From: "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>
To: Ganapatrao Kulkarni <gpkulkarni@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
Ganapatrao Kulkarni <gkulkarni@caviumnetworks.com>,
Robert Richter <rrichter@cavium.com>,
"David Daney" <david.daney@cavium.com>,
Rob Herring <robh+dt@kernel.org>,
"Frank Rowand" <frowand.list@gmail.com>,
Grant Likely <grant.likely@linaro.org>,
devicetree <devicetree@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Xinwei Hu <huxinwei@huawei.com>, Zefan Li <lizefan@huawei.com>,
Hanjun Guo <guohanjun@huawei.com>,
Tianhong Ding <dingtianhong@huawei.com>
Subject: Re: [PATCH v4 11/14] arm64/numa: support HAVE_MEMORYLESS_NODES
Date: Wed, 8 Jun 2016 15:49:18 +0800 [thread overview]
Message-ID: <5757CDFE.5020204@huawei.com> (raw)
In-Reply-To: <CAFpQJXWjZQFFnSjygW1DYJ1NRfVbkWt+FP3tN3zsGWaaf9-g=g@mail.gmail.com>
On 2016/6/8 12:45, Ganapatrao Kulkarni wrote:
> On Wed, Jun 8, 2016 at 7:46 AM, Leizhen (ThunderTown)
> <thunder.leizhen@huawei.com> wrote:
>>
>>
>> On 2016/6/7 22:01, Ganapatrao Kulkarni wrote:
>>> On Tue, Jun 7, 2016 at 6:27 PM, Leizhen (ThunderTown)
>>> <thunder.leizhen@huawei.com> wrote:
>>>>
>>>>
>>>> On 2016/6/7 16:31, Ganapatrao Kulkarni wrote:
>>>>> On Tue, Jun 7, 2016 at 1:38 PM, Zhen Lei <thunder.leizhen@huawei.com> wrote:
>>>>>> Some numa nodes may have no memory. For example:
>>>>>> 1. cpu0 on node0
>>>>>> 2. cpu1 on node1
>>>>>> 3. device0 access the momory from node0 and node1 take the same time.
>>>>>
>>>>> i am wondering, if access to both nodes is same, then why you need numa.
>>>>> the example you are quoting is against the basic principle of "numa"
>>>>> what is device0 here? cpu?
>>>> The device0 can also be a cpu. I drew a simple diagram:
>>>>
>>>> cpu0 cpu1 cpu2/device0
>>>> | | |
>>>> | | |
>>>> DDR0 DDR1 No DIMM slots or no DIMM plugged
>>>> (node0) (node1) (node2)
>>>>
>>>
>>> thanks for the clarification. your example is for 3 node system, where
>>> third node is memory less node.
>>> do you see any issue in supporting this topology with existing code?
>> If opened HAVE_MEMORYLESS_NODES, it will pick the nearest node for the cpus on
>> memoryless node.
>
> i see couple of arch enabled HAVE_MEMORYLESS_NODES, but i don't see
> any code in arch specific numa code for this
> is that means the core code will take care of this?
I just spent some time to read the implementation code of HAVE_MEMORYLESS_NODES on PPC and IA64.
For NODE_DATA initialization, it's similar to mine on IA64. But PPC have no special process, it's
similar to yours. I think the developers of PPC need to fix it.
I picked the code on IA64 as below:
static void __init *memory_less_node_alloc(int nid, unsigned long pernodesize)
{
void *ptr = NULL;
u8 best = 0xff;
int bestnode = -1, node, anynode = 0;
for_each_online_node(node) {
if (node_isset(node, memory_less_mask))
continue;
else if (node_distance(nid, node) < best) {
best = node_distance(nid, node);
bestnode = node;
}
anynode = node;
}
if (bestnode == -1)
bestnode = anynode;
ptr = __alloc_bootmem_node(pgdat_list[bestnode], pernodesize,
PERCPU_PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
return ptr;
}
/**
* memory_less_nodes - allocate and initialize CPU only nodes pernode
* information.
*/
static void __init memory_less_nodes(void)
{
unsigned long pernodesize;
void *pernode;
int node;
for_each_node_mask(node, memory_less_mask) {
pernodesize = compute_pernodesize(node);
pernode = memory_less_node_alloc(node, pernodesize);
fill_pernode(node, __pa(pernode), pernodesize);
}
return;
}
>
>>
>> For example, in include/linux/topology.h
>> #ifdef CONFIG_HAVE_MEMORYLESS_NODES
>> ...
>> static inline int cpu_to_mem(int cpu)
>> {
>> return per_cpu(_numa_mem_, cpu);
>> }
>> ...
>> #else
>> ...
>> static inline int cpu_to_mem(int cpu)
>> {
>> return cpu_to_node(cpu);
>> }
>> ...
>> #endif
>>
>>> I think, this use case should be supported with present code.
>>>
>>>>>>
>>>>>> So, we can not simply classify device0 to node0 or node1, but we can
>>>>>> define a node2 which distances to node0 and node1 are the same.
>>>>>>
>>>>>> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
>>>>>> ---
>>>>>> arch/arm64/Kconfig | 4 ++++
>>>>>> arch/arm64/kernel/smp.c | 1 +
>>>>>> arch/arm64/mm/numa.c | 43 +++++++++++++++++++++++++++++++++++++++++--
>>>>>> 3 files changed, 46 insertions(+), 2 deletions(-)
>>>>>>
>>>>>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>>>>>> index 05c1bf1..5904a62 100644
>>>>>> --- a/arch/arm64/Kconfig
>>>>>> +++ b/arch/arm64/Kconfig
>>>>>> @@ -581,6 +581,10 @@ config NEED_PER_CPU_EMBED_FIRST_CHUNK
>>>>>> def_bool y
>>>>>> depends on NUMA
>>>>>>
>>>>>> +config HAVE_MEMORYLESS_NODES
>>>>>> + def_bool y
>>>>>> + depends on NUMA
>>>>>> +
>>>>>> source kernel/Kconfig.preempt
>>>>>> source kernel/Kconfig.hz
>>>>>>
>>>>>> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
>>>>>> index d099306..9e15297 100644
>>>>>> --- a/arch/arm64/kernel/smp.c
>>>>>> +++ b/arch/arm64/kernel/smp.c
>>>>>> @@ -620,6 +620,7 @@ static void __init of_parse_and_init_cpus(void)
>>>>>> }
>>>>>>
>>>>>> bootcpu_valid = true;
>>>>>> + early_map_cpu_to_node(0, of_node_to_nid(dn));
>>>>>>
>>>>>> /*
>>>>>> * cpu_logical_map has already been
>>>>>> diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c
>>>>>> index df5c842..d73b0a0 100644
>>>>>> --- a/arch/arm64/mm/numa.c
>>>>>> +++ b/arch/arm64/mm/numa.c
>>>>>> @@ -128,6 +128,14 @@ void __init early_map_cpu_to_node(unsigned int cpu, int nid)
>>>>>> nid = 0;
>>>>>>
>>>>>> cpu_to_node_map[cpu] = nid;
>>>>>> +
>>>>>> + /*
>>>>>> + * We should set the numa node of cpu0 as soon as possible, because it
>>>>>> + * has already been set up online before. cpu_to_node(0) will soon be
>>>>>> + * called.
>>>>>> + */
>>>>>> + if (!cpu)
>>>>>> + set_cpu_numa_node(cpu, nid);
>>>>>> }
>>>>>>
>>>>>> #ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA
>>>>>> @@ -215,6 +223,35 @@ int __init numa_add_memblk(int nid, u64 start, u64 end)
>>>>>> return ret;
>>>>>> }
>>>>>>
>>>>>> +static u64 __init alloc_node_data_from_nearest_node(int nid, const size_t size)
>>>>>> +{
>>>>>> + int i, best_nid, distance;
>>>>>> + u64 pa;
>>>>>> + DECLARE_BITMAP(nodes_map, MAX_NUMNODES);
>>>>>> +
>>>>>> + bitmap_zero(nodes_map, MAX_NUMNODES);
>>>>>> + bitmap_set(nodes_map, nid, 1);
>>>>>> +
>>>>>> +find_nearest_node:
>>>>>> + best_nid = NUMA_NO_NODE;
>>>>>> + distance = INT_MAX;
>>>>>> +
>>>>>> + for_each_clear_bit(i, nodes_map, MAX_NUMNODES)
>>>>>> + if (numa_distance[nid][i] < distance) {
>>>>>> + best_nid = i;
>>>>>> + distance = numa_distance[nid][i];
>>>>>> + }
>>>>>> +
>>>>>> + pa = memblock_alloc_nid(size, SMP_CACHE_BYTES, best_nid);
>>>>>> + if (!pa) {
>>>>>> + BUG_ON(best_nid == NUMA_NO_NODE);
>>>>>> + bitmap_set(nodes_map, best_nid, 1);
>>>>>> + goto find_nearest_node;
>>>>>> + }
>>>>>> +
>>>>>> + return pa;
>>>>>> +}
>>>>>> +
>>>
>>> why do we need this function in arch specific code.
>> I also considered put these code(include HAVE_SETUP_PER_CPU_AREA) into drivers/of/of_numa.c,
>> but if I do that, it will make acpi numa dependent on of numa.
>
> numa core/common code is mainly in directory mm/
> drivers/of/of_numa.c implements only device tree numa binding.
As above, IA64 also have a similar implementation under arch/ia64 directory.
And it seems the implementation of IA64 and mine cann't be merged into one.
So I suggest that currently stay these code here.
>
>>
>>> dont you think common code will take care of this? when you define
>>> HAVE_MEMORYLESS_NODES
>>
>> I have searched CONFIG_HAVE_MEMORYLESS_NODES in *.c, but did not find the relevant content.
>> So maybe other ARCHs also missed this.
>
> as mentioned above, arch code may not need any changes for this.
>>
>>>
>>>>>> /**
>>>>>> * Initialize NODE_DATA for a node on the local memory
>>>>>> */
>>>>>> @@ -228,7 +265,9 @@ static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn)
>>>>>> pr_info("Initmem setup node %d [mem %#010Lx-%#010Lx]\n",
>>>>>> nid, start_pfn << PAGE_SHIFT, (end_pfn << PAGE_SHIFT) - 1);
>>>>>>
>>>>>> - nd_pa = memblock_alloc_try_nid(nd_size, SMP_CACHE_BYTES, nid);
>>>
>>> this function try to allocate from a nid, if fails, it allocates from
>>> node 0(local node).
>>> this is ok for memory less node i guess.
>> Yes, the function is OK, but the performance is not.
>>
>> Suppose there are 3 nodes:
>> 1. cpu0 on node0, cpu1 on node1, cpu2 on node2.
>> 2. cpu2 access the memory on node1 take 1us, but access the memory on node1 take 5us.
>> That is, distance[2,1] is shorter than distance[2,0].
>> 3. And node2 is a memoryless node.
>>
>> So if NODE_DATA(2) allocated from node0, it will take more time than allocted from node1 at run time.
>> Because NODE_DATA will be accessed at run time.
>>
>>>
>>>>>> + nd_pa = memblock_alloc_nid(nd_size, SMP_CACHE_BYTES, nid);
>>>>>> + if (!nd_pa)
>>>>>> + nd_pa = alloc_node_data_from_nearest_node(nid, nd_size);
>>>>>> nd = __va(nd_pa);
>>>>>>
>>>>>> /* report and initialize */
>>>>>> @@ -238,7 +277,7 @@ static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn)
>>>>>> if (tnid != nid)
>>>>>> pr_info(" NODE_DATA(%d) on node %d\n", nid, tnid);
>>>>>>
>>>>>> - node_data[nid] = nd;
>>>>>> + NODE_DATA(nid) = nd;
>>>>>> memset(NODE_DATA(nid), 0, sizeof(pg_data_t));
>>>>>> NODE_DATA(nid)->node_id = nid;
>>>>>> NODE_DATA(nid)->node_start_pfn = start_pfn;
>>>>>> --
>>>>>> 2.5.0
>>>>>>
>>>>>>
>>>>> Ganapat
>>>>>>
>>>>>> _______________________________________________
>>>>>> linux-arm-kernel mailing list
>>>>>> linux-arm-kernel@lists.infradead.org
>>>>>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>>>>>
>>>>> .
>>>>>
>>>>
>>>
>>> .
>>>
>>
>
> thanks
> Ganapat
>
> .
>
next prev parent reply other threads:[~2016-06-08 7:51 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-07 8:08 [PATCH v4 00/14] fix some type infos and bugs for arm64/of numa Zhen Lei
2016-06-07 8:08 ` [PATCH v4 01/14] of/numa: remove a duplicated pr_debug information Zhen Lei
2016-06-07 8:08 ` [PATCH v4 02/14] of/numa: fix a memory@ node can only contains one memory block Zhen Lei
2016-06-07 8:08 ` [PATCH v4 03/14] arm64/numa: add nid check for " Zhen Lei
2016-06-07 8:08 ` [PATCH v4 04/14] of/numa: remove a duplicated warning Zhen Lei
2016-06-07 8:08 ` [PATCH v4 05/14] arm64/numa: avoid inconsistent information to be printed Zhen Lei
2016-06-07 8:08 ` [PATCH v4 06/14] of_numa: Use of_get_next_parent to simplify code Zhen Lei
2016-06-07 8:08 ` [PATCH v4 07/14] of_numa: Use pr_fmt() Zhen Lei
2016-06-07 8:08 ` [PATCH v4 08/14] arm64: numa: " Zhen Lei
2016-06-07 8:08 ` [PATCH v4 09/14] arm64/numa: support HAVE_SETUP_PER_CPU_AREA Zhen Lei
2016-06-07 8:08 ` [PATCH v4 10/14] arm64/numa: define numa_distance as array to simplify code Zhen Lei
2016-06-07 8:08 ` [PATCH v4 11/14] arm64/numa: support HAVE_MEMORYLESS_NODES Zhen Lei
2016-06-07 8:31 ` Ganapatrao Kulkarni
2016-06-07 12:57 ` Leizhen (ThunderTown)
2016-06-07 14:01 ` Ganapatrao Kulkarni
2016-06-08 2:16 ` Leizhen (ThunderTown)
2016-06-08 4:45 ` Ganapatrao Kulkarni
2016-06-08 7:49 ` Leizhen (ThunderTown) [this message]
2016-06-07 8:08 ` [PATCH v4 12/14] arm64/numa: remove some useless code Zhen Lei
2016-06-07 8:28 ` Ganapatrao Kulkarni
2016-06-07 12:42 ` Leizhen (ThunderTown)
2016-06-07 8:08 ` [PATCH v4 13/14] of/numa: remove the constraint on the distances of node pairs Zhen Lei
2016-06-07 8:08 ` [PATCH v4 14/14] Documentation: " Zhen Lei
2016-06-10 13:08 ` Rob Herring
2016-06-07 13:58 ` [PATCH v4 00/14] fix some type infos and bugs for arm64/of numa Will Deacon
2016-06-08 8:59 ` Leizhen (ThunderTown)
2016-06-14 14:22 ` Catalin Marinas
2016-06-20 6:39 ` Leizhen (ThunderTown)
2016-06-22 1:55 ` Leizhen (ThunderTown)
2016-06-12 7:09 ` Hanjun Guo
2016-06-13 10:12 ` Will Deacon
2016-06-14 10:10 ` Hanjun Guo
2016-06-07 20:38 ` Rob Herring
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5757CDFE.5020204@huawei.com \
--to=thunder.leizhen@huawei.com \
--cc=catalin.marinas@arm.com \
--cc=david.daney@cavium.com \
--cc=devicetree@vger.kernel.org \
--cc=dingtianhong@huawei.com \
--cc=frowand.list@gmail.com \
--cc=gkulkarni@caviumnetworks.com \
--cc=gpkulkarni@gmail.com \
--cc=grant.likely@linaro.org \
--cc=guohanjun@huawei.com \
--cc=huxinwei@huawei.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lizefan@huawei.com \
--cc=robh+dt@kernel.org \
--cc=rrichter@cavium.com \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).