Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1303279 > unrolled thread

[PATCH v4 0/5] Make cpuid <-> nodeid mapping persistent.

Started byTang Chen <tangchen@cn.fujitsu.com>
First post2016-01-07 05:30 +0100
Last post2016-01-07 05:30 +0100
Articles 9 — 2 participants

Back to article view | Back to linux.kernel

Contents

  [PATCH v4 0/5] Make cpuid <-> nodeid mapping persistent. Tang Chen <tangchen@cn.fujitsu.com> - 2016-01-07 05:30 +0100
    [PATCH 1/5] x86, memhp, numa: Online memory-less nodes at boot time. Tang Chen <tangchen@cn.fujitsu.com> - 2016-01-07 05:30 +0100
      Re: [PATCH 1/5] x86, memhp, numa: Online memory-less nodes at boot  time. Tejun Heo <tj@kernel.org> - 2016-01-08 19:30 +0100
        Re: [PATCH 1/5] x86, memhp, numa: Online memory-less nodes at boot  time. Tang Chen <tangchen@cn.fujitsu.com> - 2016-01-13 06:00 +0100
    [PATCH 5/5] x86, acpi, cpu-hotplug: Set persistent cpuid <-> nodeid mapping when booting. Tang Chen <tangchen@cn.fujitsu.com> - 2016-01-07 05:30 +0100
      Re: [PATCH 5/5] x86, acpi, cpu-hotplug: Set persistent cpuid <->  nodeid mapping when booting. Tejun Heo <tj@kernel.org> - 2016-01-08 20:20 +0100
        Re: [PATCH 5/5] x86, acpi, cpu-hotplug: Set persistent cpuid <->  nodeid mapping when booting. Tang Chen <tangchen@cn.fujitsu.com> - 2016-01-13 06:00 +0100
    [PATCH 2/5] x86, acpi, cpu-hotplug: Enable acpi to register all possible cpus at boot time. Tang Chen <tangchen@cn.fujitsu.com> - 2016-01-07 05:30 +0100
    [PATCH 4/5] x86, acpi, cpu-hotplug: Enable MADT APIs to return disabled apicid. Tang Chen <tangchen@cn.fujitsu.com> - 2016-01-07 05:30 +0100

#1303279 — [PATCH v4 0/5] Make cpuid <-> nodeid mapping persistent.

FromTang Chen <tangchen@cn.fujitsu.com>
Date2016-01-07 05:30 +0100
Subject[PATCH v4 0/5] Make cpuid <-> nodeid mapping persistent.
Message-ID<qOamZ-2Sc-3@gated-at.bofh.it>
[Problem]

cpuid <-> nodeid mapping is firstly established at boot time. And workqueue caches
the mapping in wq_numa_possible_cpumask in wq_numa_init() at boot time.

When doing node online/offline, cpuid <-> nodeid mapping is established/destroyed,
which means, cpuid <-> nodeid mapping will change if node hotplug happens. But
workqueue does not update wq_numa_possible_cpumask.

So here is the problem:

Assume we have the following cpuid <-> nodeid in the beginning:

  Node | CPU
------------------------
node 0 |  0-14, 60-74
node 1 | 15-29, 75-89
node 2 | 30-44, 90-104
node 3 | 45-59, 105-119

and we hot-remove node2 and node3, it becomes:

  Node | CPU
------------------------
node 0 |  0-14, 60-74
node 1 | 15-29, 75-89

and we hot-add node4 and node5, it becomes:

  Node | CPU
------------------------
node 0 |  0-14, 60-74
node 1 | 15-29, 75-89
node 4 | 30-59
node 5 | 90-119

But in wq_numa_possible_cpumask, cpu30 is still mapped to node2, and the like.

When a pool workqueue is initialized, if its cpumask belongs to a node, its
pool->node will be mapped to that node. And memory used by this workqueue will
also be allocated on that node.

static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs){
...
        /* if cpumask is contained inside a NUMA node, we belong to that node */
        if (wq_numa_enabled) {
                for_each_node(node) {
                        if (cpumask_subset(pool->attrs->cpumask,
                                           wq_numa_possible_cpumask[node])) {
                                pool->node = node;
                                break;
                        }
                }
        }

Since wq_numa_possible_cpumask is not updated, it could be mapped to an offline node,
which will lead to memory allocation failure:

 SLUB: Unable to allocate memory on node 2 (gfp=0x80d0)
  cache: kmalloc-192, object size: 192, buffer size: 192, default order: 1, min order: 0
  node 0: slabs: 6172, objs: 259224, free: 245741
  node 1: slabs: 3261, objs: 136962, free: 127656

It happens here:

create_worker(struct worker_pool *pool)
 |--> worker = alloc_worker(pool->node);

static struct worker *alloc_worker(int node)
{
        struct worker *worker;

        worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, node); --> Here, useing the wrong node.

        ......

        return worker;
}


[Solution]

There are four mappings in the kernel:
1. nodeid (logical node id)   <->   pxm
2. apicid (physical cpu id)   <->   nodeid
3. cpuid (logical cpu id)     <->   apicid
4. cpuid (logical cpu id)     <->   nodeid

1. pxm (proximity domain) is provided by ACPI firmware in SRAT, and nodeid <-> pxm
   mapping is setup at boot time. This mapping is persistent, won't change.

2. apicid <-> nodeid mapping is setup using info in 1. The mapping is setup at boot
   time and CPU hotadd time, and cleared at CPU hotremove time. This mapping is also
   persistent.

3. cpuid <-> apicid mapping is setup at boot time and CPU hotadd time. cpuid is
   allocated, lower ids first, and released at CPU hotremove time, reused for other
   hotadded CPUs. So this mapping is not persistent.

4. cpuid <-> nodeid mapping is also setup at boot time and CPU hotadd time, and
   cleared at CPU hotremove time. As a result of 3, this mapping is not persistent.

To fix this problem, we establish cpuid <-> nodeid mapping for all the possible
cpus at boot time, and make it persistent. And according to init_cpu_to_node(),
cpuid <-> nodeid mapping is based on apicid <-> nodeid mapping and cpuid <-> apicid
mapping. So the key point is obtaining all cpus' apicid.

apicid can be obtained by _MAT (Multiple APIC Table Entry) method or found in
MADT (Multiple APIC Description Table). So we finish the job in the following steps:

1. Enable apic registeration flow to handle both enabled and disabled cpus.
   This is done by introducing an extra parameter to generic_processor_info to let the
   caller control if disabled cpus are ignored.

2. Introduce a new array storing all possible cpuid <-> apicid mapping. And also modify
   the way cpuid is calculated. Establish all possible cpuid <-> apicid mapping when
   registering local apic. Store the mapping in this array.

3. Enable _MAT and MADT relative apis to return non-presnet or disabled cpus' apicid.
   This is also done by introducing an extra parameter to these apis to let the caller
   control if disabled cpus are ignored.

4. Establish all possible cpuid <-> nodeid mapping.
   This is done via an additional acpi namespace walk for processors.


For previous discussion, please refer to:
https://lkml.org/lkml/2015/2/27/145
https://lkml.org/lkml/2015/3/25/989
https://lkml.org/lkml/2015/5/14/244
https://lkml.org/lkml/2015/7/7/200
https://lkml.org/lkml/2015/9/27/209

Change log v3 -> v4:
1. Fix the kernel panic at boot time. The cause is that I tried to build zonelists
   before per cpu areas were initialized.

Change log v2 -> v3:
1. Online memory-less nodes at boot time to map cpus of memory-less nodes.
2. Build zonelists for memory-less nodes so that memory allocator will fall 
   back to proper nodes automatically.

Change log v1 -> v2:
1. Split code movement and actual changes. Add patch 1.
2. Synchronize best near online node record when node hotplug happens. In patch 2.
3. Fix some comment.

Gu Zheng (4):
  x86, acpi, cpu-hotplug: Enable acpi to register all possible cpus at
    boot time.
  x86, acpi, cpu-hotplug: Introduce cpuid_to_apicid[] array to store
    persistent cpuid <-> apicid mapping.
  x86, acpi, cpu-hotplug: Enable MADT APIs to return disabled apicid.
  x86, acpi, cpu-hotplug: Set persistent cpuid <-> nodeid mapping when
    booting.

Tang Chen (1):
  x86, memhp, numa: Online memory-less nodes at boot time.

 arch/ia64/kernel/acpi.c       |   2 +-
 arch/x86/include/asm/mpspec.h |   1 +
 arch/x86/kernel/acpi/boot.c   |   8 ++-
 arch/x86/kernel/apic/apic.c   |  85 +++++++++++++++++++++++++----
 arch/x86/mm/numa.c            |  27 +++++-----
 drivers/acpi/acpi_processor.c |   5 +-
 drivers/acpi/bus.c            |   3 ++
 drivers/acpi/processor_core.c | 122 ++++++++++++++++++++++++++++++++++--------
 include/linux/acpi.h          |   2 +
 include/linux/mmzone.h        |   1 +
 mm/page_alloc.c               |   2 +-
 11 files changed, 206 insertions(+), 52 deletions(-)

-- 
1.9.3



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [next] | [standalone]

#1303280 — [PATCH 1/5] x86, memhp, numa: Online memory-less nodes at boot time.

FromTang Chen <tangchen@cn.fujitsu.com>
Date2016-01-07 05:30 +0100
Subject[PATCH 1/5] x86, memhp, numa: Online memory-less nodes at boot time.
Message-ID<qOan0-2Sc-5@gated-at.bofh.it>
In reply to#1303279
For now, x86 does not support memory-less node. A node without memory
will not be onlined, and the cpus on it will be mapped to the other
online nodes with memory in init_cpu_to_node(). The reason of doing this
is to ensure each cpu has mapped to a node with memory, so that it will
be able to allocate local memory for that cpu.

But we don't have to do it in this way.

In this series of patches, we are going to construct cpu <-> node mapping
for all possible cpus at boot time, which is a 1-1 mapping. It means the
cpu will be mapped to the node it belongs to, and will never be changed.
If a node has only cpus but no memory, the cpus on it will be mapped to
a memory-less node. And the memory-less node should be onlined.

This patch allocate pgdats for all memory-less nodes and online them at
boot time. As a result, when cpus on these memory-less nodes try to allocate 
memory from local node, it will automatically fall back to the proper zones 
in the zonelists.

Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
---
 arch/x86/mm/numa.c     | 27 +++++++++++++--------------
 include/linux/mmzone.h |  1 +
 mm/page_alloc.c        |  2 +-
 3 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index c3b3f65..010edb4 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -704,22 +704,19 @@ void __init x86_numa_init(void)
 	numa_init(dummy_numa_init);
 }
 
-static __init int find_near_online_node(int node)
+static void __init init_memory_less_node(int nid)
 {
-	int n, val;
-	int min_val = INT_MAX;
-	int best_node = -1;
+	unsigned long zones_size[MAX_NR_ZONES] = {0};
+	unsigned long zholes_size[MAX_NR_ZONES] = {0};
 
-	for_each_online_node(n) {
-		val = node_distance(node, n);
+	/* Allocate and initialize node data. Memory-less node is now online.*/
+	alloc_node_data(nid);
+	free_area_init_node(nid, zones_size, 0, zholes_size);
 
-		if (val < min_val) {
-			min_val = val;
-			best_node = n;
-		}
-	}
-
-	return best_node;
+	/*
+	 * All zonelists will be built later in start_kernel() after per cpu
+	 * areas are initialized.
+	 */
 }
 
 /*
@@ -748,8 +745,10 @@ void __init init_cpu_to_node(void)
 
 		if (node == NUMA_NO_NODE)
 			continue;
+
 		if (!node_online(node))
-			node = find_near_online_node(node);
+			init_memory_less_node(node);
+
 		numa_set_node(cpu, node);
 	}
 }
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index e23a9e7..9c4d4d5 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -736,6 +736,7 @@ static inline bool is_dev_zone(const struct zone *zone)
 
 extern struct mutex zonelists_mutex;
 void build_all_zonelists(pg_data_t *pgdat, struct zone *zone);
+void build_zonelists(pg_data_t *pgdat);
 void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx);
 bool zone_watermark_ok(struct zone *z, unsigned int order,
 		unsigned long mark, int classzone_idx, int alloc_flags);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 9d666df..15c0358 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4145,7 +4145,7 @@ static void set_zonelist_order(void)
 		current_zonelist_order = user_zonelist_order;
 }
 
-static void build_zonelists(pg_data_t *pgdat)
+void build_zonelists(pg_data_t *pgdat)
 {
 	int j, node, load;
 	enum zone_type i;
-- 
1.9.3



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1304868 — Re: [PATCH 1/5] x86, memhp, numa: Online memory-less nodes at boot time.

FromTejun Heo <tj@kernel.org>
Date2016-01-08 19:30 +0100
SubjectRe: [PATCH 1/5] x86, memhp, numa: Online memory-less nodes at boot time.
Message-ID<qOJXu-29h-53@gated-at.bofh.it>
In reply to#1303280
Hello,

On Thu, Jan 07, 2016 at 12:20:21PM +0800, Tang Chen wrote:
> +static void __init init_memory_less_node(int nid)
>  {
> +	unsigned long zones_size[MAX_NR_ZONES] = {0};
> +	unsigned long zholes_size[MAX_NR_ZONES] = {0};

It doesn't cause any functional difference but it's a bit weird to use
{0} because it explicitly says to initialize the first element to 0
when the whole array needs to be cleared.  Wouldnt { } make more sense?

> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index e23a9e7..9c4d4d5 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -736,6 +736,7 @@ static inline bool is_dev_zone(const struct zone *zone)
>  
>  extern struct mutex zonelists_mutex;
>  void build_all_zonelists(pg_data_t *pgdat, struct zone *zone);
> +void build_zonelists(pg_data_t *pgdat);

This isn't used in this patch.  Contamination?

Thanks.

-- 
tejun

[toc] | [prev] | [next] | [standalone]

#1308046 — Re: [PATCH 1/5] x86, memhp, numa: Online memory-less nodes at boot time.

FromTang Chen <tangchen@cn.fujitsu.com>
Date2016-01-13 06:00 +0100
SubjectRe: [PATCH 1/5] x86, memhp, numa: Online memory-less nodes at boot time.
Message-ID<qQlHk-2ZE-7@gated-at.bofh.it>
In reply to#1304868
Hi tj,

On 01/09/2016 02:28 AM, Tejun Heo wrote:
> Hello,
>
> On Thu, Jan 07, 2016 at 12:20:21PM +0800, Tang Chen wrote:
>> +static void __init init_memory_less_node(int nid)
>>   {
>> +	unsigned long zones_size[MAX_NR_ZONES] = {0};
>> +	unsigned long zholes_size[MAX_NR_ZONES] = {0};
> It doesn't cause any functional difference but it's a bit weird to use
> {0} because it explicitly says to initialize the first element to 0
> when the whole array needs to be cleared.  Wouldnt { } make more sense?

Yes. Will fix them.

>
>> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
>> index e23a9e7..9c4d4d5 100644
>> --- a/include/linux/mmzone.h
>> +++ b/include/linux/mmzone.h
>> @@ -736,6 +736,7 @@ static inline bool is_dev_zone(const struct zone *zone)
>>   
>>   extern struct mutex zonelists_mutex;
>>   void build_all_zonelists(pg_data_t *pgdat, struct zone *zone);
>> +void build_zonelists(pg_data_t *pgdat);
> This isn't used in this patch.  Contamination?

Sorry, I tried to build zone lists here. But it totally unnecessary and 
led to some problems.

I forgot to remove them when I fixed the problems. Will remove them.

Thx.

>
> Thanks.
>

[toc] | [prev] | [next] | [standalone]

#1303281 — [PATCH 5/5] x86, acpi, cpu-hotplug: Set persistent cpuid <-> nodeid mapping when booting.

FromTang Chen <tangchen@cn.fujitsu.com>
Date2016-01-07 05:30 +0100
Subject[PATCH 5/5] x86, acpi, cpu-hotplug: Set persistent cpuid <-> nodeid mapping when booting.
Message-ID<qOan0-2Sc-7@gated-at.bofh.it>
In reply to#1303279
From: Gu Zheng <guz.fnst@cn.fujitsu.com>

This patch finishes step 4.

This patch set the persistent cpuid <-> nodeid mapping for all enabled/disabled
processors at boot time via an additional acpi namespace walk for processors.

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
---
 arch/ia64/kernel/acpi.c       |  2 +-
 arch/x86/kernel/acpi/boot.c   |  2 +-
 drivers/acpi/bus.c            |  3 ++
 drivers/acpi/processor_core.c | 65 +++++++++++++++++++++++++++++++++++++++++++
 include/linux/acpi.h          |  2 ++
 5 files changed, 72 insertions(+), 2 deletions(-)

diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index b1698bc..7db5563 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -796,7 +796,7 @@ int acpi_isa_irq_to_gsi(unsigned isa_irq, u32 *gsi)
  *  ACPI based hotplug CPU support
  */
 #ifdef CONFIG_ACPI_HOTPLUG_CPU
-static int acpi_map_cpu2node(acpi_handle handle, int cpu, int physid)
+int acpi_map_cpu2node(acpi_handle handle, int cpu, int physid)
 {
 #ifdef CONFIG_ACPI_NUMA
 	/*
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 0ce06ee..7d45261 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -696,7 +696,7 @@ static void __init acpi_set_irq_model_ioapic(void)
 #ifdef CONFIG_ACPI_HOTPLUG_CPU
 #include <acpi/processor.h>
 
-static void acpi_map_cpu2node(acpi_handle handle, int cpu, int physid)
+void acpi_map_cpu2node(acpi_handle handle, int cpu, int physid)
 {
 #ifdef CONFIG_ACPI_NUMA
 	int nid;
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index a212cef..d59e1cd 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -1094,6 +1094,9 @@ static int __init acpi_init(void)
 	acpi_debugfs_init();
 	acpi_sleep_proc_init();
 	acpi_wakeup_device_init();
+#ifdef CONFIG_ACPI_HOTPLUG_CPU
+	acpi_set_processor_mapping();
+#endif
 	return 0;
 }
 
diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index 824b98b..45580ff 100644
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -261,6 +261,71 @@ int acpi_get_cpuid(acpi_handle handle, int type, u32 acpi_id)
 }
 EXPORT_SYMBOL_GPL(acpi_get_cpuid);
 
+#ifdef CONFIG_ACPI_HOTPLUG_CPU
+static bool map_processor(acpi_handle handle, int *phys_id, int *cpuid)
+{
+	int type;
+	u32 acpi_id;
+	acpi_status status;
+	acpi_object_type acpi_type;
+	unsigned long long tmp;
+	union acpi_object object = { 0 };
+	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
+
+	status = acpi_get_type(handle, &acpi_type);
+	if (ACPI_FAILURE(status))
+		return false;
+
+	switch (acpi_type) {
+	case ACPI_TYPE_PROCESSOR:
+		status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
+		if (ACPI_FAILURE(status))
+			return false;
+		acpi_id = object.processor.proc_id;
+		break;
+	case ACPI_TYPE_DEVICE:
+		status = acpi_evaluate_integer(handle, "_UID", NULL, &tmp);
+		if (ACPI_FAILURE(status))
+			return false;
+		acpi_id = tmp;
+		break;
+	default:
+		return false;
+	}
+
+	type = (acpi_type == ACPI_TYPE_DEVICE) ? 1 : 0;
+
+	*phys_id = __acpi_get_phys_id(handle, type, acpi_id, false);
+	*cpuid = acpi_map_cpuid(*phys_id, acpi_id);
+	if (*cpuid == -1)
+		return false;
+
+	return true;
+}
+
+static acpi_status __init
+set_processor_node_mapping(acpi_handle handle, u32 lvl, void *context,
+			   void **rv)
+{
+	u32 apic_id;
+	int cpu_id;
+
+	if (!map_processor(handle, &apic_id, &cpu_id))
+		return AE_ERROR;
+
+	acpi_map_cpu2node(handle, cpu_id, apic_id);
+	return AE_OK;
+}
+
+void __init acpi_set_processor_mapping(void)
+{
+	/* Set persistent cpu <-> node mapping for all processors. */
+	acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
+			    ACPI_UINT32_MAX, set_processor_node_mapping,
+			    NULL, NULL, NULL);
+}
+#endif
+
 #ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
 static int get_ioapic_id(struct acpi_subtable_header *entry, u32 gsi_base,
 			 u64 *phys_addr, int *ioapic_id)
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 1991aea..327cb7e 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -194,6 +194,8 @@ static inline bool invalid_phys_cpuid(phys_cpuid_t phys_id)
 /* Arch dependent functions for cpu hotplug support */
 int acpi_map_cpu(acpi_handle handle, phys_cpuid_t physid, int *pcpu);
 int acpi_unmap_cpu(int cpu);
+void acpi_map_cpu2node(acpi_handle handle, int cpu, int physid);
+void __init acpi_set_processor_mapping(void);
 #endif /* CONFIG_ACPI_HOTPLUG_CPU */
 
 #ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
-- 
1.9.3



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1304942 — Re: [PATCH 5/5] x86, acpi, cpu-hotplug: Set persistent cpuid <-> nodeid mapping when booting.

FromTejun Heo <tj@kernel.org>
Date2016-01-08 20:20 +0100
SubjectRe: [PATCH 5/5] x86, acpi, cpu-hotplug: Set persistent cpuid <-> nodeid mapping when booting.
Message-ID<qOKJP-2Kn-1@gated-at.bofh.it>
In reply to#1303281
Hello, Tang.

On Thu, Jan 07, 2016 at 12:20:25PM +0800, Tang Chen wrote:
> From: Gu Zheng <guz.fnst@cn.fujitsu.com>
> 
> This patch finishes step 4.

This doesn't help people trying to read the patch.  If you wanna say
it's one of the steps of something, you also need to say what the
steps are.  No need to duplicate the whole thing but a short summary
would be helpful.

> This patch set the persistent cpuid <-> nodeid mapping for all enabled/disabled
> processors at boot time via an additional acpi namespace walk for processors.

So, the patchset generally looks good to me although I'm not too
familiar with acpi.  Rafael, Len, what do you think?

Thanks.

-- 
tejun

[toc] | [prev] | [next] | [standalone]

#1308045 — Re: [PATCH 5/5] x86, acpi, cpu-hotplug: Set persistent cpuid <-> nodeid mapping when booting.

FromTang Chen <tangchen@cn.fujitsu.com>
Date2016-01-13 06:00 +0100
SubjectRe: [PATCH 5/5] x86, acpi, cpu-hotplug: Set persistent cpuid <-> nodeid mapping when booting.
Message-ID<qQlHk-2ZE-5@gated-at.bofh.it>
In reply to#1304942
On 01/09/2016 03:13 AM, Tejun Heo wrote:
> Hello, Tang.
>
> On Thu, Jan 07, 2016 at 12:20:25PM +0800, Tang Chen wrote:
>> From: Gu Zheng <guz.fnst@cn.fujitsu.com>
>>
>> This patch finishes step 4.
> This doesn't help people trying to read the patch.  If you wanna say
> it's one of the steps of something, you also need to say what the
> steps are.  No need to duplicate the whole thing but a short summary
> would be helpful.

Sure. Thx.

>
>> This patch set the persistent cpuid <-> nodeid mapping for all enabled/disabled
>> processors at boot time via an additional acpi namespace walk for processors.
> So, the patchset generally looks good to me although I'm not too
> familiar with acpi.  Rafael, Len, what do you think?
>
> Thanks.
>

[toc] | [prev] | [next] | [standalone]

#1303282 — [PATCH 2/5] x86, acpi, cpu-hotplug: Enable acpi to register all possible cpus at boot time.

FromTang Chen <tangchen@cn.fujitsu.com>
Date2016-01-07 05:30 +0100
Subject[PATCH 2/5] x86, acpi, cpu-hotplug: Enable acpi to register all possible cpus at boot time.
Message-ID<qOan0-2Sc-11@gated-at.bofh.it>
In reply to#1303279
From: Gu Zheng <guz.fnst@cn.fujitsu.com>

[Problem]

cpuid <-> nodeid mapping is firstly established at boot time. And workqueue caches
the mapping in wq_numa_possible_cpumask in wq_numa_init() at boot time.

When doing node online/offline, cpuid <-> nodeid mapping is established/destroyed,
which means, cpuid <-> nodeid mapping will change if node hotplug happens. But
workqueue does not update wq_numa_possible_cpumask.

So here is the problem:

Assume we have the following cpuid <-> nodeid in the beginning:

  Node | CPU
------------------------
node 0 |  0-14, 60-74
node 1 | 15-29, 75-89
node 2 | 30-44, 90-104
node 3 | 45-59, 105-119

and we hot-remove node2 and node3, it becomes:

  Node | CPU
------------------------
node 0 |  0-14, 60-74
node 1 | 15-29, 75-89

and we hot-add node4 and node5, it becomes:

  Node | CPU
------------------------
node 0 |  0-14, 60-74
node 1 | 15-29, 75-89
node 4 | 30-59
node 5 | 90-119

But in wq_numa_possible_cpumask, cpu30 is still mapped to node2, and the like.

When a pool workqueue is initialized, if its cpumask belongs to a node, its
pool->node will be mapped to that node. And memory used by this workqueue will
also be allocated on that node.

static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs){
...
        /* if cpumask is contained inside a NUMA node, we belong to that node */
        if (wq_numa_enabled) {
                for_each_node(node) {
                        if (cpumask_subset(pool->attrs->cpumask,
                                           wq_numa_possible_cpumask[node])) {
                                pool->node = node;
                                break;
                        }
                }
        }

Since wq_numa_possible_cpumask is not updated, it could be mapped to an offline node,
which will lead to memory allocation failure:

 SLUB: Unable to allocate memory on node 2 (gfp=0x80d0)
  cache: kmalloc-192, object size: 192, buffer size: 192, default order: 1, min order: 0
  node 0: slabs: 6172, objs: 259224, free: 245741
  node 1: slabs: 3261, objs: 136962, free: 127656

It happens here:

create_worker(struct worker_pool *pool)
 |--> worker = alloc_worker(pool->node);

static struct worker *alloc_worker(int node)
{
        struct worker *worker;

        worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, node); --> Here, useing the wrong node.

        ......

        return worker;
}

[Solution]

There are four mappings in the kernel:
1. nodeid (logical node id)   <->   pxm
2. apicid (physical cpu id)   <->   nodeid
3. cpuid (logical cpu id)     <->   apicid
4. cpuid (logical cpu id)     <->   nodeid

1. pxm (proximity domain) is provided by ACPI firmware in SRAT, and nodeid <-> pxm
   mapping is setup at boot time. This mapping is persistent, won't change.

2. apicid <-> nodeid mapping is setup using info in 1. The mapping is setup at boot
   time and CPU hotadd time, and cleared at CPU hotremove time. This mapping is also
   persistent.

3. cpuid <-> apicid mapping is setup at boot time and CPU hotadd time. cpuid is
   allocated, lower ids first, and released at CPU hotremove time, reused for other
   hotadded CPUs. So this mapping is not persistent.

4. cpuid <-> nodeid mapping is also setup at boot time and CPU hotadd time, and
   cleared at CPU hotremove time. As a result of 3, this mapping is not persistent.

To fix this problem, we establish cpuid <-> nodeid mapping for all the possible
cpus at boot time, and make it persistent. And according to init_cpu_to_node(),
cpuid <-> nodeid mapping is based on apicid <-> nodeid mapping and cpuid <-> apicid
mapping. So the key point is obtaining all cpus' apicid.

apicid can be obtained by _MAT (Multiple APIC Table Entry) method or found in
MADT (Multiple APIC Description Table). So we finish the job in the following steps:

1. Enable apic registeration flow to handle both enabled and disabled cpus.
   This is done by introducing an extra parameter to generic_processor_info to let the
   caller control if disabled cpus are ignored.

2. Introduce a new array storing all possible cpuid <-> apicid mapping. And also modify
   the way cpuid is calculated. Establish all possible cpuid <-> apicid mapping when
   registering local apic. Store the mapping in this array.

3. Enable _MAT and MADT relative apis to return non-presnet or disabled cpus' apicid.
   This is also done by introducing an extra parameter to these apis to let the caller
   control if disabled cpus are ignored.

4. Establish all possible cpuid <-> nodeid mapping.
   This is done via an additional acpi namespace walk for processors.

This patch finished step 1.

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
---
 arch/x86/kernel/apic/apic.c | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 2f69e3b..29915cf 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1988,7 +1988,7 @@ void disconnect_bsp_APIC(int virt_wire_setup)
 	apic_write(APIC_LVT1, value);
 }
 
-int generic_processor_info(int apicid, int version)
+static int __generic_processor_info(int apicid, int version, bool enabled)
 {
 	int cpu, max = nr_cpu_ids;
 	bool boot_cpu_detected = physid_isset(boot_cpu_physical_apicid,
@@ -2022,7 +2022,8 @@ int generic_processor_info(int apicid, int version)
 			   " Processor %d/0x%x ignored.\n",
 			   thiscpu, apicid);
 
-		disabled_cpus++;
+		if (enabled)
+			disabled_cpus++;
 		return -ENODEV;
 	}
 
@@ -2039,7 +2040,8 @@ int generic_processor_info(int apicid, int version)
 			" reached. Keeping one slot for boot cpu."
 			"  Processor %d/0x%x ignored.\n", max, thiscpu, apicid);
 
-		disabled_cpus++;
+		if (enabled)
+			disabled_cpus++;
 		return -ENODEV;
 	}
 
@@ -2050,11 +2052,14 @@ int generic_processor_info(int apicid, int version)
 			"ACPI: NR_CPUS/possible_cpus limit of %i reached."
 			"  Processor %d/0x%x ignored.\n", max, thiscpu, apicid);
 
-		disabled_cpus++;
+		if (enabled)
+			disabled_cpus++;
 		return -EINVAL;
 	}
 
-	num_processors++;
+	if (enabled)
+		num_processors++;
+
 	if (apicid == boot_cpu_physical_apicid) {
 		/*
 		 * x86_bios_cpu_apicid is required to have processors listed
@@ -2082,7 +2087,8 @@ int generic_processor_info(int apicid, int version)
 			apic_version[boot_cpu_physical_apicid], cpu, version);
 	}
 
-	physid_set(apicid, phys_cpu_present_map);
+	if (enabled)
+		physid_set(apicid, phys_cpu_present_map);
 	if (apicid > max_physical_apicid)
 		max_physical_apicid = apicid;
 
@@ -2095,11 +2101,17 @@ int generic_processor_info(int apicid, int version)
 		apic->x86_32_early_logical_apicid(cpu);
 #endif
 	set_cpu_possible(cpu, true);
-	set_cpu_present(cpu, true);
+	if (enabled)
+		set_cpu_present(cpu, true);
 
 	return cpu;
 }
 
+int generic_processor_info(int apicid, int version)
+{
+	return __generic_processor_info(apicid, version, true);
+}
+
 int hard_smp_processor_id(void)
 {
 	return read_apic_id();
-- 
1.9.3



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1303283 — [PATCH 4/5] x86, acpi, cpu-hotplug: Enable MADT APIs to return disabled apicid.

FromTang Chen <tangchen@cn.fujitsu.com>
Date2016-01-07 05:30 +0100
Subject[PATCH 4/5] x86, acpi, cpu-hotplug: Enable MADT APIs to return disabled apicid.
Message-ID<qOan0-2Sc-13@gated-at.bofh.it>
In reply to#1303279
From: Gu Zheng <guz.fnst@cn.fujitsu.com>

This patch finishes step 3.

There are four mappings in the kernel:
1. nodeid (logical node id)   <->   pxm
2. apicid (physical cpu id)   <->   nodeid
3. cpuid (logical cpu id)     <->   apicid
4. cpuid (logical cpu id)     <->   nodeid

1. pxm (proximity domain) is provided by ACPI firmware in SRAT, and nodeid <-> pxm
   mapping is setup at boot time. This mapping is persistent, won't change.

2. apicid <-> nodeid mapping is setup using info in 1. The mapping is setup at boot
   time and CPU hotadd time, and cleared at CPU hotremove time. This mapping is also
   persistent.

3. cpuid <-> apicid mapping is setup at boot time and CPU hotadd time. cpuid is
   allocated, lower ids first, and released at CPU hotremove time, reused for other
   hotadded CPUs. So this mapping is not persistent.

4. cpuid <-> nodeid mapping is also setup at boot time and CPU hotadd time, and
   cleared at CPU hotremove time. As a result of 3, this mapping is not persistent.

So, in order to setup persistent cpuid <-> nodeid mapping for all possible CPUs,
we should:
1. Setup cpuid <-> apicid mapping for all possible CPUs, which has been done in step 1.
2. Setup cpuid <-> nodeid mapping for all possible CPUs. But before that, we should
   obtain all apicids from MADT.

All processors' apicids can be obtained by _MAT method or from MADT in ACPI.
The current code ignores disabled processors and returns -ENODEV.

After this patch, a new parameter will be added to MADT APIs so that caller
is able to control if disabled processors are ignored.

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
---
 drivers/acpi/acpi_processor.c |  5 +++-
 drivers/acpi/processor_core.c | 57 +++++++++++++++++++++++++++----------------
 2 files changed, 40 insertions(+), 22 deletions(-)

diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index 6979186..d30111a 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -300,8 +300,11 @@ static int acpi_processor_get_info(struct acpi_device *device)
 	 *  Extra Processor objects may be enumerated on MP systems with
 	 *  less than the max # of CPUs. They should be ignored _iff
 	 *  they are physically not present.
+	 *
+	 *  NOTE: Even if the processor has a cpuid, it may not present because
+	 *  cpuid <-> apicid mapping is persistent now.
 	 */
-	if (invalid_logical_cpuid(pr->id)) {
+	if (invalid_logical_cpuid(pr->id) || !cpu_present(pr->id)) {
 		int ret = acpi_processor_hotadd_init(pr);
 		if (ret)
 			return ret;
diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index 33a38d6..824b98b 100644
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -32,12 +32,12 @@ static struct acpi_table_madt *get_madt_table(void)
 }
 
 static int map_lapic_id(struct acpi_subtable_header *entry,
-		 u32 acpi_id, phys_cpuid_t *apic_id)
+		 u32 acpi_id, phys_cpuid_t *apic_id, bool ignore_disabled)
 {
 	struct acpi_madt_local_apic *lapic =
 		container_of(entry, struct acpi_madt_local_apic, header);
 
-	if (!(lapic->lapic_flags & ACPI_MADT_ENABLED))
+	if (ignore_disabled && !(lapic->lapic_flags & ACPI_MADT_ENABLED))
 		return -ENODEV;
 
 	if (lapic->processor_id != acpi_id)
@@ -48,12 +48,13 @@ static int map_lapic_id(struct acpi_subtable_header *entry,
 }
 
 static int map_x2apic_id(struct acpi_subtable_header *entry,
-		int device_declaration, u32 acpi_id, phys_cpuid_t *apic_id)
+		int device_declaration, u32 acpi_id, phys_cpuid_t *apic_id,
+		bool ignore_disabled)
 {
 	struct acpi_madt_local_x2apic *apic =
 		container_of(entry, struct acpi_madt_local_x2apic, header);
 
-	if (!(apic->lapic_flags & ACPI_MADT_ENABLED))
+	if (ignore_disabled && !(apic->lapic_flags & ACPI_MADT_ENABLED))
 		return -ENODEV;
 
 	if (device_declaration && (apic->uid == acpi_id)) {
@@ -65,12 +66,13 @@ static int map_x2apic_id(struct acpi_subtable_header *entry,
 }
 
 static int map_lsapic_id(struct acpi_subtable_header *entry,
-		int device_declaration, u32 acpi_id, phys_cpuid_t *apic_id)
+		int device_declaration, u32 acpi_id, phys_cpuid_t *apic_id,
+		bool ignore_disabled)
 {
 	struct acpi_madt_local_sapic *lsapic =
 		container_of(entry, struct acpi_madt_local_sapic, header);
 
-	if (!(lsapic->lapic_flags & ACPI_MADT_ENABLED))
+	if (ignore_disabled && !(lsapic->lapic_flags & ACPI_MADT_ENABLED))
 		return -ENODEV;
 
 	if (device_declaration) {
@@ -87,12 +89,13 @@ static int map_lsapic_id(struct acpi_subtable_header *entry,
  * Retrieve the ARM CPU physical identifier (MPIDR)
  */
 static int map_gicc_mpidr(struct acpi_subtable_header *entry,
-		int device_declaration, u32 acpi_id, phys_cpuid_t *mpidr)
+		int device_declaration, u32 acpi_id, phys_cpuid_t *mpidr,
+		bool ignore_disabled)
 {
 	struct acpi_madt_generic_interrupt *gicc =
 	    container_of(entry, struct acpi_madt_generic_interrupt, header);
 
-	if (!(gicc->flags & ACPI_MADT_ENABLED))
+	if (ignore_disabled && !(gicc->flags & ACPI_MADT_ENABLED))
 		return -ENODEV;
 
 	/* device_declaration means Device object in DSDT, in the
@@ -108,7 +111,7 @@ static int map_gicc_mpidr(struct acpi_subtable_header *entry,
 	return -EINVAL;
 }
 
-static phys_cpuid_t map_madt_entry(int type, u32 acpi_id)
+static phys_cpuid_t map_madt_entry(int type, u32 acpi_id, bool ignore_disabled)
 {
 	unsigned long madt_end, entry;
 	phys_cpuid_t phys_id = PHYS_CPUID_INVALID;	/* CPU hardware ID */
@@ -128,16 +131,20 @@ static phys_cpuid_t map_madt_entry(int type, u32 acpi_id)
 		struct acpi_subtable_header *header =
 			(struct acpi_subtable_header *)entry;
 		if (header->type == ACPI_MADT_TYPE_LOCAL_APIC) {
-			if (!map_lapic_id(header, acpi_id, &phys_id))
+			if (!map_lapic_id(header, acpi_id, &phys_id,
+					  ignore_disabled))
 				break;
 		} else if (header->type == ACPI_MADT_TYPE_LOCAL_X2APIC) {
-			if (!map_x2apic_id(header, type, acpi_id, &phys_id))
+			if (!map_x2apic_id(header, type, acpi_id, &phys_id,
+					   ignore_disabled))
 				break;
 		} else if (header->type == ACPI_MADT_TYPE_LOCAL_SAPIC) {
-			if (!map_lsapic_id(header, type, acpi_id, &phys_id))
+			if (!map_lsapic_id(header, type, acpi_id, &phys_id,
+					   ignore_disabled))
 				break;
 		} else if (header->type == ACPI_MADT_TYPE_GENERIC_INTERRUPT) {
-			if (!map_gicc_mpidr(header, type, acpi_id, &phys_id))
+			if (!map_gicc_mpidr(header, type, acpi_id, &phys_id,
+					    ignore_disabled))
 				break;
 		}
 		entry += header->length;
@@ -145,7 +152,8 @@ static phys_cpuid_t map_madt_entry(int type, u32 acpi_id)
 	return phys_id;
 }
 
-static phys_cpuid_t map_mat_entry(acpi_handle handle, int type, u32 acpi_id)
+static phys_cpuid_t map_mat_entry(acpi_handle handle, int type, u32 acpi_id,
+				  bool ignore_disabled)
 {
 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 	union acpi_object *obj;
@@ -166,30 +174,37 @@ static phys_cpuid_t map_mat_entry(acpi_handle handle, int type, u32 acpi_id)
 
 	header = (struct acpi_subtable_header *)obj->buffer.pointer;
 	if (header->type == ACPI_MADT_TYPE_LOCAL_APIC)
-		map_lapic_id(header, acpi_id, &phys_id);
+		map_lapic_id(header, acpi_id, &phys_id, ignore_disabled);
 	else if (header->type == ACPI_MADT_TYPE_LOCAL_SAPIC)
-		map_lsapic_id(header, type, acpi_id, &phys_id);
+		map_lsapic_id(header, type, acpi_id, &phys_id, ignore_disabled);
 	else if (header->type == ACPI_MADT_TYPE_LOCAL_X2APIC)
-		map_x2apic_id(header, type, acpi_id, &phys_id);
+		map_x2apic_id(header, type, acpi_id, &phys_id, ignore_disabled);
 	else if (header->type == ACPI_MADT_TYPE_GENERIC_INTERRUPT)
-		map_gicc_mpidr(header, type, acpi_id, &phys_id);
+		map_gicc_mpidr(header, type, acpi_id, &phys_id,
+			       ignore_disabled);
 
 exit:
 	kfree(buffer.pointer);
 	return phys_id;
 }
 
-phys_cpuid_t acpi_get_phys_id(acpi_handle handle, int type, u32 acpi_id)
+static phys_cpuid_t __acpi_get_phys_id(acpi_handle handle, int type,
+				       u32 acpi_id, bool ignore_disabled)
 {
 	phys_cpuid_t phys_id;
 
-	phys_id = map_mat_entry(handle, type, acpi_id);
+	phys_id = map_mat_entry(handle, type, acpi_id, ignore_disabled);
 	if (invalid_phys_cpuid(phys_id))
-		phys_id = map_madt_entry(type, acpi_id);
+		phys_id = map_madt_entry(type, acpi_id, ignore_disabled);
 
 	return phys_id;
 }
 
+phys_cpuid_t acpi_get_phys_id(acpi_handle handle, int type, u32 acpi_id)
+{
+	return __acpi_get_phys_id(handle, type, acpi_id, true);
+}
+
 int acpi_map_cpuid(phys_cpuid_t phys_id, u32 acpi_id)
 {
 #ifdef CONFIG_SMP
-- 
1.9.3



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web