From: Oleg Nesterov <oleg@redhat.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
Alexander Z Lam <azl@google.com>,
David Sharp <dhsharp@google.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@redhat.com>,
Vaibhav Nagarnaik <vnagarnaik@google.com>,
"zhangwei(Jovi)" <jovi.zhangwei@huawei.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/7] tracing: Introduce trace_create_cpu_file() and tracing_get_cpu()
Date: Mon, 22 Jul 2013 19:14:35 +0200 [thread overview]
Message-ID: <20130722171435.GA27080@redhat.com> (raw)
In-Reply-To: <1374504957.3356.91.camel@gandalf.local.home>
On 07/22, Steven Rostedt wrote:
>
> Now here's why I'm emailing you. What Oleg is doing here is instead of
> creating this extra trace_cpu structure, he's using the inode->i_cdev to
> store the CPU information (he's wrapped this with helper functions so we
> can use any inode structure). He sets inode->i_cdev to CPU+1 or to
> RING_BUFFER_ALL_CPUS (when all CPU info is needed).
This doesn't really matter, but RING_BUFFER_ALL_CPUS is encoded as NULL
so we do not need to change init_tracer_debugfs(). inode_init_always()
clears ->i_cdev.
Al, I will appreciate it if can ack/nack this hack.
I chose i_cdev because it shares the same union with i_pipe/bdev, this
(I hope) obviously means that vfs can never use this pointer unless it
checks S_ISCHR().
Oleg.
next prev parent reply other threads:[~2013-07-22 17:19 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-22 13:43 [PATCH 0/7] tracing: Kill the buggy trace_cpu Oleg Nesterov
2013-07-22 13:43 ` [PATCH 1/7] tracing: Introduce trace_create_cpu_file() and tracing_get_cpu() Oleg Nesterov
2013-07-22 14:55 ` Steven Rostedt
2013-07-22 15:06 ` Steven Rostedt
2013-07-22 17:14 ` Oleg Nesterov [this message]
2013-07-22 17:34 ` Steven Rostedt
2013-07-22 17:45 ` Steven Rostedt
2013-07-22 15:23 ` Steven Rostedt
2013-07-22 17:15 ` Oleg Nesterov
2013-07-23 0:44 ` Steven Rostedt
2013-07-22 13:43 ` [PATCH 2/7] tracing: Change tracing_pipe_fops() to rely on tracing_get_cpu() Oleg Nesterov
2013-07-22 13:43 ` [PATCH 3/7] tracing: Change tracing_buffers_fops " Oleg Nesterov
2013-07-22 13:43 ` [PATCH 4/7] tracing: Change tracing_stats_fops " Oleg Nesterov
2013-07-22 13:43 ` [PATCH 5/7] tracing: Change tracing_entries_fops " Oleg Nesterov
2013-07-22 13:43 ` [PATCH 6/7] tracing: Change tracing_fops/snapshot_fops " Oleg Nesterov
2013-07-22 13:44 ` [PATCH 7/7] tracing: Kill trace_cpu struct/members Oleg Nesterov
2013-07-22 14:59 ` [PATCH 0/7] tracing: Kill the buggy trace_cpu Steven Rostedt
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