d284b82b3e
This doesn't have much effect on the final build, because we link libbasic.a
into libsystemd-shared.so, so in the end, all the object built from basic/
end up in libsystemd-shared. And when the static library is linked into binaries,
any objects that are included in it but are not used are trimmed. Hence, the
size of output artifacts doesn't change:
$ du -sb /var/tmp/inst*
54181861 /var/tmp/inst1 (old)
54207441 /var/tmp/inst1s (old split-usr)
54182477 /var/tmp/inst2 (new)
54208041 /var/tmp/inst2s (new split-usr)
(The negligible change in size is because libsystemd-shared.so is bigger
by a few hundred bytes. I guess it's because symbols are named differently
or something like that.)
The effect is on the build process, in particular partial builds. This change
effectively moves the requirements on some build steps toward the leaves of the
dependency tree. Two effects:
- when building items that do not depend on libsystemd-shared, we
build less stuff for libbasic.a (which wouldn't be used anyway,
so it's a net win).
- when building items that do depend on libshared, we reduce libbasic.a as a
synchronization point, possibly allowing better parallelism.
Method:
1. copy list of .h files from src/basic/meson.build to /tmp/basic
2. $ for i in $(grep '.h$' /tmp/basic); do echo $i; git --no-pager grep "include \"$i\"" src/basic/ 'src/lib*' 'src/nss-*' 'src/journal/sd-journal.c' |grep -v "${i%.h}.c";echo ;done | less
75 lines
1.8 KiB
C
75 lines
1.8 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#pragma once
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#include <stdbool.h>
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#include <stdint.h>
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#include <sys/types.h>
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#include "macro.h"
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/* See source file for an API description. */
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typedef struct Barrier Barrier;
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enum {
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BARRIER_SINGLE = 1LL,
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BARRIER_ABORTION = INT64_MAX,
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/* bias values to store state; keep @WE < @THEY < @I */
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BARRIER_BIAS = INT64_MIN,
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BARRIER_WE_ABORTED = BARRIER_BIAS + 1LL,
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BARRIER_THEY_ABORTED = BARRIER_BIAS + 2LL,
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BARRIER_I_ABORTED = BARRIER_BIAS + 3LL,
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};
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enum {
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BARRIER_PARENT,
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BARRIER_CHILD,
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};
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struct Barrier {
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int me;
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int them;
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int pipe[2];
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int64_t barriers;
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};
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#define BARRIER_NULL {-1, -1, {-1, -1}, 0}
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int barrier_create(Barrier *obj);
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void barrier_destroy(Barrier *b);
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DEFINE_TRIVIAL_CLEANUP_FUNC(Barrier*, barrier_destroy);
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void barrier_set_role(Barrier *b, unsigned role);
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bool barrier_place(Barrier *b);
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bool barrier_abort(Barrier *b);
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bool barrier_wait_next(Barrier *b);
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bool barrier_wait_abortion(Barrier *b);
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bool barrier_sync_next(Barrier *b);
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bool barrier_sync(Barrier *b);
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static inline bool barrier_i_aborted(Barrier *b) {
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return IN_SET(b->barriers, BARRIER_I_ABORTED, BARRIER_WE_ABORTED);
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}
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static inline bool barrier_they_aborted(Barrier *b) {
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return IN_SET(b->barriers, BARRIER_THEY_ABORTED, BARRIER_WE_ABORTED);
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}
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static inline bool barrier_we_aborted(Barrier *b) {
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return b->barriers == BARRIER_WE_ABORTED;
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}
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static inline bool barrier_is_aborted(Barrier *b) {
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return IN_SET(b->barriers,
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BARRIER_I_ABORTED, BARRIER_THEY_ABORTED, BARRIER_WE_ABORTED);
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}
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static inline bool barrier_place_and_sync(Barrier *b) {
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(void) barrier_place(b);
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return barrier_sync(b);
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}
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