From: Keith Busch <kbusch@xxxxxxxxxx> Provide a module that allocates and frees many blocks of various sizes and report how long it takes. This is intended to provide a consistent way to measure how changes to the dma_pool_alloc/free routines affect timing. Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx> --- v1->v2: Used appropriate dma_ops accessor, fixing: https://lore.kernel.org/all/202212061052.hMChRFTf-lkp@xxxxxxxxx/ Added ability to test arbitrary alignments and boundaries and added an entry to test the previously failing test case: https://lore.kernel.org/oe-lkp/202212112301.ad0819f7-oliver.sang@xxxxxxxxx/ mm/Kconfig | 9 +++ mm/Makefile | 1 + mm/dmapool_test.c | 146 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 156 insertions(+) create mode 100644 mm/dmapool_test.c diff --git a/mm/Kconfig b/mm/Kconfig index 34d36958b8ac9..3d71acc29c10f 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -1070,6 +1070,15 @@ config GUP_TEST comment "GUP_TEST needs to have DEBUG_FS enabled" depends on !GUP_TEST && !DEBUG_FS +config DMAPOOL_TEST + tristate "Enable a module to run time tests on dma_pool" + depends on HAS_DMA + help + Provides a module that will allocate and free many blocks of various + sizes and report how long it takes. This is intended to provide a + consistent way to measure how changes to the dma_pool_alloc/free + routines affect performance. + config GUP_GET_PTE_LOW_HIGH bool diff --git a/mm/Makefile b/mm/Makefile index 8e105e5b3e293..3a08f5d7b1782 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -103,6 +103,7 @@ obj-$(CONFIG_MEMCG) += swap_cgroup.o endif obj-$(CONFIG_CGROUP_HUGETLB) += hugetlb_cgroup.o obj-$(CONFIG_GUP_TEST) += gup_test.o +obj-$(CONFIG_DMAPOOL_TEST) += dmapool_test.o obj-$(CONFIG_MEMORY_FAILURE) += memory-failure.o obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o diff --git a/mm/dmapool_test.c b/mm/dmapool_test.c new file mode 100644 index 0000000000000..c4292dfda3690 --- /dev/null +++ b/mm/dmapool_test.c @@ -0,0 +1,146 @@ +#include <linux/device.h> +#include <linux/dma-map-ops.h> +#include <linux/dma-mapping.h> +#include <linux/dmapool.h> +#include <linux/kernel.h> +#include <linux/ktime.h> +#include <linux/module.h> + +#define NR_TESTS (100) + +struct dma_pool_pair { + dma_addr_t dma; + void *v; +}; + +struct dmapool_parms { + size_t size; + size_t align; + size_t boundary; +}; + +static const struct dmapool_parms pool_parms[] = { + { .size = 16, .align = 16, .boundary = 0 }, + { .size = 64, .align = 64, .boundary = 0 }, + { .size = 256, .align = 256, .boundary = 0 }, + { .size = 1024, .align = 1024, .boundary = 0 }, + { .size = 4096, .align = 4096, .boundary = 0 }, + { .size = 68, .align = 32, .boundary = 4096 }, +}; + +static struct dma_pool *pool; +static struct device test_dev; +static u64 dma_mask; + +static inline int nr_blocks(int size) +{ + return clamp_t(int, (PAGE_SIZE / size) * 512, 1024, 8192); +} + +static int dmapool_test_alloc(struct dma_pool_pair *p, int blocks) +{ + int i; + + for (i = 0; i < blocks; i++) { + p[i].v = dma_pool_alloc(pool, GFP_KERNEL, + &p[i].dma); + if (!p[i].v) + goto pool_fail; + } + + for (i = 0; i < blocks; i++) + dma_pool_free(pool, p[i].v, p[i].dma); + + return 0; + +pool_fail: + for (--i; i >= 0; i--) + dma_pool_free(pool, p[i].v, p[i].dma); + return -ENOMEM; +} + +static int dmapool_test_block(const struct dmapool_parms *parms) +{ + int blocks = nr_blocks(parms->size); + ktime_t start_time, end_time; + struct dma_pool_pair *p; + int i, ret; + + p = kcalloc(blocks, sizeof(*p), GFP_KERNEL); + if (!p) + return -ENOMEM; + + pool = dma_pool_create("test pool", &test_dev, parms->size, + parms->align, parms->boundary); + if (!pool) { + ret = -ENOMEM; + goto free_pairs; + } + + start_time = ktime_get(); + for (i = 0; i < NR_TESTS; i++) { + ret = dmapool_test_alloc(p, blocks); + if (ret) + goto free_pool; + if (need_resched()) + cond_resched(); + } + end_time = ktime_get(); + + printk("dmapool test: size:%-4ld blocks:%-6d time:%llu\n", parms->size, + blocks, ktime_us_delta(end_time, start_time)); + +free_pool: + dma_pool_destroy(pool); +free_pairs: + kfree(p); + return ret; +} + +static void dmapool_test_release(struct device *dev) +{ +} + +static int dmapool_checks(void) +{ + int i, ret; + + ret = dev_set_name(&test_dev, "dmapool-test"); + if (ret) + return ret; + + ret = device_register(&test_dev); + if (ret) { + printk("%s: register failed:%d\n", __func__, ret); + goto put_device; + } + + test_dev.release = dmapool_test_release; + set_dma_ops(&test_dev, NULL); + test_dev.dma_mask = &dma_mask; + ret = dma_set_mask_and_coherent(&test_dev, DMA_BIT_MASK(64)); + if (ret) { + printk("%s: mask failed:%d\n", __func__, ret); + goto del_device; + } + + for (i = 0; i < ARRAY_SIZE(pool_parms); i++) { + ret = dmapool_test_block(&pool_parms[i]); + if (ret) + break; + } + +del_device: + device_del(&test_dev); +put_device: + put_device(&test_dev); + return ret; +} + +static void dmapool_exit(void) +{ +} + +module_init(dmapool_checks); +module_exit(dmapool_exit); +MODULE_LICENSE("GPL"); -- 2.30.2
