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linux: Only use 64-bit syscall if required for clock_nanosleep

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For !__ASSUME_TIME64_SYSCALLS there is no need to issue a 64-bit syscall
if the provided timeout fits in a 32-bit one.  The 64-bit usage should
be rare since the timeout is a relative one.

Checked on i686-linux-gnu on a 4.15 kernel and on a 5.11 kernel
(with and without --enable-kernel=5.1) and on x86_64-linux-gnu.

Reviewed-by: Lukasz Majewski <lukma@denx.de>
This commit is contained in:
Adhemerval Zanella 2021-06-16 11:12:25 -03:00
parent b769b0a2cb
commit 6d97330d7a
3 changed files with 59 additions and 36 deletions
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46
sysdeps/unix/sysv/linux/clock_nanosleep.c
View File

@ -27,8 +27,9 @@
/* We can simply use the syscall. The CPU clocks are not supported
with this function. */
int
__clock_nanosleep_time64 (clockid_t clock_id, int flags, const struct __timespec64 *req,
struct __timespec64 *rem)
__clock_nanosleep_time64 (clockid_t clock_id, int flags,
const struct __timespec64 *req,
struct __timespec64 *rem)
{
if (clock_id == CLOCK_THREAD_CPUTIME_ID)
return EINVAL;
@ -37,33 +38,36 @@ __clock_nanosleep_time64 (clockid_t clock_id, int flags, const struct __timespec
/* If the call is interrupted by a signal handler or encounters an error,
it returns a positive value similar to errno. */
#ifndef __NR_clock_nanosleep_time64
# define __NR_clock_nanosleep_time64 __NR_clock_nanosleep
#endif
int r = INTERNAL_SYSCALL_CANCEL (clock_nanosleep_time64, clock_id,
flags, req, rem);
#ifndef __ASSUME_TIME64_SYSCALLS
if (r == 0 || r != -ENOSYS)
return -r;
if (! in_time_t_range (req->tv_sec))
int r;
#ifdef __ASSUME_TIME64_SYSCALLS
r = INTERNAL_SYSCALL_CANCEL (clock_nanosleep_time64, clock_id, flags, req,
rem);
#else
if (!in_time_t_range (req->tv_sec))
{
__set_errno (EOVERFLOW);
return -1;
r = INTERNAL_SYSCALL_CANCEL (clock_nanosleep_time64, clock_id, flags,
req, rem);
if (r == -ENOSYS)
r = -EOVERFLOW;
}
struct timespec tr32;
struct timespec ts32 = valid_timespec64_to_timespec (*req);
r = INTERNAL_SYSCALL_CANCEL (clock_nanosleep, clock_id, flags,
&ts32, &tr32);
if (INTERNAL_SYSCALL_ERROR_P (r))
else
{
if (r == -EINTR && rem != NULL && (flags & TIMER_ABSTIME) == 0)
*rem = valid_timespec_to_timespec64 (tr32);
struct timespec tr32;
struct timespec ts32 = valid_timespec64_to_timespec (*req);
r = INTERNAL_SYSCALL_CANCEL (clock_nanosleep, clock_id, flags, &ts32,
&tr32);
if (INTERNAL_SYSCALL_ERROR_P (r))
{
if (r == -EINTR && rem != NULL && (flags & TIMER_ABSTIME) == 0)
*rem = valid_timespec_to_timespec64 (tr32);
}
}
#endif /* __ASSUME_TIME64_SYSCALLS */
#endif
return -r;
}

9
time/Makefile
View File

@ -86,6 +86,15 @@ $(objpfx)tst-strftime2.out: $(gen-locales)
$(objpfx)tst-strftime3.out: $(gen-locales)
endif
ifeq (yes,$(build-shared))
librt = $(common-objpfx)rt/librt.so
else
librt = $(common-objpfx)rt/librt.a
endif
$(objpfx)tst-clock_nanosleep: $(librt)
$(objpfx)tst-clock_nanosleep-time64: $(librt)
tz-cflags = -DTZDIR='"$(zonedir)"' \
-DTZDEFAULT='"$(localtime-file)"' \
-DTZDEFRULES='"$(posixrules-file)"'

40
time/tst-clock_nanosleep.c
View File

@ -20,38 +20,48 @@
#include <unistd.h>
#include <sys/time.h>
#include <time.h>
#include <intprops.h>
#include <support/support.h>
#include <support/check.h>
/* Test that clock_nanosleep() does sleep. */
static int
do_test (void)
static void
clock_nanosleep_test (void)
{
/* Current time. */
struct timeval tv1;
(void) gettimeofday (&tv1, NULL);
gettimeofday (&tv1, NULL);
struct timespec ts;
ts.tv_sec = 1;
ts.tv_nsec = 0;
struct timespec ts = { 1, 0 };
TEMP_FAILURE_RETRY (clock_nanosleep (CLOCK_REALTIME, 0, &ts, &ts));
/* At least one second must have passed. */
struct timeval tv2;
(void) gettimeofday (&tv2, NULL);
gettimeofday (&tv2, NULL);
tv2.tv_sec -= tv1.tv_sec;
tv2.tv_usec -= tv1.tv_usec;
if (tv2.tv_usec < 0)
--tv2.tv_sec;
if (tv2.tv_sec < 1)
{
puts ("clock_nanosleep didn't sleep long enough");
return 1;
}
TEST_VERIFY (tv2.tv_sec >= 1);
}
static void
clock_nanosleep_large_timeout (void)
{
support_create_timer (0, 100000000, false, NULL);
struct timespec ts = { TYPE_MAXIMUM (time_t), 0 };
int r = clock_nanosleep (CLOCK_REALTIME, 0, &ts, NULL);
TEST_VERIFY (r == EINTR || r == EOVERFLOW);
}
static int
do_test (void)
{
clock_nanosleep_test ();
clock_nanosleep_large_timeout ();
return 0;
}
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"
#include <support/test-driver.c>