[Linaro-mm-sig] Re: [PATCH v2] kfence: Make test case compatible with run time set sample interval

On Fri, 28 Jan 2022 at 02:41, Peng Liu liupeng256@huawei.com wrote:

The parameter kfence_sample_interval can be set via boot parameter and late shell command, which is convenient for automatical tests

s/automatical/automated/

and KFENCE parameter optimation. However, KFENCE test case just use

s/optimation/optimization/

compile time CONFIG_KFENCE_SAMPLE_INTERVAL, this will make KFENCE test case not run as user desired. This patch will make KFENCE test case compatible with run-time-set sample interval.

I'm not too particular about it, but "This patch" is usually bad style: https://www.kernel.org/doc/html/latest/process/submitting-patches.html#descr...

v1->v2:

• Use EXPORT_SYMBOL_GPL replace EXPORT_SYMBOL

Changelog is usually placed after '---', because it's mostly redundant once committed. Often maintainers include a "Link" to the original patch which then has history and discussion.

Signed-off-by: Peng Liu liupeng256@huawei.com

Reviewed-by: Marco Elver elver@google.com

---

include/linux/kfence.h | 2 ++ mm/kfence/core.c | 3 ++- mm/kfence/kfence_test.c | 8 ++++---- 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/include/linux/kfence.h b/include/linux/kfence.h index 4b5e3679a72c..f49e64222628 100644 --- a/include/linux/kfence.h +++ b/include/linux/kfence.h @@ -17,6 +17,8 @@ #include <linux/atomic.h> #include <linux/static_key.h>

+extern unsigned long kfence_sample_interval;

/*

• We allocate an even number of pages, as it simplifies calculations to map
• address to metadata indices; effectively, the very first page serves as an

diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 5ad40e3add45..13128fa13062 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -47,7 +47,8 @@

static bool kfence_enabled __read_mostly;

-static unsigned long kfence_sample_interval __read_mostly = CONFIG_KFENCE_SAMPLE_INTERVAL; +unsigned long kfence_sample_interval __read_mostly = CONFIG_KFENCE_SAMPLE_INTERVAL; +EXPORT_SYMBOL_GPL(kfence_sample_interval); /* Export for test modules. */

#ifdef MODULE_PARAM_PREFIX #undef MODULE_PARAM_PREFIX diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c index a22b1af85577..50dbb815a2a8 100644 --- a/mm/kfence/kfence_test.c +++ b/mm/kfence/kfence_test.c @@ -268,13 +268,13 @@ static void *test_alloc(struct kunit *test, size_t size, gfp_t gfp, enum allocat * 100x the sample interval should be more than enough to ensure we get * a KFENCE allocation eventually. */

•   timeout = jiffies + msecs_to_jiffies(100 * CONFIG_KFENCE_SAMPLE_INTERVAL);
  

•   timeout = jiffies + msecs_to_jiffies(100 * kfence_sample_interval);
    /*
     * Especially for non-preemption kernels, ensure the allocation-gate
     * timer can catch up: after @resched_after, every failed allocation
     * attempt yields, to ensure the allocation-gate timer is scheduled.
     */
  

•   resched_after = jiffies + msecs_to_jiffies(CONFIG_KFENCE_SAMPLE_INTERVAL);
  

•   resched_after = jiffies + msecs_to_jiffies(kfence_sample_interval);
    do {
            if (test_cache)
                    alloc = kmem_cache_alloc(test_cache, gfp);
  

@@ -608,7 +608,7 @@ static void test_gfpzero(struct kunit *test) int i;

    /* Skip if we think it'd take too long. */

•   KFENCE_TEST_REQUIRES(test, CONFIG_KFENCE_SAMPLE_INTERVAL <= 100);
  

•   KFENCE_TEST_REQUIRES(test, kfence_sample_interval <= 100);
  
    setup_test_cache(test, size, 0, NULL);
    buf1 = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
  

@@ -739,7 +739,7 @@ static void test_memcache_alloc_bulk(struct kunit *test) * 100x the sample interval should be more than enough to ensure we get * a KFENCE allocation eventually. */

•   timeout = jiffies + msecs_to_jiffies(100 * CONFIG_KFENCE_SAMPLE_INTERVAL);
  

•   timeout = jiffies + msecs_to_jiffies(100 * kfence_sample_interval);
    do {
            void *objects[100];
            int i, num = kmem_cache_alloc_bulk(test_cache, GFP_ATOMIC, ARRAY_SIZE(objects),
  

-- 2.18.0.huawei.25