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https://gitlab.isc.org/isc-projects/bind9
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25daa047d4
Qpzone employs a locking strategy where rwlocks are grouped into buckets, and each zone gets 17 buckets. This strategy is suboptimal in two ways: - If named is serving a single zone or a zone is the majority of the traffic, this strategy pretty much guarantees contention when using more than a dozen threads. - If named is serving many small zones, it causes substantial memory usage. This commit switches the locking to a global table initialized at start time. This should have three effects: - Performance should improve in the single zone case, since now we are selecting from a bigger pool of locks. - Memory consumption should go down significantly in the many zone cases. - Performance should not degrade substantially in the many zone cases. The reason for this is that, while we could have substantially more zones than locks, we can query/edit only O(num threads) at the same time. So by making the global table much bigger than the expected number of threads, we can limit contention.
67 lines
1.3 KiB
C
67 lines
1.3 KiB
C
/*
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* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
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*
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* SPDX-License-Identifier: MPL-2.0
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, you can obtain one at https://mozilla.org/MPL/2.0/.
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*
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* See the COPYRIGHT file distributed with this work for additional
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* information regarding copyright ownership.
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*/
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/*! \file */
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#include <isc/once.h>
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#include <isc/refcount.h>
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#include "acl_p.h"
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#include "db_p.h"
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#include "dlz_p.h"
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#include "dst_internal.h"
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#include "dyndb_p.h"
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#include "qp_p.h"
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#include "qpzone_p.h"
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/***
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*** Functions
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***/
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static isc_refcount_t dns__lib_references = 0;
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void
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dns__lib_initialize(void);
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void
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dns__lib_shutdown(void);
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void
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dns__lib_initialize(void) {
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if (isc_refcount_increment0(&dns__lib_references) > 0) {
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return;
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}
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dst__lib_initialize();
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dns__acl_initialize();
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dns__dlz_initialize();
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dns__db_initialize();
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dns__dyndb_initialize();
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dns__qp_initialize();
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dns__qpzone_initialize();
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}
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void
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dns__lib_shutdown(void) {
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if (isc_refcount_decrement(&dns__lib_references) > 1) {
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return;
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}
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dns__qpzone_shutdown();
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dns__qp_shutdown();
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dns__dyndb_shutdown();
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dns__db_shutdown();
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dns__dlz_shutdown();
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dns__acl_shutdown();
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dst__lib_shutdown();
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}
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