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Message-ID: <20230903170736.513347-12-dmitry.osipenko@collabora.com>
Date: Sun, 3 Sep 2023 20:07:27 +0300
From: Dmitry Osipenko <dmitry.osipenko@...labora.com>
To: David Airlie <airlied@...il.com>,
Gerd Hoffmann <kraxel@...hat.com>,
Gurchetan Singh <gurchetansingh@...omium.org>,
Chia-I Wu <olvaffe@...il.com>, Daniel Vetter <daniel@...ll.ch>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>,
Thomas Zimmermann <tzimmermann@...e.de>,
Christian König <christian.koenig@....com>,
Qiang Yu <yuq825@...il.com>,
Steven Price <steven.price@....com>,
Boris Brezillon <boris.brezillon@...labora.com>,
Emma Anholt <emma@...olt.net>, Melissa Wen <mwen@...lia.com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
kernel@...labora.com, virtualization@...ts.linux-foundation.org
Subject: [PATCH v16 11/20] drm/shmem-helper: Use refcount_t for pages_use_count
Use atomic refcount_t helper for pages_use_count to optimize pin/unpin
functions by skipping reservation locking while GEM's pin refcount > 1.
Suggested-by: Boris Brezillon <boris.brezillon@...labora.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@...labora.com>
---
drivers/gpu/drm/drm_gem_shmem_helper.c | 35 +++++++++++--------------
drivers/gpu/drm/lima/lima_gem.c | 2 +-
drivers/gpu/drm/panfrost/panfrost_mmu.c | 2 +-
include/drm/drm_gem_shmem_helper.h | 2 +-
4 files changed, 19 insertions(+), 22 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index 7e1e674e2c9f..a0faef3e762d 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -152,12 +152,12 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem)
sg_free_table(shmem->sgt);
kfree(shmem->sgt);
}
- if (shmem->pages) {
+ if (refcount_read(&shmem->pages_use_count)) {
drm_gem_shmem_put_pages_locked(shmem);
drm_WARN_ON(obj->dev, !shmem->got_pages_sgt);
}
- drm_WARN_ON(obj->dev, shmem->pages_use_count);
+ drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_use_count));
dma_resv_unlock(shmem->base.resv);
}
@@ -174,14 +174,13 @@ static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem)
dma_resv_assert_held(shmem->base.resv);
- if (shmem->pages_use_count++ > 0)
+ if (refcount_inc_not_zero(&shmem->pages_use_count))
return 0;
pages = drm_gem_get_pages(obj);
if (IS_ERR(pages)) {
drm_dbg_kms(obj->dev, "Failed to get pages (%ld)\n",
PTR_ERR(pages));
- shmem->pages_use_count = 0;
return PTR_ERR(pages);
}
@@ -197,6 +196,8 @@ static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem)
shmem->pages = pages;
+ refcount_set(&shmem->pages_use_count, 1);
+
return 0;
}
@@ -212,21 +213,17 @@ void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem)
dma_resv_assert_held(shmem->base.resv);
- if (drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count))
- return;
-
- if (--shmem->pages_use_count > 0)
- return;
-
+ if (refcount_dec_and_test(&shmem->pages_use_count)) {
#ifdef CONFIG_X86
- if (shmem->map_wc)
- set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT);
+ if (shmem->map_wc)
+ set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT);
#endif
- drm_gem_put_pages(obj, shmem->pages,
- shmem->pages_mark_dirty_on_put,
- shmem->pages_mark_accessed_on_put);
- shmem->pages = NULL;
+ drm_gem_put_pages(obj, shmem->pages,
+ shmem->pages_mark_dirty_on_put,
+ shmem->pages_mark_accessed_on_put);
+ shmem->pages = NULL;
+ }
}
EXPORT_SYMBOL_GPL(drm_gem_shmem_put_pages_locked);
@@ -553,8 +550,8 @@ static void drm_gem_shmem_vm_open(struct vm_area_struct *vma)
* mmap'd, vm_open() just grabs an additional reference for the new
* mm the vma is getting copied into (ie. on fork()).
*/
- if (!drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count))
- shmem->pages_use_count++;
+ drm_WARN_ON_ONCE(obj->dev,
+ !refcount_inc_not_zero(&shmem->pages_use_count));
dma_resv_unlock(shmem->base.resv);
@@ -642,7 +639,7 @@ void drm_gem_shmem_print_info(const struct drm_gem_shmem_object *shmem,
return;
drm_printf_indent(p, indent, "pages_pin_count=%u\n", refcount_read(&shmem->pages_pin_count));
- drm_printf_indent(p, indent, "pages_use_count=%u\n", shmem->pages_use_count);
+ drm_printf_indent(p, indent, "pages_use_count=%u\n", refcount_read(&shmem->pages_use_count));
drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count);
drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr);
}
diff --git a/drivers/gpu/drm/lima/lima_gem.c b/drivers/gpu/drm/lima/lima_gem.c
index ec8f718aa539..4be2fccbf6d9 100644
--- a/drivers/gpu/drm/lima/lima_gem.c
+++ b/drivers/gpu/drm/lima/lima_gem.c
@@ -47,8 +47,8 @@ int lima_heap_alloc(struct lima_bo *bo, struct lima_vm *vm)
}
bo->base.pages = pages;
- bo->base.pages_use_count = 1;
bo->base.got_pages_sgt = true;
+ refcount_set(&bo->base.pages_use_count, 1);
mapping_set_unevictable(mapping);
}
diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c
index 7771769f0ce0..a91252053aa3 100644
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
@@ -487,7 +487,7 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
goto err_unlock;
}
bo->base.pages = pages;
- bo->base.pages_use_count = 1;
+ refcount_set(&bo->base.pages_use_count, 1);
} else {
pages = bo->base.pages;
if (pages[page_offset]) {
diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_shmem_helper.h
index 1cd74ae5761a..bd545428a7ee 100644
--- a/include/drm/drm_gem_shmem_helper.h
+++ b/include/drm/drm_gem_shmem_helper.h
@@ -37,7 +37,7 @@ struct drm_gem_shmem_object {
* Reference count on the pages table.
* The pages are put when the count reaches zero.
*/
- unsigned int pages_use_count;
+ refcount_t pages_use_count;
/**
* @pages_pin_count:
--
2.41.0
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