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Subject: Re: [PATCH RESEND 1/2] MIPS: cacheinfo: Add missing VCache
To:     Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc:     linux-mips@vger.kernel.org, Huacai Chen <chenhc@lemote.com>,
        Vladimir Kondratiev <vladimir.kondratiev@intel.com>,
        Paul Burton <paulburton@kernel.org>,
        linux-kernel@vger.kernel.org
References: <20200820004253.3418-1-jiaxun.yang@flygoat.com>
 <20200820004253.3418-2-jiaxun.yang@flygoat.com>
 <20200821165539.GA15948@alpha.franken.de>
From:   Jiaxun Yang <jiaxun.yang@flygoat.com>
Message-ID: <79476b22-04ef-968b-584a-10aa4357ee6b@flygoat.com>
Date:   Tue, 3 Nov 2020 13:40:16 +0800
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在 2020/8/22 0:55, Thomas Bogendoerfer 写道:
> On Thu, Aug 20, 2020 at 08:42:49AM +0800, Jiaxun Yang wrote:
>> Victim Cache is defined by Loongson as per-core unified
>> private Cache.
>> Add this into cacheinfo and make cache levels selfincrement
>> instead of hardcode levels.
>>
>> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
>> ---
>>   arch/mips/kernel/cacheinfo.c | 34 ++++++++++++++++++++++++++--------
>>   1 file changed, 26 insertions(+), 8 deletions(-)
>>
>> diff --git a/arch/mips/kernel/cacheinfo.c b/arch/mips/kernel/cacheinfo.c
>> index 47312c529410..83548331ee94 100644
>> --- a/arch/mips/kernel/cacheinfo.c
>> +++ b/arch/mips/kernel/cacheinfo.c
>> @@ -35,6 +35,11 @@ static int __init_cache_level(unsigned int cpu)
>>   
>>   	leaves += (c->icache.waysize) ? 2 : 1;
>>   
>> +	if (c->vcache.waysize) {
>> +		levels++;
>> +		leaves++;
>> +	}
>> +
>>   	if (c->scache.waysize) {
>>   		levels++;
>>   		leaves++;
>> @@ -74,25 +79,38 @@ static int __populate_cache_leaves(unsigned int cpu)
>>   	struct cpuinfo_mips *c = &current_cpu_data;
>>   	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
>>   	struct cacheinfo *this_leaf = this_cpu_ci->info_list;
>> +	int level = 1;
>>   
>>   	if (c->icache.waysize) {
>> -		/* L1 caches are per core */
>> +		/* D/I caches are per core */
>>   		fill_cpumask_siblings(cpu, &this_leaf->shared_cpu_map);
>> -		populate_cache(dcache, this_leaf, 1, CACHE_TYPE_DATA);
>> +		populate_cache(dcache, this_leaf, level, CACHE_TYPE_DATA);
>>   		fill_cpumask_siblings(cpu, &this_leaf->shared_cpu_map);
>> -		populate_cache(icache, this_leaf, 1, CACHE_TYPE_INST);
>> +		populate_cache(icache, this_leaf, level, CACHE_TYPE_INST);
>> +		level++;
>>   	} else {
>> -		populate_cache(dcache, this_leaf, 1, CACHE_TYPE_UNIFIED);
>> +		populate_cache(dcache, this_leaf, level, CACHE_TYPE_UNIFIED);
>> +		level++;
>> +	}
>> +
>> +	if (c->vcache.waysize) {
> why can't we insert vcache as level 4 and leave the rest of the file
> alone ?

Hi Thomas,

Oops I forgot this patch.

Because  VCache is physicaly placed between Scache and I/D Cache as per
core chahe, it will confuse userspace program otherwise.

Also I do think the level should be continues.

Thanks

- Jiaxun

>
> Thomas.
>