Add support for madvise and a shrinker similar to other drivers. This
allows userspace to mark BOs which can be freed when there is memory
pressure.
Unlike other implementations, we don't depend on struct_mutex. The
driver maintains a list of BOs which can be freed when the shrinker
is called. Access to the list is serialized with the shrinker_lock.
Cc: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
---
drivers/gpu/drm/panfrost/Makefile | 1 +
drivers/gpu/drm/panfrost/TODO | 3 -
drivers/gpu/drm/panfrost/panfrost_device.h | 4 +
drivers/gpu/drm/panfrost/panfrost_drv.c | 38 +++++++
drivers/gpu/drm/panfrost/panfrost_gem.c | 5 +
drivers/gpu/drm/panfrost/panfrost_gem.h | 3 +
.../gpu/drm/panfrost/panfrost_gem_shrinker.c | 107 ++++++++++++++++++
include/uapi/drm/panfrost_drm.h | 22 ++++
8 files changed, 180 insertions(+), 3 deletions(-)
create mode 100644 drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c
diff --git a/drivers/gpu/drm/panfrost/Makefile b/drivers/gpu/drm/panfrost/Makefile
index ecf0864cb515..b71935862417 100644
--- a/drivers/gpu/drm/panfrost/Makefile
+++ b/drivers/gpu/drm/panfrost/Makefile
@@ -5,6 +5,7 @@ panfrost-y := \
panfrost_device.o \
panfrost_devfreq.o \
panfrost_gem.o \
+ panfrost_gem_shrinker.o \
panfrost_gpu.o \
panfrost_job.o \
panfrost_mmu.o \
diff --git a/drivers/gpu/drm/panfrost/TODO b/drivers/gpu/drm/panfrost/TODO
index c2e44add37d8..f3beca8d4ce9 100644
--- a/drivers/gpu/drm/panfrost/TODO
+++ b/drivers/gpu/drm/panfrost/TODO
@@ -18,10 +18,7 @@
- Support userspace controlled GPU virtual addresses. Needed for Vulkan. (Tomeu)
-- Support for madvise and a shrinker.
-
- Compute job support. So called 'compute only' jobs need to be plumbed up to
userspace.
- Performance counter support. (Boris)
-
diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h
index 83cc01cafde1..9751e8dc9ec6 100644
--- a/drivers/gpu/drm/panfrost/panfrost_device.h
+++ b/drivers/gpu/drm/panfrost/panfrost_device.h
@@ -84,6 +84,10 @@ struct panfrost_device {
struct mutex sched_lock;
struct mutex reset_lock;
+ struct mutex shrinker_lock;
+ struct list_head shrinker_list;
+ struct shrinker shrinker;
+
struct {
struct devfreq *devfreq;
struct thermal_cooling_device *cooling;
diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
index cb43ff4ebf4a..399007d306ea 100644
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
@@ -301,6 +301,38 @@ static int panfrost_ioctl_get_bo_offset(struct drm_device *dev, void *data,
return 0;
}
+static int panfrost_ioctl_madvise(struct drm_device *dev, void *data,
+ struct drm_file *file_priv)
+{
+ struct drm_panfrost_madvise *args = data;
+ struct panfrost_device *pfdev = dev->dev_private;
+ struct drm_gem_object *gem_obj;
+
+ gem_obj = drm_gem_object_lookup(file_priv, args->handle);
+ if (!gem_obj) {
+ DRM_DEBUG("Failed to look up GEM BO %d\n", args->handle);
+ return -ENOENT;
+ }
+
+ args->retained = drm_gem_shmem_madvise(gem_obj, args->madv);
+
+ if (args->retained) {
+ struct panfrost_gem_object *bo = to_panfrost_bo(gem_obj);
+
+ mutex_lock(&pfdev->shrinker_lock);
+
+ if (args->madv == PANFROST_MADV_DONTNEED)
+ list_add_tail(&bo->base.madv_list, &pfdev->shrinker_list);
+ else if (args->madv == PANFROST_MADV_WILLNEED)
+ list_del_init(&bo->base.madv_list);
+
+ mutex_unlock(&pfdev->shrinker_lock);
+ }
+
+ drm_gem_object_put_unlocked(gem_obj);
+ return 0;
+}
+
int panfrost_unstable_ioctl_check(void)
{
if (!unstable_ioctls)
@@ -352,6 +384,7 @@ static const struct drm_ioctl_desc panfrost_drm_driver_ioctls[] = {
PANFROST_IOCTL(GET_BO_OFFSET, get_bo_offset, DRM_RENDER_ALLOW),
PANFROST_IOCTL(PERFCNT_ENABLE, perfcnt_enable, DRM_RENDER_ALLOW),
PANFROST_IOCTL(PERFCNT_DUMP, perfcnt_dump, DRM_RENDER_ALLOW),
+ PANFROST_IOCTL(MADVISE, madvise, DRM_RENDER_ALLOW),
};
DEFINE_DRM_GEM_SHMEM_FOPS(panfrost_drm_driver_fops);
@@ -400,6 +433,8 @@ static int panfrost_probe(struct platform_device *pdev)
pfdev->ddev = ddev;
spin_lock_init(&pfdev->mm_lock);
+ mutex_init(&pfdev->shrinker_lock);
+ INIT_LIST_HEAD(&pfdev->shrinker_list);
/* 4G enough for now. can be 48-bit */
drm_mm_init(&pfdev->mm, SZ_32M >> PAGE_SHIFT, (SZ_4G - SZ_32M) >> PAGE_SHIFT);
@@ -430,6 +465,8 @@ static int panfrost_probe(struct platform_device *pdev)
if (err < 0)
goto err_out1;
+ panfrost_gem_shrinker_init(ddev);
+
return 0;
err_out1:
@@ -446,6 +483,7 @@ static int panfrost_remove(struct platform_device *pdev)
struct drm_device *ddev = pfdev->ddev;
drm_dev_unregister(ddev);
+ panfrost_gem_shrinker_cleanup(ddev);
pm_runtime_get_sync(pfdev->dev);
pm_runtime_put_sync_autosuspend(pfdev->dev);
pm_runtime_disable(pfdev->dev);
diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c
index 543ab1b81bd5..67d374184340 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gem.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gem.c
@@ -26,6 +26,11 @@ static void panfrost_gem_free_object(struct drm_gem_object *obj)
drm_mm_remove_node(&bo->node);
spin_unlock(&pfdev->mm_lock);
+ mutex_lock(&pfdev->shrinker_lock);
+ if (!list_empty(&bo->base.madv_list))
+ list_del(&bo->base.madv_list);
+ mutex_unlock(&pfdev->shrinker_lock);
+
drm_gem_shmem_free_object(obj);
}
diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/panfrost/panfrost_gem.h
index 6dbcaba020fc..5f51f881ea3f 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gem.h
+++ b/drivers/gpu/drm/panfrost/panfrost_gem.h
@@ -27,4 +27,7 @@ panfrost_gem_prime_import_sg_table(struct drm_device *dev,
struct dma_buf_attachment *attach,
struct sg_table *sgt);
+void panfrost_gem_shrinker_init(struct drm_device *dev);
+void panfrost_gem_shrinker_cleanup(struct drm_device *dev);
+
#endif /* __PANFROST_GEM_H__ */
diff --git a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c
new file mode 100644
index 000000000000..d191632b6197
--- /dev/null
+++ b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c
@@ -0,0 +1,107 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2019 Arm Ltd.
+ *
+ * Based on msm_gem_freedreno.c:
+ * Copyright (C) 2016 Red Hat
+ * Author: Rob Clark <robdclark@xxxxxxxxx>
+ */
+
+#include <linux/list.h>
+
+#include <drm/drm_device.h>
+#include <drm/drm_gem_shmem_helper.h>
+
+#include "panfrost_device.h"
+#include "panfrost_gem.h"
+#include "panfrost_mmu.h"
+
+static unsigned long
+panfrost_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
+{
+ struct panfrost_device *pfdev =
+ container_of(shrinker, struct panfrost_device, shrinker);
+ struct drm_gem_shmem_object *shmem;
+ unsigned long count = 0;
+
+ if (!mutex_trylock(&pfdev->shrinker_lock))
+ return 0;
+
+ list_for_each_entry(shmem, &pfdev->shrinker_list, madv_list) {
+ if (drm_gem_shmem_is_purgeable(shmem))
+ count += shmem->base.size >> PAGE_SHIFT;
+ }
+
+ mutex_unlock(&pfdev->shrinker_lock);
+
+ return count;
+}
+
+static void panfrost_gem_purge(struct drm_gem_object *obj)
+{
+ struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
+ mutex_lock(&shmem->pages_lock);
+
+ panfrost_mmu_unmap(to_panfrost_bo(obj));
+ drm_gem_shmem_purge_locked(obj);
+
+ mutex_unlock(&shmem->pages_lock);
+}
+
+static unsigned long
+panfrost_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
+{
+ struct panfrost_device *pfdev =
+ container_of(shrinker, struct panfrost_device, shrinker);
+ struct drm_gem_shmem_object *shmem, *tmp;
+ unsigned long freed = 0;
+
+ if (!mutex_trylock(&pfdev->shrinker_lock))
+ return SHRINK_STOP;
+
+ list_for_each_entry_safe(shmem, tmp, &pfdev->shrinker_list, madv_list) {
+ if (freed >= sc->nr_to_scan)
+ break;
+ if (drm_gem_shmem_is_purgeable(shmem)) {
+ panfrost_gem_purge(&shmem->base);
+ freed += shmem->base.size >> PAGE_SHIFT;
+ list_del_init(&shmem->madv_list);
+ }
+ }
+
+ mutex_unlock(&pfdev->shrinker_lock);
+
+ if (freed > 0)
+ pr_info_ratelimited("Purging %lu bytes\n", freed << PAGE_SHIFT);
+
+ return freed;
+}
+
+/**
+ * panfrost_gem_shrinker_init - Initialize panfrost shrinker
+ * @dev: DRM device
+ *
+ * This function registers and sets up the panfrost shrinker.
+ */
+void panfrost_gem_shrinker_init(struct drm_device *dev)
+{
+ struct panfrost_device *pfdev = dev->dev_private;
+ pfdev->shrinker.count_objects = panfrost_gem_shrinker_count;
+ pfdev->shrinker.scan_objects = panfrost_gem_shrinker_scan;
+ pfdev->shrinker.seeks = DEFAULT_SEEKS;
+ WARN_ON(register_shrinker(&pfdev->shrinker));
+}
+
+/**
+ * panfrost_gem_shrinker_cleanup - Clean up panfrost shrinker
+ * @dev: DRM device
+ *
+ * This function unregisters the panfrost shrinker.
+ */
+void panfrost_gem_shrinker_cleanup(struct drm_device *dev)
+{
+ struct panfrost_device *pfdev = dev->dev_private;
+
+ if (pfdev->shrinker.nr_deferred) {
+ unregister_shrinker(&pfdev->shrinker);
+ }
+}
diff --git a/include/uapi/drm/panfrost_drm.h b/include/uapi/drm/panfrost_drm.h
index b5d370638846..1b3ff910ebe7 100644
--- a/include/uapi/drm/panfrost_drm.h
+++ b/include/uapi/drm/panfrost_drm.h
@@ -20,6 +20,7 @@ extern "C" {
#define DRM_PANFROST_GET_BO_OFFSET 0x05
#define DRM_PANFROST_PERFCNT_ENABLE 0x06
#define DRM_PANFROST_PERFCNT_DUMP 0x07
+#define DRM_PANFROST_MADVISE 0x08
#define DRM_IOCTL_PANFROST_SUBMIT DRM_IOW(DRM_COMMAND_BASE + DRM_PANFROST_SUBMIT, struct drm_panfrost_submit)
#define DRM_IOCTL_PANFROST_WAIT_BO DRM_IOW(DRM_COMMAND_BASE + DRM_PANFROST_WAIT_BO, struct drm_panfrost_wait_bo)
@@ -27,6 +28,7 @@ extern "C" {
#define DRM_IOCTL_PANFROST_MMAP_BO DRM_IOWR(DRM_COMMAND_BASE + DRM_PANFROST_MMAP_BO, struct drm_panfrost_mmap_bo)
#define DRM_IOCTL_PANFROST_GET_PARAM DRM_IOWR(DRM_COMMAND_BASE + DRM_PANFROST_GET_PARAM, struct drm_panfrost_get_param)
#define DRM_IOCTL_PANFROST_GET_BO_OFFSET DRM_IOWR(DRM_COMMAND_BASE + DRM_PANFROST_GET_BO_OFFSET, struct drm_panfrost_get_bo_offset)
+#define DRM_IOCTL_PANFROST_MADVISE DRM_IOWR(DRM_COMMAND_BASE + DRM_PANFROST_MADVISE, struct drm_panfrost_madvise)
/*
* Unstable ioctl(s): only exposed when the unsafe unstable_ioctls module
@@ -159,6 +161,26 @@ struct drm_panfrost_perfcnt_dump {
__u64 buf_ptr;
};
+/* madvise provides a way to tell the kernel in case a buffers contents
+ * can be discarded under memory pressure, which is useful for userspace
+ * bo cache where we want to optimistically hold on to buffer allocate
+ * and potential mmap, but allow the pages to be discarded under memory
+ * pressure.
+ *
+ * Typical usage would involve madvise(DONTNEED) when buffer enters BO
+ * cache, and madvise(WILLNEED) if trying to recycle buffer from BO cache.
+ * In the WILLNEED case, 'retained' indicates to userspace whether the
+ * backing pages still exist.
+ */
+#define PANFROST_MADV_WILLNEED 0 /* backing pages are needed, status returned in 'retained' */
+#define PANFROST_MADV_DONTNEED 1 /* backing pages not needed */
+
+struct drm_panfrost_madvise {
+ __u32 handle; /* in, GEM handle */
+ __u32 madv; /* in, PANFROST_MADV_x */
+ __u32 retained; /* out, whether backing store still exists */
+};
+
#if defined(__cplusplus)
}
#endif
--
2.20.1
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