From patchwork Thu Mar 30 22:47:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Paul E. McKenney" X-Patchwork-Id: 13194996 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 60A5FC6FD1D for ; Thu, 30 Mar 2023 22:48:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231301AbjC3WsJ (ORCPT ); Thu, 30 Mar 2023 18:48:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37930 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230477AbjC3Wrz (ORCPT ); Thu, 30 Mar 2023 18:47:55 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 90A001207D; Thu, 30 Mar 2023 15:47:33 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 34497B82A61; Thu, 30 Mar 2023 22:47:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BD277C433A1; Thu, 30 Mar 2023 22:47:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1680216448; bh=2z52HqJMXnDAlApz+l6xDJZbiniCrafGRH1u03k4yVo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qZaZr7/5urXiVAyR2eCtKe8EXBG0RwZqaFP/pf1fsPlARUundoWN03A5SeJVVQysu sJ5CUwgs8YwPxuTodrnuCi4czaBzwTOtXiGZZWDzLzlH6IJyKQ4s9Dl/TS6eq4+npJ rf4YhmU7mhHWCgqLKdrLGuH0VYI9pZtDWGIY9mPETTzEBz4/YxOp5Es+qdW1h5A6W+ l1afZTuJW667qYqHX59mBLYYwhRAEfftOK8C9glDufS7tlqRfn5EB41MCO6uTs56B8 wUvADQkyEzDf5BrPnJ9yqJUb6e4vVw0/V+PDWyPlhNvtvvN2ka+8aKV/hOOPQnE34A PwIx608vjEAtA== Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id 115D81540482; Thu, 30 Mar 2023 15:47:28 -0700 (PDT) From: "Paul E. McKenney" To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, rostedt@goodmis.org, hch@lst.de, "Paul E. McKenney" , Sachin Sant , "Zhang, Qiang1" Subject: [PATCH rcu 06/20] srcu: Move ->srcu_size_state from srcu_struct to srcu_usage Date: Thu, 30 Mar 2023 15:47:12 -0700 Message-Id: <20230330224726.662344-6-paulmck@kernel.org> X-Mailer: git-send-email 2.40.0.rc2 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org This commit moves the ->srcu_size_state field from the srcu_struct structure to the srcu_usage structure to reduce the size of the former in order to improve cache locality. Suggested-by: Christoph Hellwig Tested-by: Sachin Sant Tested-by: "Zhang, Qiang1" Signed-off-by: Paul E. McKenney --- include/linux/srcutree.h | 2 +- kernel/rcu/srcutree.c | 37 +++++++++++++++++++------------------ 2 files changed, 20 insertions(+), 19 deletions(-) diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h index c7373fe5c14b..443d27a214ef 100644 --- a/include/linux/srcutree.h +++ b/include/linux/srcutree.h @@ -64,13 +64,13 @@ struct srcu_usage { struct srcu_node *node; /* Combining tree. */ struct srcu_node *level[RCU_NUM_LVLS + 1]; /* First node at each level. */ + int srcu_size_state; /* Small-to-big transition state. */ }; /* * Per-SRCU-domain structure, similar in function to rcu_state. */ struct srcu_struct { - int srcu_size_state; /* Small-to-big transition state. */ struct mutex srcu_cb_mutex; /* Serialize CB preparation. */ spinlock_t __private lock; /* Protect counters and size state. */ struct mutex srcu_gp_mutex; /* Serialize GP work. */ diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index acb0862faafa..8428a184d506 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -225,7 +225,7 @@ static bool init_srcu_struct_nodes(struct srcu_struct *ssp, gfp_t gfp_flags) } sdp->grpmask = 1 << (cpu - sdp->mynode->grplo); } - smp_store_release(&ssp->srcu_size_state, SRCU_SIZE_WAIT_BARRIER); + smp_store_release(&ssp->srcu_sup->srcu_size_state, SRCU_SIZE_WAIT_BARRIER); return true; } @@ -240,7 +240,7 @@ static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static) ssp->srcu_sup = kzalloc(sizeof(*ssp->srcu_sup), GFP_KERNEL); if (!ssp->srcu_sup) return -ENOMEM; - ssp->srcu_size_state = SRCU_SIZE_SMALL; + ssp->srcu_sup->srcu_size_state = SRCU_SIZE_SMALL; ssp->srcu_sup->node = NULL; mutex_init(&ssp->srcu_cb_mutex); mutex_init(&ssp->srcu_gp_mutex); @@ -261,7 +261,7 @@ static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static) init_srcu_struct_data(ssp); ssp->srcu_gp_seq_needed_exp = 0; ssp->srcu_last_gp_end = ktime_get_mono_fast_ns(); - if (READ_ONCE(ssp->srcu_size_state) == SRCU_SIZE_SMALL && SRCU_SIZING_IS_INIT()) { + if (READ_ONCE(ssp->srcu_sup->srcu_size_state) == SRCU_SIZE_SMALL && SRCU_SIZING_IS_INIT()) { if (!init_srcu_struct_nodes(ssp, GFP_ATOMIC)) { if (!ssp->sda_is_static) { free_percpu(ssp->sda); @@ -270,7 +270,7 @@ static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static) return -ENOMEM; } } else { - WRITE_ONCE(ssp->srcu_size_state, SRCU_SIZE_BIG); + WRITE_ONCE(ssp->srcu_sup->srcu_size_state, SRCU_SIZE_BIG); } } smp_store_release(&ssp->srcu_gp_seq_needed, 0); /* Init done. */ @@ -315,7 +315,7 @@ EXPORT_SYMBOL_GPL(init_srcu_struct); static void __srcu_transition_to_big(struct srcu_struct *ssp) { lockdep_assert_held(&ACCESS_PRIVATE(ssp, lock)); - smp_store_release(&ssp->srcu_size_state, SRCU_SIZE_ALLOC); + smp_store_release(&ssp->srcu_sup->srcu_size_state, SRCU_SIZE_ALLOC); } /* @@ -326,10 +326,10 @@ static void srcu_transition_to_big(struct srcu_struct *ssp) unsigned long flags; /* Double-checked locking on ->srcu_size-state. */ - if (smp_load_acquire(&ssp->srcu_size_state) != SRCU_SIZE_SMALL) + if (smp_load_acquire(&ssp->srcu_sup->srcu_size_state) != SRCU_SIZE_SMALL) return; spin_lock_irqsave_rcu_node(ssp, flags); - if (smp_load_acquire(&ssp->srcu_size_state) != SRCU_SIZE_SMALL) { + if (smp_load_acquire(&ssp->srcu_sup->srcu_size_state) != SRCU_SIZE_SMALL) { spin_unlock_irqrestore_rcu_node(ssp, flags); return; } @@ -345,7 +345,7 @@ static void spin_lock_irqsave_check_contention(struct srcu_struct *ssp) { unsigned long j; - if (!SRCU_SIZING_IS_CONTEND() || ssp->srcu_size_state) + if (!SRCU_SIZING_IS_CONTEND() || ssp->srcu_sup->srcu_size_state) return; j = jiffies; if (ssp->srcu_size_jiffies != j) { @@ -666,7 +666,7 @@ void cleanup_srcu_struct(struct srcu_struct *ssp) } kfree(ssp->srcu_sup->node); ssp->srcu_sup->node = NULL; - ssp->srcu_size_state = SRCU_SIZE_SMALL; + ssp->srcu_sup->srcu_size_state = SRCU_SIZE_SMALL; if (!ssp->sda_is_static) { free_percpu(ssp->sda); ssp->sda = NULL; @@ -770,7 +770,7 @@ static void srcu_gp_start(struct srcu_struct *ssp) struct srcu_data *sdp; int state; - if (smp_load_acquire(&ssp->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER) + if (smp_load_acquire(&ssp->srcu_sup->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER) sdp = per_cpu_ptr(ssp->sda, get_boot_cpu_id()); else sdp = this_cpu_ptr(ssp->sda); @@ -880,7 +880,7 @@ static void srcu_gp_end(struct srcu_struct *ssp) /* A new grace period can start at this point. But only one. */ /* Initiate callback invocation as needed. */ - ss_state = smp_load_acquire(&ssp->srcu_size_state); + ss_state = smp_load_acquire(&ssp->srcu_sup->srcu_size_state); if (ss_state < SRCU_SIZE_WAIT_BARRIER) { srcu_schedule_cbs_sdp(per_cpu_ptr(ssp->sda, get_boot_cpu_id()), cbdelay); @@ -940,7 +940,7 @@ static void srcu_gp_end(struct srcu_struct *ssp) if (ss_state == SRCU_SIZE_ALLOC) init_srcu_struct_nodes(ssp, GFP_KERNEL); else - smp_store_release(&ssp->srcu_size_state, ss_state + 1); + smp_store_release(&ssp->srcu_sup->srcu_size_state, ss_state + 1); } } @@ -1002,7 +1002,7 @@ static void srcu_funnel_gp_start(struct srcu_struct *ssp, struct srcu_data *sdp, unsigned long snp_seq; /* Ensure that snp node tree is fully initialized before traversing it */ - if (smp_load_acquire(&ssp->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER) + if (smp_load_acquire(&ssp->srcu_sup->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER) snp_leaf = NULL; else snp_leaf = sdp->mynode; @@ -1209,7 +1209,7 @@ static unsigned long srcu_gp_start_if_needed(struct srcu_struct *ssp, * sequence number cannot wrap around in the meantime. */ idx = __srcu_read_lock_nmisafe(ssp); - ss_state = smp_load_acquire(&ssp->srcu_size_state); + ss_state = smp_load_acquire(&ssp->srcu_sup->srcu_size_state); if (ss_state < SRCU_SIZE_WAIT_CALL) sdp = per_cpu_ptr(ssp->sda, get_boot_cpu_id()); else @@ -1546,7 +1546,7 @@ void srcu_barrier(struct srcu_struct *ssp) atomic_set(&ssp->srcu_barrier_cpu_cnt, 1); idx = __srcu_read_lock_nmisafe(ssp); - if (smp_load_acquire(&ssp->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER) + if (smp_load_acquire(&ssp->srcu_sup->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER) srcu_barrier_one_cpu(ssp, per_cpu_ptr(ssp->sda, get_boot_cpu_id())); else for_each_possible_cpu(cpu) @@ -1784,7 +1784,7 @@ void srcu_torture_stats_print(struct srcu_struct *ssp, char *tt, char *tf) int cpu; int idx; unsigned long s0 = 0, s1 = 0; - int ss_state = READ_ONCE(ssp->srcu_size_state); + int ss_state = READ_ONCE(ssp->srcu_sup->srcu_size_state); int ss_state_idx = ss_state; idx = ssp->srcu_idx & 0x1; @@ -1871,8 +1871,9 @@ void __init srcu_init(void) ssp = list_first_entry(&srcu_boot_list, struct srcu_struct, work.work.entry); list_del_init(&ssp->work.work.entry); - if (SRCU_SIZING_IS(SRCU_SIZING_INIT) && ssp->srcu_size_state == SRCU_SIZE_SMALL) - ssp->srcu_size_state = SRCU_SIZE_ALLOC; + if (SRCU_SIZING_IS(SRCU_SIZING_INIT) && + ssp->srcu_sup->srcu_size_state == SRCU_SIZE_SMALL) + ssp->srcu_sup->srcu_size_state = SRCU_SIZE_ALLOC; queue_work(rcu_gp_wq, &ssp->work.work); } }