From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org, Carlos O'Donell <carlos@redhat.com>
Subject: [PATCH v4 0/6] Optimize posix_spawn signal setup with clone3
Date: Thu, 12 Jan 2023 10:58:47 -0300 [thread overview]
Message-ID: <20230112135853.3786675-1-adhemerval.zanella@linaro.org> (raw)
Currently posix_spawn has to issue at least NSIG sigaction syscalls
to obtain current signal disposition and more if they there are not
either SIG_IGN or SIG_DFL. The new clone3 CLONE_CLEAR_SIGHAND flags
introduced with Linux 5.5 resets all signal handlers of the child not
set to SIG_IGN to SIG_DFL, thus allowing posix_spawn to skip this
preparation phase.
The exception is the signals defined by posix_spawnattr_setsigdefault
when POSIX_SPAWN_SETSIGDEF is set (since they can be SIG_IGN). In
this case posix_spawn helper process needs to issue a sigction to
set the signal disposition to SIG_DFL.
The patchset also adds clone3 implementation for aarch64. The clone3
for x86_64 is change to not align the stack, since this is not
async-signal safe (although current calls does mask/unmask signals).
* Changes from v3:
- Changes commit message and comments wording.
- Removed powerpc, s390x, riscv, arm, and mips clone3 optimizations.
* Changes from v2:
- Improve clone3 internal documentation.
* Changes from v1:
- Extend clone3 documentation.
- Remove x86_64 stack alignment on clone3 child.
- Fixed powerpc64 missing initial stack frame.
- Fixed missing save/restore r7 for arm.
Adhemerval Zanella (6):
linux: Do not reset signal handler in posix_spawn if it is already
SIG_DFL
linux: Extend internal clone3 documentation
Linux: Do not align the stack for __clone3
linux: Add clone3 CLONE_CLEAR_SIGHAND optimization to posix_spawn
aarch64: Add the clone3 wrapper
Linux: optimize clone3 internal usage
include/clone_internal.h | 37 +++-
posix/Makefile | 3 +-
posix/tst-spawn7.c | 179 ++++++++++++++++++
sysdeps/unix/sysv/linux/Makefile | 3 +-
sysdeps/unix/sysv/linux/aarch64/clone3.S | 85 +++++++++
sysdeps/unix/sysv/linux/aarch64/sysdep.h | 2 +
sysdeps/unix/sysv/linux/clone-internal.c | 59 ++++--
sysdeps/unix/sysv/linux/clone3.h | 15 +-
sysdeps/unix/sysv/linux/kernel-features.h | 9 +
sysdeps/unix/sysv/linux/spawni.c | 33 +++-
.../sysv/linux/tst-misalign-clone-internal.c | 74 --------
sysdeps/unix/sysv/linux/x86_64/clone3.S | 3 -
12 files changed, 384 insertions(+), 118 deletions(-)
create mode 100644 posix/tst-spawn7.c
create mode 100644 sysdeps/unix/sysv/linux/aarch64/clone3.S
delete mode 100644 sysdeps/unix/sysv/linux/tst-misalign-clone-internal.c
--
2.34.1
next reply other threads:[~2023-01-12 13:58 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-12 13:58 Adhemerval Zanella [this message]
2023-01-12 13:58 ` [PATCH v4 1/6] linux: Do not reset signal handler in posix_spawn if it is already SIG_DFL Adhemerval Zanella
2023-01-18 22:24 ` Carlos O'Donell
2023-01-12 13:58 ` [PATCH v4 2/6] linux: Extend internal clone3 documentation Adhemerval Zanella
2023-01-18 22:25 ` Carlos O'Donell
2023-01-12 13:58 ` [PATCH v4 3/6] Linux: Do not align the stack for __clone3 Adhemerval Zanella
2023-01-18 22:26 ` Carlos O'Donell
2023-01-12 13:58 ` [PATCH v4 4/6] linux: Add clone3 CLONE_CLEAR_SIGHAND optimization to posix_spawn Adhemerval Zanella
2023-01-18 22:28 ` Carlos O'Donell
2023-01-12 13:58 ` [PATCH v4 5/6] aarch64: Add the clone3 wrapper Adhemerval Zanella
2023-01-18 22:29 ` Carlos O'Donell
2023-01-12 13:58 ` [PATCH v4 6/6] Linux: optimize clone3 internal usage Adhemerval Zanella
2023-01-18 22:31 ` Carlos O'Donell
2023-01-18 17:53 ` [PATCH v4 0/6] Optimize posix_spawn signal setup with clone3 Adhemerval Zanella Netto
2023-01-18 22:24 ` Carlos O'Donell
2023-01-19 14:39 ` Adhemerval Zanella Netto
2023-01-22 23:21 ` Carlos O'Donell
2023-02-28 16:34 ` H.J. Lu
2023-02-28 17:11 ` Adhemerval Zanella Netto
2023-02-28 18:09 ` Florian Weimer
2023-02-28 18:16 ` Adhemerval Zanella Netto
2023-02-28 19:07 ` H.J. Lu
2023-02-28 21:19 ` Andreas Schwab
2023-02-28 21:31 ` H.J. Lu
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