Messages in this thread | | | Subject | Re: [RFC PATCH 0/2] arm64: memory-hotplug: Add Memory Hotplug support | From | Scott Branden <> | Date | Thu, 1 Dec 2016 18:38:46 -0800 |
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Hi Xishi,
Thanks for the reply - please see comments below.
On 16-12-01 05:49 PM, Xishi Qiu wrote: > On 2016/12/2 8:19, Scott Branden wrote: > >> This patchset is sent for comment to add memory hotplug support for ARM64 >> based platforms. It follows hotplug code added for other architectures >> in the linux kernel. >> >> I tried testing the memory hotplug feature following documentation from >> Documentation/memory-hotplug.txt. I don't think it is working as expected >> - see below: >> >> To add memory to the system I did the following: >> echo 0x400000000 > /sys/devices/system/memory/probe >> >> The memory is displayed as system ram: >> cat /proc/iomem: >> 74000000-77ffffff : System RAM >> 74080000-748dffff : Kernel code >> 74950000-749d2fff : Kernel data >> 400000000-43fffffff : System RAM >> >> But does not seem to be added to the kernel memory. >> /proc/meminfo did not change. >> >> What else needs to be done so the memory is added to the kernel memory >> pool for normal allocation? >> > > Hi Scott, > > Do you mean it still don't support hod-add after apply this patchset?
After applying the patch it appears to partially support hot-add. Please let me know if you think it is working as expected?
The memory probe functions in that the memory is registered with the system and shows up in /proc/iomem. But, the memory is not available in /proc/meminfo. Do you think something else needs to be adjusted for ARM64 to hotadd the memory
I just found another clue: under /sys/devices/system/memory I only see one memory entry (before or after I try to hotadd additional memory).
/sys/devices/system/memory # ls auto_online_blocks memory0 uevent block_size_bytes probe
In arch/arm64/include/asm/sparsemem.h if I change SECTION_SIZE_BITS from 30 to 28 and recompile I get the following: /sys/devices/system/memory # ls auto_online_blocks memory7 uevent block_size_bytes probe
In arch/arm64/include/asm/sparsemem.h if I change SECTION_SIZE_BITS from 30 to 27 and recompile I get the following: /sys/devices/system/memory # ls auto_online_blocks memory14 uevent block_size_bytes probe
If looks to me like something is not working properly in the ARM64 implementation. I should expect to see multiple memoryX entries under /sys/devices/system/memory?
> > Thanks, > Xishi Qiu > >> Scott Branden (2): >> arm64: memory-hotplug: Add MEMORY_HOTPLUG, MEMORY_HOTREMOVE, >> MEMORY_PROBE >> arm64: defconfig: enable MEMORY_HOTPLUG config options >> >> arch/arm64/Kconfig | 10 ++++++++++ >> arch/arm64/configs/defconfig | 3 +++ >> arch/arm64/mm/init.c | 42 ++++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 55 insertions(+) >> > > >
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