From e7dac4c3231c0e8adeef8dbb732b2cde7c162b14 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Fri, 2 Oct 2020 02:48:26 +0000 Subject: [PATCH] ANDROID: dma-buf: heaps: Add a shrinker controlled page pool MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch adds a simple shrinker controlled page pool to the dmabuf heaps subsystem. This replaces the use of the networking page_pool, over concerns that the lack of a shrinker for that implementation may cause additional low-memory kills TODO: Take another pass at trying to unify this w/ the ttm pool Thoughts and feedback would be greatly appreciated! Cc: Sumit Semwal Cc: Liam Mark Cc: Laura Abbott Cc: Brian Starkey Cc: Hridya Valsaraju Cc: Suren Baghdasaryan Cc: Sandeep Patil Cc: Daniel Mentz Cc: Chris Goldsworthy Cc: Ørjan Eide Cc: Robin Murphy Cc: Ezequiel Garcia Cc: Simon Ser Cc: James Jones Cc: Andrew Morton Cc: Dave Hansen Cc: linux-mm@kvack.org Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Signed-off-by: John Stultz Bug: 168742043 Change-Id: Ic385e27a352d2fbf665ca288fee4f34eea5666d0 --- drivers/dma-buf/heaps/Kconfig | 3 + drivers/dma-buf/heaps/Makefile | 1 + drivers/dma-buf/heaps/page_pool.c | 247 ++++++++++++++++++++++++++++++ drivers/dma-buf/heaps/page_pool.h | 55 +++++++ 4 files changed, 306 insertions(+) create mode 100644 drivers/dma-buf/heaps/page_pool.c create mode 100644 drivers/dma-buf/heaps/page_pool.h diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig index 1c46b90fd2f4..a7c124058875 100644 --- a/drivers/dma-buf/heaps/Kconfig +++ b/drivers/dma-buf/heaps/Kconfig @@ -1,6 +1,9 @@ config DMABUF_HEAPS_DEFERRED_FREE tristate +config DMABUF_HEAPS_PAGE_POOL + tristate + config DMABUF_HEAPS_SYSTEM tristate "DMA-BUF System Heap" depends on DMABUF_HEAPS diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile index 4e7839875615..4d4cd94a3a4a 100644 --- a/drivers/dma-buf/heaps/Makefile +++ b/drivers/dma-buf/heaps/Makefile @@ -1,4 +1,5 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_DMABUF_HEAPS_DEFERRED_FREE) += deferred-free-helper.o +obj-$(CONFIG_DMABUF_HEAPS_PAGE_POOL) += page_pool.o obj-$(CONFIG_DMABUF_HEAPS_SYSTEM) += system_heap.o obj-$(CONFIG_DMABUF_HEAPS_CMA) += cma_heap.o diff --git a/drivers/dma-buf/heaps/page_pool.c b/drivers/dma-buf/heaps/page_pool.c new file mode 100644 index 000000000000..81d154cb0ae6 --- /dev/null +++ b/drivers/dma-buf/heaps/page_pool.c @@ -0,0 +1,247 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * DMA BUF page pool system + * + * Copyright (C) 2020 Linaro Ltd. + * + * Based on the ION page pool code + * Copyright (C) 2011 Google, Inc. + */ + +#include +#include +#include +#include +#include +#include "page_pool.h" + +static LIST_HEAD(pool_list); +static DEFINE_MUTEX(pool_list_lock); + +static inline +struct page *dmabuf_page_pool_alloc_pages(struct dmabuf_page_pool *pool) +{ + if (fatal_signal_pending(current)) + return NULL; + return alloc_pages(pool->gfp_mask, pool->order); +} + +static inline void dmabuf_page_pool_free_pages(struct dmabuf_page_pool *pool, + struct page *page) +{ + __free_pages(page, pool->order); +} + +static void dmabuf_page_pool_add(struct dmabuf_page_pool *pool, struct page *page) +{ + int index; + + if (PageHighMem(page)) + index = POOL_HIGHPAGE; + else + index = POOL_LOWPAGE; + + mutex_lock(&pool->mutex); + list_add_tail(&page->lru, &pool->items[index]); + pool->count[index]++; + mutex_unlock(&pool->mutex); + mod_node_page_state(page_pgdat(page), NR_KERNEL_MISC_RECLAIMABLE, + 1 << pool->order); +} + +static struct page *dmabuf_page_pool_remove(struct dmabuf_page_pool *pool, int index) +{ + struct page *page; + + mutex_lock(&pool->mutex); + page = list_first_entry_or_null(&pool->items[index], struct page, lru); + if (page) { + pool->count[index]--; + list_del(&page->lru); + mod_node_page_state(page_pgdat(page), NR_KERNEL_MISC_RECLAIMABLE, + -(1 << pool->order)); + } + mutex_unlock(&pool->mutex); + + return page; +} + +static struct page *dmabuf_page_pool_fetch(struct dmabuf_page_pool *pool) +{ + struct page *page = NULL; + + page = dmabuf_page_pool_remove(pool, POOL_HIGHPAGE); + if (!page) + page = dmabuf_page_pool_remove(pool, POOL_LOWPAGE); + + return page; +} + +struct page *dmabuf_page_pool_alloc(struct dmabuf_page_pool *pool) +{ + struct page *page = NULL; + + if (WARN_ON(!pool)) + return NULL; + + page = dmabuf_page_pool_fetch(pool); + + if (!page) + page = dmabuf_page_pool_alloc_pages(pool); + return page; +} +EXPORT_SYMBOL_GPL(dmabuf_page_pool_alloc); + +void dmabuf_page_pool_free(struct dmabuf_page_pool *pool, struct page *page) +{ + if (WARN_ON(pool->order != compound_order(page))) + return; + + dmabuf_page_pool_add(pool, page); +} +EXPORT_SYMBOL_GPL(dmabuf_page_pool_free); + +static int dmabuf_page_pool_total(struct dmabuf_page_pool *pool, bool high) +{ + int count = pool->count[POOL_LOWPAGE]; + + if (high) + count += pool->count[POOL_HIGHPAGE]; + + return count << pool->order; +} + +struct dmabuf_page_pool *dmabuf_page_pool_create(gfp_t gfp_mask, unsigned int order) +{ + struct dmabuf_page_pool *pool = kmalloc(sizeof(*pool), GFP_KERNEL); + int i; + + if (!pool) + return NULL; + + for (i = 0; i < POOL_TYPE_SIZE; i++) { + pool->count[i] = 0; + INIT_LIST_HEAD(&pool->items[i]); + } + pool->gfp_mask = gfp_mask | __GFP_COMP; + pool->order = order; + mutex_init(&pool->mutex); + + mutex_lock(&pool_list_lock); + list_add(&pool->list, &pool_list); + mutex_unlock(&pool_list_lock); + + return pool; +} +EXPORT_SYMBOL_GPL(dmabuf_page_pool_create); + +void dmabuf_page_pool_destroy(struct dmabuf_page_pool *pool) +{ + struct page *page; + int i; + + /* Remove us from the pool list */ + mutex_lock(&pool_list_lock); + list_del(&pool->list); + mutex_unlock(&pool_list_lock); + + /* Free any remaining pages in the pool */ + for (i = 0; i < POOL_TYPE_SIZE; i++) { + while ((page = dmabuf_page_pool_remove(pool, i))) + dmabuf_page_pool_free_pages(pool, page); + } + + kfree(pool); +} +EXPORT_SYMBOL_GPL(dmabuf_page_pool_destroy); + +static int dmabuf_page_pool_do_shrink(struct dmabuf_page_pool *pool, gfp_t gfp_mask, + int nr_to_scan) +{ + int freed = 0; + bool high; + + if (current_is_kswapd()) + high = true; + else + high = !!(gfp_mask & __GFP_HIGHMEM); + + if (nr_to_scan == 0) + return dmabuf_page_pool_total(pool, high); + + while (freed < nr_to_scan) { + struct page *page; + + /* Try to free low pages first */ + page = dmabuf_page_pool_remove(pool, POOL_LOWPAGE); + if (!page) + page = dmabuf_page_pool_remove(pool, POOL_HIGHPAGE); + + if (!page) + break; + + dmabuf_page_pool_free_pages(pool, page); + freed += (1 << pool->order); + } + + return freed; +} + +static int dmabuf_page_pool_shrink(gfp_t gfp_mask, int nr_to_scan) +{ + struct dmabuf_page_pool *pool; + int nr_total = 0; + int nr_freed; + int only_scan = 0; + + if (!nr_to_scan) + only_scan = 1; + + mutex_lock(&pool_list_lock); + list_for_each_entry(pool, &pool_list, list) { + if (only_scan) { + nr_total += dmabuf_page_pool_do_shrink(pool, + gfp_mask, + nr_to_scan); + } else { + nr_freed = dmabuf_page_pool_do_shrink(pool, + gfp_mask, + nr_to_scan); + nr_to_scan -= nr_freed; + nr_total += nr_freed; + if (nr_to_scan <= 0) + break; + } + } + mutex_unlock(&pool_list_lock); + + return nr_total; +} + +static unsigned long dmabuf_page_pool_shrink_count(struct shrinker *shrinker, + struct shrink_control *sc) +{ + return dmabuf_page_pool_shrink(sc->gfp_mask, 0); +} + +static unsigned long dmabuf_page_pool_shrink_scan(struct shrinker *shrinker, + struct shrink_control *sc) +{ + if (sc->nr_to_scan == 0) + return 0; + return dmabuf_page_pool_shrink(sc->gfp_mask, sc->nr_to_scan); +} + +struct shrinker pool_shrinker = { + .count_objects = dmabuf_page_pool_shrink_count, + .scan_objects = dmabuf_page_pool_shrink_scan, + .seeks = DEFAULT_SEEKS, + .batch = 0, +}; + +int dmabuf_page_pool_init_shrinker(void) +{ + return register_shrinker(&pool_shrinker); +} +module_init(dmabuf_page_pool_init_shrinker); +MODULE_LICENSE("GPL v2"); diff --git a/drivers/dma-buf/heaps/page_pool.h b/drivers/dma-buf/heaps/page_pool.h new file mode 100644 index 000000000000..6b083b04f195 --- /dev/null +++ b/drivers/dma-buf/heaps/page_pool.h @@ -0,0 +1,55 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * DMA BUF PagePool implementation + * Based on earlier ION code by Google + * + * Copyright (C) 2011 Google, Inc. + * Copyright (C) 2020 Linaro Ltd. + */ + +#ifndef _DMABUF_PAGE_POOL_H +#define _DMABUF_PAGE_POOL_H + +#include +#include +#include +#include +#include +#include + +/* page types we track in the pool */ +enum { + POOL_LOWPAGE, /* Clean lowmem pages */ + POOL_HIGHPAGE, /* Clean highmem pages */ + + POOL_TYPE_SIZE, +}; + +/** + * struct dmabuf_page_pool - pagepool struct + * @count[]: array of number of pages of that type in the pool + * @items[]: array of list of pages of the specific type + * @mutex: lock protecting this struct and especially the count + * item list + * @gfp_mask: gfp_mask to use from alloc + * @order: order of pages in the pool + * @list: list node for list of pools + * + * Allows you to keep a pool of pre allocated pages to use + */ +struct dmabuf_page_pool { + int count[POOL_TYPE_SIZE]; + struct list_head items[POOL_TYPE_SIZE]; + struct mutex mutex; + gfp_t gfp_mask; + unsigned int order; + struct list_head list; +}; + +struct dmabuf_page_pool *dmabuf_page_pool_create(gfp_t gfp_mask, + unsigned int order); +void dmabuf_page_pool_destroy(struct dmabuf_page_pool *pool); +struct page *dmabuf_page_pool_alloc(struct dmabuf_page_pool *pool); +void dmabuf_page_pool_free(struct dmabuf_page_pool *pool, struct page *page); + +#endif /* _DMABUF_PAGE_POOL_H */