[Intel-gfx] [PATCH 05/26] drm/i915: Remove locking from i915_gem_object_prepare_read/write
Tvrtko Ursulin
tvrtko.ursulin at linux.intel.com
Mon Jun 29 12:56:09 UTC 2020
On 23/06/2020 15:28, Maarten Lankhorst wrote:
> Execbuffer submission will perform its own WW locking, and we
> cannot rely on the implicit lock there.
>
> This also makes it clear that the GVT code will get a lockdep splat when
> multiple batchbuffer shadows need to be performed in the same instance,
> fix that up.
>
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> ---
> drivers/gpu/drm/i915/gem/i915_gem_domain.c | 20 ++++++-------------
> .../gpu/drm/i915/gem/i915_gem_execbuffer.c | 13 ++++++++++--
> drivers/gpu/drm/i915/gem/i915_gem_object.h | 1 -
> .../gpu/drm/i915/gem/selftests/huge_pages.c | 5 ++++-
> .../i915/gem/selftests/i915_gem_coherency.c | 14 +++++++++----
> .../drm/i915/gem/selftests/i915_gem_context.c | 12 ++++++++---
> drivers/gpu/drm/i915/gvt/cmd_parser.c | 1 +
> drivers/gpu/drm/i915/i915_gem.c | 20 +++++++++++++++++--
> 8 files changed, 59 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_domain.c b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
> index c0acfc97fae3..8ebceebd11b0 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_domain.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
> @@ -576,19 +576,17 @@ int i915_gem_object_prepare_read(struct drm_i915_gem_object *obj,
> if (!i915_gem_object_has_struct_page(obj))
> return -ENODEV;
>
> - ret = i915_gem_object_lock_interruptible(obj, NULL);
> - if (ret)
> - return ret;
> + assert_object_held(obj);
>
> ret = i915_gem_object_wait(obj,
> I915_WAIT_INTERRUPTIBLE,
> MAX_SCHEDULE_TIMEOUT);
> if (ret)
> - goto err_unlock;
> + return ret;
>
> ret = i915_gem_object_pin_pages(obj);
> if (ret)
> - goto err_unlock;
> + return ret;
>
> if (obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_READ ||
> !static_cpu_has(X86_FEATURE_CLFLUSH)) {
> @@ -616,8 +614,6 @@ int i915_gem_object_prepare_read(struct drm_i915_gem_object *obj,
>
> err_unpin:
> i915_gem_object_unpin_pages(obj);
> -err_unlock:
> - i915_gem_object_unlock(obj);
> return ret;
> }
>
> @@ -630,20 +626,18 @@ int i915_gem_object_prepare_write(struct drm_i915_gem_object *obj,
> if (!i915_gem_object_has_struct_page(obj))
> return -ENODEV;
>
> - ret = i915_gem_object_lock_interruptible(obj, NULL);
> - if (ret)
> - return ret;
> + assert_object_held(obj);
>
> ret = i915_gem_object_wait(obj,
> I915_WAIT_INTERRUPTIBLE |
> I915_WAIT_ALL,
> MAX_SCHEDULE_TIMEOUT);
> if (ret)
> - goto err_unlock;
> + return ret;
>
> ret = i915_gem_object_pin_pages(obj);
> if (ret)
> - goto err_unlock;
> + return ret;
>
> if (obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_WRITE ||
> !static_cpu_has(X86_FEATURE_CLFLUSH)) {
> @@ -680,7 +674,5 @@ int i915_gem_object_prepare_write(struct drm_i915_gem_object *obj,
>
> err_unpin:
> i915_gem_object_unpin_pages(obj);
> -err_unlock:
> - i915_gem_object_unlock(obj);
> return ret;
> }
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> index 391d22051b20..f896b1a4b38a 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> @@ -1003,11 +1003,14 @@ static void reloc_cache_reset(struct reloc_cache *cache)
>
> vaddr = unmask_page(cache->vaddr);
> if (cache->vaddr & KMAP) {
> + struct drm_i915_gem_object *obj =
> + (struct drm_i915_gem_object *)cache->node.mm;
> if (cache->vaddr & CLFLUSH_AFTER)
> mb();
>
> kunmap_atomic(vaddr);
> - i915_gem_object_finish_access((struct drm_i915_gem_object *)cache->node.mm);
> + i915_gem_object_finish_access(obj);
> + i915_gem_object_unlock(obj);
> } else {
> struct i915_ggtt *ggtt = cache_to_ggtt(cache);
>
> @@ -1042,10 +1045,16 @@ static void *reloc_kmap(struct drm_i915_gem_object *obj,
> unsigned int flushes;
> int err;
>
> - err = i915_gem_object_prepare_write(obj, &flushes);
> + err = i915_gem_object_lock_interruptible(obj, NULL);
> if (err)
> return ERR_PTR(err);
>
> + err = i915_gem_object_prepare_write(obj, &flushes);
> + if (err) {
> + i915_gem_object_unlock(obj);
> + return ERR_PTR(err);
> + }
> +
> BUILD_BUG_ON(KMAP & CLFLUSH_FLAGS);
> BUILD_BUG_ON((KMAP | CLFLUSH_FLAGS) & PAGE_MASK);
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> index 5103067269b0..11b8e2735071 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> @@ -434,7 +434,6 @@ static inline void
> i915_gem_object_finish_access(struct drm_i915_gem_object *obj)
> {
> i915_gem_object_unpin_pages(obj);
> - i915_gem_object_unlock(obj);
> }
>
> static inline struct intel_engine_cs *
> diff --git a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
> index eb2011ccb92b..fff11327a8da 100644
> --- a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
> +++ b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
> @@ -964,9 +964,10 @@ __cpu_check_shmem(struct drm_i915_gem_object *obj, u32 dword, u32 val)
> unsigned long n;
> int err;
>
> + i915_gem_object_lock(obj, NULL);
> err = i915_gem_object_prepare_read(obj, &needs_flush);
> if (err)
> - return err;
> + goto err_unlock;
>
> for (n = 0; n < obj->base.size >> PAGE_SHIFT; ++n) {
> u32 *ptr = kmap_atomic(i915_gem_object_get_page(obj, n));
> @@ -986,6 +987,8 @@ __cpu_check_shmem(struct drm_i915_gem_object *obj, u32 dword, u32 val)
> }
>
> i915_gem_object_finish_access(obj);
> +err_unlock:
> + i915_gem_object_unlock(obj);
>
> return err;
> }
> diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
> index 1de2959b153c..dcdfc396f2f8 100644
> --- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
> +++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_coherency.c
> @@ -27,9 +27,10 @@ static int cpu_set(struct context *ctx, unsigned long offset, u32 v)
> u32 *cpu;
> int err;
>
> + i915_gem_object_lock(ctx->obj, NULL);
> err = i915_gem_object_prepare_write(ctx->obj, &needs_clflush);
> if (err)
> - return err;
> + goto out;
>
> page = i915_gem_object_get_page(ctx->obj, offset >> PAGE_SHIFT);
> map = kmap_atomic(page);
> @@ -46,7 +47,9 @@ static int cpu_set(struct context *ctx, unsigned long offset, u32 v)
> kunmap_atomic(map);
> i915_gem_object_finish_access(ctx->obj);
>
> - return 0;
> +out:
> + i915_gem_object_unlock(ctx->obj);
> + return err;
> }
>
> static int cpu_get(struct context *ctx, unsigned long offset, u32 *v)
> @@ -57,9 +60,10 @@ static int cpu_get(struct context *ctx, unsigned long offset, u32 *v)
> u32 *cpu;
> int err;
>
> + i915_gem_object_lock(ctx->obj, NULL);
> err = i915_gem_object_prepare_read(ctx->obj, &needs_clflush);
> if (err)
> - return err;
> + goto out;
>
> page = i915_gem_object_get_page(ctx->obj, offset >> PAGE_SHIFT);
> map = kmap_atomic(page);
> @@ -73,7 +77,9 @@ static int cpu_get(struct context *ctx, unsigned long offset, u32 *v)
> kunmap_atomic(map);
> i915_gem_object_finish_access(ctx->obj);
>
> - return 0;
> +out:
> + i915_gem_object_unlock(ctx->obj);
> + return err;
> }
>
> static int gtt_set(struct context *ctx, unsigned long offset, u32 v)
> diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
> index 438c15ef2184..76671f587b9d 100644
> --- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
> @@ -461,9 +461,10 @@ static int cpu_fill(struct drm_i915_gem_object *obj, u32 value)
> unsigned int n, m, need_flush;
> int err;
>
> + i915_gem_object_lock(obj, NULL);
> err = i915_gem_object_prepare_write(obj, &need_flush);
> if (err)
> - return err;
> + goto out;
>
> for (n = 0; n < real_page_count(obj); n++) {
> u32 *map;
> @@ -479,7 +480,9 @@ static int cpu_fill(struct drm_i915_gem_object *obj, u32 value)
> i915_gem_object_finish_access(obj);
> obj->read_domains = I915_GEM_DOMAIN_GTT | I915_GEM_DOMAIN_CPU;
> obj->write_domain = 0;
> - return 0;
> +out:
> + i915_gem_object_unlock(obj);
> + return err;
> }
>
> static noinline int cpu_check(struct drm_i915_gem_object *obj,
> @@ -488,9 +491,10 @@ static noinline int cpu_check(struct drm_i915_gem_object *obj,
> unsigned int n, m, needs_flush;
> int err;
>
> + i915_gem_object_lock(obj, NULL);
> err = i915_gem_object_prepare_read(obj, &needs_flush);
> if (err)
> - return err;
> + goto out_unlock;
>
> for (n = 0; n < real_page_count(obj); n++) {
> u32 *map;
> @@ -527,6 +531,8 @@ static noinline int cpu_check(struct drm_i915_gem_object *obj,
> }
>
> i915_gem_object_finish_access(obj);
> +out_unlock:
> + i915_gem_object_unlock(obj);
> return err;
> }
>
> diff --git a/drivers/gpu/drm/i915/gvt/cmd_parser.c b/drivers/gpu/drm/i915/gvt/cmd_parser.c
> index 943c8d232703..d0a599b51bfe 100644
> --- a/drivers/gpu/drm/i915/gvt/cmd_parser.c
> +++ b/drivers/gpu/drm/i915/gvt/cmd_parser.c
> @@ -1923,6 +1923,7 @@ static int perform_bb_shadow(struct parser_exec_state *s)
> if (ret)
> goto err_unmap;
>
> + i915_gem_object_unlock(bb->obj);
> INIT_LIST_HEAD(&bb->list);
> list_add(&bb->list, &s->workload->shadow_bb);
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 1e06752835e5..33f6f88c8b08 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -335,12 +335,20 @@ i915_gem_shmem_pread(struct drm_i915_gem_object *obj,
> u64 remain;
> int ret;
>
> - ret = i915_gem_object_prepare_read(obj, &needs_clflush);
> + ret = i915_gem_object_lock_interruptible(obj, NULL);
> if (ret)
> return ret;
>
> + ret = i915_gem_object_prepare_read(obj, &needs_clflush);
> + if (ret) {
> + i915_gem_object_unlock(obj);
> + return ret;
> + }
> +
> fence = i915_gem_object_lock_fence(obj);
> i915_gem_object_finish_access(obj);
> + i915_gem_object_unlock(obj);
> +
> if (!fence)
> return -ENOMEM;
>
> @@ -734,12 +742,20 @@ i915_gem_shmem_pwrite(struct drm_i915_gem_object *obj,
> u64 remain;
> int ret;
>
> - ret = i915_gem_object_prepare_write(obj, &needs_clflush);
> + ret = i915_gem_object_lock_interruptible(obj, NULL);
> if (ret)
> return ret;
>
> + ret = i915_gem_object_prepare_write(obj, &needs_clflush);
> + if (ret) {
> + i915_gem_object_unlock(obj);
> + return ret;
> + }
> +
> fence = i915_gem_object_lock_fence(obj);
> i915_gem_object_finish_access(obj);
> + i915_gem_object_unlock(obj);
> +
> if (!fence)
> return -ENOMEM;
>
>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Regards,
Tvrtko
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