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[2620:137:e000::1:20]) by mx.google.com with ESMTP id gs37-20020a1709072d2500b0078dcd448f99si4495115ejc.855.2022.11.05.23.09.11; Sat, 05 Nov 2022 23:09:34 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@bytedance-com.20210112.gappssmtp.com header.s=20210112 header.b=53Mxwpcn; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=bytedance.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229610AbiKFFgG (ORCPT + 96 others); Sun, 6 Nov 2022 01:36:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58024 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229617AbiKFFgD (ORCPT ); Sun, 6 Nov 2022 01:36:03 -0400 Received: from mail-pj1-x102a.google.com (mail-pj1-x102a.google.com [IPv6:2607:f8b0:4864:20::102a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E7BDD630D for ; Sat, 5 Nov 2022 22:36:00 -0700 (PDT) Received: by mail-pj1-x102a.google.com with SMTP id f5-20020a17090a4a8500b002131bb59d61so10283227pjh.1 for ; Sat, 05 Nov 2022 22:36:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=Gk832WoCDtaxlq4TEG6HOzhexXKucVIRZxYRPYc5c4U=; b=53MxwpcnQH363++4DHr3++99z8LkWNoQlOBnn1IDI1DS7PZZ7Vr+Ty5OAXmjPNHRdb yVUx4Ao09xMtPhBzVvF1x/cFQ+PqM1wChSBAZbcQgy7v2DVveztzAq1U1WByHOEYn8FQ IENL1GYVUhQEK0L7TxqT+qjiqnXArmwDNV+en2jADQfWpnZPMOFpe0OME24QEGrIM+vL 16QhMWHeFF+Cn1fB3n+BqDYdlRHfz3Tbu+OKZuWLa2EnQhoSN1YjKL73i1AkFBxd/EdE sEteSbBjH72QxNftBKuVjGoybruQonZltVqGCCTNAYhO9imVG1XeTQbmKmOoZi88wD9w Kj4A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Gk832WoCDtaxlq4TEG6HOzhexXKucVIRZxYRPYc5c4U=; b=zNgiugti9VBz+52otZj5xSjm81a8F22fgDL7FvJwQKCyHmGJTIYajXBm2SDycR8jm3 aZFmQjWF37SWDRpzk2QvfLIMmYiSUZuy1vpl1c2uIAPMaFUEHtyPS/wF4afVuq8G39tt q8xaTLj9qFohRG+aoumw7MvIRWbiof3ZSsVMl8/PohnjuQ/ET9QS9+DyaxqB9PxIcTtX T6/luoz6RPWVaaZkjuLbSwzFGlbqSIJ3U1+TT7OADC0SMaiwT2zfOiHT7vgRNkWg3JlZ wuxuAIphOaJ+WHVb8kjzM6nDTlI5Qt+dWJBkWjDddl9tfiGK3SBzFKSicfSzBKKTg71V uh8A== X-Gm-Message-State: ACrzQf1jCLayg8hYjXxGPXlbnYEK4vME9IeJkYgk8zecjCEJEhYYdt/r JMYNdnUEFu6UDMeUQZQa3NylWJieIEncoQ== X-Received: by 2002:a17:903:24e:b0:179:b755:b82f with SMTP id j14-20020a170903024e00b00179b755b82fmr42629240plh.34.1667712960363; Sat, 05 Nov 2022 22:36:00 -0700 (PDT) Received: from devtp.bytedance.net ([139.177.225.243]) by smtp.gmail.com with ESMTPSA id q27-20020aa7961b000000b0056bee236e9csm2127121pfg.142.2022.11.05.22.35.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 05 Nov 2022 22:36:00 -0700 (PDT) From: wuqiang To: mhiramat@kernel.org, davem@davemloft.net, anil.s.keshavamurthy@intel.com, naveen.n.rao@linux.ibm.com, rostedt@goodmis.org, peterz@infradead.org, akpm@linux-foundation.org, sander@svanheule.net, ebiggers@google.com, dan.j.williams@intel.com, jpoimboe@kernel.org Cc: linux-kernel@vger.kernel.org, lkp@intel.com, mattwu@163.com, wuqiang Subject: [PATCH v5 3/4] kprobes: kretprobe scalability improvement with objpool Date: Sun, 6 Nov 2022 13:34:40 +0800 Message-Id: <20221106053441.103199-4-wuqiang.matt@bytedance.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221106053441.103199-1-wuqiang.matt@bytedance.com> References: <20221102023012.6362-1-wuqiang.matt@bytedance.com> <20221106053441.103199-1-wuqiang.matt@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org kretprobe is using freelist to manage return-instances, but freelist, as LIFO queue based on singly linked list, scales badly and reduces the overall throughput of kretprobed routines, especially for high contention scenarios. Here's a typical throughput test of sys_flock (counts in 10 seconds, measured with perf stat -a -I 10000 -e syscalls:sys_enter_flock): OS: Debian 10 X86_64, Linux 6.1rc2 HW: XEON 8336C x 2, 64 cores/128 threads, DDR4 3200MT/s 1X 2X 4X 6X 8X 12X 16X 34762430 36546920 17949900 13101899 12569595 12646601 14729195 24X 32X 48X 64X 72X 96X 128X 19263546 10102064 8985418 11936495 11493980 7127789 9330985 This patch introduces objpool to kretprobe and rethook, with orginal freelist replaced and brings near-linear scalability to kretprobed routines. Tests of kretprobe throughput show the biggest ratio as 333.9x of the original freelist. Here's the comparison: 1X 2X 4X 8X 16X freelist: 34762430 36546920 17949900 12569595 14729195 objpool: 35627544 72182095 144068494 287564688 576903916 32X 48X 64X 96X 128X freelist: 10102064 8985418 11936495 7127789 9330985 objpool: 1158876372 1737828164 2324371724 2380310472 2463182819 Tests on 96-core ARM64 system output similarly, but with the biggest ratio up to 642.2x: OS: Debian 10 AARCH64, Linux 6.1rc2 HW: Kunpeng-920 96 cores/2 sockets/4 NUMA nodes, DDR4 2933 MT/s 1X 2X 4X 8X 16X freelist: 17498299 10887037 10224710 8499132 6421751 objpool: 18715726 35549845 71615884 144258971 283707220 24X 32X 48X 64X 96X freelist: 5339868 4819116 3593919 3121575 2687167 objpool: 419830913 571609748 877456139 1143316315 1725668029 Signed-off-by: wuqiang --- include/linux/kprobes.h | 9 ++-- include/linux/rethook.h | 15 +++---- kernel/kprobes.c | 95 +++++++++++++++++++---------------------- kernel/trace/fprobe.c | 17 +++----- kernel/trace/rethook.c | 80 +++++++++++++++++----------------- 5 files changed, 96 insertions(+), 120 deletions(-) diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index a0b92be98984..f13f01e600c2 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -27,7 +27,7 @@ #include #include #include -#include +#include #include #include @@ -141,6 +141,7 @@ static inline bool kprobe_ftrace(struct kprobe *p) */ struct kretprobe_holder { struct kretprobe *rp; + struct objpool_head oh; refcount_t ref; }; @@ -154,7 +155,6 @@ struct kretprobe { #ifdef CONFIG_KRETPROBE_ON_RETHOOK struct rethook *rh; #else - struct freelist_head freelist; struct kretprobe_holder *rph; #endif }; @@ -165,10 +165,7 @@ 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/rethook.h b/include/linux/rethook.h index c8ac1e5afcd1..278ec65e71fe 100644 --- a/include/linux/rethook.h +++ b/include/linux/rethook.h @@ -6,7 +6,7 @@ #define _LINUX_RETHOOK_H #include -#include +#include #include #include #include @@ -30,14 +30,14 @@ typedef void (*rethook_handler_t) (struct rethook_node *, void *, struct pt_regs struct rethook { void *data; rethook_handler_t handler; - struct freelist_head pool; + struct objpool_head pool; refcount_t ref; struct rcu_head rcu; }; /** * struct rethook_node - The rethook shadow-stack entry node. - * @freelist: The freelist, linked to struct rethook::pool. + * @nod: The objpool node, 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. @@ -48,19 +48,15 @@ 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, gfp_t gfp, int size, int max); 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); @@ -97,4 +93,3 @@ void rethook_flush_task(struct task_struct *tk); #endif #endif - diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 3220b0a2fb4a..e8526a0d29b6 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1865,10 +1865,12 @@ static struct notifier_block kprobe_exceptions_nb = { 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); + if (refcount_dec_and_test(&rph->ref)) { + objpool_fini(&rph->oh); + kfree(rph); + } } NOKPROBE_SYMBOL(free_rp_inst_rcu); @@ -1877,7 +1879,7 @@ 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->oh); else call_rcu(&ri->rcu, free_rp_inst_rcu); } @@ -1914,23 +1916,19 @@ 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; + void *nod; - if (refcount_sub_and_test(count, &rp->rph->ref)) { - kfree(rp->rph); - rp->rph = NULL; - } + rp->rph = NULL; + do { + nod = objpool_pop(&rph->oh); + /* deref anyway since we've one extra ref grabbed */ + if (refcount_dec_and_test(&rph->ref)) { + objpool_fini(&rph->oh); + kfree(rph); + break; + } + } while (nod); } /* This assumes the 'tsk' is the current task or the is not running. */ @@ -2072,19 +2070,17 @@ 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->oh); + 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->oh); return 0; } @@ -2174,10 +2170,19 @@ int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long o return 0; } +#ifndef CONFIG_KRETPROBE_ON_RETHOOK +static int kretprobe_init_inst(void *context, void *nod) +{ + struct kretprobe_instance *ri = nod; + + ri->rph = context; + return 0; +} +#endif + int register_kretprobe(struct kretprobe *rp) { int ret; - struct kretprobe_instance *inst; int i; void *addr; @@ -2215,20 +2220,12 @@ int register_kretprobe(struct kretprobe *rp) #endif } #ifdef CONFIG_KRETPROBE_ON_RETHOOK - rp->rh = rethook_alloc((void *)rp, kretprobe_rethook_handler); + rp->rh = rethook_alloc((void *)rp, kretprobe_rethook_handler, GFP_KERNEL, + sizeof(struct kretprobe_instance) + rp->data_size, + rp->maxactive); if (!rp->rh) return -ENOMEM; - for (i = 0; i < rp->maxactive; i++) { - inst = kzalloc(sizeof(struct kretprobe_instance) + - 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); @@ -2237,25 +2234,19 @@ 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(sizeof(struct kretprobe_instance) + - 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->oh, rp->maxactive, rp->maxactive, + rp->data_size + sizeof(struct kretprobe_instance), + GFP_KERNEL, rp->rph, kretprobe_init_inst, NULL)) { + kfree(rp->rph); + rp->rph = NULL; + return -ENOMEM; } - refcount_set(&rp->rph->ref, i); - + refcount_set(&rp->rph->ref, rp->maxactive + 1); + 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 aac63ca9c3d1..99b4ab0f6468 100644 --- a/kernel/trace/fprobe.c +++ b/kernel/trace/fprobe.c @@ -125,7 +125,7 @@ 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; @@ -140,18 +140,11 @@ static int fprobe_init_rethook(struct fprobe *fp, int num) if (size < 0) return -E2BIG; - fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler); - for (i = 0; i < size; i++) { - struct fprobe_rethook_node *node; + fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler, GFP_KERNEL, + sizeof(struct fprobe_rethook_node), size); + if (!fp->rethook) + return -ENOMEM; - node = kzalloc(sizeof(*node), GFP_KERNEL); - if (!node) { - rethook_free(fp->rethook); - fp->rethook = NULL; - return -ENOMEM; - } - rethook_add_node(fp->rethook, &node->node); - } return 0; } diff --git a/kernel/trace/rethook.c b/kernel/trace/rethook.c index c69d82273ce7..01df98db2fbe 100644 --- a/kernel/trace/rethook.c +++ b/kernel/trace/rethook.c @@ -36,21 +36,17 @@ 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; + struct rethook_node *nod; - 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); + do { + nod = objpool_pop(&rh->pool); + /* deref anyway since we've one extra ref grabbed */ + if (refcount_dec_and_test(&rh->ref)) { + objpool_fini(&rh->pool); + kfree(rh); + break; + } + } while (nod); } /** @@ -70,16 +66,28 @@ void rethook_free(struct rethook *rh) call_rcu(&rh->rcu, rethook_free_rcu); } +static int rethook_init_node(void *context, void *nod) +{ + struct rethook_node *node = nod; + + node->rethook = 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. + * @gfp: default gfp for objpool allocation + * @size: rethook node size + * @max: 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. * 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, gfp_t gfp, + int size, int max) { struct rethook *rh = kzalloc(sizeof(struct rethook), GFP_KERNEL); @@ -88,34 +96,26 @@ struct rethook *rethook_alloc(void *data, rethook_handler_t handler) 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, max, max, size, gfp, rh, rethook_init_node, + NULL)) { + kfree(rh); + return NULL; + } + refcount_set(&rh->ref, max + 1); 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); + if (refcount_dec_and_test(&rh->ref)) { + objpool_fini(&rh->pool); + kfree(rh); + } } /** @@ -130,7 +130,7 @@ 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); } @@ -146,7 +146,7 @@ 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; + struct rethook_node *nod; lockdep_assert_preemption_disabled(); @@ -163,11 +163,11 @@ struct rethook_node *rethook_try_get(struct rethook *rh) if (unlikely(!rcu_is_watching())) return NULL; - fn = freelist_try_get(&rh->pool); - if (!fn) + nod = (struct rethook_node *)objpool_pop(&rh->pool); + if (!nod) return NULL; - return container_of(fn, struct rethook_node, freelist); + return nod; } NOKPROBE_SYMBOL(rethook_try_get); -- 2.34.1