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From: Lai Jiangshan <laijs@cn.fujitsu.com>
To: rostedt@goodmis.org
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
	Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] trace_syscalls: cleanup for syscalls_metadata
Date: Thu, 07 Jan 2010 09:01:52 +0800	[thread overview]
Message-ID: <4B453280.7040800@cn.fujitsu.com> (raw)
In-Reply-To: <1262797070.28171.2972.camel@gandalf.stny.rr.com>

Steven Rostedt wrote:
> On Wed, 2010-01-06 at 20:39 +0800, Lai Jiangshan wrote:
>> NR_syscalls is compile-time constant.
> 
> The question is, is that always true on all archs, and will that always
> be true?
> 
> Unless we can guarantee somewhere that NR_syscalls must be constant on
> all archs, we can't make this change. If it is guaranteed, then sure,
> this patch is fine.
> 

It seems that there is no spec/document guarantees it.

I searched all NR_syscalls in current kernel source code,
and I found it is a constant in header file (all archs).

trace_syscalls.c has already used it as a compile-time constant:

static DECLARE_BITMAP(enabled_enter_syscalls, NR_syscalls);
static DECLARE_BITMAP(enabled_exit_syscalls, NR_syscalls);

Thanks, Lai

  reply	other threads:[~2010-01-07  1:03 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-06 12:39 [PATCH] trace_syscalls: cleanup for syscalls_metadata Lai Jiangshan
2010-01-06 16:57 ` Steven Rostedt
2010-01-07  1:01   ` Lai Jiangshan [this message]
2010-01-07 14:03     ` Steven Rostedt

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