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https://gitlab.isc.org/isc-projects/bind9
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cbbecfcc82
The current isc_hp API uses internal tid_v variable that gets incremented for each new thread using hazard pointers. This tid_v variable is then used as a index to global shared table with hazard pointers state. Since the tid_v is only incremented and never decremented the table could overflow very quickly if we create set of threads for short period of time, they finish the work and cease to exist. Then we create identical set of threads and so on and so on. This is not a problem for a normal `named` operation as the set of threads is stable, but the problematic place are the unit tests where we test network manager or other APIs (task, timer) that create threads. This commits adds a thin wrapper around any function called from isc_thread_create() that adds unique-but-reusable small digit thread id that can be used as index to f.e. hazard pointer tables. The trampoline wrapper ensures that the thread ids will be reused, so the highest thread_id number doesn't grow indefinitely when threads are created and destroyed and then created again. This fixes the hazard pointer table overflow on machines with many cores. [GL #2396]
54 lines
1.4 KiB
C
54 lines
1.4 KiB
C
/*
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* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
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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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#pragma once
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#include <isc/thread.h>
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typedef struct isc__trampoline isc__trampoline_t;
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void
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isc__trampoline_initialize(void);
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/*%<
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* Initialize the thread trampoline internal structures, must be called only
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* once as a library constructor (see lib/isc/lib.c).
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*/
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void
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isc__trampoline_shutdown(void);
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/*%<
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* Destroy the thread trampoline internal structures, must be called only
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* once as a library destructor (see lib/isc/lib.c).
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*/
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isc__trampoline_t *
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isc__trampoline_get(isc_threadfunc_t start_routine, isc_threadarg_t arg);
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/*%<
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* Get a free thread trampoline structure and initialize it with
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* start_routine and arg passed to start_routine.
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*
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* Requires:
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*\li 'start_routine' is a valid non-NULL thread start_routine
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*/
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isc_threadresult_t
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isc__trampoline_run(isc_threadarg_t arg);
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/*%<
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* Run the thread trampoline, this will get passed to the actual
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* pthread_create() (or Windows equivalent), initialize the isc_tid_v.
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*
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* Requires:
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*\li 'arg' is a valid isc_trampoline_t
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*
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* Returns:
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*\li return value from start_routine (see isc__trampoline_get())
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*/
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