From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org, Lukasz Majewski <lukma@denx.de>,
Carlos O'Donell <carlos@redhat.com>
Subject: [PATCH 17/18] linux: Only use 64-bit syscall if required for internal futex
Date: Thu, 17 Jun 2021 08:51:03 -0300 [thread overview]
Message-ID: <20210617115104.1359598-18-adhemerval.zanella@linaro.org> (raw)
In-Reply-To: <20210617115104.1359598-1-adhemerval.zanella@linaro.org>
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.
---
nptl/futex-internal.c | 52 +++++++++++++++++++++++------------
sysdeps/nptl/futex-internal.h | 24 ++++++++++------
2 files changed, 50 insertions(+), 26 deletions(-)
diff --git a/nptl/futex-internal.c b/nptl/futex-internal.c
index 850bf4fd83..277e60986e 100644
--- a/nptl/futex-internal.c
+++ b/nptl/futex-internal.c
@@ -32,9 +32,6 @@ __futex_abstimed_wait_common32 (unsigned int* futex_word,
struct timespec ts32, *pts32 = NULL;
if (abstime != NULL)
{
- if (! in_time_t_range (abstime->tv_sec))
- return -EOVERFLOW;
-
ts32 = valid_timespec64_to_timespec (*abstime);
pts32 = &ts32;
}
@@ -52,12 +49,28 @@ __futex_abstimed_wait_common32 (unsigned int* futex_word,
static int
__futex_abstimed_wait_common64 (unsigned int* futex_word,
- unsigned int expected, clockid_t clockid,
+ unsigned int expected, int op,
const struct __timespec64* abstime,
int private, bool cancel)
{
- unsigned int clockbit;
+ if (cancel)
+ return INTERNAL_SYSCALL_CANCEL (futex_time64, futex_word, op, expected,
+ abstime, NULL /* Unused. */,
+ FUTEX_BITSET_MATCH_ANY);
+ else
+ return INTERNAL_SYSCALL_CALL (futex_time64, futex_word, op, expected,
+ abstime, NULL /* Ununsed. */,
+ FUTEX_BITSET_MATCH_ANY);
+}
+
+static int
+__futex_abstimed_wait_common (unsigned int* futex_word,
+ unsigned int expected, clockid_t clockid,
+ const struct __timespec64* abstime,
+ int private, bool cancel)
+{
int err;
+ unsigned int clockbit;
/* Work around the fact that the kernel rejects negative timeout values
despite them being valid. */
@@ -70,16 +83,19 @@ __futex_abstimed_wait_common64 (unsigned int* futex_word,
clockbit = (clockid == CLOCK_REALTIME) ? FUTEX_CLOCK_REALTIME : 0;
int op = __lll_private_flag (FUTEX_WAIT_BITSET | clockbit, private);
- if (cancel)
- err = INTERNAL_SYSCALL_CANCEL (futex_time64, futex_word, op, expected,
- abstime, NULL /* Unused. */,
- FUTEX_BITSET_MATCH_ANY);
+#ifdef __ASSUME_TIME64_SYSCALLS
+ err = __futex_abstimed_wait_common64 (futex_word, expected, op, abstime,
+ private, cancel);
+#else
+ bool is32bit = abstime != NULL ? in_time_t_range (abstime->tv_sec) : true;
+ if (!is32bit)
+ {
+ err = __futex_abstimed_wait_common64 (futex_word, expected, op, abstime,
+ private, cancel);
+ if (err == -ENOSYS)
+ err = -EOVERFLOW;
+ }
else
- err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word, op, expected,
- abstime, NULL /* Ununsed. */,
- FUTEX_BITSET_MATCH_ANY);
-#ifndef __ASSUME_TIME64_SYSCALLS
- if (err == -ENOSYS)
err = __futex_abstimed_wait_common32 (futex_word, expected, op, abstime,
private, cancel);
#endif
@@ -109,8 +125,8 @@ __futex_abstimed_wait64 (unsigned int* futex_word, unsigned int expected,
clockid_t clockid,
const struct __timespec64* abstime, int private)
{
- return __futex_abstimed_wait_common64 (futex_word, expected, clockid,
- abstime, private, false);
+ return __futex_abstimed_wait_common (futex_word, expected, clockid,
+ abstime, private, false);
}
libc_hidden_def (__futex_abstimed_wait64)
@@ -120,7 +136,7 @@ __futex_abstimed_wait_cancelable64 (unsigned int* futex_word,
const struct __timespec64* abstime,
int private)
{
- return __futex_abstimed_wait_common64 (futex_word, expected, clockid,
- abstime, private, true);
+ return __futex_abstimed_wait_common (futex_word, expected, clockid,
+ abstime, private, true);
}
libc_hidden_def (__futex_abstimed_wait_cancelable64)
diff --git a/sysdeps/nptl/futex-internal.h b/sysdeps/nptl/futex-internal.h
index 969ab2bf4b..b54fdd44c1 100644
--- a/sysdeps/nptl/futex-internal.h
+++ b/sysdeps/nptl/futex-internal.h
@@ -254,15 +254,23 @@ static __always_inline int
futex_lock_pi64 (int *futex_word, const struct __timespec64 *abstime,
int private)
{
- int err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word,
- __lll_private_flag
- (FUTEX_LOCK_PI, private), 0, abstime);
-#ifndef __ASSUME_TIME64_SYSCALLS
- if (err == -ENOSYS)
+ int err;
+#ifdef __ASSUME_TIME64_SYSCALLS
+ err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word,
+ __lll_private_flag (FUTEX_LOCK_PI, private), 0,
+ abstime);
+#else
+ bool is32bit = abstime != NULL ? in_time_t_range (abstime->tv_sec) : true;
+ if (!is32bit)
+ {
+ err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word,
+ __lll_private_flag (FUTEX_LOCK_PI, private),
+ 0, abstime);
+ if (err == -ENOSYS)
+ err = -EOVERFLOW;
+ }
+ else
{
- if (abstime != NULL && ! in_time_t_range (abstime->tv_sec))
- return EOVERFLOW;
-
struct timespec ts32;
if (abstime != NULL)
ts32 = valid_timespec64_to_timespec (*abstime);
--
2.30.2
next prev parent reply other threads:[~2021-06-17 11:51 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-17 11:50 [PATCH 00/18] More y2038 fixes Adhemerval Zanella
2021-06-17 11:50 ` [PATCH 01/18] Use 64 bit time_t stat internally Adhemerval Zanella
2021-06-21 7:42 ` Lukasz Majewski
2021-06-22 19:37 ` Florian Weimer
2021-06-22 19:51 ` Adhemerval Zanella
2021-06-17 11:50 ` [PATCH 02/18] Use LFS and 64 bit time for installed programs Adhemerval Zanella
2021-06-17 12:19 ` Andreas Schwab
2021-06-18 18:50 ` Adhemerval Zanella
2021-06-17 20:49 ` Joseph Myers
2021-06-18 18:14 ` Adhemerval Zanella
2021-06-17 11:50 ` [PATCH 03/18] support: Add support_create_timer Adhemerval Zanella
2021-06-21 7:42 ` Lukasz Majewski
2021-06-17 11:50 ` [PATCH 04/18] linux: Only use 64-bit syscall if required for ppoll Adhemerval Zanella
2021-06-21 7:42 ` Lukasz Majewski
2021-06-17 11:50 ` [PATCH 05/18] linux: Only use 64-bit syscall if required for pselect Adhemerval Zanella
2021-06-21 7:42 ` Lukasz Majewski
2021-06-17 11:50 ` [PATCH 06/18] linux: Only use 64-bit syscall if required for select Adhemerval Zanella
2021-06-21 7:43 ` Lukasz Majewski
2021-06-17 11:50 ` [PATCH 07/18] linux: Remove supports_time64 () from clock_getres Adhemerval Zanella
2021-06-21 7:43 ` Lukasz Majewski
2021-06-17 11:50 ` [PATCH 08/18] linux: Remove supports_time64 () from clock_gettime Adhemerval Zanella
2021-06-21 7:43 ` Lukasz Majewski
2021-06-17 11:50 ` [PATCH 09/18] linux: Remove time64-support Adhemerval Zanella
2021-06-21 7:43 ` Lukasz Majewski
2021-06-17 11:50 ` [PATCH 10/18] linux: timerfd_gettime minor cleanup Adhemerval Zanella
2021-06-21 7:43 ` Lukasz Majewski
2021-06-17 11:50 ` [PATCH 11/18] linux: Only use 64-bit syscall if required for semtimedop Adhemerval Zanella
2021-06-21 7:43 ` Lukasz Majewski
2021-06-17 11:50 ` [PATCH 12/18] linux: Only use 64-bit syscall if required for timerfd_settime Adhemerval Zanella
2021-06-21 7:44 ` Lukasz Majewski
2021-06-17 11:50 ` [PATCH 13/18] linux: Only use 64-bit syscall if required for mq_timedreceive Adhemerval Zanella
2021-06-21 7:44 ` Lukasz Majewski
2021-06-17 11:51 ` [PATCH 14/18] linux: Only use 64-bit syscall if required for mq_timedsend Adhemerval Zanella
2021-06-21 7:44 ` Lukasz Majewski
2021-06-17 11:51 ` [PATCH 15/18] linux: Only use 64-bit syscall if required for sigtimedwait Adhemerval Zanella
2021-06-17 12:25 ` Andreas Schwab
2021-06-22 14:58 ` Adhemerval Zanella
2021-06-17 11:51 ` [PATCH 16/18] linux: Only use 64-bit syscall if required for utimensat family Adhemerval Zanella
2021-06-21 7:45 ` Lukasz Majewski
2021-06-17 11:51 ` Adhemerval Zanella [this message]
2021-06-21 7:45 ` [PATCH 17/18] linux: Only use 64-bit syscall if required for internal futex Lukasz Majewski
2021-06-17 11:51 ` [PATCH 18/18] linux: Only use 64-bit syscall if required for clock_nanosleep Adhemerval Zanella
2021-06-17 15:11 ` Lukasz Majewski
2021-06-17 17:45 ` Adhemerval Zanella
2021-06-21 7:46 ` Lukasz Majewski
2021-06-17 14:20 ` [PATCH 00/18] More y2038 fixes Lukasz Majewski
2021-06-17 17:41 ` Adhemerval Zanella
2021-06-17 20:58 ` Joseph Myers
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