From patchwork Thu Jan 28 06:21:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: John Stultz X-Patchwork-Id: 372520 Delivered-To: patches@linaro.org Received: by 2002:a02:a60d:0:0:0:0:0 with SMTP id c13csp939770jam; Wed, 27 Jan 2021 22:21:53 -0800 (PST) X-Received: by 2002:a62:3485:0:b029:1b7:d521:29e9 with SMTP id b127-20020a6234850000b02901b7d52129e9mr14377251pfa.81.1611814913459; Wed, 27 Jan 2021 22:21:53 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1611814913; cv=none; d=google.com; s=arc-20160816; b=FqSgYAVbwrcX/Jc4Vm7BtEwVeNq4L06IWMMrD1KCII5PlzPcN/V5D1xKy6gFnj8+ld 79bDBC4kSw/CyJRl7dvuDLvN7rzzd1V4euIVm/M5KNLFOFGjHs7H+NBLekt+Vgc1beQ5 Ue97P08j9bJNMli9pMktH0CHb7/4N2dESZX50iuXnUBJgAIu+AK6WyriJtExByNJA0xa 6y9HPVULKZr4Q2uDvQ3Nnk7Fd1ZJXGDjfGIlUbv2A5gOuMJXLF66y9sByKMoB1Fca6I5 efsnmnAOQJEGvdHYEwsxcNzagUI2Arc84AHXVa7zIZXHZc6eUbCP9fybyDPAHu7HaB72 tw5w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:dkim-signature; bh=lQKUqtdrTcnk28eLZN1LLjXCJVs6RFMKJof9ORakdfg=; b=ChC8jPuzI5a9GFjx4HMG4fFDtN/8nUnNQ7Jgw5YvnUZ5i2zLoBE+aZ7015iyQa+dwz aXwHdyqv9PVmrpx0DKMdmseZYBatQlIokO/xohPQZEKDbhkGI4o5K0AaLAsDT2rtwX5S 3tGlIskPflWeD3lvOpir+8x4asrAmnu0s6ILlsoiJw2DSYYTfw7JlD3k63ebhSHZ4cVw AIfWzwVSho4qVYlN4WtUqU/p+r44X1QE4GkNo86Mga21XZ0MAb+qL/lZaaAU+MGJrotv WwFzdZ6kRU0ef9oMRy2CjCKKrPmaFhtXY3X9Pf+YWH4tLMKwggTW72uTgkyKlIMJL+yH l39Q== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=hQQ08eHK; spf=pass (google.com: domain of john.stultz@linaro.org designates 209.85.220.41 as permitted sender) smtp.mailfrom=john.stultz@linaro.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Return-Path: Received: from mail-sor-f41.google.com (mail-sor-f41.google.com. [209.85.220.41]) by mx.google.com with SMTPS id v68sor2460808pfb.8.2021.01.27.22.21.53 for (Google Transport Security); Wed, 27 Jan 2021 22:21:53 -0800 (PST) Received-SPF: pass (google.com: domain of john.stultz@linaro.org designates 209.85.220.41 as permitted sender) client-ip=209.85.220.41; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=hQQ08eHK; spf=pass (google.com: domain of john.stultz@linaro.org designates 209.85.220.41 as permitted sender) smtp.mailfrom=john.stultz@linaro.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=lQKUqtdrTcnk28eLZN1LLjXCJVs6RFMKJof9ORakdfg=; b=hQQ08eHKvLiu1ciqXdW1aU5ubNGq3+Tetvb4GALagIfNAte6aBzyC3IhEBnPE6pex7 kSokfDhJfDNk+vABz4WUjsqX8DC6fAcdNVRDyNyAeLXhnEoU5ErLSIzy2LVF80jOG+tU kSrgZnQtQhgoP52x9JdH6T6BqPgP0oZmbdZxKyqrpoDipA2VikJBhqcNy0ypG7wQK6r1 0xLPUC1xWyyAYX+31KDv7eW/NTaBOivqGh7kiNRvYmh6k8+uBmBM+y0IquoLsdXvRfR8 5Hn2J/kM5oIUgPCX8Vl4GNXqeVH2KaZtoYYu2addeJ2Jy+nHK76nuSHpXnQR2CjMwG/p UIwQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=lQKUqtdrTcnk28eLZN1LLjXCJVs6RFMKJof9ORakdfg=; b=uJlFcuLuaLkJqXhtl90xCdEiz0rnJ6o/mGNIC7ZuQB49jV4Dm+ueIYK5IQGQIlcWUS 4OdZHydhrlkNJZo+W+gfJecm5EkwK3FwrPjTd9gk/H3GFAiNdxNi/ojWLUW072U0o/S1 8C++5nteD2P5hc0zsITN2199wHDfJJBEOmkBIXIXAXK71CcpFV39pmrmxtJ7bB9ksznO HQb2xFeu34y8sv/QCdOYQl9FS9EYyMIfxplOm9i/a70g1MHMPw3qA70U+gvGkrdDspxJ gEZ/vcgpWsREiwVmLRhScPZgwpBwqkS8eLy/7HhyvTwTY8eAykyFImISayZoIiq/p8wE zIkw== X-Gm-Message-State: AOAM532kppjyTazSz3h+2p0Y8Ob2u3FUnEihNj6Wirys2mcemPb2XP7M Vo4P2OmspMxivp17Of+mxb0rzeKi X-Google-Smtp-Source: ABdhPJy/ut8GXR1xnCqoqBQZgh1s59pOYgtSESRYPfXiKBQUppgnZwc78djE5ADIKzx8uD9PczCdIg== X-Received: by 2002:a62:18c5:0:b029:1bd:e72c:b4f2 with SMTP id 188-20020a6218c50000b02901bde72cb4f2mr14598918pfy.50.1611814912953; Wed, 27 Jan 2021 22:21:52 -0800 (PST) Return-Path: Received: from localhost.localdomain ([2601:1c2:680:1319:692:26ff:feda:3a81]) by smtp.gmail.com with ESMTPSA id s9sm4477765pfd.38.2021.01.27.22.21.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 27 Jan 2021 22:21:51 -0800 (PST) From: John Stultz To: lkml Cc: John Stultz , Daniel Vetter , Sumit Semwal , Liam Mark , Chris Goldsworthy , Laura Abbott , Brian Starkey , Hridya Valsaraju , Suren Baghdasaryan , Sandeep Patil , Daniel Mentz , =?utf-8?q?=C3=98rjan_Eide?= , Robin Murphy , Ezequiel Garcia , Simon Ser , James Jones , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: [PATCH v3 1/3] dma-buf: heaps: Add deferred-free-helper library code Date: Thu, 28 Jan 2021 06:21:45 +0000 Message-Id: <20210128062147.438413-1-john.stultz@linaro.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 This patch provides infrastructure for deferring buffer frees. This is a feature ION provided which when used with some form of a page pool, provides a nice performance boost in an allocation microbenchmark. The reason it helps is it allows the page-zeroing to be done out of the normal allocation/free path, and pushed off to a kthread. As not all heaps will find this useful, its implemented as a optional helper library that heaps can utilize. Cc: Daniel Vetter Cc: Sumit Semwal Cc: Liam Mark Cc: Chris Goldsworthy Cc: Laura Abbott Cc: Brian Starkey Cc: Hridya Valsaraju Cc: Suren Baghdasaryan Cc: Sandeep Patil Cc: Daniel Mentz Cc: Ørjan Eide Cc: Robin Murphy Cc: Ezequiel Garcia Cc: Simon Ser Cc: James Jones Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Signed-off-by: John Stultz --- v2: * Fix sleep in atomic issue from using a mutex, by switching to a spinlock as Reported-by: kernel test robot * Cleanup API to use a reason enum for clarity and add some documentation comments as suggested by Suren Baghdasaryan. v3: * Minor tweaks so it can be built as a module * A few small fixups suggested by Daniel Mentz --- drivers/dma-buf/heaps/Kconfig | 3 + drivers/dma-buf/heaps/Makefile | 1 + drivers/dma-buf/heaps/deferred-free-helper.c | 138 +++++++++++++++++++ drivers/dma-buf/heaps/deferred-free-helper.h | 55 ++++++++ 4 files changed, 197 insertions(+) create mode 100644 drivers/dma-buf/heaps/deferred-free-helper.c create mode 100644 drivers/dma-buf/heaps/deferred-free-helper.h -- 2.25.1 diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig index a5eef06c4226..f7aef8bc7119 100644 --- a/drivers/dma-buf/heaps/Kconfig +++ b/drivers/dma-buf/heaps/Kconfig @@ -1,3 +1,6 @@ +config DMABUF_HEAPS_DEFERRED_FREE + tristate + config DMABUF_HEAPS_SYSTEM bool "DMA-BUF System Heap" depends on DMABUF_HEAPS diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile index 974467791032..4e7839875615 100644 --- a/drivers/dma-buf/heaps/Makefile +++ b/drivers/dma-buf/heaps/Makefile @@ -1,3 +1,4 @@ # SPDX-License-Identifier: GPL-2.0 +obj-$(CONFIG_DMABUF_HEAPS_DEFERRED_FREE) += deferred-free-helper.o obj-$(CONFIG_DMABUF_HEAPS_SYSTEM) += system_heap.o obj-$(CONFIG_DMABUF_HEAPS_CMA) += cma_heap.o diff --git a/drivers/dma-buf/heaps/deferred-free-helper.c b/drivers/dma-buf/heaps/deferred-free-helper.c new file mode 100644 index 000000000000..941608319a94 --- /dev/null +++ b/drivers/dma-buf/heaps/deferred-free-helper.c @@ -0,0 +1,138 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Deferred dmabuf freeing helper + * + * Copyright (C) 2020 Linaro, Ltd. + * + * Based on the ION page pool code + * Copyright (C) 2011 Google, Inc. + */ + +#include +#include +#include +#include +#include + +#include "deferred-free-helper.h" + +static LIST_HEAD(free_list); +static size_t list_size; +wait_queue_head_t freelist_waitqueue; +struct task_struct *freelist_task; +static DEFINE_SPINLOCK(free_list_lock); + +void deferred_free(struct deferred_freelist_item *item, + void (*free)(struct deferred_freelist_item*, + enum df_reason), + size_t size) +{ + unsigned long flags; + + INIT_LIST_HEAD(&item->list); + item->size = size; + item->free = free; + + spin_lock_irqsave(&free_list_lock, flags); + list_add(&item->list, &free_list); + list_size += size; + spin_unlock_irqrestore(&free_list_lock, flags); + wake_up(&freelist_waitqueue); +} +EXPORT_SYMBOL_GPL(deferred_free); + +static size_t free_one_item(enum df_reason reason) +{ + unsigned long flags; + size_t size = 0; + struct deferred_freelist_item *item; + + spin_lock_irqsave(&free_list_lock, flags); + if (list_empty(&free_list)) { + spin_unlock_irqrestore(&free_list_lock, flags); + return 0; + } + item = list_first_entry(&free_list, struct deferred_freelist_item, list); + list_del(&item->list); + size = item->size; + list_size -= size; + spin_unlock_irqrestore(&free_list_lock, flags); + + item->free(item, reason); + return size; +} + +static unsigned long get_freelist_size(void) +{ + unsigned long size; + unsigned long flags; + + spin_lock_irqsave(&free_list_lock, flags); + size = list_size; + spin_unlock_irqrestore(&free_list_lock, flags); + return size; +} + +static unsigned long freelist_shrink_count(struct shrinker *shrinker, + struct shrink_control *sc) +{ + return get_freelist_size(); +} + +static unsigned long freelist_shrink_scan(struct shrinker *shrinker, + struct shrink_control *sc) +{ + unsigned long total_freed = 0; + + if (sc->nr_to_scan == 0) + return 0; + + while (total_freed < sc->nr_to_scan) { + size_t freed = free_one_item(DF_UNDER_PRESSURE); + + if (!freed) + break; + + total_freed += freed; + } + + return total_freed; +} + +static struct shrinker freelist_shrinker = { + .count_objects = freelist_shrink_count, + .scan_objects = freelist_shrink_scan, + .seeks = DEFAULT_SEEKS, + .batch = 0, +}; + +static int deferred_free_thread(void *data) +{ + while (true) { + wait_event_freezable(freelist_waitqueue, + get_freelist_size() > 0); + + free_one_item(DF_NORMAL); + } + + return 0; +} + +static int deferred_freelist_init(void) +{ + list_size = 0; + + init_waitqueue_head(&freelist_waitqueue); + freelist_task = kthread_run(deferred_free_thread, NULL, + "%s", "dmabuf-deferred-free-worker"); + if (IS_ERR(freelist_task)) { + pr_err("Creating thread for deferred free failed\n"); + return -1; + } + sched_set_normal(freelist_task, 19); + + return register_shrinker(&freelist_shrinker); +} +module_init(deferred_freelist_init); +MODULE_LICENSE("GPL v2"); + diff --git a/drivers/dma-buf/heaps/deferred-free-helper.h b/drivers/dma-buf/heaps/deferred-free-helper.h new file mode 100644 index 000000000000..18b44ac86ef6 --- /dev/null +++ b/drivers/dma-buf/heaps/deferred-free-helper.h @@ -0,0 +1,55 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef DEFERRED_FREE_HELPER_H +#define DEFERRED_FREE_HELPER_H + +/** + * df_reason - enum for reason why item was freed + * + * This provides a reason for why the free function was called + * on the item. This is useful when deferred_free is used in + * combination with a pagepool, so under pressure the page can + * be immediately freed. + * + * DF_NORMAL: Normal deferred free + * + * DF_UNDER_PRESSURE: Free was called because the system + * is under memory pressure. Usually + * from a shrinker. Avoid allocating + * memory in the free call, as it may + * fail. + */ +enum df_reason { + DF_NORMAL, + DF_UNDER_PRESSURE, +}; + +/** + * deferred_freelist_item - item structure for deferred freelist + * + * This is to be added to the structure for whatever you want to + * defer freeing on. + * + * @size: size of the item to be freed + * @free: function pointer to be called when freeing the item + * @list: list entry for the deferred list + */ +struct deferred_freelist_item { + size_t size; + void (*free)(struct deferred_freelist_item *i, + enum df_reason reason); + struct list_head list; +}; + +/** + * deferred_free - call to add item to the deferred free list + * + * @item: Pointer to deferred_freelist_item field of a structure + * @free: Function pointer to the free call + * @size: Size of the item to be freed + */ +void deferred_free(struct deferred_freelist_item *item, + void (*free)(struct deferred_freelist_item *i, + enum df_reason reason), + size_t size); +#endif