diff options
| -rw-r--r-- | MAINTAINERS | 7 | ||||
| -rw-r--r-- | include/linux/freelist.h | 129 | ||||
| -rw-r--r-- | include/linux/kprobes.h | 11 | ||||
| -rw-r--r-- | include/linux/objpool.h | 181 | ||||
| -rw-r--r-- | include/linux/rethook.h | 16 | ||||
| -rw-r--r-- | kernel/kprobes.c | 91 | ||||
| -rw-r--r-- | kernel/trace/fprobe.c | 28 | ||||
| -rw-r--r-- | kernel/trace/rethook.c | 90 | ||||
| -rw-r--r-- | kernel/trace/trace_eprobe.c | 5 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 11 | ||||
| -rw-r--r-- | lib/Makefile | 4 | ||||
| -rw-r--r-- | lib/objpool.c | 280 | ||||
| -rw-r--r-- | lib/test_objpool.c | 690 | ||||
| -rw-r--r-- | samples/kprobes/kretprobe_example.c | 2 |
14 files changed, 1269 insertions, 276 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index 6f0dda0603b8..14e1194faa4b 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -15553,6 +15553,13 @@ F: include/linux/objagg.h F: lib/objagg.c F: lib/test_objagg.c +OBJPOOL +M: Matt Wu <wuqiang.matt@bytedance.com> +S: Supported +F: include/linux/objpool.h +F: lib/objpool.c +F: lib/test_objpool.c + OBJTOOL M: Josh Poimboeuf <jpoimboe@kernel.org> M: Peter Zijlstra <peterz@infradead.org> diff --git a/include/linux/freelist.h b/include/linux/freelist.h deleted file mode 100644 index fc1842b96469..000000000000 --- a/include/linux/freelist.h +++ /dev/null @@ -1,129 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause */ -#ifndef FREELIST_H -#define FREELIST_H - -#include <linux/atomic.h> - -/* - * Copyright: cameron@moodycamel.com - * - * A simple CAS-based lock-free free list. Not the fastest thing in the world - * under heavy contention, but simple and correct (assuming nodes are never - * freed until after the free list is destroyed), and fairly speedy under low - * contention. - * - * Adapted from: https://moodycamel.com/blog/2014/solving-the-aba-problem-for-lock-free-free-lists - */ - -struct freelist_node { - atomic_t refs; - struct freelist_node *next; -}; - -struct freelist_head { - struct freelist_node *head; -}; - -#define REFS_ON_FREELIST 0x80000000 -#define REFS_MASK 0x7FFFFFFF - -static inline void __freelist_add(struct freelist_node *node, struct freelist_head *list) -{ - /* - * Since the refcount is zero, and nobody can increase it once it's - * zero (except us, and we run only one copy of this method per node at - * a time, i.e. the single thread case), then we know we can safely - * change the next pointer of the node; however, once the refcount is - * back above zero, then other threads could increase it (happens under - * heavy contention, when the refcount goes to zero in between a load - * and a refcount increment of a node in try_get, then back up to - * something non-zero, then the refcount increment is done by the other - * thread) -- so if the CAS to add the node to the actual list fails, - * decrese the refcount and leave the add operation to the next thread - * who puts the refcount back to zero (which could be us, hence the - * loop). - */ - struct freelist_node *head = READ_ONCE(list->head); - - for (;;) { - WRITE_ONCE(node->next, head); - atomic_set_release(&node->refs, 1); - - if (!try_cmpxchg_release(&list->head, &head, node)) { - /* - * Hmm, the add failed, but we can only try again when - * the refcount goes back to zero. - */ - if (atomic_fetch_add_release(REFS_ON_FREELIST - 1, &node->refs) == 1) - continue; - } - return; - } -} - -static inline void freelist_add(struct freelist_node *node, struct freelist_head *list) -{ - /* - * We know that the should-be-on-freelist bit is 0 at this point, so - * it's safe to set it using a fetch_add. - */ - if (!atomic_fetch_add_release(REFS_ON_FREELIST, &node->refs)) { - /* - * Oh look! We were the last ones referencing this node, and we - * know we want to add it to the free list, so let's do it! - */ - __freelist_add(node, list); - } -} - -static inline struct freelist_node *freelist_try_get(struct freelist_head *list) -{ - struct freelist_node *prev, *next, *head = smp_load_acquire(&list->head); - unsigned int refs; - - while (head) { - prev = head; - refs = atomic_read(&head->refs); - if ((refs & REFS_MASK) == 0 || - !atomic_try_cmpxchg_acquire(&head->refs, &refs, refs+1)) { - head = smp_load_acquire(&list->head); - continue; - } - - /* - * Good, reference count has been incremented (it wasn't at - * zero), which means we can read the next and not worry about - * it changing between now and the time we do the CAS. - */ - next = READ_ONCE(head->next); - if (try_cmpxchg_acquire(&list->head, &head, next)) { - /* - * Yay, got the node. This means it was on the list, - * which means should-be-on-freelist must be false no - * matter the refcount (because nobody else knows it's - * been taken off yet, it can't have been put back on). - */ - WARN_ON_ONCE(atomic_read(&head->refs) & REFS_ON_FREELIST); - - /* - * Decrease refcount twice, once for our ref, and once - * for the list's ref. - */ - atomic_fetch_add(-2, &head->refs); - - return head; - } - - /* - * OK, the head must have changed on us, but we still need to decrement - * the refcount we increased. - */ - refs = atomic_fetch_add(-1, &prev->refs); - if (refs == REFS_ON_FREELIST + 1) - __freelist_add(prev, list); - } - - return NULL; -} - -#endif /* FREELIST_H */ diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index 85a64cb95d75..365eb092e9c4 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -26,8 +26,7 @@ #include <linux/rcupdate.h> #include <linux/mutex.h> #include <linux/ftrace.h> -#include <linux/refcount.h> -#include <linux/freelist.h> +#include <linux/objpool.h> #include <linux/rethook.h> #include <asm/kprobes.h> @@ -141,7 +140,7 @@ static inline bool kprobe_ftrace(struct kprobe *p) */ struct kretprobe_holder { struct kretprobe *rp; - refcount_t ref; + struct objpool_head pool; }; struct kretprobe { @@ -154,7 +153,6 @@ struct kretprobe { #ifdef CONFIG_KRETPROBE_ON_RETHOOK struct rethook *rh; #else - struct freelist_head freelist; struct kretprobe_holder *rph; #endif }; @@ -165,10 +163,7 @@ struct kretprobe_instance { #ifdef CONFIG_KRETPROBE_ON_RETHOOK struct rethook_node node; #else - union { - struct freelist_node freelist; - struct rcu_head rcu; - }; + struct rcu_head rcu; struct llist_node llist; struct kretprobe_holder *rph; kprobe_opcode_t *ret_addr; diff --git a/include/linux/objpool.h b/include/linux/objpool.h new file mode 100644 index 000000000000..15aff4a17f0c --- /dev/null +++ b/include/linux/objpool.h @@ -0,0 +1,181 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _LINUX_OBJPOOL_H +#define _LINUX_OBJPOOL_H + +#include <linux/types.h> +#include <linux/refcount.h> + +/* + * objpool: ring-array based lockless MPMC queue + * + * Copyright: wuqiang.matt@bytedance.com,mhiramat@kernel.org + * + * objpool is a scalable implementation of high performance queue for + * object allocation and reclamation, such as kretprobe instances. + * + * With leveraging percpu ring-array to mitigate hot spots of memory + * contention, it delivers near-linear scalability for high parallel + * scenarios. The objpool is best suited for the following cases: + * 1) Memory allocation or reclamation are prohibited or too expensive + * 2) Consumers are of different priorities, such as irqs and threads + * + * Limitations: + * 1) Maximum objects (capacity) is fixed after objpool creation + * 2) All pre-allocated objects are managed in percpu ring array, + * which consumes more memory than linked lists + */ + +/** + * struct objpool_slot - percpu ring array of objpool + * @head: head sequence of the local ring array (to retrieve at) + * @tail: tail sequence of the local ring array (to append at) + * @last: the last sequence number marked as ready for retrieve + * @mask: bits mask for modulo capacity to compute array indexes + * @entries: object entries on this slot + * + * Represents a cpu-local array-based ring buffer, its size is specialized + * during initialization of object pool. The percpu objpool node is to be + * allocated from local memory for NUMA system, and to be kept compact in + * continuous memory: CPU assigned number of objects are stored just after + * the body of objpool_node. + * + * Real size of the ring array is far too smaller than the value range of + * head and tail, typed as uint32_t: [0, 2^32), so only lower bits (mask) + * of head and tail are used as the actual position in the ring array. In + * general the ring array is acting like a small sliding window, which is + * always moving forward in the loop of [0, 2^32). + */ +struct objpool_slot { + uint32_t head; + uint32_t tail; + uint32_t last; + uint32_t mask; + void *entries[]; +} __packed; + +struct objpool_head; + +/* + * caller-specified callback for object initial setup, it's only called + * once for each object (just after the memory allocation of the object) + */ +typedef int (*objpool_init_obj_cb)(void *obj, void *context); + +/* caller-specified cleanup callback for objpool destruction */ +typedef int (*objpool_fini_cb)(struct objpool_head *head, void *context); + +/** + * struct objpool_head - object pooling metadata + * @obj_size: object size, aligned to sizeof(void *) + * @nr_objs: total objs (to be pre-allocated with objpool) + * @nr_cpus: local copy of nr_cpu_ids + * @capacity: max objs can be managed by one objpool_slot + * @gfp: gfp flags for kmalloc & vmalloc + * @ref: refcount of objpool + * @flags: flags for objpool management + * @cpu_slots: pointer to the array of objpool_slot + * @release: resource cleanup callback + * @context: caller-provided context + */ +struct objpool_head { + int obj_size; + int nr_objs; + int nr_cpus; + int capacity; + gfp_t gfp; + refcount_t ref; + unsigned long flags; + struct objpool_slot **cpu_slots; + objpool_fini_cb release; + void *context; +}; + +#define OBJPOOL_NR_OBJECT_MAX (1UL << 24) /* maximum numbers of total objects */ +#define OBJPOOL_OBJECT_SIZE_MAX (1UL << 16) /* maximum size of an object */ + +/** + * objpool_init() - initialize objpool and pre-allocated objects + * @pool: the object pool to be initialized, declared by caller + * @nr_objs: total objects to be pre-allocated by this object pool + * @object_size: size of an object (should be > 0) + * @gfp: flags for memory allocation (via kmalloc or vmalloc) + * @context: user context for object initialization callback + * @objinit: object initialization callback for extra setup + * @release: cleanup callback for extra cleanup task + * + * return value: 0 for success, otherwise error code + * + * All pre-allocated objects are to be zeroed after memory allocation. + * Caller could do extra initialization in objinit callback. objinit() + * will be called just after slot allocation and called only once for + * each object. After that the objpool won't touch any content of the + * objects. It's caller's duty to perform reinitialization after each + * pop (object allocation) or do clearance before each push (object + * reclamation). + */ +int objpool_init(struct objpool_head *pool, int nr_objs, int object_size, + gfp_t gfp, void *context, objpool_init_obj_cb objinit, + objpool_fini_cb release); + +/** + * objpool_pop() - allocate an object from objpool + * @pool: object pool + * + * return value: object ptr or NULL if failed + */ +void *objpool_pop(struct objpool_head *pool); + +/** + * objpool_push() - reclaim the object and return back to objpool + * @obj: object ptr to be pushed to objpool + * @pool: object pool + * + * return: 0 or error code (it fails only when user tries to push + * the same object multiple times or wrong "objects" into objpool) + */ +int objpool_push(void *obj, struct objpool_head *pool); + +/** + * objpool_drop() - discard the object and deref objpool + * @obj: object ptr to be discarded + * @pool: object pool + * + * return: 0 if objpool was released; -EAGAIN if there are still + * outstanding objects + * + * objpool_drop is normally for the release of outstanding objects + * after objpool cleanup (objpool_fini). Thinking of this example: + * kretprobe is unregistered and objpool_fini() is called to release + * all remained objects, but there are still objects being used by + * unfinished kretprobes (like blockable function: sys_accept). So + * only when the last outstanding object is dropped could the whole + * objpool be released along with the call of objpool_drop() + */ +int objpool_drop(void *obj, struct objpool_head *pool); + +/** + * objpool_free() - release objpool forcely (all objects to be freed) + * @pool: object pool to be released + */ +void objpool_free(struct objpool_head *pool); + +/** + * objpool_fini() - deref object pool (also releasing unused objects) + * @pool: object pool to be dereferenced + * + * objpool_fini() will try to release all remained free objects and + * then drop an extra reference of the objpool. If all objects are + * already returned to objpool (so called synchronous use cases), + * the objpool itself will be freed together. But if there are still + * outstanding objects (so called asynchronous use cases, such like + * blockable kretprobe), the objpool won't be released until all + * the outstanding objects are dropped, but the caller must assure + * there are no concurrent objpool_push() on the fly. Normally RCU + * is being required to make sure all ongoing objpool_push() must + * be finished before calling objpool_fini(), so does test_objpool, + * kretprobe or rethook + */ +void objpool_fini(struct objpool_head *pool); + +#endif /* _LINUX_OBJPOOL_H */ diff --git a/include/linux/rethook.h b/include/linux/rethook.h index 26b6f3c81a76..ce69b2b7bc35 100644 --- a/include/linux/rethook.h +++ b/include/linux/rethook.h @@ -6,11 +6,10 @@ #define _LINUX_RETHOOK_H #include <linux/compiler.h> -#include <linux/freelist.h> +#include <linux/objpool.h> #include <linux/kallsyms.h> #include <linux/llist.h> #include <linux/rcupdate.h> -#include <linux/refcount.h> struct rethook_node; @@ -30,14 +29,12 @@ typedef void (*rethook_handler_t) (struct rethook_node *, void *, unsigned long, struct rethook { void *data; rethook_handler_t handler; - struct freelist_head pool; - refcount_t ref; + struct objpool_head pool; struct rcu_head rcu; }; /** * struct rethook_node - The rethook shadow-stack entry node. - * @freelist: The freelist, linked to struct rethook::pool. * @rcu: The rcu_head for deferred freeing. * @llist: The llist, linked to a struct task_struct::rethooks. * @rethook: The pointer to the struct rethook. @@ -48,20 +45,16 @@ struct rethook { * on each entry of the shadow stack. */ struct rethook_node { - union { - struct freelist_node freelist; - struct rcu_head rcu; - }; + struct rcu_head rcu; struct llist_node llist; struct rethook *rethook; unsigned long ret_addr; unsigned long frame; }; -struct rethook *rethook_alloc(void *data, rethook_handler_t handler); +struct rethook *rethook_alloc(void *data, rethook_handler_t handler, int size, int num); void rethook_stop(struct rethook *rh); void rethook_free(struct rethook *rh); -void rethook_add_node(struct rethook *rh, struct rethook_node *node); struct rethook_node *rethook_try_get(struct rethook *rh); void rethook_recycle(struct rethook_node *node); void rethook_hook(struct rethook_node *node, struct pt_regs *regs, bool mcount); @@ -98,4 +91,3 @@ void rethook_flush_task(struct task_struct *tk); #endif #endif - diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 0c6185aefaef..075a632e6c7c 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1877,13 +1877,27 @@ static struct notifier_block kprobe_exceptions_nb = { #ifdef CONFIG_KRETPROBES #if !defined(CONFIG_KRETPROBE_ON_RETHOOK) + +/* callbacks for objpool of kretprobe instances */ +static int kretprobe_init_inst(void *nod, void *context) +{ + struct kretprobe_instance *ri = nod; + + ri->rph = context; + return 0; +} +static int kretprobe_fini_pool(struct objpool_head *head, void *context) +{ + kfree(context); + return 0; +} + static void free_rp_inst_rcu(struct rcu_head *head) { struct kretprobe_instance *ri = container_of(head, struct kretprobe_instance, rcu); + struct kretprobe_holder *rph = ri->rph; - if (refcount_dec_and_test(&ri->rph->ref)) - kfree(ri->rph); - kfree(ri); + objpool_drop(ri, &rph->pool); } NOKPROBE_SYMBOL(free_rp_inst_rcu); @@ -1892,7 +1906,7 @@ static void recycle_rp_inst(struct kretprobe_instance *ri) struct kretprobe *rp = get_kretprobe(ri); if (likely(rp)) - freelist_add(&ri->freelist, &rp->freelist); + objpool_push(ri, &rp->rph->pool); else call_rcu(&ri->rcu, free_rp_inst_rcu); } @@ -1929,23 +1943,12 @@ NOKPROBE_SYMBOL(kprobe_flush_task); static inline void free_rp_inst(struct kretprobe *rp) { - struct kretprobe_instance *ri; - struct freelist_node *node; - int count = 0; - - node = rp->freelist.head; - while (node) { - ri = container_of(node, struct kretprobe_instance, freelist); - node = node->next; - - kfree(ri); - count++; - } + struct kretprobe_holder *rph = rp->rph; - if (refcount_sub_and_test(count, &rp->rph->ref)) { - kfree(rp->rph); - rp->rph = NULL; - } + if (!rph) + return; + rp->rph = NULL; + objpool_fini(&rph->pool); } /* This assumes the 'tsk' is the current task or the is not running. */ @@ -2087,19 +2090,17 @@ NOKPROBE_SYMBOL(__kretprobe_trampoline_handler) static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) { struct kretprobe *rp = container_of(p, struct kretprobe, kp); + struct kretprobe_holder *rph = rp->rph; struct kretprobe_instance *ri; - struct freelist_node *fn; - fn = freelist_try_get(&rp->freelist); - if (!fn) { + ri = objpool_pop(&rph->pool); + if (!ri) { rp->nmissed++; return 0; } - ri = container_of(fn, struct kretprobe_instance, freelist); - if (rp->entry_handler && rp->entry_handler(ri, regs)) { - freelist_add(&ri->freelist, &rp->freelist); + objpool_push(ri, &rph->pool); return 0; } @@ -2193,7 +2194,6 @@ int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long o int register_kretprobe(struct kretprobe *rp) { int ret; - struct kretprobe_instance *inst; int i; void *addr; @@ -2227,19 +2227,12 @@ int register_kretprobe(struct kretprobe *rp) rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); #ifdef CONFIG_KRETPROBE_ON_RETHOOK - rp->rh = rethook_alloc((void *)rp, kretprobe_rethook_handler); - if (!rp->rh) - return -ENOMEM; + rp->rh = rethook_alloc((void *)rp, kretprobe_rethook_handler, + sizeof(struct kretprobe_instance) + + rp->data_size, rp->maxactive); + if (IS_ERR(rp->rh)) + return PTR_ERR(rp->rh); - for (i = 0; i < rp->maxactive; i++) { - inst = kzalloc(struct_size(inst, data, rp->data_size), GFP_KERNEL); - if (inst == NULL) { - rethook_free(rp->rh); - rp->rh = NULL; - return -ENOMEM; - } - rethook_add_node(rp->rh, &inst->node); - } rp->nmissed = 0; /* Establish function entry probe point */ ret = register_kprobe(&rp->kp); @@ -2248,24 +2241,18 @@ int register_kretprobe(struct kretprobe *rp) rp->rh = NULL; } #else /* !CONFIG_KRETPROBE_ON_RETHOOK */ - rp->freelist.head = NULL; rp->rph = kzalloc(sizeof(struct kretprobe_holder), GFP_KERNEL); if (!rp->rph) return -ENOMEM; - rp->rph->rp = rp; - for (i = 0; i < rp->maxactive; i++) { - inst = kzalloc(struct_size(inst, data, rp->data_size), GFP_KERNEL); - if (inst == NULL) { - refcount_set(&rp->rph->ref, i); - free_rp_inst(rp); - return -ENOMEM; - } - inst->rph = rp->rph; - freelist_add(&inst->freelist, &rp->freelist); + if (objpool_init(&rp->rph->pool, rp->maxactive, rp->data_size + + sizeof(struct kretprobe_instance), GFP_KERNEL, + rp->rph, kretprobe_init_inst, kretprobe_fini_pool)) { + kfree(rp->rph); + rp->rph = NULL; + return -ENOMEM; } - refcount_set(&rp->rph->ref, i); - + rp->rph->rp = rp; rp->nmissed = 0; /* Establish function entry probe point */ ret = register_kprobe(&rp->kp); diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c index 881f90f0cbcf..6cd2a4e3afb8 100644 --- a/kernel/trace/fprobe.c +++ b/kernel/trace/fprobe.c @@ -187,7 +187,7 @@ static void fprobe_init(struct fprobe *fp) static int fprobe_init_rethook(struct fprobe *fp, int num) { - int i, size; + int size; if (num <= 0) return -EINVAL; @@ -205,26 +205,18 @@ static int fprobe_init_rethook(struct fprobe *fp, int num) if (size <= 0) return -EINVAL; - fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler); - if (!fp->rethook) - return -ENOMEM; - for (i = 0; i < size; i++) { - struct fprobe_rethook_node *node; - - node = kzalloc(sizeof(*node) + fp->entry_data_size, GFP_KERNEL); - if (!node) { - rethook_free(fp->rethook); - fp->rethook = NULL; - return -ENOMEM; - } - rethook_add_node(fp->rethook, &node->node); - } + /* Initialize rethook */ + fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler, + sizeof(struct fprobe_rethook_node), size); + if (IS_ERR(fp->rethook)) + return PTR_ERR(fp->rethook); + return 0; } static void fprobe_fail_cleanup(struct fprobe *fp) { - if (fp->rethook) { + if (!IS_ERR_OR_NULL(fp->rethook)) { /* Don't need to cleanup rethook->handler because this is not used. */ rethook_free(fp->rethook); fp->rethook = NULL; @@ -379,14 +371,14 @@ int unregister_fprobe(struct fprobe *fp) if (!fprobe_is_registered(fp)) return -EINVAL; - if (fp->rethook) + if (!IS_ERR_OR_NULL(fp->rethook)) rethook_stop(fp->rethook); ret = unregister_ftrace_function(&fp->ops); if (ret < 0) return ret; - if (fp->rethook) + if (!IS_ERR_OR_NULL(fp->rethook)) rethook_free(fp->rethook); ftrace_free_filter(&fp->ops); diff --git a/kernel/trace/rethook.c b/kernel/trace/rethook.c index 5eb9b598f4e9..6fd7d4ecbbc6 100644 --- a/kernel/trace/rethook.c +++ b/kernel/trace/rethook.c @@ -8,7 +8,6 @@ #include <linux/preempt.h> #include <linux/rethook.h> #include <linux/slab.h> -#include <linux/sort.h> /* Return hook list (shadow stack by list) */ @@ -36,21 +35,7 @@ void rethook_flush_task(struct task_struct *tk) static void rethook_free_rcu(struct rcu_head *head) { struct rethook *rh = container_of(head, struct rethook, rcu); - struct rethook_node *rhn; - struct freelist_node *node; - int count = 1; - - node = rh->pool.head; - while (node) { - rhn = container_of(node, struct rethook_node, freelist); - node = node->next; - kfree(rhn); - count++; - } - - /* The rh->ref is the number of pooled node + 1 */ - if (refcount_sub_and_test(count, &rh->ref)) - kfree(rh); + objpool_fini(&rh->pool); } /** @@ -83,54 +68,62 @@ void rethook_free(struct rethook *rh) call_rcu(&rh->rcu, rethook_free_rcu); } +static int rethook_init_node(void *nod, void *context) +{ + struct rethook_node *node = nod; + + node->rethook = context; + return 0; +} + +static int rethook_fini_pool(struct objpool_head *head, void *context) +{ + kfree(context); + return 0; +} + /** * rethook_alloc() - Allocate struct rethook. * @data: a data to pass the @handler when hooking the return. - * @handler: the return hook callback function. + * @handler: the return hook callback function, must NOT be NULL + * @size: node size: rethook node and additional data + * @num: number of rethook nodes to be preallocated * * Allocate and initialize a new rethook with @data and @handler. - * Return NULL if memory allocation fails or @handler is NULL. + * Return pointer of new rethook, or error codes for failures. + * * Note that @handler == NULL means this rethook is going to be freed. */ -struct rethook *rethook_alloc(void *data, rethook_handler_t handler) +struct rethook *rethook_alloc(void *data, rethook_handler_t handler, + int size, int num) { - struct rethook *rh = kzalloc(sizeof(struct rethook), GFP_KERNEL); + struct rethook *rh; - if (!rh || !handler) { - kfree(rh); - return NULL; - } + if (!handler || num <= 0 || size < sizeof(struct rethook_node)) + return ERR_PTR(-EINVAL); + + rh = kzalloc(sizeof(struct rethook), GFP_KERNEL); + if (!rh) + return ERR_PTR(-ENOMEM); rh->data = data; rh->handler = handler; - rh->pool.head = NULL; - refcount_set(&rh->ref, 1); + /* initialize the objpool for rethook nodes */ + if (objpool_init(&rh->pool, num, size, GFP_KERNEL, rh, + rethook_init_node, rethook_fini_pool)) { + kfree(rh); + return ERR_PTR(-ENOMEM); + } return rh; } -/** - * rethook_add_node() - Add a new node to the rethook. - * @rh: the struct rethook. - * @node: the struct rethook_node to be added. - * - * Add @node to @rh. User must allocate @node (as a part of user's - * data structure.) The @node fields are initialized in this function. - */ -void rethook_add_node(struct rethook *rh, struct rethook_node *node) -{ - node->rethook = rh; - freelist_add(&node->freelist, &rh->pool); - refcount_inc(&rh->ref); -} - static void free_rethook_node_rcu(struct rcu_head *head) { struct rethook_node *node = container_of(head, struct rethook_node, rcu); + struct rethook *rh = node->rethook; - if (refcount_dec_and_test(&node->rethook->ref)) - kfree(node->rethook); - kfree(node); + objpool_drop(node, &rh->pool); } /** @@ -145,7 +138,7 @@ void rethook_recycle(struct rethook_node *node) lockdep_assert_preemption_disabled(); if (likely(READ_ONCE(node->rethook->handler))) - freelist_add(&node->freelist, &node->rethook->pool); + objpool_push(node, &node->rethook->pool); else call_rcu(&node->rcu, free_rethook_node_rcu); } @@ -161,7 +154,6 @@ NOKPROBE_SYMBOL(rethook_recycle); struct rethook_node *rethook_try_get(struct rethook *rh) { rethook_handler_t handler = READ_ONCE(rh->handler); - struct freelist_node *fn; lockdep_assert_preemption_disabled(); @@ -178,11 +170,7 @@ struct rethook_node *rethook_try_get(struct rethook *rh) if (unlikely(!rcu_is_watching())) return NULL; - fn = freelist_try_get(&rh->pool); - if (!fn) - return NULL; - - return container_of(fn, struct rethook_node, freelist); + return (struct rethook_node *)objpool_pop(&rh->pool); } NOKPROBE_SYMBOL(rethook_try_get); diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c index 72714cbf475c..03c851f57969 100644 --- a/kernel/trace/trace_eprobe.c +++ b/kernel/trace/trace_eprobe.c @@ -788,12 +788,9 @@ find_and_get_event(const char *system, const char *event_name) name = trace_event_name(tp_event); if (!name || strcmp(event_name, name)) continue; - if (!trace_event_try_get_ref(tp_event)) { + if (!trace_event_try_get_ref(tp_event)) return NULL; - break; - } return tp_event; - break; } return NULL; } diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 40b77c437a74..cc7d53d9dc01 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2954,6 +2954,17 @@ config TEST_CLOCKSOURCE_WATCHDOG If unsure, say N. +config TEST_OBJPOOL + tristate "Test module for correctness and stress of objpool" + default n + depends on m && DEBUG_KERNEL + help + This builds the "test_objpool" module that should be used for + correctness verification and concurrent testings of objects + allocation and reclamation. + + If unsure, say N. + endif # RUNTIME_TESTING_MENU config ARCH_USE_MEMTEST diff --git a/lib/Makefile b/lib/Makefile index 1b311c7fd32b..9e0972f7b764 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -34,7 +34,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ is_single_threaded.o plist.o decompress.o kobject_uevent.o \ earlycpio.o seq_buf.o siphash.o dec_and_lock.o \ nmi_backtrace.o win_minmax.o memcat_p.o \ - buildid.o + buildid.o objpool.o lib-$(CONFIG_PRINTK) += dump_stack.o lib-$(CONFIG_SMP) += cpumask.o @@ -107,6 +107,8 @@ obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o obj-$(CONFIG_TEST_REF_TRACKER) += test_ref_tracker.o CFLAGS_test_fprobe.o += $(CC_FLAGS_FTRACE) obj-$(CONFIG_FPROBE_SANITY_TEST) += test_fprobe.o +obj-$(CONFIG_TEST_OBJPOOL) += test_objpool.o + # # CFLAGS for compiling floating point code inside the kernel. x86/Makefile turns # off the generation of FPU/SSE* instructions for kernel proper but FPU_FLAGS diff --git a/lib/objpool.c b/lib/objpool.c new file mode 100644 index 000000000000..ce0087f64400 --- /dev/null +++ b/lib/objpool.c @@ -0,0 +1,280 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/objpool.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> +#include <linux/atomic.h> +#include <linux/irqflags.h> +#include <linux/cpumask.h> +#include <linux/log2.h> + +/* + * objpool: ring-array based lockless MPMC/FIFO queues + * + * Copyright: wuqiang.matt@bytedance.com,mhiramat@kernel.org + */ + +/* initialize percpu objpool_slot */ +static int +objpool_init_percpu_slot(struct objpool_head *pool, + struct objpool_slot *slot, + int nodes, void *context, + objpool_init_obj_cb objinit) +{ + void *obj = (void *)&slot->entries[pool->capacity]; + int i; + + /* initialize elements of percpu objpool_slot */ + slot->mask = pool->capacity - 1; + + for (i = 0; i < nodes; i++) { + if (objinit) { + int rc = objinit(obj, context); + if (rc) + return rc; + } + slot->entries[slot->tail & slot->mask] = obj; + obj = obj + pool->obj_size; + slot->tail++; + slot->last = slot->tail; + pool->nr_objs++; + } + + return 0; +} + +/* allocate and initialize percpu slots */ +static int +objpool_init_percpu_slots(struct objpool_head *pool, int nr_objs, + void *context, objpool_init_obj_cb objinit) +{ + int i, cpu_count = 0; + + for (i = 0; i < pool->nr_cpus; i++) { + + struct objpool_slot *slot; + int nodes, size, rc; + + /* skip the cpu node which could never be present */ + if (!cpu_possible(i)) + continue; + + /* compute how many objects to be allocated with this slot */ + nodes = nr_objs / num_possible_cpus(); + if (cpu_count < (nr_objs % num_possible_cpus())) + nodes++; + cpu_count++; + + size = struct_size(slot, entries, pool->capacity) + + pool->obj_size * nodes; + + /* + * here we allocate percpu-slot & objs together in a single + * allocation to make it more compact, taking advantage of + * warm caches and TLB hits. in default vmalloc is used to + * reduce the pressure of kernel slab system. as we know, + * mimimal size of vmalloc is one page since vmalloc would + * always align the requested size to page size + */ + if (pool->gfp & GFP_ATOMIC) + slot = kmalloc_node(size, pool->gfp, cpu_to_node(i)); + else + slot = __vmalloc_node(size, sizeof(void *), pool->gfp, + cpu_to_node(i), __builtin_return_address(0)); + if (!slot) + return -ENOMEM; + memset(slot, 0, size); + pool->cpu_slots[i] = slot; + + /* initialize the objpool_slot of cpu node i */ + rc = objpool_init_percpu_slot(pool, slot, nodes, context, objinit); + if (rc) + return rc; + } + + return 0; +} + +/* cleanup all percpu slots of the object pool */ +static void objpool_fini_percpu_slots(struct objpool_head *pool) +{ + int i; + + if (!pool->cpu_slots) + return; + + for (i = 0; i < pool->nr_cpus; i++) + kvfree(pool->cpu_slots[i]); + kfree(pool->cpu_slots); +} + +/* initialize object pool and pre-allocate objects */ +int objpool_init(struct objpool_head *pool, int nr_objs, int object_size, + gfp_t gfp, void *context, objpool_init_obj_cb objinit, + objpool_fini_cb release) +{ + int rc, capacity, slot_size; + + /* check input parameters */ + if (nr_objs <= 0 || nr_objs > OBJPOOL_NR_OBJECT_MAX || + object_size <= 0 || object_size > OBJPOOL_OBJECT_SIZE_MAX) + return -EINVAL; + + /* align up to unsigned long size */ + object_size = ALIGN(object_size, sizeof(long)); + + /* calculate capacity of percpu objpool_slot */ + capacity = roundup_pow_of_two(nr_objs); + if (!capacity) + return -EINVAL; + + /* initialize objpool pool */ + memset(pool, 0, sizeof(struct objpool_head)); + pool->nr_cpus = nr_cpu_ids; + pool->obj_size = object_size; + pool->capacity = capacity; + pool->gfp = gfp & ~__GFP_ZERO; + pool->context = context; + pool->release = release; + slot_size = pool->nr_cpus * sizeof(struct objpool_slot); + pool->cpu_slots = kzalloc(slot_size, pool->gfp); + if (!pool->cpu_slots) + return -ENOMEM; + + /* initialize per-cpu slots */ + rc = objpool_init_percpu_slots(pool, nr_objs, context, objinit); + if (rc) + objpool_fini_percpu_slots(pool); + else + refcount_set(&pool->ref, pool->nr_objs + 1); + + return rc; +} +EXPORT_SYMBOL_GPL(objpool_init); + +/* adding object to slot, abort if the slot was already full */ +static inline int +objpool_try_add_slot(void *obj, struct objpool_head *pool, int cpu) +{ + struct objpool_slot *slot = pool->cpu_slots[cpu]; + uint32_t head, tail; + + /* loading tail and head as a local snapshot, tail first */ + tail = READ_ONCE(slot->tail); + + do { + head = READ_ONCE(slot->head); + /* fault caught: something must be wrong */ + WARN_ON_ONCE(tail - head > pool->nr_objs); + } while (!try_cmpxchg_acquire(&slot->tail, &tail, tail + 1)); + + /* now the tail position is reserved for the given obj */ + WRITE_ONCE(slot->entries[tail & slot->mask], obj); + /* update sequence to make this obj available for pop() */ + smp_store_release(&slot->last, tail + 1); + + return 0; +} + +/* reclaim an object to object pool */ +int objpool_push(void *obj, struct objpool_head *pool) +{ + unsigned long flags; + int rc; + + /* disable local irq to avoid preemption & interruption */ + raw_local_irq_save(flags); + rc = objpool_try_add_slot(obj, pool, raw_smp_processor_id()); + raw_local_irq_restore(flags); + + return rc; +} +EXPORT_SYMBOL_GPL(objpool_push); + +/* try to retrieve object from slot */ +static inline void *objpool_try_get_slot(struct objpool_head *pool, int cpu) +{ + struct objpool_slot *slot = pool->cpu_slots[cpu]; + /* load head snapshot, other cpus may change it */ + uint32_t head = smp_load_acquire(&slot->head); + + while (head != READ_ONCE(slot->last)) { + void *obj; + + /* obj must be retrieved before moving forward head */ + obj = READ_ONCE(slot->entries[head & slot->mask]); + + /* move head forward to mark it's consumption */ + if (try_cmpxchg_release(&slot->head, &head, head + 1)) + return obj; + } + + return NULL; +} + +/* allocate an object from object pool */ +void *objpool_pop(struct objpool_head *pool) +{ + void *obj = NULL; + unsigned long flags; + int i, cpu; + + /* disable local irq to avoid preemption & interruption */ + raw_local_irq_save(flags); + + cpu = raw_smp_processor_id(); + for (i = 0; i < num_possible_cpus(); i++) { + obj = objpool_try_get_slot(pool, cpu); + if (obj) + break; + cpu = cpumask_next_wrap(cpu, cpu_possible_mask, -1, 1); + } + raw_local_irq_restore(flags); + + return obj; +} +EXPORT_SYMBOL_GPL(objpool_pop); + +/* release whole objpool forcely */ +void objpool_free(struct objpool_head *pool) +{ + if (!pool->cpu_slots) + return; + + /* release percpu slots */ + objpool_fini_percpu_slots(pool); + + /* call user's cleanup callback if provided */ + if (pool->release) + pool->release(pool, pool->context); +} +EXPORT_SYMBOL_GPL(objpool_free); + +/* drop the allocated object, rather reclaim it to objpool */ +int objpool_drop(void *obj, struct objpool_head *pool) +{ + if (!obj || !pool) + return -EINVAL; + + if (refcount_dec_and_test(&pool->ref)) { + objpool_free(pool); + return 0; + } + + return -EAGAIN; +} +EXPORT_SYMBOL_GPL(objpool_drop); + +/* drop unused objects and defref objpool for releasing */ +void objpool_fini(struct objpool_head *pool) +{ + int count = 1; /* extra ref for objpool itself */ + + /* drop all remained objects from objpool */ + while (objpool_pop(pool)) + count++; + + if (refcount_sub_and_test(count, &pool->ref)) + objpool_free(pool); +} +EXPORT_SYMBOL_GPL(objpool_fini); diff --git a/lib/test_objpool.c b/lib/test_objpool.c new file mode 100644 index 000000000000..a94078402138 --- /dev/null +++ b/lib/test_objpool.c @@ -0,0 +1,690 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Test module for lockless object pool + * + * Copyright: wuqiang.matt@bytedance.com + */ + +#include <linux/errno.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/completion.h> +#include <linux/kthread.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> +#include <linux/delay.h> +#include <linux/hrtimer.h> +#include <linux/objpool.h> + +#define OT_NR_MAX_BULK (16) + +/* memory usage */ +struct ot_mem_stat { + atomic_long_t alloc; + atomic_long_t free; +}; + +/* object allocation results */ +struct ot_obj_stat { + unsigned long nhits; + unsigned long nmiss; +}; + +/* control & results per testcase */ +struct ot_data { + struct rw_semaphore start; + struct completion wait; + struct completion rcu; + atomic_t nthreads ____cacheline_aligned_in_smp; + atomic_t stop ____cacheline_aligned_in_smp; + struct ot_mem_stat kmalloc; + struct ot_mem_stat vmalloc; + struct ot_obj_stat objects; + u64 duration; +}; + +/* testcase */ +struct ot_test { + int async; /* synchronous or asynchronous */ + int mode; /* only mode 0 supported */ + int objsz; /* object size */ + int duration; /* ms */ + int delay; /* ms */ + int bulk_normal; + int bulk_irq; + unsigned long hrtimer; /* ms */ + const char *name; + struct ot_data data; +}; + +/* per-cpu worker */ +struct ot_item { + struct objpool_head *pool; /* pool head */ + struct ot_test *test; /* test parameters */ + + void (*worker)(struct ot_item *item, int irq); + + /* hrtimer control */ + ktime_t hrtcycle; + struct hrtimer hrtimer; + + int bulk[2]; /* for thread and irq */ + int delay; + u32 niters; + + /* summary per thread */ + struct ot_obj_stat stat[2]; /* thread and irq */ + u64 duration; +}; + +/* + * memory leakage checking + */ + +static void *ot_kzalloc(struct ot_test *test, long size) +{ + void *ptr = kzalloc(size, GFP_KERNEL); + + if (ptr) + atomic_long_add(size, &test->data.kmalloc.alloc); + return ptr; +} + +static void ot_kfree(struct ot_test *test, void *ptr, long size) +{ + if (!ptr) + return; + atomic_long_add(size, &test->data.kmalloc.free); + kfree(ptr); +} + +static void ot_mem_report(struct ot_test *test) +{ + long alloc, free; + + pr_info("memory allocation summary for %s\n", test->name); + + alloc = atomic_long_read(&test->data.kmalloc.alloc); + free = atomic_long_read(&test->data.kmalloc.free); + pr_info(" kmalloc: %lu - %lu = %lu\n", alloc, free, alloc - free); + + alloc = atomic_long_read(&test->data.vmalloc.alloc); + free = atomic_long_read(&test->data.vmalloc.free); + pr_info(" vmalloc: %lu - %lu = %lu\n", alloc, free, alloc - free); +} + +/* user object instance */ +struct ot_node { + void *owner; + unsigned long data; + unsigned long refs; + unsigned long payload[32]; +}; + +/* user objpool manager */ +struct ot_context { + struct objpool_head pool; /* objpool head */ + struct ot_test *test; /* test parameters */ + void *ptr; /* user pool buffer */ + unsigned long size; /* buffer size */ + struct rcu_head rcu; +}; + +static DEFINE_PER_CPU(struct ot_item, ot_pcup_items); + +static int ot_init_data(struct ot_data *data) +{ + memset(data, 0, sizeof(*data)); + init_rwsem(&data->start); + init_completion(&data->wait); + init_completion(&data->rcu); + atomic_set(&data->nthreads, 1); + + return 0; +} + +static int ot_init_node(void *nod, void *context) +{ + struct ot_context *sop = context; + struct ot_node *on = nod; + + on->owner = &sop->pool; + return 0; +} + +static enum hrtimer_restart ot_hrtimer_handler(struct hrtimer *hrt) +{ + struct ot_item *item = container_of(hrt, struct ot_item, hrtimer); + struct ot_test *test = item->test; + + if (atomic_read_acquire(&test->data.stop)) + return HRTIMER_NORESTART; + + /* do bulk-testings for objects pop/push */ + item->worker(item, 1); + + hrtimer_forward(hrt, hrt->base->get_time(), item->hrtcycle); + return HRTIMER_RESTART; +} + +static void ot_start_hrtimer(struct ot_item *item) +{ + if (!item->test->hrtimer) + return; + hrtimer_start(&item->hrtimer, item->hrtcycle, HRTIMER_MODE_REL); +} + +static void ot_stop_hrtimer(struct ot_item *item) +{ + if (!item->test->hrtimer) + return; + hrtimer_cancel(&item->hrtimer); +} + +static int ot_init_hrtimer(struct ot_item *item, unsigned long hrtimer) +{ + struct hrtimer *hrt = &item->hrtimer; + + if (!hrtimer) + return -ENOENT; + + item->hrtcycle = ktime_set(0, hrtimer * 1000000UL); + hrtimer_init(hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + hrt->function = ot_hrtimer_handler; + return 0; +} + +static int ot_init_cpu_item(struct ot_item *item, + struct ot_test *test, + struct objpool_head *pool, + void (*worker)(struct ot_item *, int)) +{ + memset(item, 0, sizeof(*item)); + item->pool = pool; + item->test = test; + item->worker = worker; + + item->bulk[0] = test->bulk_normal; + item->bulk[1] = test->bulk_irq; + item->delay = test->delay; + + /* initialize hrtimer */ + ot_init_hrtimer(item, item->test->hrtimer); + return 0; +} + +static int ot_thread_worker(void *arg) +{ + struct ot_item *item = arg; + struct ot_test *test = item->test; + ktime_t start; + + atomic_inc(&test->data.nthreads); + down_read(&test->data.start); + up_read(&test->data.start); + start = ktime_get(); + ot_start_hrtimer(item); + do { + if (atomic_read_acquire(&test->data.stop)) + break; + /* do bulk-testings for objects pop/push */ + item->worker(item, 0); + } while (!kthread_should_stop()); + ot_stop_hrtimer(item); + item->duration = (u64) ktime_us_delta(ktime_get(), start); + if (atomic_dec_and_test(&test->data.nthreads)) + complete(&test->data.wait); + + return 0; +} + +static void ot_perf_report(struct ot_test *test, u64 duration) +{ + struct ot_obj_stat total, normal = {0}, irq = {0}; + int cpu, nthreads = 0; + + pr_info("\n"); + pr_info("Testing summary for %s\n", test->name); + + for_each_possible_cpu(cpu) { + struct ot_item *item = per_cpu_ptr(&ot_pcup_items, cpu); + if (!item->duration) + continue; + normal.nhits += item->stat[0].nhits; + normal.nmiss += item->stat[0].nmiss; + irq.nhits += item->stat[1].nhits; + irq.nmiss += item->stat[1].nmiss; + pr_info("CPU: %d duration: %lluus\n", cpu, item->duration); + pr_info("\tthread:\t%16lu hits \t%16lu miss\n", + item->stat[0].nhits, item->stat[0].nmiss); + pr_info("\tirq: \t%16lu hits \t%16lu miss\n", + item->stat[1].nhits, item->stat[1].nmiss); + pr_info("\ttotal: \t%16lu hits \t%16lu miss\n", + item->stat[0].nhits + item->stat[1].nhits, + item->stat[0].nmiss + item->stat[1].nmiss); + nthreads++; + } + + total.nhits = normal.nhits + irq.nhits; + total.nmiss = normal.nmiss + irq.nmiss; + + pr_info("ALL: \tnthreads: %d duration: %lluus\n", nthreads, duration); + pr_info("SUM: \t%16lu hits \t%16lu miss\n", + total.nhits, total.nmiss); + + test->data.objects = total; + test->data.duration = duration; +} + +/* + * synchronous test cases for objpool manipulation + */ + +/* objpool manipulation for synchronous mode (percpu objpool) */ +static struct ot_context *ot_init_sync_m0(struct ot_test *test) +{ + struct ot_context *sop = NULL; + int max = num_possible_cpus() << 3; + gfp_t gfp = GFP_KERNEL; + + sop = (struct ot_context *)ot_kzalloc(test, sizeof(*sop)); + if (!sop) + return NULL; + sop->test = test; + if (test->objsz < 512) + gfp = GFP_ATOMIC; + + if (objpool_init(&sop->pool, max, test->objsz, + gfp, sop, ot_init_node, NULL)) { + ot_kfree(test, sop, sizeof(*sop)); + return NULL; + } + WARN_ON(max != sop->pool.nr_objs); + + return sop; +} + +static void ot_fini_sync(struct ot_context *sop) +{ + objpool_fini(&sop->pool); + ot_kfree(sop->test, sop, sizeof(*sop)); +} + +struct { + struct ot_context * (*init)(struct ot_test *oc); + void (*fini)(struct ot_context *sop); +} g_ot_sync_ops[] = { + {.init = ot_init_sync_m0, .fini = ot_fini_sync}, +}; + +/* + * synchronous test cases: performance mode + */ + +static void ot_bulk_sync(struct ot_item *item, int irq) +{ + struct ot_node *nods[OT_NR_MAX_BULK]; + int i; + + for (i = 0; i < item->bulk[irq]; i++) + nods[i] = objpool_pop(item->pool); + + if (!irq && (item->delay || !(++(item->niters) & 0x7FFF))) + msleep(item->delay); + + while (i-- > 0) { + struct ot_node *on = nods[i]; + if (on) { + on->refs++; + objpool_push(on, item->pool); + item->stat[irq].nhits++; + } else { + item->stat[irq].nmiss++; + } + } +} + +static int ot_start_sync(struct ot_test *test) +{ + struct ot_context *sop; + ktime_t start; + u64 duration; + unsigned long timeout; + int cpu; + + /* initialize objpool for syncrhonous testcase */ + sop = g_ot_sync_ops[test->mode].init(test); + if (!sop) + return -ENOMEM; + + /* grab rwsem to block testing threads */ + down_write(&test->data.start); + + for_each_possible_cpu(cpu) { + struct ot_item *item = per_cpu_ptr(&ot_pcup_items, cpu); + struct task_struct *work; + + ot_init_cpu_item(item, test, &sop->pool, ot_bulk_sync); + + /* skip offline cpus */ + if (!cpu_online(cpu)) + continue; + + work = kthread_create_on_node(ot_thread_worker, item, + cpu_to_node(cpu), "ot_worker_%d", cpu); + if (IS_ERR(work)) { + pr_err("failed to create thread for cpu %d\n", cpu); + } else { + kthread_bind(work, cpu); + wake_up_process(work); + } + } + + /* wait a while to make sure all threads waiting at start line */ + msleep(20); + + /* in case no threads were created: memory insufficient ? */ + if (atomic_dec_and_test(&test->data.nthreads)) + complete(&test->data.wait); + + // sched_set_fifo_low(current); + + /* start objpool testing threads */ + start = ktime_get(); + up_write(&test->data.start); + + /* yeild cpu to worker threads for duration ms */ + timeout = msecs_to_jiffies(test->duration); + schedule_timeout_interruptible(timeout); + + /* tell workers threads to quit */ + atomic_set_release(&test->data.stop, 1); + + /* wait all workers threads finish and quit */ + wait_for_completion(&test->data.wait); + duration = (u64) ktime_us_delta(ktime_get(), start); + + /* cleanup objpool */ + g_ot_sync_ops[test->mode].fini(sop); + + /* report testing summary and performance results */ + ot_perf_report(test, duration); + + /* report memory allocation summary */ + ot_mem_report(test); + + return 0; +} + +/* + * asynchronous test cases: pool lifecycle controlled by refcount + */ + +static void ot_fini_async_rcu(struct rcu_head *rcu) +{ + struct ot_context *sop = container_of(rcu, struct ot_context, rcu); + struct ot_test *test = sop->test; + + /* here all cpus are aware of the stop event: test->data.stop = 1 */ + WARN_ON(!atomic_read_acquire(&test->data.stop)); + + objpool_fini(&sop->pool); + complete(&test->data.rcu); +} + +static void ot_fini_async(struct ot_context *sop) +{ + /* make sure the stop event is acknowledged by all cores */ + call_rcu(&sop->rcu, ot_fini_async_rcu); +} + +static int ot_objpool_release(struct objpool_head *head, void *context) +{ + struct ot_context *sop = context; + + WARN_ON(!head || !sop || head != &sop->pool); + + /* do context cleaning if needed */ + if (sop) + ot_kfree(sop->test, sop, sizeof(*sop)); + + return 0; +} + +static struct ot_context *ot_init_async_m0(struct ot_test *test) +{ + struct ot_context *sop = NULL; + int max = num_possible_cpus() << 3; + gfp_t gfp = GFP_KERNEL; + + sop = (struct ot_context *)ot_kzalloc(test, sizeof(*sop)); + if (!sop) + return NULL; + sop->test = test; + if (test->objsz < 512) + gfp = GFP_ATOMIC; + + if (objpool_init(&sop->pool, max, test->objsz, gfp, sop, + ot_init_node, ot_objpool_release)) { + ot_kfree(test, sop, sizeof(*sop)); + return NULL; + } + WARN_ON(max != sop->pool.nr_objs); + + return sop; +} + +struct { + struct ot_context * (*init)(struct ot_test *oc); + void (*fini)(struct ot_context *sop); +} g_ot_async_ops[] = { + {.init = ot_init_async_m0, .fini = ot_fini_async}, +}; + +static void ot_nod_recycle(struct ot_node *on, struct objpool_head *pool, + int release) +{ + struct ot_context *sop; + + on->refs++; + + if (!release) { + /* push object back to opjpool for reuse */ + objpool_push(on, pool); + return; + } + + sop = container_of(pool, struct ot_context, pool); + WARN_ON(sop != pool->context); + + /* unref objpool with nod removed forever */ + objpool_drop(on, pool); +} + +static void ot_bulk_async(struct ot_item *item, int irq) +{ + struct ot_test *test = item->test; + struct ot_node *nods[OT_NR_MAX_BULK]; + int i, stop; + + for (i = 0; i < item->bulk[irq]; i++) + nods[i] = objpool_pop(item->pool); + + if (!irq) { + if (item->delay || !(++(item->niters) & 0x7FFF)) + msleep(item->delay); + get_cpu(); + } + + stop = atomic_read_acquire(&test->data.stop); + + /* drop all objects and deref objpool */ + while (i-- > 0) { + struct ot_node *on = nods[i]; + + if (on) { + on->refs++; + ot_nod_recycle(on, item->pool, stop); + item->stat[irq].nhits++; + } else { + item->stat[irq].nmiss++; + } + } + + if (!irq) + put_cpu(); +} + +static int ot_start_async(struct ot_test *test) +{ + struct ot_context *sop; + ktime_t start; + u64 duration; + unsigned long timeout; + int cpu; + + /* initialize objpool for syncrhonous testcase */ + sop = g_ot_async_ops[test->mode].init(test); + if (!sop) + return -ENOMEM; + + /* grab rwsem to block testing threads */ + down_write(&test->data.start); + + for_each_possible_cpu(cpu) { + struct ot_item *item = per_cpu_ptr(&ot_pcup_items, cpu); + struct task_struct *work; + + ot_init_cpu_item(item, test, &sop->pool, ot_bulk_async); + + /* skip offline cpus */ + if (!cpu_online(cpu)) + continue; + + work = kthread_create_on_node(ot_thread_worker, item, + cpu_to_node(cpu), "ot_worker_%d", cpu); + if (IS_ERR(work)) { + pr_err("failed to create thread for cpu %d\n", cpu); + } else { + kthread_bind(work, cpu); + wake_up_process(work); + } + } + + /* wait a while to make sure all threads waiting at start line */ + msleep(20); + + /* in case no threads were created: memory insufficient ? */ + if (atomic_dec_and_test(&test->data.nthreads)) + complete(&test->data.wait); + + /* start objpool testing threads */ + start = ktime_get(); + up_write(&test->data.start); + + /* yeild cpu to worker threads for duration ms */ + timeout = msecs_to_jiffies(test->duration); + schedule_timeout_interruptible(timeout); + + /* tell workers threads to quit */ + atomic_set_release(&test->data.stop, 1); + + /* do async-finalization */ + g_ot_async_ops[test->mode].fini(sop); + + /* wait all workers threads finish and quit */ + wait_for_completion(&test->data.wait); + duration = (u64) ktime_us_delta(ktime_get(), start); + + /* assure rcu callback is triggered */ + wait_for_completion(&test->data.rcu); + + /* + * now we are sure that objpool is finalized either + * by rcu callback or by worker threads + */ + + /* report testing summary and performance results */ + ot_perf_report(test, duration); + + /* report memory allocation summary */ + ot_mem_report(test); + + return 0; +} + +/* + * predefined testing cases: + * synchronous case / overrun case / async case + * + * async: synchronous or asynchronous testing + * mode: only mode 0 supported + * objsz: object size + * duration: int, total test time in ms + * delay: int, delay (in ms) between each iteration + * bulk_normal: int, repeat times for thread worker + * bulk_irq: int, repeat times for irq consumer + * hrtimer: unsigned long, hrtimer intervnal in ms + * name: char *, tag for current test ot_item + */ + +#define NODE_COMPACT sizeof(struct ot_node) +#define NODE_VMALLOC (512) + +struct ot_test g_testcases[] = { + + /* sync & normal */ + {0, 0, NODE_COMPACT, 1000, 0, 1, 0, 0, "sync: percpu objpool"}, + {0, 0, NODE_VMALLOC, 1000, 0, 1, 0, 0, "sync: percpu objpool from vmalloc"}, + + /* sync & hrtimer */ + {0, 0, NODE_COMPACT, 1000, 0, 1, 1, 4, "sync & hrtimer: percpu objpool"}, + {0, 0, NODE_VMALLOC, 1000, 0, 1, 1, 4, "sync & hrtimer: percpu objpool from vmalloc"}, + + /* sync & overrun */ + {0, 0, NODE_COMPACT, 1000, 0, 16, 0, 0, "sync overrun: percpu objpool"}, + {0, 0, NODE_VMALLOC, 1000, 0, 16, 0, 0, "sync overrun: percpu objpool from vmalloc"}, + + /* async mode */ + {1, 0, NODE_COMPACT, 1000, 100, 1, 0, 0, "async: percpu objpool"}, + {1, 0, NODE_VMALLOC, 1000, 100, 1, 0, 0, "async: percpu objpool from vmalloc"}, + + /* async + hrtimer mode */ + {1, 0, NODE_COMPACT, 1000, 0, 4, 4, 4, "async & hrtimer: percpu objpool"}, + {1, 0, NODE_VMALLOC, 1000, 0, 4, 4, 4, "async & hrtimer: percpu objpool from vmalloc"}, +}; + +static int __init ot_mod_init(void) +{ + int i; + + /* perform testings */ + for (i = 0; i < ARRAY_SIZE(g_testcases); i++) { + ot_init_data(&g_testcases[i].data); + if (g_testcases[i].async) + ot_start_async(&g_testcases[i]); + else + ot_start_sync(&g_testcases[i]); + } + + /* show tests summary */ + pr_info("\n"); + pr_info("Summary of testcases:\n"); + for (i = 0; i < ARRAY_SIZE(g_testcases); i++) { + pr_info(" duration: %lluus \thits: %10lu \tmiss: %10lu \t%s\n", + g_testcases[i].data.duration, g_testcases[i].data.objects.nhits, + g_testcases[i].data.objects.nmiss, g_testcases[i].name); + } + + return -EAGAIN; +} + +static void __exit ot_mod_exit(void) +{ +} + +module_init(ot_mod_init); +module_exit(ot_mod_exit); + +MODULE_LICENSE("GPL");
\ No newline at end of file diff --git a/samples/kprobes/kretprobe_example.c b/samples/kprobes/kretprobe_example.c index cbf16542d84e..ed79fd3d48fb 100644 --- a/samples/kprobes/kretprobe_example.c +++ b/samples/kprobes/kretprobe_example.c @@ -35,7 +35,7 @@ struct my_data { ktime_t entry_stamp; }; -/* Here we use the entry_hanlder to timestamp function entry */ +/* Here we use the entry_handler to timestamp function entry */ static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs) { struct my_data *data; |