From 013b6510131568ce4e01856d5360bfdfe9c3632f Mon Sep 17 00:00:00 2001 From: Rob Herring Date: Mon, 5 Aug 2019 08:33:58 -0600 Subject: [PATCH] drm/panfrost: Add madvise and shrinker support 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 Cc: David Airlie Cc: Daniel Vetter Acked-by: Alyssa Rosenzweig Signed-off-by: Rob Herring Link: https://patchwork.freedesktop.org/patch/msgid/20190805143358.21245-2-robh@kernel.org --- drivers/gpu/drm/panfrost/Makefile | 1 + drivers/gpu/drm/panfrost/TODO | 2 - 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 + drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c | 107 +++++++++++++++++++++++ include/uapi/drm/panfrost_drm.h | 22 +++++ 8 files changed, 180 insertions(+), 2 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 a01eae4bd8ba..d4c7fb7e7d13 100644 --- a/drivers/gpu/drm/panfrost/TODO +++ b/drivers/gpu/drm/panfrost/TODO @@ -14,7 +14,5 @@ - 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. diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h index ea5948ff3647..038b32c62484 100644 --- a/drivers/gpu/drm/panfrost/panfrost_device.h +++ b/drivers/gpu/drm/panfrost/panfrost_device.h @@ -85,6 +85,10 @@ 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 b187daa4da85..926d021ee202 100644 --- a/drivers/gpu/drm/panfrost/panfrost_drv.c +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c @@ -333,6 +333,38 @@ 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) @@ -384,6 +416,7 @@ 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); @@ -432,6 +465,8 @@ 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); @@ -462,6 +497,8 @@ static int panfrost_probe(struct platform_device *pdev) if (err < 0) goto err_out1; + panfrost_gem_shrinker_init(ddev); + return 0; err_out1: @@ -478,6 +515,7 @@ 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 + */ + +#include + +#include +#include + +#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 cb577fb96b38..1e547f9692e9 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 @@ -198,6 +200,26 @@ 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 -- 2.11.0