It is not node 0, it is whatever node the kernel resides in.
Tang Chen <tangchen@xxxxxxxxxxxxxx> wrote:
>When using movablemem_map=acpi, always set node0 as unhotpluggable,
>otherwise
>if all the memory is hotpluggable, the kernel will fail to boot.
>
>When using movablemem_map=nn[KMG]@ss[KMG], we don't stop users
>specifying
>node0 as hotpluggable, and ignore all the info in SRAT, so that this
>option
>can be used as a workaround of firmware bugs.
>
>Reported-by: H. Peter Anvin <hpa@xxxxxxxxx>
>Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
>---
> Documentation/kernel-parameters.txt | 6 ++++++
> arch/x86/mm/srat.c | 10 ++++++++--
> 2 files changed, 14 insertions(+), 2 deletions(-)
>
>diff --git a/Documentation/kernel-parameters.txt
>b/Documentation/kernel-parameters.txt
>index 7d1b6fc..81b6f15 100644
>--- a/Documentation/kernel-parameters.txt
>+++ b/Documentation/kernel-parameters.txt
>@@ -1645,6 +1645,8 @@ bytes respectively. Such letter suffixes can also
>be entirely omitted.
> in flags from SRAT from ACPI BIOS to determine which
> memory devices could be hotplugged. The corresponding
> memory ranges will be set as ZONE_MOVABLE.
>+ NOTE: node0 should always be unhotpluggable, otherwise
>+ the kernel will fail to boot.
>
> movablemem_map=nn[KMG]@ss[KMG]
> [KNL,X86,IA-64,PPC] This parameter is similar to
>@@ -1666,6 +1668,10 @@ bytes respectively. Such letter suffixes can
>also be entirely omitted.
> satisfied. So the administrator should be careful that
> the amount of movablemem_map areas are not too large.
> Otherwise kernel won't have enough memory to start.
>+ NOTE: We don't stop users specifying node0 as
>+ hotpluggable, and ingore all the info in SRAT so
>+ that this option can be used as a workaround of
>+ firmware bugs.
>
> MTD_Partition= [MTD]
> Format: <name>,<region-number>,<size>,<offset>
>diff --git a/arch/x86/mm/srat.c b/arch/x86/mm/srat.c
>index b20b5b7..a85d2b7 100644
>--- a/arch/x86/mm/srat.c
>+++ b/arch/x86/mm/srat.c
>@@ -161,9 +161,13 @@ handle_movablemem(int node, u64 start, u64 end,
>u32 hotpluggable)
> *
> * Using movablemem_map, we can prevent memblock from allocating
>memory
> * on ZONE_MOVABLE at boot time.
>+ *
>+ * NOTE: node0 shoule always be unhotpluggable, otherwise, if all the
>+ * memory is hotpluggable, there will be no memory kernel can
>use.
> */
> if (hotpluggable && movablemem_map.acpi) {
>- insert_movablemem_map(start_pfn, end_pfn);
>+ if (node != 0)
>+ insert_movablemem_map(start_pfn, end_pfn);
> goto out;
> }
>
>@@ -178,7 +182,9 @@ handle_movablemem(int node, u64 start, u64 end, u32
>hotpluggable)
> * Using movablemem_map, we can prevent memblock from allocating
>memory
> * on ZONE_MOVABLE at boot time.
> *
>- * NOTE: In this case, SRAT info will be ingored.
>+ * NOTE: We don't stop users specifying node0 as hotpluggable, and
>+ * ignore all the info in SRAT, so that this option can be used
>+ * as a workaround of firmware bugs.
> */
> overlap = movablemem_map_overlap(start_pfn, end_pfn);
> if (overlap >= 0) {
--
Sent from my mobile phone. Please excuse brevity and lack of formatting.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>