[ltt-dev] [PATCH] Separateltt_trace_create()intoltt_trace_create() and ltt_trace_alloc()

[Zhaolei]

*Mathieu wrote:
>* Zhaolei (zhaolei at cn.fujitsu.com) wrote:
>> `-- debugfs
>>     `-- ltt
>>         |-- buffers
>>         |   `-- ...
>>         |-- control
>>         |   `-- trace1
>>         |       |-- alloc
>>         |       |-- channel
>>         |       |   |-- control
>>         |       |   |   |-- interrupts
>>         |       |   |   |   |-- subbuf_num
>>         |       |   |   |   `-- subbuf_size
>>         |       |   |   |-- metadata
>>         |       |   |   |   |-- subbuf_num
>>         |       |   |   |   `-- subbuf_size
>>         |       |   |   |-- modules
>>         |       |   |   |   |-- subbuf_num
>>         |       |   |   |   `-- subbuf_size
>>         |       |   |   |-- network
>>         |       |   |   |   |-- subbuf_num
>>         |       |   |   |   `-- subbuf_size
>>         |       |   |   `-- processes
>>         |       |   |       |-- subbuf_num
>>         |       |   |       `-- subbuf_size
>>         |       |   `-- cpu
>>         |       |       |-- mode
>>         |       |       |-- subbuf_num
>>         |       |       `-- subbuf_size
>>         |       `-- enabled
>>         `-- setup_trace
>> 
>> It lakes control-file for destroy a trace and setup trace_type.
>> So I think we should change tree struct as follow,
>> Do you hace some comment?
>> 
>> `-- debugfs
>>     `-- ltt
>>         |-- buffers
>>         |   `-- ...
>>         |-- control
>>         |   `-- trace1
>>         |       |-- alloc
> 
> echo 1 > alloc -> allocate
> echo 0 > alloc -> free ?
> 
Hello, Mathieu,
Thanks for your answer.
>>         |       |-- channel
>>         |       |   |-- control
>>         |       |   |   |-- interrupts
>>         |       |   |   |   |-- subbuf_num
>>         |       |   |   |   `-- subbuf_size
>                              \-- overwrite (1/0)
>>         |       |   |   |-- metadata
>>         |       |   |   |   |-- subbuf_num
>>         |       |   |   |   `-- subbuf_size
>                              \-- overwrite
>>         |       |   |   |-- modules
>>         |       |   |   |   |-- subbuf_num
>>         |       |   |   |   `-- subbuf_size
>                              \-- overwrite
>>         |       |   |   |-- network
>>         |       |   |   |   |-- subbuf_num
>>         |       |   |   |   `-- subbuf_size
>                              \-- overwrite
>>         |       |   |   `-- processes
>>         |       |   |       |-- subbuf_num
>>         |       |   |       `-- subbuf_size
>                              \-- overwrite
>>         |       |   `-- cpu
>>         |       |       |-- mode
>>         |       |       |-- subbuf_num
>>         |       |       `-- subbuf_size
>>         |       |-- enabled
>>         |       `-- type ******new******
> 
> Nope, the overwrite above will be more flexible. Then people can select
> per-channel which one they want in flight recorder mode (overwrite = 1).
> Default would be non-flight (normal mode, overwrite = 0). Hybrid is
> really just a combination of the two.
> 
> Note that the metadata channel must be forced to "normal" mode. This is
> a special-case.
"type" in my question means const char *type in:
static int ltt_trace_create(const char *trace_name, const char *trace_type,
    enum trace_mode mode,
    unsigned subbuf_size_low, unsigned n_subbufs_low,
    unsigned subbuf_size_med, unsigned n_subbufs_med,
    unsigned subbuf_size_high, unsigned n_subbufs_high);

Its value is "relay" and "relay-locked", so i think we can add a control file named:
/debugfs/ltt/control/trace_name/channel/type (or  transport) for it.

And, we will add function for set each channel's overwrite, so control tree will be:

`-- debugfs
    `-- ltt
        |-- buffers
        |   `-- ...
        |-- control
        |   `-- trace1
        |       |-- alloc
        |       |-- channel
        |       |   |-- control
        |       |   |   |-- interrupts
        |       |   |   |   |-- subbuf_num
        |       |   |   |   |-- subbuf_size
        |       |   |   |   `-- overwrite
        |       |   |   |-- metadata
        |       |   |   |   |-- subbuf_num
        |       |   |   |   |-- subbuf_size
        |       |   |   |   `-- overwrite
        |       |   |   |-- modules
        |       |   |   |   |-- subbuf_num
        |       |   |   |   |-- subbuf_size
        |       |   |   |   `-- overwrite
        |       |   |   |-- network
        |       |   |   |   |-- subbuf_num
        |       |   |   |   |-- subbuf_size
        |       |   |   |   `-- overwrite
        |       |   |   `-- processes
        |       |   |       |-- subbuf_num
        |       |   |       |-- subbuf_size
        |       |   |       `-- overwrite
        |       |   `-- cpu
        |       |       |-- subbuf_num
        |       |       |-- subbuf_size
        |       |       `-- overwrite
        |       |-- enabled
        |       `-- transport
         `-- setup_trace

Changes are:
1: add transport to set ltt_trace_create()'s const char *trace_type.
2: delete cpu's mode file
3: add overwrite for each channel include cpu.

Questions:
1: make echo 1 > metadata/overwrite return error (*it is my prefer)
   OR
   make metadata/overwrite non-exist?
2: Why we put channel of cpu in channel/control/?
   it looks some complex for user.

btw:
Following mail failed sending to you because our mail-server.
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Date: Wed, 29 Oct 2008 12:04:30 +0800
To: Mathieu Desnoyers <compudj at krystal.dyndns.org>
Cc: ltt-dev at lists.casi.polymtl.ca
X-Mailer: Microsoft Outlook Express 6.00.2900.5512
From: Zhaolei <zhaolei at cn.fujitsu.com>
Subject: Re: [ltt-dev] [PATCH] Separate ltt_trace_create()
intoltt_trace_create() and ltt_trace_alloc()