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Message-ID: <20080906193820.GC23729@lenovo>
Date: Sat, 6 Sep 2008 23:38:20 +0400
From: Cyrill Gorcunov <gorcunov@...il.com>
To: Yinghai Lu <yhlu.kernel@...il.com>
Cc: "Maciej W. Rozycki" <macro@...ux-mips.org>,
Ingo Molnar <mingo@...e.hu>, hpa@...or.com,
linux-kernel@...r.kernel.org, tglx@...utronix.de
Subject: Re: [patch 3/3] x86: io-apic - code style cleaning for
setup_IO_APIC_irqs
[Yinghai Lu - Sat, Sep 06, 2008 at 12:16:28PM -0700]
| On Sat, Sep 6, 2008 at 12:04 PM, Cyrill Gorcunov <gorcunov@...il.com> wrote:
| > [Maciej W. Rozycki - Sat, Sep 06, 2008 at 07:45:08PM +0100]
| > | On Sat, 6 Sep 2008, Cyrill Gorcunov wrote:
| > |
| > | > Ingo, how about the following approach? We don't introduce new
| > | > functions but rather srink the code by new printout form.
| > |
| > | Honestly, this one should probably use sprintf() or suchlike to avoid the
| > | mess of printk() calls building a line of output from pieces. It's quite
| > | easy to calculate here what the maximum size of the buffer required could
| > | be and automatic arrays can have variable size, so no need for the hassle
| > | of heap management. Calls to printk() without a trailing newline should
| > | be avoided where possible as it messes up logging priority if a message
| > | pops up from an interrupt inbetween.
| > |
| > | Maciej
| > |
| >
| > The easiest way would be just print this info on separate
| > lines like
| >
| > IO-APIC (apicid-pin) 1-1 not connected
| >
| > and just drop all this troubles :)
| >
| > I'm not sure how much memory we need for every io-apic
| > pins - iirc there only 32 redirection entry so it could
| > be about 32 bytes from stack would be enough. Will take
| > a look. Thanks Maciej! Ingo?
|
| no. some system could have 3 or 4 ioapic controller, and every one
| have 24...(like three mcp55/io55)
| 4*24
|
| or old system have 1 8111 and 7 8132. will have 32 + 7*2*7
|
| YH
|
Didn't really understand all numbers :)
We have
24 io-apic route entries
128 io-apic maximum in quantity
so the worst (hardly possible if ever) is when on last io-apic
all pins are wrong. So for this case we would need
(3 + 1) * ((10 + 1) + (13 + 1)) = 100
where
3 - strlen("127") - max io-apic number
10 - Sum(strlen(0)+...+strlen(9)) - pin numbers
13 - same sum for two-digit numbers
+1 number - either "-" sign or " "
100 bytes to print not connected pins. Ugh :-)
- Cyrill -
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