Date: Thu, 14 Aug 2003 10:19:14 -0700 (PDT)
From: Linus Torvalds <torvalds@osdl.org>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
cc: John Levon <levon@movementarian.org>, Russell King <rmk@arm.linux.org.uk>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Make modules work in Linus' tree on ARM
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On 14 Aug 2003, Alan Cox wrote:
> 
> And why can't you put the pointer size at the start of the buffer ?

Historical aside: this was pretty much _exactly_ the bug that we used to
have in the old style timer tick profiler: it was impossible to figure out 
what the "profile shift" value was. So you got a series of "unsigned int" 
counts, but you didn't know what the granularity was for the hit counting.

That was fixed by just making read_profile() return the sample step size 
as the first word. See

	fs/proc/proc_misc.c: read_profile()

and note the small 

        while (p < sizeof(unsigned int) && count > 0) {
                put_user(*((char *)(&sample_step)+p),buf);
                buf++; p++; count--; read++;
        }

loop (and a few "+1" things for adjusting size comparisons).

		Linus

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