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Use initalization instead of explicit zeroing

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Before, we would initialize many fields twice: first
by filling the structure with zeros, and then a second
time with the real values. We can let the compiler do
the job for us, avoiding one copy.

A downside of this patch is that text gets slightly
bigger. This is because all zero() calls are effectively
inlined:

$ size build/.libs/systemd
         text    data     bss     dec     hex filename
before 897737  107300    2560 1007597   f5fed build/.libs/systemd
after  897873  107300    2560 1007733   f6075 build/.libs/systemd

… actually less than 1‰.

A few asserts that the parameter is not null had to be removed. I
don't think this changes much, because first, it is quite unlikely
for the assert to fail, and second, an immediate SEGV is almost as
good as an assert.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek
2013-04-05 19:50:57 -04:00
parent 8c62ecf1a9
commit b92bea5d2a
49 changed files with 392 additions and 554 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/core/unit.c
+9 -13
View File
@@ -1520,17 +1520,16 @@ void unit_notify(Unit *u, UnitActiveState os, UnitActiveState ns, bool reload_su
}
int unit_watch_fd(Unit *u, int fd, uint32_t events, Watch *w) {
struct epoll_event ev;
struct epoll_event ev = {
.data.ptr = w,
.events = events,
};
assert(u);
assert(fd >= 0);
assert(w);
assert(w->type == WATCH_INVALID || (w->type == WATCH_FD && w->fd == fd && w->data.unit == u));
zero(ev);
ev.data.ptr = w;
ev.events = events;
if (epoll_ctl(u->manager->epoll_fd,
w->type == WATCH_INVALID ? EPOLL_CTL_ADD : EPOLL_CTL_MOD,
fd,
@@ -1578,7 +1577,7 @@ void unit_unwatch_pid(Unit *u, pid_t pid) {
}
int unit_watch_timer(Unit *u, clockid_t clock_id, bool relative, usec_t usec, Watch *w) {
struct itimerspec its;
struct itimerspec its = {};
int flags, fd;
bool ours;
@@ -1603,8 +1602,6 @@ int unit_watch_timer(Unit *u, clockid_t clock_id, bool relative, usec_t usec, Wa
} else
assert_not_reached("Invalid watch type");
zero(its);
if (usec <= 0) {
/* Set absolute time in the past, but not 0, since we
* don't want to disarm the timer */
@@ -1622,11 +1619,10 @@ int unit_watch_timer(Unit *u, clockid_t clock_id, bool relative, usec_t usec, Wa
goto fail;
if (w->type == WATCH_INVALID) {
struct epoll_event ev;
zero(ev);
ev.data.ptr = w;
ev.events = EPOLLIN;
struct epoll_event ev = {
.data.ptr = w,
.events = EPOLLIN,
};
if (epoll_ctl(u->manager->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0)
goto fail;