Commit-ID: 2a0c11282881875dc44f166a20eedf0d866dd0ef Gitweb: http://git.kernel.org/tip/2a0c11282881875dc44f166a20eedf0d866dd0ef Author: Chris Wilson <ch...@chris-wilson.co.uk> AuthorDate: Thu, 1 Dec 2016 11:47:10 +0000 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Sat, 14 Jan 2017 11:37:17 +0100
locking/ww_mutex: Add kselftests for ww_mutex stress Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Maarten Lankhorst <d...@mblankhorst.nl> Cc: Nicolai Hähnle <nhaeh...@gmail.com> Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Link: http://lkml.kernel.org/r/20161201114711.28697-8-ch...@chris-wilson.co.uk Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/locking/test-ww_mutex.c | 254 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 254 insertions(+) diff --git a/kernel/locking/test-ww_mutex.c b/kernel/locking/test-ww_mutex.c index 84da738..da6c9a3 100644 --- a/kernel/locking/test-ww_mutex.c +++ b/kernel/locking/test-ww_mutex.c @@ -19,8 +19,10 @@ #include <linux/kernel.h> #include <linux/completion.h> +#include <linux/delay.h> #include <linux/kthread.h> #include <linux/module.h> +#include <linux/random.h> #include <linux/slab.h> #include <linux/ww_mutex.h> @@ -348,6 +350,246 @@ static int test_cycle(unsigned int ncpus) return 0; } +struct stress { + struct work_struct work; + struct ww_mutex *locks; + int nlocks; + int nloops; +}; + +static int *get_random_order(int count) +{ + int *order; + int n, r, tmp; + + order = kmalloc_array(count, sizeof(*order), GFP_TEMPORARY); + if (!order) + return order; + + for (n = 0; n < count; n++) + order[n] = n; + + for (n = count - 1; n > 1; n--) { + r = get_random_int() % (n + 1); + if (r != n) { + tmp = order[n]; + order[n] = order[r]; + order[r] = tmp; + } + } + + return order; +} + +static void dummy_load(struct stress *stress) +{ + usleep_range(1000, 2000); +} + +static void stress_inorder_work(struct work_struct *work) +{ + struct stress *stress = container_of(work, typeof(*stress), work); + const int nlocks = stress->nlocks; + struct ww_mutex *locks = stress->locks; + struct ww_acquire_ctx ctx; + int *order; + + order = get_random_order(nlocks); + if (!order) + return; + + ww_acquire_init(&ctx, &ww_class); + + do { + int contended = -1; + int n, err; + +retry: + err = 0; + for (n = 0; n < nlocks; n++) { + if (n == contended) + continue; + + err = ww_mutex_lock(&locks[order[n]], &ctx); + if (err < 0) + break; + } + if (!err) + dummy_load(stress); + + if (contended > n) + ww_mutex_unlock(&locks[order[contended]]); + contended = n; + while (n--) + ww_mutex_unlock(&locks[order[n]]); + + if (err == -EDEADLK) { + ww_mutex_lock_slow(&locks[order[contended]], &ctx); + goto retry; + } + + if (err) { + pr_err_once("stress (%s) failed with %d\n", + __func__, err); + break; + } + } while (--stress->nloops); + + ww_acquire_fini(&ctx); + + kfree(order); + kfree(stress); +} + +struct reorder_lock { + struct list_head link; + struct ww_mutex *lock; +}; + +static void stress_reorder_work(struct work_struct *work) +{ + struct stress *stress = container_of(work, typeof(*stress), work); + LIST_HEAD(locks); + struct ww_acquire_ctx ctx; + struct reorder_lock *ll, *ln; + int *order; + int n, err; + + order = get_random_order(stress->nlocks); + if (!order) + return; + + for (n = 0; n < stress->nlocks; n++) { + ll = kmalloc(sizeof(*ll), GFP_KERNEL); + if (!ll) + goto out; + + ll->lock = &stress->locks[order[n]]; + list_add(&ll->link, &locks); + } + kfree(order); + order = NULL; + + ww_acquire_init(&ctx, &ww_class); + + do { + list_for_each_entry(ll, &locks, link) { + err = ww_mutex_lock(ll->lock, &ctx); + if (!err) + continue; + + ln = ll; + list_for_each_entry_continue_reverse(ln, &locks, link) + ww_mutex_unlock(ln->lock); + + if (err != -EDEADLK) { + pr_err_once("stress (%s) failed with %d\n", + __func__, err); + break; + } + + ww_mutex_lock_slow(ll->lock, &ctx); + list_move(&ll->link, &locks); /* restarts iteration */ + } + + dummy_load(stress); + list_for_each_entry(ll, &locks, link) + ww_mutex_unlock(ll->lock); + } while (--stress->nloops); + + ww_acquire_fini(&ctx); + +out: + list_for_each_entry_safe(ll, ln, &locks, link) + kfree(ll); + kfree(order); + kfree(stress); +} + +static void stress_one_work(struct work_struct *work) +{ + struct stress *stress = container_of(work, typeof(*stress), work); + const int nlocks = stress->nlocks; + struct ww_mutex *lock = stress->locks + (get_random_int() % nlocks); + int err; + + do { + err = ww_mutex_lock(lock, NULL); + if (!err) { + dummy_load(stress); + ww_mutex_unlock(lock); + } else { + pr_err_once("stress (%s) failed with %d\n", + __func__, err); + break; + } + } while (--stress->nloops); + + kfree(stress); +} + +#define STRESS_INORDER BIT(0) +#define STRESS_REORDER BIT(1) +#define STRESS_ONE BIT(2) +#define STRESS_ALL (STRESS_INORDER | STRESS_REORDER | STRESS_ONE) + +static int stress(int nlocks, int nthreads, int nloops, unsigned int flags) +{ + struct ww_mutex *locks; + int n; + + locks = kmalloc_array(nlocks, sizeof(*locks), GFP_KERNEL); + if (!locks) + return -ENOMEM; + + for (n = 0; n < nlocks; n++) + ww_mutex_init(&locks[n], &ww_class); + + for (n = 0; nthreads; n++) { + struct stress *stress; + void (*fn)(struct work_struct *work); + + fn = NULL; + switch (n & 3) { + case 0: + if (flags & STRESS_INORDER) + fn = stress_inorder_work; + break; + case 1: + if (flags & STRESS_REORDER) + fn = stress_reorder_work; + break; + case 2: + if (flags & STRESS_ONE) + fn = stress_one_work; + break; + } + + if (!fn) + continue; + + stress = kmalloc(sizeof(*stress), GFP_KERNEL); + if (!stress) + break; + + INIT_WORK(&stress->work, fn); + stress->locks = locks; + stress->nlocks = nlocks; + stress->nloops = nloops; + + queue_work(wq, &stress->work); + nthreads--; + } + + flush_workqueue(wq); + + for (n = 0; n < nlocks; n++) + ww_mutex_destroy(&locks[n]); + kfree(locks); + + return 0; +} + static int __init test_ww_mutex_init(void) { int ncpus = num_online_cpus(); @@ -377,6 +619,18 @@ static int __init test_ww_mutex_init(void) if (ret) return ret; + ret = stress(16, 2*ncpus, 1<<10, STRESS_INORDER); + if (ret) + return ret; + + ret = stress(16, 2*ncpus, 1<<10, STRESS_REORDER); + if (ret) + return ret; + + ret = stress(4096, hweight32(STRESS_ALL)*ncpus, 1<<12, STRESS_ALL); + if (ret) + return ret; + return 0; }
