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[Qemu-devel] [PULL 2/9] Revert "rcu: do not create thread in pthread_atf
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PULL 2/9] Revert "rcu: do not create thread in pthread_atfork callback" |
Date: |
Tue, 8 Aug 2017 17:29:34 +0200 |
This reverts commit a59629fcc6f603e19b516dc08f75334e5c480bd0.
This is not needed anymore because the IOThread mutex is not
"magic" anymore (need not kick the CPU thread)and also because
fork callbacks are only enabled at the very beginning of
QEMU's execution.
Signed-off-by: Paolo Bonzini <address@hidden>
---
include/qemu/rcu.h | 1 -
linux-user/syscall.c | 1 -
os-posix.c | 2 --
util/rcu.c | 10 +++++++---
4 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/include/qemu/rcu.h b/include/qemu/rcu.h
index c0da9907e8..f19413d649 100644
--- a/include/qemu/rcu.h
+++ b/include/qemu/rcu.h
@@ -111,7 +111,6 @@ extern void rcu_unregister_thread(void);
*/
extern void rcu_enable_atfork(void);
extern void rcu_disable_atfork(void);
-extern void rcu_after_fork(void);
struct rcu_head;
typedef void RCUCBFunc(struct rcu_head *head);
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 54343c06be..9b6364a266 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -6354,7 +6354,6 @@ static int do_fork(CPUArchState *env, unsigned int flags,
abi_ulong newsp,
ret = fork();
if (ret == 0) {
/* Child Process. */
- rcu_after_fork();
cpu_clone_regs(env, newsp);
fork_end(1);
/* There is a race condition here. The parent process could
diff --git a/os-posix.c b/os-posix.c
index c6ddb7d830..92e9d85215 100644
--- a/os-posix.c
+++ b/os-posix.c
@@ -34,7 +34,6 @@
#include "sysemu/sysemu.h"
#include "net/slirp.h"
#include "qemu-options.h"
-#include "qemu/rcu.h"
#include "qemu/error-report.h"
#include "qemu/log.h"
#include "qemu/cutils.h"
@@ -249,7 +248,6 @@ void os_daemonize(void)
signal(SIGTSTP, SIG_IGN);
signal(SIGTTOU, SIG_IGN);
signal(SIGTTIN, SIG_IGN);
- rcu_after_fork();
}
}
diff --git a/util/rcu.c b/util/rcu.c
index 2142ddd93b..ca5a63e36a 100644
--- a/util/rcu.c
+++ b/util/rcu.c
@@ -350,18 +350,22 @@ static void rcu_init_unlock(void)
qemu_mutex_unlock(&rcu_registry_lock);
qemu_mutex_unlock(&rcu_sync_lock);
}
-#endif
-void rcu_after_fork(void)
+static void rcu_init_child(void)
{
+ if (atfork_depth < 1) {
+ return;
+ }
+
memset(®istry, 0, sizeof(registry));
rcu_init_complete();
}
+#endif
static void __attribute__((__constructor__)) rcu_init(void)
{
#ifdef CONFIG_POSIX
- pthread_atfork(rcu_init_lock, rcu_init_unlock, rcu_init_unlock);
+ pthread_atfork(rcu_init_lock, rcu_init_unlock, rcu_init_child);
#endif
rcu_init_complete();
}
--
2.13.3
- [Qemu-devel] [PULL 0/9] Misc patches for 2017-08-08, Paolo Bonzini, 2017/08/08
- [Qemu-devel] [PULL 1/9] rcu: completely disable pthread_atfork callbacks as soon as possible, Paolo Bonzini, 2017/08/08
- [Qemu-devel] [PULL 5/9] target/i386: set rip_offset for some SSE4.1 instructions, Paolo Bonzini, 2017/08/08
- [Qemu-devel] [PULL 6/9] qemu-img: Sort sub-command names in --help, Paolo Bonzini, 2017/08/08
- [Qemu-devel] [PULL 3/9] kvm: workaround build break on gcc-7.1.1 / fedora26, Paolo Bonzini, 2017/08/08
- [Qemu-devel] [PULL 4/9] scsi: clarify sense codes for LUN0 emulation, Paolo Bonzini, 2017/08/08
- [Qemu-devel] [PULL 2/9] Revert "rcu: do not create thread in pthread_atfork callback",
Paolo Bonzini <=
- [Qemu-devel] [PULL 7/9] qemu-io: Give more --version information, Paolo Bonzini, 2017/08/08
- [Qemu-devel] [PULL 8/9] qga: Give more --version information, Paolo Bonzini, 2017/08/08
- [Qemu-devel] [PULL 9/9] maint: Include bug-reporting info in --help output, Paolo Bonzini, 2017/08/08
- Re: [Qemu-devel] [PULL 0/9] Misc patches for 2017-08-08, Peter Maydell, 2017/08/08