From: Milton Miller <miltonm@bga•com>
To: mohan@in•ibm.com
Cc: ppcdev <linuxppc-dev@ozlabs•org>,
Paul Mackerras <paulus@samba•org>,
Anton Blanchard <anton@samba•org>,
fastboot@lists•osdl.org
Subject: Re: [PATCH] Fix interrupt distribution in ppc970
Date: Fri, 20 Apr 2007 00:45:15 -0500 [thread overview]
Message-ID: <080126626f9bea228426c0c3d7bf1730@bga.com> (raw)
In-Reply-To: <20070419115233.GA4172@in.ibm.com>
On Apr 19, 2007, at 6:52 AM, Mohan Kumar M wrote:
> On Wed, Apr 11, 2007 at 11:16:41AM +1000, Michael Ellerman wrote:
>> On Tue, 2007-04-10 at 11:59 -0500, Milton Miller wrote:
>>>
>>> This means we are doing population counts of two masks, when we
>>> really
>>> just care that they are the same. How about using
>>> cpus_equal(cpu_online_mask, cpu_present_mask)?
>>
>> Yep that's sensible.
>>
>>> This shows how close these two functions are. The difference is
>>> what happens when cpus_empty is true -- we default in one and
>>> ignore in the other.
>>>
>>> How about adding another arg to get_server, that says to fail
>>> or default for the empty case, with failure being -1?
>
> I modified the patch based on suggestions given by Milton and Mike.
> Milton is this patch okay?
Well, its part of the way there.
>
> Tested on 2.6.21-rc7.
> Index: linux-2.6.21-rc4/arch/powerpc/platforms/pseries/xics.c
> ===================================================================
> --- linux-2.6.21-rc4.orig/arch/powerpc/platforms/pseries/xics.c
> +++ linux-2.6.21-rc4/arch/powerpc/platforms/pseries/xics.c
> @@ -156,9 +156,9 @@ static inline void lpar_qirr_info(int n_
>
>
> #ifdef CONFIG_SMP
> -static int get_irq_server(unsigned int virq)
> +static int get_irq_server(unsigned int virq, unsigned int
> strict_check)
> {
> - unsigned int server;
> + int server;
> /* For the moment only implement delivery to all cpus or one cpu */
> cpumask_t cpumask = irq_desc[virq].affinity;
> cpumask_t tmp = CPU_MASK_NONE;
> @@ -167,21 +167,25 @@ static int get_irq_server(unsigned int v
> return default_server;
>
> if (cpus_equal(cpumask, CPU_MASK_ALL)) {
> - server = default_distrib_server;
> + if (cpus_equal(cpu_online_map, cpu_present_map))
> + server = default_distrib_server;
> + else
> + server = default_server;
> } else {
> cpus_and(tmp, cpu_online_map, cpumask);
>
> - if (cpus_empty(tmp))
> + if (cpus_empty(tmp) && !strict_check)
> server = default_distrib_server;
> + else if(cpus_empty(tmp) && strict_check)
> + server = -1;
> else
> server = get_hard_smp_processor_id(first_cpu(tmp));
> }
Don't test cpus_empty twice, instead do a nested if.
Actually, looking at this a bit, you need your default_distrib or
default_server check again.
How about reorder to be if (!cpus_equal(...ALL)) {
cpus_and
if !cpus_empty(tmp
return get_hard(first);
if (strict)
return -1;
}
if (cpus_equal(online, preseent)
return distrib
return default_server
For that matter, can we just call first_cpu, and check its <= NUM_CPUS
elminating the call to cpus_empty ? Only call get_hard_cpu if its
valid.
...
> @@ -415,7 +419,10 @@ static void xics_set_affinity(unsigned i
...
> /* For the moment only implement delivery to all cpus or one cpu */
> if (cpus_equal(cpumask, CPU_MASK_ALL)) {
> - newmask = default_distrib_server;
> + if (cpus_equal(cpu_online_map, cpu_present_map))
>
this was supposed to be the call with strict = 1
milton
next prev parent reply other threads:[~2007-04-20 5:45 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-08 4:55 [PATCH] Fix interrupt distribution in ppc970 Mohan Kumar M
2006-12-18 4:37 ` Paul Mackerras
2006-12-18 5:14 ` Mohan Kumar M
2006-12-18 10:57 ` Mohan Kumar M
2007-01-02 11:42 ` [Fastboot] " Mohan Kumar M
2007-01-02 15:07 ` Doug Maxey
2007-03-06 13:57 ` Mohan Kumar M
2007-03-06 14:16 ` Michael Ellerman
2007-03-06 16:55 ` Mohan Kumar M
2007-03-06 17:37 ` Michael Ellerman
2007-03-07 4:53 ` Mohan Kumar M
2007-03-07 10:52 ` Michael Ellerman
2007-04-09 8:57 ` Mohan Kumar M
2007-04-10 7:06 ` Michael Ellerman
2007-04-10 12:54 ` Mohan Kumar M
2007-04-10 16:59 ` Milton Miller
2007-04-11 1:16 ` Michael Ellerman
2007-04-19 11:52 ` Mohan Kumar M
2007-04-20 5:45 ` Milton Miller [this message]
2007-04-26 9:24 ` Mohan Kumar M
2007-04-26 14:42 ` Milton Miller
2007-05-03 14:47 ` Mohan Kumar M
2007-05-06 6:52 ` Milton Miller
2007-06-04 10:54 ` Mohan Kumar M
2007-06-06 9:43 ` Milton Miller
2007-06-06 11:31 ` Mohan Kumar M
2007-06-11 1:58 ` Milton Miller
2007-06-11 18:07 ` Mohan Kumar M
2007-06-12 14:51 ` Mohan Kumar M
2007-06-15 16:35 ` Milton Miller
2007-03-07 6:06 ` [Fastboot] " Vivek Goyal
2007-03-07 10:46 ` Michael Ellerman
2007-03-06 22:05 ` Nathan Lynch
2007-03-07 5:01 ` Mohan Kumar M
2007-03-07 8:52 ` Benjamin Herrenschmidt
2007-03-07 9:10 ` Mohan Kumar M
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