From: Oleg Nesterov <oleg@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>,
Frederic Weisbecker <fweisbec@gmail.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, Kees Cook <keescook@chromium.org>,
Will Drewry <wad@chromium.org>,
x86@kernel.org, linux-arm-kernel@lists.infradead.org,
linux-mips@linux-mips.org, linux-arch@vger.kernel.org,
linux-security-module@vger.kernel.org,
Alexei Starovoitov <ast@plumgrid.com>,
hpa@zytor.com
Subject: TIF_NOHZ can escape nonhz mask? (Was: [PATCH v3 6/8] x86: Split syscall_trace_enter into two phases)
Date: Mon, 28 Jul 2014 20:58:03 +0200 [thread overview]
Message-ID: <20140728185803.GA24663@redhat.com> (raw)
In-Reply-To: <20140728173723.GA20993@redhat.com>
Off-topic, but...
On 07/28, Oleg Nesterov wrote:
>
> But we should always call user_exit() unconditionally?
Frederic, don't we need the patch below? In fact clear_() can be moved
under "if ()" too. and probably copy_process() should clear this flag...
Or. __context_tracking_task_switch() can simply do
if (context_tracking_cpu_is_enabled())
set_tsk_thread_flag(next, TIF_NOHZ);
else
clear_tsk_thread_flag(next, TIF_NOHZ);
and then we can forget about copy_process(). Or I am totally confused?
I am also wondering if we can extend user_return_notifier to handle
enter/exit and kill TIF_NOHZ.
Oleg.
--- x/kernel/context_tracking.c
+++ x/kernel/context_tracking.c
@@ -202,7 +202,8 @@ void __context_tracking_task_switch(stru
struct task_struct *next)
{
clear_tsk_thread_flag(prev, TIF_NOHZ);
- set_tsk_thread_flag(next, TIF_NOHZ);
+ if (context_tracking_cpu_is_enabled())
+ set_tsk_thread_flag(next, TIF_NOHZ);
}
#ifdef CONFIG_CONTEXT_TRACKING_FORCE
WARNING: multiple messages have this Message-ID (diff)
From: oleg@redhat.com (Oleg Nesterov)
To: linux-arm-kernel@lists.infradead.org
Subject: TIF_NOHZ can escape nonhz mask? (Was: [PATCH v3 6/8] x86: Split syscall_trace_enter into two phases)
Date: Mon, 28 Jul 2014 20:58:03 +0200 [thread overview]
Message-ID: <20140728185803.GA24663@redhat.com> (raw)
In-Reply-To: <20140728173723.GA20993@redhat.com>
Off-topic, but...
On 07/28, Oleg Nesterov wrote:
>
> But we should always call user_exit() unconditionally?
Frederic, don't we need the patch below? In fact clear_() can be moved
under "if ()" too. and probably copy_process() should clear this flag...
Or. __context_tracking_task_switch() can simply do
if (context_tracking_cpu_is_enabled())
set_tsk_thread_flag(next, TIF_NOHZ);
else
clear_tsk_thread_flag(next, TIF_NOHZ);
and then we can forget about copy_process(). Or I am totally confused?
I am also wondering if we can extend user_return_notifier to handle
enter/exit and kill TIF_NOHZ.
Oleg.
--- x/kernel/context_tracking.c
+++ x/kernel/context_tracking.c
@@ -202,7 +202,8 @@ void __context_tracking_task_switch(stru
struct task_struct *next)
{
clear_tsk_thread_flag(prev, TIF_NOHZ);
- set_tsk_thread_flag(next, TIF_NOHZ);
+ if (context_tracking_cpu_is_enabled())
+ set_tsk_thread_flag(next, TIF_NOHZ);
}
#ifdef CONFIG_CONTEXT_TRACKING_FORCE
next prev parent reply other threads:[~2014-07-28 18:58 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-22 1:49 [PATCH v3 0/8] Two-phase seccomp and x86 tracing changes Andy Lutomirski
2014-07-22 1:49 ` Andy Lutomirski
2014-07-22 1:49 ` [PATCH v3 1/8] seccomp,x86,arm,mips,s390: Remove nr parameter from secure_computing Andy Lutomirski
2014-07-22 1:49 ` [PATCH v3 1/8] seccomp, x86, arm, mips, s390: " Andy Lutomirski
2014-07-22 1:49 ` [PATCH v3 2/8] seccomp: Refactor the filter callback and the API Andy Lutomirski
2014-07-22 1:49 ` Andy Lutomirski
2014-07-22 1:49 ` [PATCH v3 3/8] seccomp: Allow arch code to provide seccomp_data Andy Lutomirski
2014-07-22 1:49 ` Andy Lutomirski
2014-07-22 1:49 ` [PATCH v3 4/8] seccomp: Document two-phase seccomp and arch-provided seccomp_data Andy Lutomirski
2014-07-22 1:49 ` Andy Lutomirski
2014-07-22 1:49 ` Andy Lutomirski
2014-07-22 1:53 ` [PATCH v3 5/8] x86,x32,audit: Fix x32's AUDIT_ARCH wrt audit Andy Lutomirski
2014-07-22 1:53 ` Andy Lutomirski
2014-07-22 1:53 ` [PATCH v3 6/8] x86: Split syscall_trace_enter into two phases Andy Lutomirski
2014-07-22 1:53 ` Andy Lutomirski
2014-07-28 17:37 ` Oleg Nesterov
2014-07-28 17:37 ` Oleg Nesterov
2014-07-28 18:58 ` Oleg Nesterov [this message]
2014-07-28 18:58 ` TIF_NOHZ can escape nonhz mask? (Was: [PATCH v3 6/8] x86: Split syscall_trace_enter into two phases) Oleg Nesterov
2014-07-28 19:22 ` Frederic Weisbecker
2014-07-28 19:22 ` Frederic Weisbecker
2014-07-29 17:54 ` Oleg Nesterov
2014-07-29 17:54 ` Oleg Nesterov
2014-07-30 16:35 ` Frederic Weisbecker
2014-07-30 16:35 ` Frederic Weisbecker
2014-07-30 17:46 ` Oleg Nesterov
2014-07-30 17:46 ` Oleg Nesterov
2014-07-31 0:30 ` Frederic Weisbecker
2014-07-31 0:30 ` Frederic Weisbecker
2014-07-31 16:03 ` Oleg Nesterov
2014-07-31 16:03 ` Oleg Nesterov
2014-07-31 17:13 ` Frederic Weisbecker
2014-07-31 17:13 ` Frederic Weisbecker
2014-07-31 18:12 ` Oleg Nesterov
2014-07-31 18:12 ` Oleg Nesterov
2014-07-31 18:47 ` Frederic Weisbecker
2014-07-31 18:47 ` Frederic Weisbecker
2014-07-31 18:50 ` Frederic Weisbecker
2014-07-31 18:50 ` Frederic Weisbecker
2014-07-31 19:05 ` Oleg Nesterov
2014-07-31 19:05 ` Oleg Nesterov
2014-08-02 17:30 ` Oleg Nesterov
2014-08-02 17:30 ` Oleg Nesterov
2014-08-04 12:02 ` Paul E. McKenney
2014-08-04 12:02 ` Paul E. McKenney
2014-08-04 12:02 ` Paul E. McKenney
2014-07-28 20:23 ` [PATCH v3 6/8] x86: Split syscall_trace_enter into two phases Andy Lutomirski
2014-07-28 20:23 ` Andy Lutomirski
2014-07-29 16:54 ` Oleg Nesterov
2014-07-29 16:54 ` Oleg Nesterov
2014-07-29 17:01 ` Andy Lutomirski
2014-07-29 17:01 ` Andy Lutomirski
2014-07-29 17:31 ` Oleg Nesterov
2014-07-29 17:31 ` Oleg Nesterov
2014-07-29 17:55 ` Andy Lutomirski
2014-07-29 17:55 ` Andy Lutomirski
2014-07-29 18:16 ` Oleg Nesterov
2014-07-29 18:16 ` Oleg Nesterov
2014-07-29 18:22 ` Andy Lutomirski
2014-07-29 18:22 ` Andy Lutomirski
2014-07-29 18:44 ` Oleg Nesterov
2014-07-29 18:44 ` Oleg Nesterov
2014-07-22 1:53 ` [PATCH v3 7/8] x86_64,entry: Treat regs->ax the same in fastpath and slowpath syscalls Andy Lutomirski
2014-07-22 1:53 ` [PATCH v3 7/8] x86_64, entry: " Andy Lutomirski
2014-07-22 1:53 ` [PATCH v3 8/8] x86_64,entry: Use split-phase syscall_trace_enter for 64-bit syscalls Andy Lutomirski
2014-07-22 1:53 ` [PATCH v3 8/8] x86_64, entry: " Andy Lutomirski
2014-07-22 19:37 ` [PATCH v3 0/8] Two-phase seccomp and x86 tracing changes Kees Cook
2014-07-22 19:37 ` Kees Cook
2014-07-23 19:20 ` Andy Lutomirski
2014-07-23 19:20 ` Andy Lutomirski
2014-07-28 17:59 ` H. Peter Anvin
2014-07-28 17:59 ` H. Peter Anvin
2014-07-28 23:29 ` Kees Cook
2014-07-28 23:29 ` Kees Cook
2014-07-28 23:34 ` H. Peter Anvin
2014-07-28 23:34 ` H. Peter Anvin
2014-07-28 23:42 ` Kees Cook
2014-07-28 23:42 ` Kees Cook
2014-07-28 23:45 ` H. Peter Anvin
2014-07-28 23:45 ` H. Peter Anvin
2014-07-28 23:54 ` Kees Cook
2014-07-28 23:54 ` Kees Cook
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