* [PATCH] ACPI: NUMA: Process hotpluggable memblocks when !CONFIG_MEMORY_HOTPLUG
@ 2021-12-16 9:58 Vitaly Kuznetsov
2021-12-17 18:12 ` Rafael J. Wysocki
0 siblings, 1 reply; 2+ messages in thread
From: Vitaly Kuznetsov @ 2021-12-16 9:58 UTC (permalink / raw)
To: linux-acpi
Cc: Rafael J. Wysocki, Len Brown, Huacai Chen, Igor Mammedov,
linux-kernel
Some systems (e.g. Hyper-V guests) have all their memory marked as
hotpluggable in SRAT. acpi_numa_memory_affinity_init(), however,
ignores all such regions when !CONFIG_MEMORY_HOTPLUG and this is
unfortunate as memory affinity (NUMA) information gets lost.
'Hot Pluggable' flag in SRAT only means that "system hardware supports
hot-add and hot-remove of this memory region", it doesn't prevent
memory from being cold-plugged there.
Ignore 'Hot Pluggable' bit instead of skipping the whole memory
affinity information when !CONFIG_MEMORY_HOTPLUG.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
drivers/acpi/numa/srat.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/acpi/numa/srat.c b/drivers/acpi/numa/srat.c
index b8795fc49097..6c884f3e8332 100644
--- a/drivers/acpi/numa/srat.c
+++ b/drivers/acpi/numa/srat.c
@@ -254,9 +254,8 @@ acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)
}
if ((ma->flags & ACPI_SRAT_MEM_ENABLED) == 0)
goto out_err;
- hotpluggable = ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE;
- if (hotpluggable && !IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
- goto out_err;
+ hotpluggable = IS_ENABLED(CONFIG_MEMORY_HOTPLUG) &&
+ (ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE);
start = ma->base_address;
end = start + ma->length;
--
2.33.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] ACPI: NUMA: Process hotpluggable memblocks when !CONFIG_MEMORY_HOTPLUG
2021-12-16 9:58 [PATCH] ACPI: NUMA: Process hotpluggable memblocks when !CONFIG_MEMORY_HOTPLUG Vitaly Kuznetsov
@ 2021-12-17 18:12 ` Rafael J. Wysocki
0 siblings, 0 replies; 2+ messages in thread
From: Rafael J. Wysocki @ 2021-12-17 18:12 UTC (permalink / raw)
To: Vitaly Kuznetsov
Cc: ACPI Devel Maling List, Rafael J. Wysocki, Len Brown, Huacai Chen,
Igor Mammedov, Linux Kernel Mailing List, Jonathan Cameron,
Dan Williams
On Thu, Dec 16, 2021 at 10:58 AM Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>
> Some systems (e.g. Hyper-V guests) have all their memory marked as
> hotpluggable in SRAT. acpi_numa_memory_affinity_init(), however,
> ignores all such regions when !CONFIG_MEMORY_HOTPLUG and this is
> unfortunate as memory affinity (NUMA) information gets lost.
>
> 'Hot Pluggable' flag in SRAT only means that "system hardware supports
> hot-add and hot-remove of this memory region", it doesn't prevent
> memory from being cold-plugged there.
>
> Ignore 'Hot Pluggable' bit instead of skipping the whole memory
> affinity information when !CONFIG_MEMORY_HOTPLUG.
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Makes sense to me, so applied as 5.17 material, but CC Dan and
Jonathan in case this can be problematic for some mm-related reason.
> ---
> drivers/acpi/numa/srat.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/acpi/numa/srat.c b/drivers/acpi/numa/srat.c
> index b8795fc49097..6c884f3e8332 100644
> --- a/drivers/acpi/numa/srat.c
> +++ b/drivers/acpi/numa/srat.c
> @@ -254,9 +254,8 @@ acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)
> }
> if ((ma->flags & ACPI_SRAT_MEM_ENABLED) == 0)
> goto out_err;
> - hotpluggable = ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE;
> - if (hotpluggable && !IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
> - goto out_err;
> + hotpluggable = IS_ENABLED(CONFIG_MEMORY_HOTPLUG) &&
> + (ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE);
>
> start = ma->base_address;
> end = start + ma->length;
> --
> 2.33.1
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-12-16 9:58 [PATCH] ACPI: NUMA: Process hotpluggable memblocks when !CONFIG_MEMORY_HOTPLUG Vitaly Kuznetsov
2021-12-17 18:12 ` Rafael J. Wysocki
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