From 3fc1f1e27a5b807791d72e5d992aa33b668a6626 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 6 May 2010 18:49:20 +0200 Subject: stop_machine: reimplement using cpu_stop Reimplement stop_machine using cpu_stop. As cpu stoppers are guaranteed to be available for all online cpus, stop_machine_create/destroy() are no longer necessary and removed. With resource management and synchronization handled by cpu_stop, the new implementation is much simpler. Asking the cpu_stop to execute the stop_cpu() state machine on all online cpus with cpu hotplug disabled is enough. stop_machine itself doesn't need to manage any global resources anymore, so all per-instance information is rolled into struct stop_machine_data and the mutex and all static data variables are removed. The previous implementation created and destroyed RT workqueues as necessary which made stop_machine() calls highly expensive on very large machines. According to Dimitri Sivanich, preventing the dynamic creation/destruction makes booting faster more than twice on very large machines. cpu_stop resources are preallocated for all online cpus and should have the same effect. Signed-off-by: Tejun Heo Acked-by: Rusty Russell Acked-by: Peter Zijlstra Cc: Oleg Nesterov Cc: Dimitri Sivanich --- arch/s390/kernel/time.c | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/s390') diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c index fba6dec156bf..03d96569f187 100644 --- a/arch/s390/kernel/time.c +++ b/arch/s390/kernel/time.c @@ -390,7 +390,6 @@ static void __init time_init_wq(void) if (time_sync_wq) return; time_sync_wq = create_singlethread_workqueue("timesync"); - stop_machine_create(); } /* -- cgit v1.2.3 From 545c174d1f093a462b4bb9131b23d5ea72a600e1 Mon Sep 17 00:00:00 2001 From: Gerald Schaefer Date: Wed, 12 May 2010 09:32:12 +0200 Subject: [S390] ptrace: fix return value of do_syscall_trace_enter() strace may change the system call number, so regs->gprs[2] must not be read before tracehook_report_syscall_entry(). This fixes a bug where "strace -f" will hang after a vfork(). Cc: Signed-off-by: Gerald Schaefer Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/ptrace.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'arch/s390') diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c index 33fdc5a79764..9f654da4cecc 100644 --- a/arch/s390/kernel/ptrace.c +++ b/arch/s390/kernel/ptrace.c @@ -640,7 +640,7 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) { - long ret; + long ret = 0; /* Do the secure computing check first. */ secure_computing(regs->gprs[2]); @@ -649,7 +649,6 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) * The sysc_tracesys code in entry.S stored the system * call number to gprs[2]. */ - ret = regs->gprs[2]; if (test_thread_flag(TIF_SYSCALL_TRACE) && (tracehook_report_syscall_entry(regs) || regs->gprs[2] >= NR_syscalls)) { @@ -671,7 +670,7 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) regs->gprs[2], regs->orig_gpr2, regs->gprs[3], regs->gprs[4], regs->gprs[5]); - return ret; + return ret ?: regs->gprs[2]; } asmlinkage void do_syscall_trace_exit(struct pt_regs *regs) -- cgit v1.2.3 From 57d84906f0f3005d4d22e13a3f5102a16a7fc4a2 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Wed, 12 May 2010 09:32:13 +0200 Subject: [S390] correct address of _stext with CONFIG_SHARED_KERNEL=y As of git commit 1844c9bc0b2fed3023551c1affe033ab38e90b9a head64.S/head31.S are not included in head.S anymore but build as an extra object. This breaks shared kernel support because the .org statement in head64.S/head31.S for CONFIG_SHARED_KERNEL=y will have a different effect. The end address of the head.text section in head.o will be added to the .org value, to compensate for this subtract 0x11000 to get the required value of 0x100000 again. Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/head31.S | 2 +- arch/s390/kernel/head64.S | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/s390') diff --git a/arch/s390/kernel/head31.S b/arch/s390/kernel/head31.S index 1bbcc499d455..b8f8dc126102 100644 --- a/arch/s390/kernel/head31.S +++ b/arch/s390/kernel/head31.S @@ -82,7 +82,7 @@ startup_continue: _ehead: #ifdef CONFIG_SHARED_KERNEL - .org 0x100000 + .org 0x100000 - 0x11000 # head.o ends at 0x11000 #endif # diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S index 1f70970de0aa..cdef68717416 100644 --- a/arch/s390/kernel/head64.S +++ b/arch/s390/kernel/head64.S @@ -80,7 +80,7 @@ startup_continue: _ehead: #ifdef CONFIG_SHARED_KERNEL - .org 0x100000 + .org 0x100000 - 0x11000 # head.o ends at 0x11000 #endif # -- cgit v1.2.3