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33237fe83d
And make always supported. The configure option was added on glibc 2.25 and some features require it (such as hwcap mask, huge pages support, and lock elisition tuning). It also simplifies the build permutations. Changes from v1: * Remove glibc.rtld.dynamic_sort changes, it is orthogonal and needs more discussion. * Cleanup more code. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
140 lines
4.7 KiB
C++
140 lines
4.7 KiB
C++
/* The tunable framework. See the README to know how to use the tunable in
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a glibc module.
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Copyright (C) 2016-2023 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _TUNABLES_H_
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#define _TUNABLES_H_
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdint.h>
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typedef intmax_t tunable_num_t;
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typedef union
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{
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tunable_num_t numval;
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const char *strval;
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} tunable_val_t;
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typedef void (*tunable_callback_t) (tunable_val_t *);
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/* Full name for a tunable is top_ns.tunable_ns.id. */
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#define TUNABLE_NAME_S(top,ns,id) #top "." #ns "." #id
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#define TUNABLE_ENUM_NAME(__top,__ns,__id) TUNABLE_ENUM_NAME1 (__top,__ns,__id)
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#define TUNABLE_ENUM_NAME1(__top,__ns,__id) __top ## _ ## __ns ## _ ## __id
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#include "dl-tunable-list.h"
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extern void __tunables_init (char **);
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extern void __tunables_print (void);
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extern void __tunable_get_val (tunable_id_t, void *, tunable_callback_t);
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extern void __tunable_set_val (tunable_id_t, tunable_val_t *, tunable_num_t *,
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tunable_num_t *);
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rtld_hidden_proto (__tunables_init)
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rtld_hidden_proto (__tunables_print)
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rtld_hidden_proto (__tunable_get_val)
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rtld_hidden_proto (__tunable_set_val)
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/* Define TUNABLE_GET and TUNABLE_SET in short form if TOP_NAMESPACE and
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TUNABLE_NAMESPACE are defined. This is useful shorthand to get and set
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tunables within a module. */
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#if defined TOP_NAMESPACE && defined TUNABLE_NAMESPACE
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# define TUNABLE_GET(__id, __type, __cb) \
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TUNABLE_GET_FULL (TOP_NAMESPACE, TUNABLE_NAMESPACE, __id, __type, __cb)
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# define TUNABLE_SET(__id, __val) \
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TUNABLE_SET_FULL (TOP_NAMESPACE, TUNABLE_NAMESPACE, __id, __val)
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# define TUNABLE_SET_WITH_BOUNDS(__id, __val, __min, __max) \
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TUNABLE_SET_WITH_BOUNDS_FULL (TOP_NAMESPACE, TUNABLE_NAMESPACE, __id, \
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__val, __min, __max)
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#else
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# define TUNABLE_GET(__top, __ns, __id, __type, __cb) \
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TUNABLE_GET_FULL (__top, __ns, __id, __type, __cb)
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# define TUNABLE_SET(__top, __ns, __id, __val) \
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TUNABLE_SET_FULL (__top, __ns, __id, __val)
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# define TUNABLE_SET_WITH_BOUNDS(__top, __ns, __id, __val, __min, __max) \
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TUNABLE_SET_WITH_BOUNDS_FULL (__top, __ns, __id, __val, __min, __max)
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#endif
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/* Get and return a tunable value. If the tunable was set externally and __CB
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is defined then call __CB before returning the value. */
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#define TUNABLE_GET_FULL(__top, __ns, __id, __type, __cb) \
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({ \
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tunable_id_t id = TUNABLE_ENUM_NAME (__top, __ns, __id); \
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__type ret; \
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__tunable_get_val (id, &ret, __cb); \
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ret; \
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})
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/* Set a tunable value. */
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#define TUNABLE_SET_FULL(__top, __ns, __id, __val) \
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({ \
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__tunable_set_val (TUNABLE_ENUM_NAME (__top, __ns, __id), \
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& (tunable_val_t) {.numval = __val}, NULL, NULL); \
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})
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/* Set a tunable value together with min/max values. */
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#define TUNABLE_SET_WITH_BOUNDS_FULL(__top, __ns, __id,__val, __min, __max) \
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({ \
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__tunable_set_val (TUNABLE_ENUM_NAME (__top, __ns, __id), \
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& (tunable_val_t) {.numval = __val}, \
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& (tunable_num_t) {__min}, \
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& (tunable_num_t) {__max}); \
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})
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/* Namespace sanity for callback functions. Use this macro to keep the
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namespace of the modules clean. */
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#define TUNABLE_CALLBACK(__name) _dl_tunable_ ## __name
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static __always_inline bool
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tunable_val_lt (tunable_num_t lhs, tunable_num_t rhs, bool unsigned_cmp)
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{
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if (unsigned_cmp)
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return (uintmax_t) lhs < (uintmax_t) rhs;
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else
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return lhs < rhs;
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}
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static __always_inline bool
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tunable_val_gt (tunable_num_t lhs, tunable_num_t rhs, bool unsigned_cmp)
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{
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if (unsigned_cmp)
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return (uintmax_t) lhs > (uintmax_t) rhs;
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else
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return lhs > rhs;
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}
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/* Compare two name strings, bounded by the name hardcoded in glibc. */
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static __always_inline bool
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tunable_is_name (const char *orig, const char *envname)
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{
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for (;*orig != '\0' && *envname != '\0'; envname++, orig++)
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if (*orig != *envname)
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break;
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/* The ENVNAME is immediately followed by a value. */
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if (*orig == '\0' && *envname == '=')
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return true;
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else
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return false;
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}
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#endif
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