From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from [87.239.111.99] (localhost [127.0.0.1]) by dev.tarantool.org (Postfix) with ESMTP id CB8896EC55; Fri, 10 Sep 2021 18:31:16 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 dev.tarantool.org CB8896EC55 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=tarantool.org; s=dev; t=1631287876; bh=avthfEuo8eohVgKPERNRPi4JBFA2jdrM3d070s0wzH8=; h=To:Date:In-Reply-To:References:Subject:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=VY04jU7UmcsOMWdbtZBilcNN6zFPUhuy9z0fZgu4Ib0uQ4yIZ7i1+hQEGYVsGP0Vn 5m83epqg7caMqbUvhjpqcE6kw4Wgd6geRIUKInT4i527Ahd7Qht/ZplEs6RIor/FoJ 7ATA8kvYA64anSJBokLK/mjmNaCrRAHzMow389g8= Received: from mail-lf1-f50.google.com (mail-lf1-f50.google.com [209.85.167.50]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by dev.tarantool.org (Postfix) with ESMTPS id 724956EC55 for ; Fri, 10 Sep 2021 18:30:04 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 dev.tarantool.org 724956EC55 Received: by mail-lf1-f50.google.com with SMTP id k4so4809227lfj.7 for ; Fri, 10 Sep 2021 08:30:04 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=1bUaI2hoiMjOiruETiXHhzP+ZGB3vXRG/3vtnVql8OI=; b=dE8YQ4VE1EjE/Mw9IAQOdFv3/S7SBAw0LdvmFFjyf1fA+aiTEWcws6hUj5ZzYX9s85 oRj0scBWyy2Fwp6lKB8zffihidLUP0gtQOWzNiH0azh5ninxtOayerkowdHVUfOvEDOK ToHP/0zxbXvd0dpyQ1DDx0jJG3y3fKOz2FXG2ktJj1Nknsa9CDrq2PKfmfw3b2LEjPtZ uWyZfhbxKCAJbTi9QiCq52QGTEIT0iXjo3iyCHXBjXjDVlPrhYHRnt/gCPGoRh6AvzvR kqPA5ePSKLgPzRel8Y9ATone6Yeun5FzixqNVZNnLYxGzyPEmTz42rVl0dX33pBUUwnq imRA== X-Gm-Message-State: AOAM530YbvhsMgh/u3+5UwnxLW9r/GpAicb4t2xUlXcANqNHUmDabfpQ EnH+j6FbZbsrTjxyfRj7f8gBKfkd9/ySVQ== X-Google-Smtp-Source: ABdhPJya6D0hLtJyUye1HUKhgiJG2Zby6+YAU5HpQW7zjH9JZqt131M9DauRtDCdMEtA71wF4Ob/qg== X-Received: by 2002:a05:6512:c3:: with SMTP id c3mr4484361lfp.364.1631287803343; Fri, 10 Sep 2021 08:30:03 -0700 (PDT) Received: from grain.localdomain ([5.18.253.97]) by smtp.gmail.com with ESMTPSA id y3sm592398ljy.60.2021.09.10.08.30.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 10 Sep 2021 08:30:02 -0700 (PDT) Received: by grain.localdomain (Postfix, from userid 1000) id C2CF15A0022; Fri, 10 Sep 2021 18:29:11 +0300 (MSK) To: tml Date: Fri, 10 Sep 2021 18:29:08 +0300 Message-Id: <20210910152910.607398-5-gorcunov@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210910152910.607398-1-gorcunov@gmail.com> References: <20210910152910.607398-1-gorcunov@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [Tarantool-patches] [PATCH v14 4/6] qsync: order access to the limbo terms X-BeenThere: tarantool-patches@dev.tarantool.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Cyrill Gorcunov via Tarantool-patches Reply-To: Cyrill Gorcunov Cc: Vladislav Shpilevoy Errors-To: tarantool-patches-bounces@dev.tarantool.org Sender: "Tarantool-patches" Limbo terms tracking is shared between appliers and when one of appliers is waiting for write to complete inside journal_write() routine, an other may need to access read term value to figure out if promote request is valid to apply. Due to cooperative multitasking access to the terms is not consistent so we need to be sure that other fibers either read up to date terms (ie written to the WAL). For this sake we use latching mechanism, when one fiber took terms lock for updating other readers are waiting until the operation is complete. For example here is a call graph of two appliers applier 1 --------- applier_apply_tx (promote term = 3 current max term = 2) applier_synchro_filter_tx apply_synchro_row journal_write (sleeping) at this moment another applier comes in with obsolete data and term 2 applier 2 --------- applier_apply_tx (term 2) applier_synchro_filter_tx txn_limbo_is_replica_outdated -> false journal_write (sleep) applier 1 --------- journal wakes up apply_synchro_row_cb set max term to 3 So the applier 2 didn't notice that term 3 is already seen and wrote obsolete data. With locking the applier 2 will wait until applier 1 has finished its write. Part-of #6036 Signed-off-by: Cyrill Gorcunov --- src/box/applier.cc | 5 ++++- src/box/txn_limbo.c | 17 ++++++++++++++-- src/box/txn_limbo.h | 48 ++++++++++++++++++++++++++++++++++++++++----- 3 files changed, 62 insertions(+), 8 deletions(-) diff --git a/src/box/applier.cc b/src/box/applier.cc index b981bd436..845a7d015 100644 --- a/src/box/applier.cc +++ b/src/box/applier.cc @@ -857,7 +857,7 @@ apply_synchro_row_cb(struct journal_entry *entry) applier_rollback_by_wal_io(entry->res); } else { replica_txn_wal_write_cb(synchro_entry->rcb); - txn_limbo_process(&txn_limbo, synchro_entry->req); + txn_limbo_process_locked(&txn_limbo, synchro_entry->req); trigger_run(&replicaset.applier.on_wal_write, NULL); } fiber_wakeup(synchro_entry->owner); @@ -873,6 +873,7 @@ apply_synchro_row(uint32_t replica_id, struct xrow_header *row) if (xrow_decode_synchro(row, &req) != 0) goto err; + txn_limbo_term_lock(&txn_limbo); struct replica_cb_data rcb_data; struct synchro_entry entry; /* @@ -915,8 +916,10 @@ apply_synchro_row(uint32_t replica_id, struct xrow_header *row) diag_set_journal_res(entry.base.res); goto err; } + txn_limbo_term_unlock(&txn_limbo); return 0; err: + txn_limbo_term_unlock(&txn_limbo); diag_log(); return -1; } diff --git a/src/box/txn_limbo.c b/src/box/txn_limbo.c index 08463219d..65fbd0cac 100644 --- a/src/box/txn_limbo.c +++ b/src/box/txn_limbo.c @@ -47,6 +47,7 @@ txn_limbo_create(struct txn_limbo *limbo) vclock_create(&limbo->vclock); vclock_create(&limbo->promote_term_map); limbo->promote_greatest_term = 0; + latch_create(&limbo->promote_latch); limbo->confirmed_lsn = 0; limbo->rollback_count = 0; limbo->is_in_rollback = false; @@ -737,11 +738,14 @@ txn_limbo_wait_empty(struct txn_limbo *limbo, double timeout) } void -txn_limbo_process(struct txn_limbo *limbo, const struct synchro_request *req) +txn_limbo_process_locked(struct txn_limbo *limbo, + const struct synchro_request *req) { + assert(latch_is_locked(&limbo->promote_latch)); + uint64_t term = req->term; uint32_t origin = req->origin_id; - if (txn_limbo_replica_term(limbo, origin) < term) { + if (txn_limbo_replica_term_locked(limbo, origin) < term) { vclock_follow(&limbo->promote_term_map, origin, term); if (term > limbo->promote_greatest_term) limbo->promote_greatest_term = term; @@ -799,6 +803,15 @@ txn_limbo_process(struct txn_limbo *limbo, const struct synchro_request *req) return; } +void +txn_limbo_process(struct txn_limbo *limbo, + const struct synchro_request *req) +{ + txn_limbo_term_lock(limbo); + txn_limbo_process_locked(limbo, req); + txn_limbo_term_unlock(limbo); +} + void txn_limbo_on_parameters_change(struct txn_limbo *limbo) { diff --git a/src/box/txn_limbo.h b/src/box/txn_limbo.h index e0d17de4b..1ee815d1c 100644 --- a/src/box/txn_limbo.h +++ b/src/box/txn_limbo.h @@ -31,6 +31,7 @@ */ #include "small/rlist.h" #include "vclock/vclock.h" +#include "latch.h" #include @@ -147,6 +148,10 @@ struct txn_limbo { * limbo and raft are in sync and the terms are the same. */ uint64_t promote_greatest_term; + /** + * To order access to the promote data. + */ + struct latch promote_latch; /** * Maximal LSN gathered quorum and either already confirmed in WAL, or * whose confirmation is in progress right now. Any attempt to confirm @@ -217,14 +222,39 @@ txn_limbo_last_entry(struct txn_limbo *limbo) in_queue); } +/** Lock promote data. */ +static inline void +txn_limbo_term_lock(struct txn_limbo *limbo) +{ + latch_lock(&limbo->promote_latch); +} + +/** Unlock promote data. */ +static inline void +txn_limbo_term_unlock(struct txn_limbo *limbo) +{ + latch_unlock(&limbo->promote_latch); +} + +/** Fetch replica's term with lock taken. */ +static inline uint64_t +txn_limbo_replica_term_locked(struct txn_limbo *limbo, uint32_t replica_id) +{ + assert(latch_is_locked(&limbo->promote_latch)); + return vclock_get(&limbo->promote_term_map, replica_id); +} + /** * Return the latest term as seen in PROMOTE requests from instance with id * @a replica_id. */ static inline uint64_t -txn_limbo_replica_term(const struct txn_limbo *limbo, uint32_t replica_id) +txn_limbo_replica_term(struct txn_limbo *limbo, uint32_t replica_id) { - return vclock_get(&limbo->promote_term_map, replica_id); + txn_limbo_term_lock(limbo); + uint64_t v = txn_limbo_replica_term_locked(limbo, replica_id); + txn_limbo_term_unlock(limbo); + return v; } /** @@ -232,11 +262,14 @@ txn_limbo_replica_term(const struct txn_limbo *limbo, uint32_t replica_id) * data from it. The check is only valid when elections are enabled. */ static inline bool -txn_limbo_is_replica_outdated(const struct txn_limbo *limbo, +txn_limbo_is_replica_outdated(struct txn_limbo *limbo, uint32_t replica_id) { - return txn_limbo_replica_term(limbo, replica_id) < - limbo->promote_greatest_term; + txn_limbo_term_lock(limbo); + bool res = txn_limbo_replica_term_locked(limbo, replica_id) < + limbo->promote_greatest_term; + txn_limbo_term_unlock(limbo); + return res; } /** @@ -308,6 +341,11 @@ txn_limbo_wait_complete(struct txn_limbo *limbo, struct txn_limbo_entry *entry); /** Execute a synchronous replication request. */ void +txn_limbo_process_locked(struct txn_limbo *limbo, + const struct synchro_request *req); + +/** Lock limbo terms and execute a synchronous replication request. */ +void txn_limbo_process(struct txn_limbo *limbo, const struct synchro_request *req); /** -- 2.31.1