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author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2017-11-17 15:31:22 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-11-17 16:10:04 -0800 |
commit | 64c349f4ae78723248c474531d0cbc524fc5ba77 (patch) | |
tree | b8284ccb8224f9f4023d5b4c1caa6bc053a2c90f /mm | |
parent | 15df03c87983660a4d1eedb4541778592bd97684 (diff) | |
download | linux-stable-64c349f4ae78723248c474531d0cbc524fc5ba77.tar.gz linux-stable-64c349f4ae78723248c474531d0cbc524fc5ba77.tar.bz2 linux-stable-64c349f4ae78723248c474531d0cbc524fc5ba77.zip |
mm: add infrastructure for get_user_pages_fast() benchmarking
Performance of get_user_pages_fast() is critical for some workloads, but
it's tricky to test it directly.
This patch provides /sys/kernel/debug/gup_benchmark that helps with
testing performance of it.
See tools/testing/selftests/vm/gup_benchmark.c for userspace
counterpart.
Link: http://lkml.kernel.org/r/20170908215603.9189-2-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/Kconfig | 9 | ||||
-rw-r--r-- | mm/Makefile | 1 | ||||
-rw-r--r-- | mm/gup_benchmark.c | 100 |
3 files changed, 110 insertions, 0 deletions
diff --git a/mm/Kconfig b/mm/Kconfig index 9c4bdddd80c2..03ff7703d322 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -756,3 +756,12 @@ config PERCPU_STATS This feature collects and exposes statistics via debugfs. The information includes global and per chunk statistics, which can be used to help understand percpu memory usage. + +config GUP_BENCHMARK + bool "Enable infrastructure for get_user_pages_fast() benchmarking" + default n + help + Provides /sys/kernel/debug/gup_benchmark that helps with testing + performance of get_user_pages_fast(). + + See tools/testing/selftests/vm/gup_benchmark.c diff --git a/mm/Makefile b/mm/Makefile index e7ebd176fb93..e669f02c5a54 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -80,6 +80,7 @@ obj-$(CONFIG_PAGE_COUNTER) += page_counter.o obj-$(CONFIG_MEMCG) += memcontrol.o vmpressure.o obj-$(CONFIG_MEMCG_SWAP) += swap_cgroup.o obj-$(CONFIG_CGROUP_HUGETLB) += hugetlb_cgroup.o +obj-$(CONFIG_GUP_BENCHMARK) += gup_benchmark.o obj-$(CONFIG_MEMORY_FAILURE) += memory-failure.o obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o diff --git a/mm/gup_benchmark.c b/mm/gup_benchmark.c new file mode 100644 index 000000000000..5c8e2abeaa15 --- /dev/null +++ b/mm/gup_benchmark.c @@ -0,0 +1,100 @@ +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/uaccess.h> +#include <linux/ktime.h> +#include <linux/debugfs.h> + +#define GUP_FAST_BENCHMARK _IOWR('g', 1, struct gup_benchmark) + +struct gup_benchmark { + __u64 delta_usec; + __u64 addr; + __u64 size; + __u32 nr_pages_per_call; + __u32 flags; +}; + +static int __gup_benchmark_ioctl(unsigned int cmd, + struct gup_benchmark *gup) +{ + ktime_t start_time, end_time; + unsigned long i, nr, nr_pages, addr, next; + struct page **pages; + + nr_pages = gup->size / PAGE_SIZE; + pages = kvmalloc(sizeof(void *) * nr_pages, GFP_KERNEL); + if (!pages) + return -ENOMEM; + + i = 0; + nr = gup->nr_pages_per_call; + start_time = ktime_get(); + for (addr = gup->addr; addr < gup->addr + gup->size; addr = next) { + if (nr != gup->nr_pages_per_call) + break; + + next = addr + nr * PAGE_SIZE; + if (next > gup->addr + gup->size) { + next = gup->addr + gup->size; + nr = (next - addr) / PAGE_SIZE; + } + + nr = get_user_pages_fast(addr, nr, gup->flags & 1, pages + i); + i += nr; + } + end_time = ktime_get(); + + gup->delta_usec = ktime_us_delta(end_time, start_time); + gup->size = addr - gup->addr; + + for (i = 0; i < nr_pages; i++) { + if (!pages[i]) + break; + put_page(pages[i]); + } + + kvfree(pages); + return 0; +} + +static long gup_benchmark_ioctl(struct file *filep, unsigned int cmd, + unsigned long arg) +{ + struct gup_benchmark gup; + int ret; + + if (cmd != GUP_FAST_BENCHMARK) + return -EINVAL; + + if (copy_from_user(&gup, (void __user *)arg, sizeof(gup))) + return -EFAULT; + + ret = __gup_benchmark_ioctl(cmd, &gup); + if (ret) + return ret; + + if (copy_to_user((void __user *)arg, &gup, sizeof(gup))) + return -EFAULT; + + return 0; +} + +static const struct file_operations gup_benchmark_fops = { + .open = nonseekable_open, + .unlocked_ioctl = gup_benchmark_ioctl, +}; + +static int gup_benchmark_init(void) +{ + void *ret; + + ret = debugfs_create_file_unsafe("gup_benchmark", 0600, NULL, NULL, + &gup_benchmark_fops); + if (!ret) + pr_warn("Failed to create gup_benchmark in debugfs"); + + return 0; +} + +late_initcall(gup_benchmark_init); |