linux-kernel - Re: How to determine whether a file was opened O

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Message-ID: <4830.213.163.11.81.1156842958.squirrel@www.dunaweb.hu>
Date:	Tue, 29 Aug 2006 11:15:58 +0200 (CEST)
From:	Böszörményi Zoltán <zboszor@...aweb.hu>
To:	"Helge Hafting" <helge.hafting@...el.hist.no>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: How to determine whether a file was opened O_DIRECT?

> BĂśszĂśrmĂŠnyi ZoltĂĄn wrote:
>> Hi,
>>
>> I would like to run some diagnostics on a database
>> process and I would like to know what flags it used
>> for opening its files. Is there any way to get this info?
>>
>> Thanks in advance,
>> ZoltĂĄn BĂśszĂśrmĂŠnyi
>>
> 1. Look at the source code for the database - if you have it.

Unfortunately not.

> 2. Run your database under strace, then search the voluminous
>     output for "open" calls and look at the flags.

I can't do that, it's a production machine. But ...

> 3. Patch your kernel to "printk" information whenever
>     someone opens with O_DIRECT.

... this should have been obvious. :-) Thanks.

I just thought a command like fuser
may already exists to give me this info.
Or something under /proc/PID/fd.

>
> Helge Hafting
>

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