From patchwork Tue Oct 13 19:04:15 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "H.J. Lu" X-Patchwork-Id: 9092 Received: (qmail 61975 invoked by alias); 13 Oct 2015 19:04:20 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 61959 invoked by uid 89); 13 Oct 2015 19:04:19 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-0.1 required=5.0 tests=AWL, BAYES_50, FREEMAIL_FROM, RCVD_IN_DNSWL_LOW, SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-oi0-f43.google.com MIME-Version: 1.0 X-Received: by 10.202.2.133 with SMTP id 127mr19353611oic.108.1444763055985; Tue, 13 Oct 2015 12:04:15 -0700 (PDT) In-Reply-To: <20151012231958.GA8797@intel.com> References: <20151012231958.GA8797@intel.com> Date: Tue, 13 Oct 2015 12:04:15 -0700 Message-ID: Subject: Re: [PATCH 3/6] Avoid reading errno in syscall implementations From: "H.J. Lu" To: GNU C Library On Mon, Oct 12, 2015 at 4:19 PM, H.J. Lu wrote: > Reading errno is expensive for x86 PIC. With INTERNAL_SYSCALL, > INTERNAL_SYSCALL_ERROR_P, INTERNAL_SYSCALL_ERRNO and > INLINE_SYSCALL_ERROR_RETURN, we can avoid reading errno. > > * sysdeps/unix/sysv/linux/eventfd.c (eventfd): Use > INTERNAL_SYSCALL, INTERNAL_SYSCALL_ERROR_P and > INTERNAL_SYSCALL_ERRNO to avoid reading errno. > * sysdeps/unix/sysv/linux/fstatfs64.c (__fstatfs64): Likewise. > * sysdeps/unix/sysv/linux/getrlimit64.c (__getrlimit64): > Likewise. > * sysdeps/unix/sysv/linux/setrlimit64.c (setrlimit64): > Likewise. > * sysdeps/unix/sysv/linux/signalfd.c (signalfd): Likewise. > * sysdeps/unix/sysv/linux/statfs64.c (__statfs64): Likewise. First 2 patches have been checked into master. Here is the updated patch. There is no code change in libc.so on x86-64. OK for master? Thanks. From 4e66aee3711050ae863076542cf94a6e6367c665 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Fri, 21 Aug 2015 14:46:05 -0700 Subject: [PATCH 3/6] Avoid reading errno in syscall implementations Reading errno is expensive for x86 PIC. With INTERNAL_SYSCALL, INTERNAL_SYSCALL_ERROR_P, INTERNAL_SYSCALL_ERRNO and INLINE_SYSCALL_ERROR_RETURN_VALUE, we can avoid reading errno. * sysdeps/unix/sysv/linux/eventfd.c (eventfd): Use INTERNAL_SYSCALL, INTERNAL_SYSCALL_ERROR_P and INTERNAL_SYSCALL_ERRNO to avoid reading errno. * sysdeps/unix/sysv/linux/fstatfs64.c (__fstatfs64): Likewise. * sysdeps/unix/sysv/linux/getrlimit64.c (__getrlimit64): Likewise. * sysdeps/unix/sysv/linux/setrlimit64.c (setrlimit64): Likewise. * sysdeps/unix/sysv/linux/signalfd.c (signalfd): Likewise. * sysdeps/unix/sysv/linux/statfs64.c (__statfs64): Likewise. --- sysdeps/unix/sysv/linux/eventfd.c | 10 +++++++--- sysdeps/unix/sysv/linux/fstatfs64.c | 12 ++++++++---- sysdeps/unix/sysv/linux/getrlimit64.c | 7 +++++-- sysdeps/unix/sysv/linux/lxstat64.c | 7 +++++-- sysdeps/unix/sysv/linux/setrlimit64.c | 7 +++++-- sysdeps/unix/sysv/linux/signalfd.c | 11 ++++++++--- sysdeps/unix/sysv/linux/statfs64.c | 13 +++++++++---- 7 files changed, 47 insertions(+), 20 deletions(-) diff --git a/sysdeps/unix/sysv/linux/eventfd.c b/sysdeps/unix/sysv/linux/eventfd.c index efce282..a13be32 100644 --- a/sysdeps/unix/sysv/linux/eventfd.c +++ b/sysdeps/unix/sysv/linux/eventfd.c @@ -25,11 +25,15 @@ int eventfd (unsigned int count, int flags) { #ifdef __NR_eventfd2 - int res = INLINE_SYSCALL (eventfd2, 2, count, flags); # ifndef __ASSUME_EVENTFD2 - if (res != -1 || errno != ENOSYS) -# endif + INTERNAL_SYSCALL_DECL (err); + int res = INTERNAL_SYSCALL (eventfd2, err, 2, count, flags); + if (!__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (res, err)) + || INTERNAL_SYSCALL_ERRNO (res, err) != ENOSYS) return res; +# else + return INLINE_SYSCALL (eventfd2, 2, count, flags); +# endif #endif #ifndef __ASSUME_EVENTFD2 diff --git a/sysdeps/unix/sysv/linux/fstatfs64.c b/sysdeps/unix/sysv/linux/fstatfs64.c index af83830..eb21d42 100644 --- a/sysdeps/unix/sysv/linux/fstatfs64.c +++ b/sysdeps/unix/sysv/linux/fstatfs64.c @@ -35,12 +35,16 @@ __fstatfs64 (int fd, struct statfs64 *buf) if (! __no_statfs64) # endif { - int result = INLINE_SYSCALL (fstatfs64, 3, fd, sizeof (*buf), buf); - # if __ASSUME_STATFS64 == 0 - if (result == 0 || errno != ENOSYS) -# endif + INTERNAL_SYSCALL_DECL (err); + int result = INTERNAL_SYSCALL (fstatfs64, err, 3, fd, + sizeof (*buf), buf); + if (!__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result, err)) + || INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS) return result; +# else + return INLINE_SYSCALL (fstatfs64, 3, fd, sizeof (*buf), buf); +# endif # if __ASSUME_STATFS64 == 0 __no_statfs64 = 1; diff --git a/sysdeps/unix/sysv/linux/getrlimit64.c b/sysdeps/unix/sysv/linux/getrlimit64.c index 100ba62..cca1265 100644 --- a/sysdeps/unix/sysv/linux/getrlimit64.c +++ b/sysdeps/unix/sysv/linux/getrlimit64.c @@ -30,8 +30,11 @@ __getrlimit64 (enum __rlimit_resource resource, struct rlimit64 *rlimits) return INLINE_SYSCALL (prlimit64, 4, 0, resource, NULL, rlimits); #else # ifdef __NR_prlimit64 - int res = INLINE_SYSCALL (prlimit64, 4, 0, resource, NULL, rlimits); - if (res == 0 || errno != ENOSYS) + INTERNAL_SYSCALL_DECL (err); + int res = INTERNAL_SYSCALL (prlimit64, err, 4, 0, resource, NULL, + rlimits); + if (!__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (res, err)) + || INTERNAL_SYSCALL_ERRNO (res, err) != ENOSYS) return res; # endif struct rlimit rlimits32; diff --git a/sysdeps/unix/sysv/linux/lxstat64.c b/sysdeps/unix/sysv/linux/lxstat64.c index 5d0c051..63959cf 100644 --- a/sysdeps/unix/sysv/linux/lxstat64.c +++ b/sysdeps/unix/sysv/linux/lxstat64.c @@ -30,8 +30,11 @@ int ___lxstat64 (int vers, const char *name, struct stat64 *buf) { - int result; - result = INLINE_SYSCALL (lstat64, 2, name, buf); + INTERNAL_SYSCALL_DECL (err); + int result = INTERNAL_SYSCALL (lstat64, err, 2, name, buf); + if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result, err))) + return INLINE_SYSCALL_ERROR_RETURN_VALUE (INTERNAL_SYSCALL_ERRNO (result, + err)); #if defined _HAVE_STAT64___ST_INO && __ASSUME_ST_INO_64_BIT == 0 if (__builtin_expect (!result, 1) && buf->__st_ino != (__ino_t) buf->st_ino) buf->st_ino = buf->__st_ino; diff --git a/sysdeps/unix/sysv/linux/setrlimit64.c b/sysdeps/unix/sysv/linux/setrlimit64.c index 17f95cb..33e1500 100644 --- a/sysdeps/unix/sysv/linux/setrlimit64.c +++ b/sysdeps/unix/sysv/linux/setrlimit64.c @@ -33,8 +33,11 @@ setrlimit64 (resource, rlimits) return INLINE_SYSCALL (prlimit64, 4, 0, resource, rlimits, NULL); #else # ifdef __NR_prlimit64 - int res = INLINE_SYSCALL (prlimit64, 4, 0, resource, rlimits, NULL); - if (res == 0 || errno != ENOSYS) + INTERNAL_SYSCALL_DECL (err); + int res = INTERNAL_SYSCALL (prlimit64, err, 4, 0, resource, rlimits, + NULL); + if (!__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (res, err)) + || INTERNAL_SYSCALL_ERRNO (res, err) != ENOSYS) return res; # endif struct rlimit rlimits32; diff --git a/sysdeps/unix/sysv/linux/signalfd.c b/sysdeps/unix/sysv/linux/signalfd.c index 8573450..d58edc7 100644 --- a/sysdeps/unix/sysv/linux/signalfd.c +++ b/sysdeps/unix/sysv/linux/signalfd.c @@ -26,11 +26,16 @@ int signalfd (int fd, const sigset_t *mask, int flags) { #ifdef __NR_signalfd4 - int res = INLINE_SYSCALL (signalfd4, 4, fd, mask, _NSIG / 8, flags); # ifndef __ASSUME_SIGNALFD4 - if (res != -1 || errno != ENOSYS) -# endif + INTERNAL_SYSCALL_DECL (err); + int res = INTERNAL_SYSCALL (signalfd4, err, 4, fd, mask, _NSIG / 8, + flags); + if (!__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (res, err)) + || INTERNAL_SYSCALL_ERRNO (res, err) != ENOSYS) return res; +# else + return INLINE_SYSCALL (signalfd4, 4, fd, mask, _NSIG / 8, flags); +# endif #endif #ifndef __ASSUME_SIGNALFD4 diff --git a/sysdeps/unix/sysv/linux/statfs64.c b/sysdeps/unix/sysv/linux/statfs64.c index ac5c33f..fdd1667 100644 --- a/sysdeps/unix/sysv/linux/statfs64.c +++ b/sysdeps/unix/sysv/linux/statfs64.c @@ -37,12 +37,17 @@ __statfs64 (const char *file, struct statfs64 *buf) if (! __no_statfs64) # endif { - int result = INLINE_SYSCALL (statfs64, 3, file, sizeof (*buf), buf); - # if __ASSUME_STATFS64 == 0 - if (result == 0 || errno != ENOSYS) -# endif + INTERNAL_SYSCALL_DECL (err); + int result = INTERNAL_SYSCALL (statfs64, err, 3, file, + sizeof (*buf), buf); + + if (!__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result, err)) + || INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS) return result; +# else + return INLINE_SYSCALL (statfs64, 3, file, sizeof (*buf), buf); +# endif # if __ASSUME_STATFS64 == 0 __no_statfs64 = 1; -- 2.4.3