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 743356FC82; Thu, 30 Sep 2021 12:45:52 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 dev.tarantool.org 743356FC82 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=tarantool.org; s=dev; t=1632995152; bh=Uw+epFlnHLE47//3nqYS3x/llhzNS26olx986HvWNKA=; 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=FabCvRgGY3QVLaLTb+5NeCA5vLgulYx770G2QGsJBWzcxaP1nBAA+7KJcrZ49BDl/ VBxLIUqmpnUQwmWIDqI2w1P7MTkJOO9iX9wNL8NsZ3+BW3rV4qw/jfOS814qXU2mxf 4KgeU6brG2TPbRYY6tBI2IA19eDXqjyHl5yMpvjo= Received: from mail-lf1-f51.google.com (mail-lf1-f51.google.com [209.85.167.51]) (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 9CF216FC82 for ; Thu, 30 Sep 2021 12:45:13 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 dev.tarantool.org 9CF216FC82 Received: by mail-lf1-f51.google.com with SMTP id j5so17942086lfg.8 for ; Thu, 30 Sep 2021 02:45:13 -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=d2cvxQCDFNYJ71gOENNCsBBdAH1jRAL5uTZBgYgG86I=; b=3TznIenML7uvqnV/d/D82Wq+DPpiwKg4JeTJ84Xkn6z5SL4gvNqH0qme5LhMpwfaoB 6gCiQwgIYj2ahqX4F8ut4hQLHuCIKq+U4sk5W++Mvs8EBQlo/ZzoA4iBdUBDjJS7CoMe 4/xJPuAaMHhZNmbUd3IsVUWRX2VLy5GaIhmfEMM1iMPsHDEGAlU8Ce6pCbZoFG5J16N1 0ZEihl4nb9PFIzZd9ZR+IDcPabfy1eE/5Nnpc7YtN8Z/TpjWoXmGJafp1B7eR+VJ3o69 yUSMAN+uQvgNTDm7V3wgictbvdE/6POQ5qNhjjsGW9CjdsbZFEoG4IFk7y3vMx+EG3tz hRsA== X-Gm-Message-State: AOAM533czeEhmJX5Rfd3LcuyU/m2aLPDsrmxU/H2bZEfcSqAmDk/7OKT 6tuicLL5YZ68if4DbC5+iUR6ZCuwV8tP7A== X-Google-Smtp-Source: ABdhPJzvz5tX2T5AbFHIxOtfkIRG/NTMg2gK/+bZSYXmyH+r2aatuGmHmPJ4qP8o36Q2M4/i4Xzv9w== X-Received: by 2002:ac2:4e98:: with SMTP id o24mr4640210lfr.295.1632995112529; Thu, 30 Sep 2021 02:45:12 -0700 (PDT) Received: from grain.localdomain ([5.18.253.97]) by smtp.gmail.com with ESMTPSA id j13sm343284lfm.100.2021.09.30.02.45.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Sep 2021 02:45:11 -0700 (PDT) Received: by grain.localdomain (Postfix, from userid 1000) id 679AE5A0020; Thu, 30 Sep 2021 12:44:46 +0300 (MSK) To: tml Date: Thu, 30 Sep 2021 12:44:44 +0300 Message-Id: <20210930094445.316694-3-gorcunov@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210930094445.316694-1-gorcunov@gmail.com> References: <20210930094445.316694-1-gorcunov@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [Tarantool-patches] [PATCH v19 2/3] 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 read up to date terms (ie written to the WAL). For this sake we use a latching mechanism, when one fiber takes a 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. We introduce the following helpers: 1) txn_limbo_process_begin: which takes a lock 2) txn_limbo_process_commit and txn_limbo_process_rollback which simply release the lock but have different names for better semantics 3) txn_limbo_process is a general function which uses x_begin and x_commit helper internally 4) txn_limbo_process_core to do a real job over processing the request, it implies that txn_limbo_process_begin been called Part-of #6036 Signed-off-by: Cyrill Gorcunov --- src/box/applier.cc | 12 +++++++--- src/box/box.cc | 15 ++++++++----- src/box/txn_limbo.c | 17 +++++++++++++-- src/box/txn_limbo.h | 53 ++++++++++++++++++++++++++++++++++++++++----- 4 files changed, 80 insertions(+), 17 deletions(-) diff --git a/src/box/applier.cc b/src/box/applier.cc index b981bd436..46c36e259 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_core(&txn_limbo, synchro_entry->req); trigger_run(&replicaset.applier.on_wal_write, NULL); } fiber_wakeup(synchro_entry->owner); @@ -873,6 +873,8 @@ apply_synchro_row(uint32_t replica_id, struct xrow_header *row) if (xrow_decode_synchro(row, &req) != 0) goto err; + txn_limbo_process_begin(&txn_limbo); + struct replica_cb_data rcb_data; struct synchro_entry entry; /* @@ -910,12 +912,16 @@ apply_synchro_row(uint32_t replica_id, struct xrow_header *row) * transactions side, including the async ones. */ if (journal_write(&entry.base) != 0) - goto err; + goto err_rollback; if (entry.base.res < 0) { diag_set_journal_res(entry.base.res); - goto err; + goto err_rollback; } + txn_limbo_process_commit(&txn_limbo); return 0; + +err_rollback: + txn_limbo_process_rollback(&txn_limbo); err: diag_log(); return -1; diff --git a/src/box/box.cc b/src/box/box.cc index e082e1a3d..6a9be745a 100644 --- a/src/box/box.cc +++ b/src/box/box.cc @@ -1677,8 +1677,6 @@ box_issue_promote(uint32_t prev_leader_id, int64_t promote_lsn) struct raft *raft = box_raft(); assert(raft->volatile_term == raft->term); assert(promote_lsn >= 0); - txn_limbo_write_promote(&txn_limbo, promote_lsn, - raft->term); struct synchro_request req = { .type = IPROTO_RAFT_PROMOTE, .replica_id = prev_leader_id, @@ -1686,8 +1684,11 @@ box_issue_promote(uint32_t prev_leader_id, int64_t promote_lsn) .lsn = promote_lsn, .term = raft->term, }; - txn_limbo_process(&txn_limbo, &req); + txn_limbo_process_begin(&txn_limbo); + txn_limbo_write_promote(&txn_limbo, req.lsn, req.term); + txn_limbo_process_core(&txn_limbo, &req); assert(txn_limbo_is_empty(&txn_limbo)); + txn_limbo_process_commit(&txn_limbo); } /** A guard to block multiple simultaneous promote()/demote() invocations. */ @@ -1699,8 +1700,6 @@ box_issue_demote(uint32_t prev_leader_id, int64_t promote_lsn) { assert(box_raft()->volatile_term == box_raft()->term); assert(promote_lsn >= 0); - txn_limbo_write_demote(&txn_limbo, promote_lsn, - box_raft()->term); struct synchro_request req = { .type = IPROTO_RAFT_DEMOTE, .replica_id = prev_leader_id, @@ -1708,8 +1707,12 @@ box_issue_demote(uint32_t prev_leader_id, int64_t promote_lsn) .lsn = promote_lsn, .term = box_raft()->term, }; - txn_limbo_process(&txn_limbo, &req); + txn_limbo_process_begin(&txn_limbo); + txn_limbo_write_demote(&txn_limbo, promote_lsn, + box_raft()->term); + txn_limbo_process_core(&txn_limbo, &req); assert(txn_limbo_is_empty(&txn_limbo)); + txn_limbo_process_commit(&txn_limbo); } int diff --git a/src/box/txn_limbo.c b/src/box/txn_limbo.c index 70447caaf..855c98c98 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; @@ -724,11 +725,14 @@ 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_core(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 (vclock_get(&limbo->promote_term_map, origin) < (int64_t)term) { vclock_follow(&limbo->promote_term_map, origin, term); if (term > limbo->promote_greatest_term) limbo->promote_greatest_term = term; @@ -786,6 +790,15 @@ 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_process_begin(limbo); + txn_limbo_process_core(limbo, req); + txn_limbo_process_commit(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 53e52f676..fdb214711 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 @@ -216,9 +221,12 @@ txn_limbo_last_entry(struct txn_limbo *limbo) * @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); + latch_lock(&limbo->promote_latch); + uint64_t v = vclock_get(&limbo->promote_term_map, replica_id); + latch_unlock(&limbo->promote_latch); + return v; } /** @@ -226,11 +234,14 @@ 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; + latch_lock(&limbo->promote_latch); + uint64_t v = vclock_get(&limbo->promote_term_map, replica_id); + bool res = v < limbo->promote_greatest_term; + latch_unlock(&limbo->promote_latch); + return res; } /** @@ -300,7 +311,37 @@ txn_limbo_ack(struct txn_limbo *limbo, uint32_t replica_id, int64_t lsn); int txn_limbo_wait_complete(struct txn_limbo *limbo, struct txn_limbo_entry *entry); -/** Execute a synchronous replication request. */ +/** + * Initiate execution of a synchronous replication request. + */ +static inline void +txn_limbo_process_begin(struct txn_limbo *limbo) +{ + latch_lock(&limbo->promote_latch); +} + +/** Commit a synchronous replication request. */ +static inline void +txn_limbo_process_commit(struct txn_limbo *limbo) +{ + assert(latch_is_locked(&limbo->promote_latch)); + latch_unlock(&limbo->promote_latch); +} + +/** Rollback a synchronous replication request. */ +static inline void +txn_limbo_process_rollback(struct txn_limbo *limbo) +{ + assert(latch_is_locked(&limbo->promote_latch)); + latch_unlock(&limbo->promote_latch); +} + +/** Core of processing synchronous replication request. */ +void +txn_limbo_process_core(struct txn_limbo *limbo, + const struct synchro_request *req); + +/** Process a synchronous replication request. */ void txn_limbo_process(struct txn_limbo *limbo, const struct synchro_request *req); -- 2.31.1