engine->default_state);
if (engine->kernel_context) {
intel_context_unpin(engine->kernel_context);
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
index 3be679741d22..446e35ac0224 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
@@ -15,6 +15,7 @@
#include "intel_gt_pm.h"
#include "intel_rc6.h"
#include "intel_ring.h"
+#include "shmem_utils.h"
static int __engine_unpark(struct intel_wakeref *wf)
{
@@ -30,10 +31,8 @@ static int __engine_unpark(struct intel_wakeref *wf)
/* Pin the default state for fast resets from atomic context. */
map = NULL;
if (engine->default_state)
- map = i915_gem_object_pin_map(engine->default_state,
- I915_MAP_WB);
- if (!IS_ERR_OR_NULL(map))
- engine->pinned_default_state = map;
+ map = shmem_pin_map(engine->default_state);
+ engine->pinned_default_state = map;
/* Discard stale context state from across idling */
ce = engine->kernel_context;
@@ -264,7 +263,8 @@ static int __engine_park(struct intel_wakeref *wf)
engine->park(engine);
if (engine->pinned_default_state) {
- i915_gem_object_unpin_map(engine->default_state);
+ shmem_unpin_map(engine->default_state,
+ engine->pinned_default_state);
engine->pinned_default_state = NULL;
}
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
index cfe4feaee982..483d8ff39a0d 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
@@ -339,7 +339,7 @@ struct intel_engine_cs {
unsigned long wakeref_serial;
struct intel_wakeref wakeref;
- struct drm_i915_gem_object *default_state;
+ struct file *default_state;
void *pinned_default_state;
struct {
diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c
index d9cf8194c997..c3f25a2a5706 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt.c
@@ -16,6 +16,7 @@
#include "intel_rps.h"
#include "intel_uncore.h"
#include "intel_pm.h"
+#include "shmem_utils.h"
void intel_gt_init_early(struct intel_gt *gt, struct drm_i915_private *i915)
{
@@ -501,7 +502,8 @@ static int __engines_record_defaults(struct intel_gt *gt)
goto out;
}
- rq->engine->default_state = i915_gem_object_get(state->obj);
+ rq->engine->default_state =
+ shmem_create_from_object(state->obj);
i915_gem_object_unpin_map(state->obj);
}
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 90acc3d2440b..7fc4081c34fe 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -147,6 +147,7 @@
#include "intel_reset.h"
#include "intel_ring.h"
#include "intel_workarounds.h"
+#include "shmem_utils.h"
#define RING_EXECLIST_QFULL (1 << 0x2)
#define RING_EXECLIST1_VALID (1 << 0x3)
@@ -5083,30 +5084,18 @@ populate_lr_context(struct intel_context *ce,
{
bool inhibit = true;
void *vaddr;
- int ret;
vaddr = i915_gem_object_pin_map(ctx_obj, I915_MAP_WB);
if (IS_ERR(vaddr)) {
- ret = PTR_ERR(vaddr);
- drm_dbg(&engine->i915->drm,
- "Could not map object pages! (%d)\n", ret);
- return ret;
+ drm_dbg(&engine->i915->drm, "Could not map object pages!\n");
+ return PTR_ERR(vaddr);
}
set_redzone(vaddr, engine);
if (engine->default_state) {
- void *defaults;
-
- defaults = i915_gem_object_pin_map(engine->default_state,
- I915_MAP_WB);
- if (IS_ERR(defaults)) {
- ret = PTR_ERR(defaults);
- goto err_unpin_ctx;
- }
-
- memcpy(vaddr, defaults, engine->context_size);
- i915_gem_object_unpin_map(engine->default_state);
+ shmem_read(engine->default_state, 0,
+ vaddr, engine->context_size);
__set_bit(CONTEXT_VALID_BIT, &ce->flags);
inhibit = false;
}
@@ -5121,11 +5110,9 @@ populate_lr_context(struct intel_context *ce,
execlists_init_reg_state(vaddr + LRC_STATE_OFFSET,
ce, engine, ring, inhibit);
- ret = 0;
-err_unpin_ctx:
__i915_gem_object_flush_map(ctx_obj, 0, engine->context_size);
i915_gem_object_unpin_map(ctx_obj);
- return ret;
+ return 0;
}
static int __execlists_context_alloc(struct intel_context *ce,
diff --git a/drivers/gpu/drm/i915/gt/intel_ring_submission.c b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
index d015f7b8b28e..ca7286e58409 100644
--- a/drivers/gpu/drm/i915/gt/intel_ring_submission.c
+++ b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
@@ -42,6 +42,7 @@
#include "intel_reset.h"
#include "intel_ring.h"
#include "intel_workarounds.h"
+#include "shmem_utils.h"
/* Rough estimate of the typical request size, performing a flush,
* set-context and then emitting the batch.
@@ -1241,7 +1242,7 @@ alloc_context_vma(struct intel_engine_cs *engine)
i915_gem_object_set_cache_coherency(obj, I915_CACHE_L3_LLC);
if (engine->default_state) {
- void *defaults, *vaddr;
+ void *vaddr;
vaddr = i915_gem_object_pin_map(obj, I915_MAP_WB);
if (IS_ERR(vaddr)) {
@@ -1249,15 +1250,8 @@ alloc_context_vma(struct intel_engine_cs *engine)
goto err_obj;
}
- defaults = i915_gem_object_pin_map(engine->default_state,
- I915_MAP_WB);
- if (IS_ERR(defaults)) {
- err = PTR_ERR(defaults);
- goto err_map;
- }
-
- memcpy(vaddr, defaults, engine->context_size);
- i915_gem_object_unpin_map(engine->default_state);
+ shmem_read(engine->default_state, 0,
+ vaddr, engine->context_size);
i915_gem_object_flush_map(obj);
i915_gem_object_unpin_map(obj);
@@ -1271,8 +1265,6 @@ alloc_context_vma(struct intel_engine_cs *engine)
return vma;
-err_map:
- i915_gem_object_unpin_map(obj);
err_obj:
i915_gem_object_put(obj);
return ERR_PTR(err);
diff --git a/drivers/gpu/drm/i915/gt/selftest_context.c b/drivers/gpu/drm/i915/gt/selftest_context.c
index e874dfaa5316..b8ed3cbe1277 100644
--- a/drivers/gpu/drm/i915/gt/selftest_context.c
+++ b/drivers/gpu/drm/i915/gt/selftest_context.c
@@ -155,7 +155,7 @@ static int live_context_size(void *arg)
for_each_engine(engine, gt, id) {
struct {
- struct drm_i915_gem_object *state;
+ struct file *state;
void *pinned;
} saved;
diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c
index d3fa91aed7de..d900bbccd5db 100644
--- a/drivers/gpu/drm/i915/gt/selftest_lrc.c
+++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c
@@ -4452,8 +4452,7 @@ static int live_lrc_layout(void *arg)
if (!engine->default_state)
continue;
- hw = i915_gem_object_pin_map(engine->default_state,
- I915_MAP_WB);
+ hw = shmem_pin_map(engine->default_state);
if (IS_ERR(hw)) {
err = PTR_ERR(hw);
break;
@@ -4525,7 +4524,7 @@ static int live_lrc_layout(void *arg)
hexdump(lrc, PAGE_SIZE);
}
- i915_gem_object_unpin_map(engine->default_state);
+ shmem_unpin_map(engine->default_state, hw);
if (err)
break;
}
@@ -4630,8 +4629,7 @@ static int live_lrc_fixed(void *arg)
if (!engine->default_state)
continue;
- hw = i915_gem_object_pin_map(engine->default_state,
- I915_MAP_WB);
+ hw = shmem_pin_map(engine->default_state);
if (IS_ERR(hw)) {
err = PTR_ERR(hw);
break;
@@ -4652,7 +4650,7 @@ static int live_lrc_fixed(void *arg)
}
}
- i915_gem_object_unpin_map(engine->default_state);
+ shmem_unpin_map(engine->default_state, hw);
}
return err;
diff --git a/drivers/gpu/drm/i915/gt/shmem_utils.c b/drivers/gpu/drm/i915/gt/shmem_utils.c
new file mode 100644
index 000000000000..efbe51096dc6
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/shmem_utils.c
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2020 Intel Corporation
+ */
+
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/shmem_fs.h>
+
+#include "gem/i915_gem_object.h"
+#include "shmem_utils.h"
+
+struct file *shmem_create_from_data(const char *name, void *data, size_t len)
+{
+ struct file *file;
+ unsigned long pfn;
+ unsigned long sz;
+ int err;
+
+ sz = PAGE_ALIGN(len);
+ file = shmem_file_setup(name, sz, VM_NORESERVE);
+ if (IS_ERR(file))
+ return file;
+
+ for (pfn = 0; pfn < sz >> PAGE_SHIFT; pfn++) {
+ struct page *page;
+ unsigned int this;
+ void *vaddr;
+
+ page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
+ GFP_KERNEL);
+ if (IS_ERR(page)) {
+ err = PTR_ERR(page);
+ goto err_file;
+ }
+
+ this = min_t(size_t, PAGE_SIZE, len);
+
+ vaddr = kmap(page);
+ memcpy(vaddr, data, this);
+ kunmap(page);
+ put_page(page);
+
+ len -= this;
+ data += this;
+ }
+
+ return file;
+
+err_file:
+ fput(file);
+ return ERR_PTR(err);
+}
+
+struct file *shmem_create_from_object(struct drm_i915_gem_object *obj)
+{
+ struct file *file;
+ void *ptr;
+
+ if (obj->ops == &i915_gem_shmem_ops) {
+ file = obj->base.filp;
+ atomic_long_inc(&file->f_count);
+ return file;
+ }
+
+ ptr = i915_gem_object_pin_map(obj, I915_MAP_WB);
+ if (IS_ERR(ptr))
+ return ERR_CAST(ptr);
+
+ file = shmem_create_from_data("", ptr, obj->base.size);
+ i915_gem_object_unpin_map(obj);
+
+ return file;
+}
+
+static size_t shmem_npte(struct file *file)
+{
+ return file->f_mapping->host->i_size >> PAGE_SHIFT;
+}
+
+static void __shmem_unpin_map(struct file *file, void *ptr, size_t n_pte)
+{
+ unsigned long pfn;
+
+ vunmap(ptr);
+
+ for (pfn = 0; pfn < n_pte; pfn++) {
+ struct page *page;
+
+ page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
+ GFP_KERNEL);
+ if (!WARN_ON(IS_ERR(page))) {
+ put_page(page);
+ put_page(page);
+ }
+ }
+}
+
+void *shmem_pin_map(struct file *file)
+{
+ const size_t n_pte = shmem_npte(file);
+ pte_t *stack[32], **ptes, **mem;
+ struct vm_struct *area;
+ unsigned long pfn;
+
+ mem = stack;
+ if (n_pte > ARRAY_SIZE(stack)) {
+ mem = kvmalloc_array(n_pte, sizeof(*mem), GFP_KERNEL);
+ if (!mem)
+ return NULL;
+ }
+
+ area = alloc_vm_area(n_pte << PAGE_SHIFT, mem);
+ if (!area) {
+ if (mem != stack)
+ kvfree(mem);
+ return NULL;
+ }
+
+ ptes = mem;
+ for (pfn = 0; pfn < n_pte; pfn++) {
+ struct page *page;
+
+ page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
+ GFP_KERNEL);
+ if (IS_ERR(page))
+ goto err_page;
+
+ **ptes++ = mk_pte(page, PAGE_KERNEL);
+ }
+
+ if (mem != stack)
+ kvfree(mem);
+
+ mapping_set_unevictable(file->f_mapping);
+ return area->addr;
+
+err_page:
+ if (mem != stack)
+ kvfree(mem);
+
+ __shmem_unpin_map(file, area->addr, pfn);
+ return NULL;
+}
+
+void shmem_unpin_map(struct file *file, void *ptr)
+{
+ mapping_clear_unevictable(file->f_mapping);
+ __shmem_unpin_map(file, ptr, shmem_npte(file));
+}
+
+int shmem_read(struct file *file, loff_t off, void *dst, size_t len)
+{
+ unsigned long pfn;
+
+ for (pfn = off >> PAGE_SHIFT; len; pfn++) {
+ unsigned int this =
+ min_t(size_t, PAGE_SIZE - offset_in_page(off), len);
+ struct page *page;
+ void *vaddr;
+
+ page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
+ GFP_KERNEL);
+ if (IS_ERR(page))
+ return PTR_ERR(page);
+
+ vaddr = kmap(page);
+ memcpy(dst, vaddr + offset_in_page(off), this);
+ kunmap(page);
+ put_page(page);
+
+ len -= this;
+ dst += this;
+ off = 0;
+ }
+
+ return 0;
+}
diff --git a/drivers/gpu/drm/i915/gt/shmem_utils.h b/drivers/gpu/drm/i915/gt/shmem_utils.h
new file mode 100644
index 000000000000..213fae8a943a
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/shmem_utils.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2020 Intel Corporation
+ */
+
+#ifndef SHMEM_UTILS_H
+#define SHMEM_UTILS_H
+
+#include <linux/types.h>
+
+struct drm_i915_gem_object;
+struct file;
+
+struct file *shmem_create_from_data(const char *name, void *data, size_t len);
+struct file *shmem_create_from_object(struct drm_i915_gem_object *obj);
+
+void *shmem_pin_map(struct file *file);
+void shmem_unpin_map(struct file *file, void *ptr);
+
+int shmem_read(struct file *file, loff_t off, void *dst, size_t len);
+
+#endif /* SHMEM_UTILS_H */
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index 4d54dba35302..8506ca43eca6 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -1318,26 +1318,6 @@ capture_user(struct intel_engine_capture_vma *capture,
return capture;
}
-static struct i915_vma_coredump *
-capture_object(const struct intel_gt *gt,
- struct drm_i915_gem_object *obj,
- const char *name,
- struct i915_vma_compress *compress)
-{
- if (obj && i915_gem_object_has_pages(obj)) {
- struct i915_vma fake = {
- .node = { .start = U64_MAX, .size = obj->base.size },
- .size = obj->base.size,
- .pages = obj->mm.pages,
- .obj = obj,
- };
-
- return i915_vma_coredump_create(gt, &fake, name, compress);
- } else {
- return NULL;
- }
-}
-
static void add_vma(struct intel_engine_coredump *ee,
struct i915_vma_coredump *vma)
{
@@ -1426,12 +1406,6 @@ intel_engine_coredump_add_vma(struct intel_engine_coredump *ee,
engine->wa_ctx.vma,
"WA context",
compress));
-
- add_vma(ee,
- capture_object(engine->gt,
- engine->default_state,
- "NULL context",
- compress));
}
static struct intel_engine_coredump *
--
2.20.1
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