Cannot hot remove a memory device

By following commit, I cannot hot remove a memory device.

ACPI / memhotplug: Bind removable memory blocks to ACPI device nodes commit e2ff39400d81233374e780b133496a2296643d7d

Details are follows:
When I add a memory device, acpi_memory_enable_device() always fails as follows:

...

[ 1271.114116]  [ffffea121c400000-ffffea121c7fffff] PMD -> [ffff880813c00000-ffff880813ffffff] on node 3
[ 1271.128682]  [ffffea121c800000-ffffea121cbfffff] PMD -> [ffff880813800000-ffff880813bfffff] on node 3
[ 1271.143298]  [ffffea121cc00000-ffffea121cffffff] PMD -> [ffff880813000000-ffff8808133fffff] on node 3
[ 1271.157799]  [ffffea121d000000-ffffea121d3fffff] PMD -> [ffff880812c00000-ffff880812ffffff] on node 3
[ 1271.172341]  [ffffea121d400000-ffffea121d7fffff] PMD -> [ffff880812800000-ffff880812bfffff] on node 3
[ 1271.186872]  [ffffea121d800000-ffffea121dbfffff] PMD -> [ffff880812400000-ffff8808127fffff] on node 3
[ 1271.201481]  [ffffea121dc00000-ffffea121dffffff] PMD -> [ffff880812000000-ffff8808123fffff] on node 3
[ 1271.216041]  [ffffea121e000000-ffffea121e3fffff] PMD -> [ffff880811c00000-ffff880811ffffff] on node 3
[ 1271.230623]  [ffffea121e400000-ffffea121e7fffff] PMD -> [ffff880811800000-ffff880811bfffff] on node 3
[ 1271.245148]  [ffffea121e800000-ffffea121ebfffff] PMD -> [ffff880811400000-ffff8808117fffff] on node 3
[ 1271.259683]  [ffffea121ec00000-ffffea121effffff] PMD -> [ffff880811000000-ffff8808113fffff] on node 3
[ 1271.274194]  [ffffea121f000000-ffffea121f3fffff] PMD -> [ffff880810c00000-ffff880810ffffff] on node 3
[ 1271.288764]  [ffffea121f400000-ffffea121f7fffff] PMD -> [ffff880810800000-ffff880810bfffff] on node 3
...	
[ 1271.325841] acpi PNP0C80:03: acpi_memory_enable_device() error

Hi,

Thanks for your report.

Quoted 23 lines · Yasuaki Ishimatsu

By following commit, I cannot hot remove a memory device.

ACPI / memhotplug: Bind removable memory blocks to ACPI device nodes commit e2ff39400d81233374e780b133496a2296643d7d

Details are follows:
When I add a memory device, acpi_memory_enable_device() always fails as follows:

...

[ 1271.114116]  [ffffea121c400000-ffffea121c7fffff] PMD -> [ffff880813c00000-ffff880813ffffff] on node 3
[ 1271.128682]  [ffffea121c800000-ffffea121cbfffff] PMD -> [ffff880813800000-ffff880813bfffff] on node 3
[ 1271.143298]  [ffffea121cc00000-ffffea121cffffff] PMD -> [ffff880813000000-ffff8808133fffff] on node 3
[ 1271.157799]  [ffffea121d000000-ffffea121d3fffff] PMD -> [ffff880812c00000-ffff880812ffffff] on node 3
[ 1271.172341]  [ffffea121d400000-ffffea121d7fffff] PMD -> [ffff880812800000-ffff880812bfffff] on node 3
[ 1271.186872]  [ffffea121d800000-ffffea121dbfffff] PMD -> [ffff880812400000-ffff8808127fffff] on node 3
[ 1271.201481]  [ffffea121dc00000-ffffea121dffffff] PMD -> [ffff880812000000-ffff8808123fffff] on node 3
[ 1271.216041]  [ffffea121e000000-ffffea121e3fffff] PMD -> [ffff880811c00000-ffff880811ffffff] on node 3
[ 1271.230623]  [ffffea121e400000-ffffea121e7fffff] PMD -> [ffff880811800000-ffff880811bfffff] on node 3
[ 1271.245148]  [ffffea121e800000-ffffea121ebfffff] PMD -> [ffff880811400000-ffff8808117fffff] on node 3
[ 1271.259683]  [ffffea121ec00000-ffffea121effffff] PMD -> [ffff880811000000-ffff8808113fffff] on node 3
[ 1271.274194]  [ffffea121f000000-ffffea121f3fffff] PMD -> [ffff880810c00000-ffff880810ffffff] on node 3
[ 1271.288764]  [ffffea121f400000-ffffea121f7fffff] PMD -> [ffff880810800000-ffff880810bfffff] on node 3

Quoted 2 lines

...

[ 1271.325841] acpi PNP0C80:03: acpi_memory_enable_device() error

Well, the only new way acpi_memory_enable_device() can fail after that commit is a failure in acpi_bind_memory_blocks().

This means that either handle is NULL, which I think we can exclude, because acpi_memory_enable_device() wouldn't be called at all if that were the case, or there's a more subtle error in acpi_bind_one().

One that comes to mind is that we may be calling acpi_bind_one() twice for the same memory region, in which it will trigger -EINVAL from the sanity check in there.

Quoted 28 lines · Rafael J. Wysocki

Hi,

Thanks for your report.

Quoted 23 lines · Yasuaki Ishimatsu

By following commit, I cannot hot remove a memory device.

ACPI / memhotplug: Bind removable memory blocks to ACPI device nodes commit e2ff39400d81233374e780b133496a2296643d7d

Details are follows:
When I add a memory device, acpi_memory_enable_device() always fails as follows:

...

[ 1271.114116]  [ffffea121c400000-ffffea121c7fffff] PMD -> [ffff880813c00000-ffff880813ffffff] on node 3
[ 1271.128682]  [ffffea121c800000-ffffea121cbfffff] PMD -> [ffff880813800000-ffff880813bfffff] on node 3
[ 1271.143298]  [ffffea121cc00000-ffffea121cffffff] PMD -> [ffff880813000000-ffff8808133fffff] on node 3
[ 1271.157799]  [ffffea121d000000-ffffea121d3fffff] PMD -> [ffff880812c00000-ffff880812ffffff] on node 3
[ 1271.172341]  [ffffea121d400000-ffffea121d7fffff] PMD -> [ffff880812800000-ffff880812bfffff] on node 3
[ 1271.186872]  [ffffea121d800000-ffffea121dbfffff] PMD -> [ffff880812400000-ffff8808127fffff] on node 3
[ 1271.201481]  [ffffea121dc00000-ffffea121dffffff] PMD -> [ffff880812000000-ffff8808123fffff] on node 3
[ 1271.216041]  [ffffea121e000000-ffffea121e3fffff] PMD -> [ffff880811c00000-ffff880811ffffff] on node 3
[ 1271.230623]  [ffffea121e400000-ffffea121e7fffff] PMD -> [ffff880811800000-ffff880811bfffff] on node 3
[ 1271.245148]  [ffffea121e800000-ffffea121ebfffff] PMD -> [ffff880811400000-ffff8808117fffff] on node 3
[ 1271.259683]  [ffffea121ec00000-ffffea121effffff] PMD -> [ffff880811000000-ffff8808113fffff] on node 3
[ 1271.274194]  [ffffea121f000000-ffffea121f3fffff] PMD -> [ffff880810c00000-ffff880810ffffff] on node 3
[ 1271.288764]  [ffffea121f400000-ffffea121f7fffff] PMD -> [ffff880810800000-ffff880810bfffff] on node 3

It appears that each memory object only has 64MB of memory. This is less than the memory block size, which is 128MB. This means that a single memory block associates with two ACPI memory device objects.

Quoted 5 lines

Quoted 2 lines

...

[ 1271.325841] acpi PNP0C80:03: acpi_memory_enable_device() error

Well, the only new way acpi_memory_enable_device() can fail after that commit is a failure in acpi_bind_memory_blocks().

Agreed.

Quoted 4 lines

This means that either handle is NULL, which I think we can exclude, because acpi_memory_enable_device() wouldn't be called at all if that were the case, or there's a more subtle error in acpi_bind_one().

Quoted 3 lines

One that comes to mind is that we may be calling acpi_bind_one() twice for the same memory region, in which it will trigger -EINVAL from the sanity check in there.

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

Quoted 30 lines · Toshi Kani

Quoted 28 lines · Rafael J. Wysocki

Hi,

Thanks for your report.

Quoted 23 lines · Yasuaki Ishimatsu

By following commit, I cannot hot remove a memory device.

ACPI / memhotplug: Bind removable memory blocks to ACPI device nodes commit e2ff39400d81233374e780b133496a2296643d7d

Details are follows:
When I add a memory device, acpi_memory_enable_device() always fails as follows:

...

[ 1271.114116]  [ffffea121c400000-ffffea121c7fffff] PMD -> [ffff880813c00000-ffff880813ffffff] on node 3
[ 1271.128682]  [ffffea121c800000-ffffea121cbfffff] PMD -> [ffff880813800000-ffff880813bfffff] on node 3
[ 1271.143298]  [ffffea121cc00000-ffffea121cffffff] PMD -> [ffff880813000000-ffff8808133fffff] on node 3
[ 1271.157799]  [ffffea121d000000-ffffea121d3fffff] PMD -> [ffff880812c00000-ffff880812ffffff] on node 3
[ 1271.172341]  [ffffea121d400000-ffffea121d7fffff] PMD -> [ffff880812800000-ffff880812bfffff] on node 3
[ 1271.186872]  [ffffea121d800000-ffffea121dbfffff] PMD -> [ffff880812400000-ffff8808127fffff] on node 3
[ 1271.201481]  [ffffea121dc00000-ffffea121dffffff] PMD -> [ffff880812000000-ffff8808123fffff] on node 3
[ 1271.216041]  [ffffea121e000000-ffffea121e3fffff] PMD -> [ffff880811c00000-ffff880811ffffff] on node 3
[ 1271.230623]  [ffffea121e400000-ffffea121e7fffff] PMD -> [ffff880811800000-ffff880811bfffff] on node 3
[ 1271.245148]  [ffffea121e800000-ffffea121ebfffff] PMD -> [ffff880811400000-ffff8808117fffff] on node 3
[ 1271.259683]  [ffffea121ec00000-ffffea121effffff] PMD -> [ffff880811000000-ffff8808113fffff] on node 3
[ 1271.274194]  [ffffea121f000000-ffffea121f3fffff] PMD -> [ffff880810c00000-ffff880810ffffff] on node 3
[ 1271.288764]  [ffffea121f400000-ffffea121f7fffff] PMD -> [ffff880810800000-ffff880810bfffff] on node 3

Quoted 3 lines

It appears that each memory object only has 64MB of memory. This is less than the memory block size, which is 128MB. This means that a single memory block associates with two ACPI memory device objects.

That'd be bad.

How did that work before if that indeed is the case?

Quoted 12 lines

Quoted 5 lines

Quoted 2 lines

...

[ 1271.325841] acpi PNP0C80:03: acpi_memory_enable_device() error

Well, the only new way acpi_memory_enable_device() can fail after that commit is a failure in acpi_bind_memory_blocks().

Agreed.

Quoted 4 lines

This means that either handle is NULL, which I think we can exclude, because acpi_memory_enable_device() wouldn't be called at all if that were the case, or there's a more subtle error in acpi_bind_one().

Quoted 8 lines

Quoted 3 lines

One that comes to mind is that we may be calling acpi_bind_one() twice for the same memory region, in which it will trigger -EINVAL from the sanity check in there.

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Quoted 31 lines · Rafael J. Wysocki

Quoted 30 lines · Toshi Kani

Quoted 28 lines · Rafael J. Wysocki

Hi,

Thanks for your report.

Quoted 23 lines · Yasuaki Ishimatsu

By following commit, I cannot hot remove a memory device.

ACPI / memhotplug: Bind removable memory blocks to ACPI device nodes commit e2ff39400d81233374e780b133496a2296643d7d

Details are follows:
When I add a memory device, acpi_memory_enable_device() always fails as follows:

...

[ 1271.114116]  [ffffea121c400000-ffffea121c7fffff] PMD -> [ffff880813c00000-ffff880813ffffff] on node 3
[ 1271.128682]  [ffffea121c800000-ffffea121cbfffff] PMD -> [ffff880813800000-ffff880813bfffff] on node 3
[ 1271.143298]  [ffffea121cc00000-ffffea121cffffff] PMD -> [ffff880813000000-ffff8808133fffff] on node 3
[ 1271.157799]  [ffffea121d000000-ffffea121d3fffff] PMD -> [ffff880812c00000-ffff880812ffffff] on node 3
[ 1271.172341]  [ffffea121d400000-ffffea121d7fffff] PMD -> [ffff880812800000-ffff880812bfffff] on node 3
[ 1271.186872]  [ffffea121d800000-ffffea121dbfffff] PMD -> [ffff880812400000-ffff8808127fffff] on node 3
[ 1271.201481]  [ffffea121dc00000-ffffea121dffffff] PMD -> [ffff880812000000-ffff8808123fffff] on node 3
[ 1271.216041]  [ffffea121e000000-ffffea121e3fffff] PMD -> [ffff880811c00000-ffff880811ffffff] on node 3
[ 1271.230623]  [ffffea121e400000-ffffea121e7fffff] PMD -> [ffff880811800000-ffff880811bfffff] on node 3
[ 1271.245148]  [ffffea121e800000-ffffea121ebfffff] PMD -> [ffff880811400000-ffff8808117fffff] on node 3
[ 1271.259683]  [ffffea121ec00000-ffffea121effffff] PMD -> [ffff880811000000-ffff8808113fffff] on node 3
[ 1271.274194]  [ffffea121f000000-ffffea121f3fffff] PMD -> [ffff880810c00000-ffff880810ffffff] on node 3
[ 1271.288764]  [ffffea121f400000-ffffea121f7fffff] PMD -> [ffff880810800000-ffff880810bfffff] on node 3

Quoted 7 lines

Quoted 3 lines

It appears that each memory object only has 64MB of memory. This is less than the memory block size, which is 128MB. This means that a single memory block associates with two ACPI memory device objects.

That'd be bad.

How did that work before if that indeed is the case?

Well, it looks to me that it has never worked before...

Quoted 21 lines

Quoted 12 lines

Quoted 5 lines

Quoted 2 lines

...

[ 1271.325841] acpi PNP0C80:03: acpi_memory_enable_device() error

Well, the only new way acpi_memory_enable_device() can fail after that commit is a failure in acpi_bind_memory_blocks().

Agreed.

Quoted 4 lines

This means that either handle is NULL, which I think we can exclude, because acpi_memory_enable_device() wouldn't be called at all if that were the case, or there's a more subtle error in acpi_bind_one().

Quoted 8 lines

Quoted 3 lines

One that comes to mind is that we may be calling acpi_bind_one() twice for the same memory region, in which it will trigger -EINVAL from the sanity check in there.

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

Quoted 7 lines

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Right. Even bigger issue is that I do not think __add_pages() and __remove_pages() can add / delete a memory chunk that is less than 128MB. 128MB is the granularity of them. So, we may just have to fail this case gracefully.

Quoted 71 lines · Toshi Kani

Quoted 31 lines · Rafael J. Wysocki

Quoted 30 lines · Toshi Kani

Quoted 28 lines · Rafael J. Wysocki

Hi,

Thanks for your report.

Quoted 23 lines · Yasuaki Ishimatsu

By following commit, I cannot hot remove a memory device.

ACPI / memhotplug: Bind removable memory blocks to ACPI device nodes commit e2ff39400d81233374e780b133496a2296643d7d

Details are follows:
When I add a memory device, acpi_memory_enable_device() always fails as follows:

...

[ 1271.114116]  [ffffea121c400000-ffffea121c7fffff] PMD -> [ffff880813c00000-ffff880813ffffff] on node 3
[ 1271.128682]  [ffffea121c800000-ffffea121cbfffff] PMD -> [ffff880813800000-ffff880813bfffff] on node 3
[ 1271.143298]  [ffffea121cc00000-ffffea121cffffff] PMD -> [ffff880813000000-ffff8808133fffff] on node 3
[ 1271.157799]  [ffffea121d000000-ffffea121d3fffff] PMD -> [ffff880812c00000-ffff880812ffffff] on node 3
[ 1271.172341]  [ffffea121d400000-ffffea121d7fffff] PMD -> [ffff880812800000-ffff880812bfffff] on node 3
[ 1271.186872]  [ffffea121d800000-ffffea121dbfffff] PMD -> [ffff880812400000-ffff8808127fffff] on node 3
[ 1271.201481]  [ffffea121dc00000-ffffea121dffffff] PMD -> [ffff880812000000-ffff8808123fffff] on node 3
[ 1271.216041]  [ffffea121e000000-ffffea121e3fffff] PMD -> [ffff880811c00000-ffff880811ffffff] on node 3
[ 1271.230623]  [ffffea121e400000-ffffea121e7fffff] PMD -> [ffff880811800000-ffff880811bfffff] on node 3
[ 1271.245148]  [ffffea121e800000-ffffea121ebfffff] PMD -> [ffff880811400000-ffff8808117fffff] on node 3
[ 1271.259683]  [ffffea121ec00000-ffffea121effffff] PMD -> [ffff880811000000-ffff8808113fffff] on node 3
[ 1271.274194]  [ffffea121f000000-ffffea121f3fffff] PMD -> [ffff880810c00000-ffff880810ffffff] on node 3
[ 1271.288764]  [ffffea121f400000-ffffea121f7fffff] PMD -> [ffff880810800000-ffff880810bfffff] on node 3

Quoted 7 lines

Quoted 3 lines

It appears that each memory object only has 64MB of memory. This is less than the memory block size, which is 128MB. This means that a single memory block associates with two ACPI memory device objects.

That'd be bad.

How did that work before if that indeed is the case?

Well, it looks to me that it has never worked before...

Quoted 28 lines

Quoted 12 lines

Quoted 5 lines

Quoted 2 lines

...

[ 1271.325841] acpi PNP0C80:03: acpi_memory_enable_device() error

Well, the only new way acpi_memory_enable_device() can fail after that commit is a failure in acpi_bind_memory_blocks().

Agreed.

Quoted 4 lines

This means that either handle is NULL, which I think we can exclude, because acpi_memory_enable_device() wouldn't be called at all if that were the case, or there's a more subtle error in acpi_bind_one().

Quoted 8 lines

Quoted 3 lines

One that comes to mind is that we may be calling acpi_bind_one() twice for the same memory region, in which it will trigger -EINVAL from the sanity check in there.

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Quoted 4 lines

Right. Even bigger issue is that I do not think __add_pages() and __remove_pages() can add / delete a memory chunk that is less than 128MB. 128MB is the granularity of them. So, we may just have to fail this case gracefully.

Sigh.

BTW, why do you think they are 64 M each (it's late and I'm obviously tired)?

Quoted 72 lines · Rafael J. Wysocki

Quoted 71 lines · Toshi Kani

Quoted 31 lines · Rafael J. Wysocki

Quoted 30 lines · Toshi Kani

Quoted 28 lines · Rafael J. Wysocki

Hi,

Thanks for your report.

Quoted 23 lines · Yasuaki Ishimatsu

By following commit, I cannot hot remove a memory device.

ACPI / memhotplug: Bind removable memory blocks to ACPI device nodes commit e2ff39400d81233374e780b133496a2296643d7d

Details are follows:
When I add a memory device, acpi_memory_enable_device() always fails as follows:

...

[ 1271.114116]  [ffffea121c400000-ffffea121c7fffff] PMD -> [ffff880813c00000-ffff880813ffffff] on node 3
[ 1271.128682]  [ffffea121c800000-ffffea121cbfffff] PMD -> [ffff880813800000-ffff880813bfffff] on node 3
[ 1271.143298]  [ffffea121cc00000-ffffea121cffffff] PMD -> [ffff880813000000-ffff8808133fffff] on node 3
[ 1271.157799]  [ffffea121d000000-ffffea121d3fffff] PMD -> [ffff880812c00000-ffff880812ffffff] on node 3
[ 1271.172341]  [ffffea121d400000-ffffea121d7fffff] PMD -> [ffff880812800000-ffff880812bfffff] on node 3
[ 1271.186872]  [ffffea121d800000-ffffea121dbfffff] PMD -> [ffff880812400000-ffff8808127fffff] on node 3
[ 1271.201481]  [ffffea121dc00000-ffffea121dffffff] PMD -> [ffff880812000000-ffff8808123fffff] on node 3
[ 1271.216041]  [ffffea121e000000-ffffea121e3fffff] PMD -> [ffff880811c00000-ffff880811ffffff] on node 3
[ 1271.230623]  [ffffea121e400000-ffffea121e7fffff] PMD -> [ffff880811800000-ffff880811bfffff] on node 3
[ 1271.245148]  [ffffea121e800000-ffffea121ebfffff] PMD -> [ffff880811400000-ffff8808117fffff] on node 3
[ 1271.259683]  [ffffea121ec00000-ffffea121effffff] PMD -> [ffff880811000000-ffff8808113fffff] on node 3
[ 1271.274194]  [ffffea121f000000-ffffea121f3fffff] PMD -> [ffff880810c00000-ffff880810ffffff] on node 3
[ 1271.288764]  [ffffea121f400000-ffffea121f7fffff] PMD -> [ffff880810800000-ffff880810bfffff] on node 3

Quoted 7 lines

Quoted 3 lines

It appears that each memory object only has 64MB of memory. This is less than the memory block size, which is 128MB. This means that a single memory block associates with two ACPI memory device objects.

That'd be bad.

How did that work before if that indeed is the case?

Well, it looks to me that it has never worked before...

Quoted 28 lines

Quoted 12 lines

Quoted 5 lines

Quoted 2 lines

...

[ 1271.325841] acpi PNP0C80:03: acpi_memory_enable_device() error

Well, the only new way acpi_memory_enable_device() can fail after that commit is a failure in acpi_bind_memory_blocks().

Agreed.

Quoted 4 lines

This means that either handle is NULL, which I think we can exclude, because acpi_memory_enable_device() wouldn't be called at all if that were the case, or there's a more subtle error in acpi_bind_one().

Quoted 8 lines

Quoted 3 lines

One that comes to mind is that we may be calling acpi_bind_one() twice for the same memory region, in which it will trigger -EINVAL from the sanity check in there.

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Quoted 8 lines

Quoted 4 lines

Right. Even bigger issue is that I do not think __add_pages() and __remove_pages() can add / delete a memory chunk that is less than 128MB. 128MB is the granularity of them. So, we may just have to fail this case gracefully.

Sigh.

BTW, why do you think they are 64 M each (it's late and I'm obviously tired)?

Oops! Sorry, I had confused the above messages with the one in init_memory_mapping(), which shows a memory range being added, i.e. the size of an ACPI memory device object. But the above messages actually came from vmemmap_populate_hugepages(), which was called during boot-up. So, these messages have nothing to do with ACPI memory device objects. And even worse, I do not seem to be able to count a number of zeros... In the above messages, each memory range is 4MB (0x400000), not 64MB (0x4000000)... My bad. :-(

So, while we may still need to do something for the less-than-128MB issue, Yasuaki may be hitting a different one. Let's wait for Yasuaki to give us more info.

Quoted 72 lines · Rafael J. Wysocki

Quoted 71 lines · Toshi Kani

Quoted 31 lines · Rafael J. Wysocki

Quoted 30 lines · Toshi Kani

Quoted 28 lines · Rafael J. Wysocki

Hi,

Thanks for your report.

Quoted 23 lines · Yasuaki Ishimatsu

By following commit, I cannot hot remove a memory device.

ACPI / memhotplug: Bind removable memory blocks to ACPI device nodes commit e2ff39400d81233374e780b133496a2296643d7d

Details are follows:
When I add a memory device, acpi_memory_enable_device() always fails as follows:

...

[ 1271.114116]  [ffffea121c400000-ffffea121c7fffff] PMD -> [ffff880813c00000-ffff880813ffffff] on node 3
[ 1271.128682]  [ffffea121c800000-ffffea121cbfffff] PMD -> [ffff880813800000-ffff880813bfffff] on node 3
[ 1271.143298]  [ffffea121cc00000-ffffea121cffffff] PMD -> [ffff880813000000-ffff8808133fffff] on node 3
[ 1271.157799]  [ffffea121d000000-ffffea121d3fffff] PMD -> [ffff880812c00000-ffff880812ffffff] on node 3
[ 1271.172341]  [ffffea121d400000-ffffea121d7fffff] PMD -> [ffff880812800000-ffff880812bfffff] on node 3
[ 1271.186872]  [ffffea121d800000-ffffea121dbfffff] PMD -> [ffff880812400000-ffff8808127fffff] on node 3
[ 1271.201481]  [ffffea121dc00000-ffffea121dffffff] PMD -> [ffff880812000000-ffff8808123fffff] on node 3
[ 1271.216041]  [ffffea121e000000-ffffea121e3fffff] PMD -> [ffff880811c00000-ffff880811ffffff] on node 3
[ 1271.230623]  [ffffea121e400000-ffffea121e7fffff] PMD -> [ffff880811800000-ffff880811bfffff] on node 3
[ 1271.245148]  [ffffea121e800000-ffffea121ebfffff] PMD -> [ffff880811400000-ffff8808117fffff] on node 3
[ 1271.259683]  [ffffea121ec00000-ffffea121effffff] PMD -> [ffff880811000000-ffff8808113fffff] on node 3
[ 1271.274194]  [ffffea121f000000-ffffea121f3fffff] PMD -> [ffff880810c00000-ffff880810ffffff] on node 3
[ 1271.288764]  [ffffea121f400000-ffffea121f7fffff] PMD -> [ffff880810800000-ffff880810bfffff] on node 3

Quoted 7 lines

Quoted 3 lines

It appears that each memory object only has 64MB of memory. This is less than the memory block size, which is 128MB. This means that a single memory block associates with two ACPI memory device objects.

That'd be bad.

How did that work before if that indeed is the case?

Well, it looks to me that it has never worked before...

Quoted 28 lines

Quoted 12 lines

Quoted 5 lines

Quoted 2 lines

...

[ 1271.325841] acpi PNP0C80:03: acpi_memory_enable_device() error

Well, the only new way acpi_memory_enable_device() can fail after that commit is a failure in acpi_bind_memory_blocks().

Agreed.

Quoted 4 lines

This means that either handle is NULL, which I think we can exclude, because acpi_memory_enable_device() wouldn't be called at all if that were the case, or there's a more subtle error in acpi_bind_one().

Quoted 8 lines

Quoted 3 lines

One that comes to mind is that we may be calling acpi_bind_one() twice for the same memory region, in which it will trigger -EINVAL from the sanity check in there.

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Quoted 8 lines

Quoted 4 lines

Right. Even bigger issue is that I do not think __add_pages() and __remove_pages() can add / delete a memory chunk that is less than 128MB. 128MB is the granularity of them. So, we may just have to fail this case gracefully.

Sigh.

BTW, why do you think they are 64 M each (it's late and I'm obviously tired)?

Oops! Sorry, I had confused the above messages with the one in init_memory_mapping(), which shows a memory range being added, i.e. the size of an ACPI memory device object. But the above messages actually came from vmemmap_populate_hugepages(), which was called during boot-up. So, these messages have nothing to do with ACPI memory device objects. And even worse, I do not seem to be able to count a number of zeros... In the above messages, each memory range is 4MB (0x400000), not 64MB (0x4000000)... My bad. :-(

So, while we may still need to do something for the less-than-128MB issue, Yasuaki may be hitting a different one. Let's wait for Yasuaki to give us more info.

Thanks,
-Toshi

Quoted 91 lines · Toshi Kani

Quoted 72 lines · Rafael J. Wysocki

Quoted 71 lines · Toshi Kani

Quoted 31 lines · Rafael J. Wysocki

Quoted 30 lines · Toshi Kani

Quoted 28 lines · Rafael J. Wysocki

Hi,

Thanks for your report.

Quoted 23 lines · Yasuaki Ishimatsu

By following commit, I cannot hot remove a memory device.

ACPI / memhotplug: Bind removable memory blocks to ACPI device nodes commit e2ff39400d81233374e780b133496a2296643d7d

Details are follows:
When I add a memory device, acpi_memory_enable_device() always fails as follows:

...

[ 1271.114116]  [ffffea121c400000-ffffea121c7fffff] PMD -> [ffff880813c00000-ffff880813ffffff] on node 3
[ 1271.128682]  [ffffea121c800000-ffffea121cbfffff] PMD -> [ffff880813800000-ffff880813bfffff] on node 3
[ 1271.143298]  [ffffea121cc00000-ffffea121cffffff] PMD -> [ffff880813000000-ffff8808133fffff] on node 3
[ 1271.157799]  [ffffea121d000000-ffffea121d3fffff] PMD -> [ffff880812c00000-ffff880812ffffff] on node 3
[ 1271.172341]  [ffffea121d400000-ffffea121d7fffff] PMD -> [ffff880812800000-ffff880812bfffff] on node 3
[ 1271.186872]  [ffffea121d800000-ffffea121dbfffff] PMD -> [ffff880812400000-ffff8808127fffff] on node 3
[ 1271.201481]  [ffffea121dc00000-ffffea121dffffff] PMD -> [ffff880812000000-ffff8808123fffff] on node 3
[ 1271.216041]  [ffffea121e000000-ffffea121e3fffff] PMD -> [ffff880811c00000-ffff880811ffffff] on node 3
[ 1271.230623]  [ffffea121e400000-ffffea121e7fffff] PMD -> [ffff880811800000-ffff880811bfffff] on node 3
[ 1271.245148]  [ffffea121e800000-ffffea121ebfffff] PMD -> [ffff880811400000-ffff8808117fffff] on node 3
[ 1271.259683]  [ffffea121ec00000-ffffea121effffff] PMD -> [ffff880811000000-ffff8808113fffff] on node 3
[ 1271.274194]  [ffffea121f000000-ffffea121f3fffff] PMD -> [ffff880810c00000-ffff880810ffffff] on node 3
[ 1271.288764]  [ffffea121f400000-ffffea121f7fffff] PMD -> [ffff880810800000-ffff880810bfffff] on node 3

Quoted 7 lines

Quoted 3 lines

It appears that each memory object only has 64MB of memory. This is less than the memory block size, which is 128MB. This means that a single memory block associates with two ACPI memory device objects.

That'd be bad.

How did that work before if that indeed is the case?

Well, it looks to me that it has never worked before...

Quoted 28 lines

Quoted 12 lines

Quoted 5 lines

Quoted 2 lines

...

[ 1271.325841] acpi PNP0C80:03: acpi_memory_enable_device() error

Well, the only new way acpi_memory_enable_device() can fail after that commit is a failure in acpi_bind_memory_blocks().

Agreed.

Quoted 4 lines

This means that either handle is NULL, which I think we can exclude, because acpi_memory_enable_device() wouldn't be called at all if that were the case, or there's a more subtle error in acpi_bind_one().

Quoted 8 lines

Quoted 3 lines

One that comes to mind is that we may be calling acpi_bind_one() twice for the same memory region, in which it will trigger -EINVAL from the sanity check in there.

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Quoted 8 lines

Quoted 4 lines

Right. Even bigger issue is that I do not think __add_pages() and __remove_pages() can add / delete a memory chunk that is less than 128MB. 128MB is the granularity of them. So, we may just have to fail this case gracefully.

Sigh.

BTW, why do you think they are 64 M each (it's late and I'm obviously tired)?

Oops! Sorry, I had confused the above messages with the one in init_memory_mapping(), which shows a memory range being added, i.e. the size of an ACPI memory device object. But the above messages actually came from vmemmap_populate_hugepages(), which was called during boot-up. So, these messages have nothing to do with ACPI memory device objects. And even worse, I do not seem to be able to count a number of zeros... In the above messages, each memory range is 4MB (0x400000), not 64MB (0x4000000)... My bad. :-(

Quoted 3 lines

So, while we may still need to do something for the less-than-128MB issue, Yasuaki may be hitting a different one. Let's wait for Yasuaki to give us more info.

acpi_bind_memory_blocks() failed with -ENOSPC.

int acpi_bind_one(struct device *dev, acpi_handle handle) {
...

     /* allocate physical node id according to physical_node_id_bitmap */
     physical_node->node_id =
         find_first_zero_bit(acpi_dev->physical_node_id_bitmap,
         ACPI_MAX_PHYSICAL_NODE);
     if (physical_node->node_id >= ACPI_MAX_PHYSICAL_NODE) {
         retval = -ENOSPC; => here
         goto err_free;
     }

When adding memory device, acpi_bind_memroy_blocks() calls acpi_bind_one() "memory device size / 128MiB" times. So ACPI_MAX_PHYSICAL_NODE need to be set "memory device size / 128MiB" or more. But ACPI_MAX_PHYSICAL_NODE is 32. So acpi_bind_memory_blocks() always failed with -ENOSPC.

I'll test again after increasing ACPI_MAX_PHYSICAL_NODE to enough size.

Thanks,
Yasuaki Ishimatsu

Quoted 12 lines

Thanks,
-Toshi

Quoted 115 lines · Yasuaki Ishimatsu

Quoted 91 lines · Toshi Kani

Quoted 72 lines · Rafael J. Wysocki

Quoted 71 lines · Toshi Kani

Quoted 31 lines · Rafael J. Wysocki

Quoted 30 lines · Toshi Kani

Quoted 28 lines · Rafael J. Wysocki

Hi,

Thanks for your report.

Quoted 23 lines · Yasuaki Ishimatsu

By following commit, I cannot hot remove a memory device.

ACPI / memhotplug: Bind removable memory blocks to ACPI device nodes commit e2ff39400d81233374e780b133496a2296643d7d

Details are follows:
When I add a memory device, acpi_memory_enable_device() always fails as follows:

...

[ 1271.114116]  [ffffea121c400000-ffffea121c7fffff] PMD -> [ffff880813c00000-ffff880813ffffff] on node 3
[ 1271.128682]  [ffffea121c800000-ffffea121cbfffff] PMD -> [ffff880813800000-ffff880813bfffff] on node 3
[ 1271.143298]  [ffffea121cc00000-ffffea121cffffff] PMD -> [ffff880813000000-ffff8808133fffff] on node 3
[ 1271.157799]  [ffffea121d000000-ffffea121d3fffff] PMD -> [ffff880812c00000-ffff880812ffffff] on node 3
[ 1271.172341]  [ffffea121d400000-ffffea121d7fffff] PMD -> [ffff880812800000-ffff880812bfffff] on node 3
[ 1271.186872]  [ffffea121d800000-ffffea121dbfffff] PMD -> [ffff880812400000-ffff8808127fffff] on node 3
[ 1271.201481]  [ffffea121dc00000-ffffea121dffffff] PMD -> [ffff880812000000-ffff8808123fffff] on node 3
[ 1271.216041]  [ffffea121e000000-ffffea121e3fffff] PMD -> [ffff880811c00000-ffff880811ffffff] on node 3
[ 1271.230623]  [ffffea121e400000-ffffea121e7fffff] PMD -> [ffff880811800000-ffff880811bfffff] on node 3
[ 1271.245148]  [ffffea121e800000-ffffea121ebfffff] PMD -> [ffff880811400000-ffff8808117fffff] on node 3
[ 1271.259683]  [ffffea121ec00000-ffffea121effffff] PMD -> [ffff880811000000-ffff8808113fffff] on node 3
[ 1271.274194]  [ffffea121f000000-ffffea121f3fffff] PMD -> [ffff880810c00000-ffff880810ffffff] on node 3
[ 1271.288764]  [ffffea121f400000-ffffea121f7fffff] PMD -> [ffff880810800000-ffff880810bfffff] on node 3

Quoted 7 lines

Quoted 3 lines

It appears that each memory object only has 64MB of memory. This is less than the memory block size, which is 128MB. This means that a single memory block associates with two ACPI memory device objects.

That'd be bad.

How did that work before if that indeed is the case?

Well, it looks to me that it has never worked before...

Quoted 28 lines

Quoted 12 lines

Quoted 5 lines

Quoted 2 lines

...

[ 1271.325841] acpi PNP0C80:03: acpi_memory_enable_device() error

Well, the only new way acpi_memory_enable_device() can fail after that commit is a failure in acpi_bind_memory_blocks().

Agreed.

Quoted 4 lines

This means that either handle is NULL, which I think we can exclude, because acpi_memory_enable_device() wouldn't be called at all if that were the case, or there's a more subtle error in acpi_bind_one().

Quoted 8 lines

Quoted 3 lines

One that comes to mind is that we may be calling acpi_bind_one() twice for the same memory region, in which it will trigger -EINVAL from the sanity check in there.

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Quoted 8 lines

Quoted 4 lines

Right. Even bigger issue is that I do not think __add_pages() and __remove_pages() can add / delete a memory chunk that is less than 128MB. 128MB is the granularity of them. So, we may just have to fail this case gracefully.

Sigh.

BTW, why do you think they are 64 M each (it's late and I'm obviously tired)?

Oops! Sorry, I had confused the above messages with the one in init_memory_mapping(), which shows a memory range being added, i.e. the size of an ACPI memory device object. But the above messages actually came from vmemmap_populate_hugepages(), which was called during boot-up. So, these messages have nothing to do with ACPI memory device objects. And even worse, I do not seem to be able to count a number of zeros... In the above messages, each memory range is 4MB (0x400000), not 64MB (0x4000000)... My bad. :-(

Quoted 3 lines

So, while we may still need to do something for the less-than-128MB issue, Yasuaki may be hitting a different one. Let's wait for Yasuaki to give us more info.

acpi_bind_memory_blocks() failed with -ENOSPC.

int acpi_bind_one(struct device *dev, acpi_handle handle) {
...

     /* allocate physical node id according to physical_node_id_bitmap */
     physical_node->node_id =
         find_first_zero_bit(acpi_dev->physical_node_id_bitmap,
         ACPI_MAX_PHYSICAL_NODE);
     if (physical_node->node_id >= ACPI_MAX_PHYSICAL_NODE) {
         retval = -ENOSPC; => here
         goto err_free;
     }

When adding memory device, acpi_bind_memroy_blocks() calls acpi_bind_one() "memory device size / 128MiB" times. So ACPI_MAX_PHYSICAL_NODE need to be set "memory device size / 128MiB" or more. But ACPI_MAX_PHYSICAL_NODE is 32. So acpi_bind_memory_blocks() always failed with -ENOSPC.

Quoted 1 line

I'll test again after increasing ACPI_MAX_PHYSICAL_NODE to enough size.

Additional info:
When I increased ACPI_MAX_PHYSICAL_NODE to 1024 and change size of acpi_device_physical_node->node_it into u32, I could hot remove memory device. But even if ACPI_MAX_PHYSICAL_NODE is set to 1024, same problem will occurs since it just supports 124GiB memory. So we need a way to change ACPI_MAX_PHYSICAL_NODE dynamically.

Can you please test the appended patch? I tested it somewhat, but since the greatest number of physical nodes per ACPI device object I can get on my test machines is 2 (and even that after hacking the kernel somewhat), that was kind of unconclusive.

Thanks,
Rafael

---
From: Rafael J. Wysocki <[email protected]>
Subject: ACPI: Drop physical_node_id_bitmap from struct acpi_device

The physical_node_id_bitmap in struct acpi_device is only used for looking up the first currently unused phyiscal dependent node ID by acpi_bind_one(). It is not really necessary, however, because acpi_bind_one() walks the entire physical_node_list of the given device object for sanity checking anyway and if that list is always sorted by node_id, it is straightforward to find the first gap between the currently used node IDs and use that number as the ID of the new list node.

This also removes the artificial limit of the maximum number of dependent physical devices per ACPI device object, which now depends only on the capacity of unsigend int.

Signed-off-by Rafael J. Wysocki <[email protected]>

On Mon, 2013-08-05 at 15:14 +0200, Rafael J. Wysocki wrote:
:

Quoted 26 lines

Can you please test the appended patch? I tested it somewhat, but since the greatest number of physical nodes per ACPI device object I can get on my test machines is 2 (and even that after hacking the kernel somewhat), that was kind of unconclusive.

Thanks,
Rafael

---
From: Rafael J. Wysocki <[email protected]>
Subject: ACPI: Drop physical_node_id_bitmap from struct acpi_device

The physical_node_id_bitmap in struct acpi_device is only used for looking up the first currently unused phyiscal dependent node ID by acpi_bind_one(). It is not really necessary, however, because acpi_bind_one() walks the entire physical_node_list of the given device object for sanity checking anyway and if that list is always sorted by node_id, it is straightforward to find the first gap between the currently used node IDs and use that number as the ID of the new list node.

This also removes the artificial limit of the maximum number of dependent physical devices per ACPI device object, which now depends only on the capacity of unsigend int.

Quoted 1 line

Signed-off-by Rafael J. Wysocki <[email protected]>

I like the change. Much better :-)

Acked-by Toshi Kani <[email protected]>

Quoted 28 lines · Toshi Kani

On Mon, 2013-08-05 at 15:14 +0200, Rafael J. Wysocki wrote:

   :

Quoted 26 lines

Can you please test the appended patch? I tested it somewhat, but since the greatest number of physical nodes per ACPI device object I can get on my test machines is 2 (and even that after hacking the kernel somewhat), that was kind of unconclusive.

Thanks,
Rafael

---
From: Rafael J. Wysocki <[email protected]>
Subject: ACPI: Drop physical_node_id_bitmap from struct acpi_device

The physical_node_id_bitmap in struct acpi_device is only used for looking up the first currently unused phyiscal dependent node ID by acpi_bind_one(). It is not really necessary, however, because acpi_bind_one() walks the entire physical_node_list of the given device object for sanity checking anyway and if that list is always sorted by node_id, it is straightforward to find the first gap between the currently used node IDs and use that number as the ID of the new list node.

This also removes the artificial limit of the maximum number of dependent physical devices per ACPI device object, which now depends only on the capacity of unsigend int.

Quoted 5 lines

Quoted 1 line

Signed-off-by Rafael J. Wysocki <[email protected]>

I like the change. Much better :-)

Acked-by Toshi Kani <[email protected]>

However, it introduces a bug in acpi_unbind_one(), because the size of the name array in there has to be increased too. Updated patch follows.

Thanks,
Rafael

---
From: Rafael J. Wysocki <[email protected]>
Subject: ACPI: Drop physical_node_id_bitmap from struct acpi_device

The physical_node_id_bitmap in struct acpi_device is only used for looking up the first currently unused dependent phyiscal node ID by acpi_bind_one(). It is not really necessary, however, because acpi_bind_one() walks the entire physical_node_list of the given device object for sanity checking anyway and if that list is always sorted by node_id, it is straightforward to find the first gap between the currently used node IDs and use that number as the ID of the new list node.

This also removes the artificial limit of the maximum number of dependent physical devices per ACPI device object, which now depends only on the capacity of unsigend int.

Signed-off-by Rafael J. Wysocki <[email protected]>

---
  drivers/acpi/glue.c     |   34 +++++++++++++++++++---------------
  include/acpi/acpi_bus.h |    8 ++------
  2 files changed, 21 insertions(+), 21 deletions(-)

Index: linux-pm/drivers/acpi/glue.c
===================================================================

drivers/acpi/glue.c +19 -15

@@ -31,6 +31,7 @@ static LIST_HEAD(bus_type_list);
  static DECLARE_RWSEM(bus_type_sem);
 
  #define PHYSICAL_NODE_STRING "physical_node"
+#define PHYSICAL_NODE_NAME_SIZE (sizeof(PHYSICAL_NODE_STRING) + 10)
 
  int register_acpi_bus_type(struct acpi_bus_type *type)
  {

@@ -112,7 +113,9 @@ int acpi_bind_one(struct device *dev, ac
  	struct acpi_device *acpi_dev;
  	acpi_status status;
  	struct acpi_device_physical_node *physical_node, *pn;
-	char physical_node_name[sizeof(PHYSICAL_NODE_STRING) + 2];
+	char physical_node_name[PHYSICAL_NODE_NAME_SIZE];
+	struct list_head *physnode_list;
+	unsigned int node_id;
  	int retval = -EINVAL;
 
  	if (ACPI_HANDLE(dev)) {

@@ -139,8 +142,14 @@ int acpi_bind_one(struct device *dev, ac
 
  	mutex_lock(&acpi_dev->physical_node_lock);
 
-	/* Sanity check. */
-	list_for_each_entry(pn, &acpi_dev->physical_node_list, node)
+	/*
+	 * Keep the list sorted by node_id so that the IDs of removed nodes can
+	 * be recycled.
+	 */
+	physnode_list = &acpi_dev->physical_node_list;
+	node_id = 0;
+	list_for_each_entry(pn, &acpi_dev->physical_node_list, node) {
+		/* Sanity check. */
  		if (pn->dev == dev) {
  			dev_warn(dev, "Already associated with ACPI node\n");
  			if (ACPI_HANDLE(dev) == handle)

@@ -148,19 +157,15 @@ int acpi_bind_one(struct device *dev, ac
 
  			goto out_free;
  		}
-
-	/* allocate physical node id according to physical_node_id_bitmap */
-	physical_node->node_id =
-		find_first_zero_bit(acpi_dev->physical_node_id_bitmap,
-		ACPI_MAX_PHYSICAL_NODE);
-	if (physical_node->node_id >= ACPI_MAX_PHYSICAL_NODE) {
-		retval = -ENOSPC;
-		goto out_free;
+		if (pn->node_id == node_id) {
+			physnode_list = &pn->node;
+			node_id++;
+		}
  	}
 
-	set_bit(physical_node->node_id, acpi_dev->physical_node_id_bitmap);
+	physical_node->node_id = node_id;
  	physical_node->dev = dev;
-	list_add_tail(&physical_node->node, &acpi_dev->physical_node_list);
+	list_add(&physical_node->node, physnode_list);
  	acpi_dev->physical_node_count++;
 
  	mutex_unlock(&acpi_dev->physical_node_lock);

@@ -215,7 +220,7 @@ int acpi_unbind_one(struct device *dev)
 
  	mutex_lock(&acpi_dev->physical_node_lock);
  	list_for_each_safe(node, next, &acpi_dev->physical_node_list) {
-		char physical_node_name[sizeof(PHYSICAL_NODE_STRING) + 2];
+		char physical_node_name[PHYSICAL_NODE_NAME_SIZE];
 
  		entry = list_entry(node, struct acpi_device_physical_node,
  			node);

@@ -223,7 +228,6 @@ int acpi_unbind_one(struct device *dev)
  			continue;
 
  		list_del(node);
-		clear_bit(entry->node_id, acpi_dev->physical_node_id_bitmap);
 
  		acpi_dev->physical_node_count--;
 

Index: linux-pm/include/acpi/acpi_bus.h
===================================================================

include/acpi/acpi_bus.h +2 -6

@@ -284,15 +284,12 @@ struct acpi_device_wakeup {
  };
 
  struct acpi_device_physical_node {
-	u8 node_id;
+	unsigned int node_id;
  	struct list_head node;
  	struct device *dev;
  	bool put_online:1;
  };
 
-/* set maximum of physical nodes to 32 for expansibility */
-#define ACPI_MAX_PHYSICAL_NODE	32
-
  /* Device */
  struct acpi_device {
  	int device_type;

@@ -312,10 +309,9 @@ struct acpi_device {
  	struct acpi_driver *driver;
  	void *driver_data;
  	struct device dev;
-	u8 physical_node_count;
+	unsigned int physical_node_count;
  	struct list_head physical_node_list;
  	struct mutex physical_node_lock;
-	DECLARE_BITMAP(physical_node_id_bitmap, ACPI_MAX_PHYSICAL_NODE);
  	struct list_head power_dependent;
  	void (*remove)(struct acpi_device *);
  };

Quoted 59 lines · Rafael J. Wysocki

Quoted 28 lines · Toshi Kani

On Mon, 2013-08-05 at 15:14 +0200, Rafael J. Wysocki wrote:

   :

Quoted 26 lines

Can you please test the appended patch? I tested it somewhat, but since the greatest number of physical nodes per ACPI device object I can get on my test machines is 2 (and even that after hacking the kernel somewhat), that was kind of unconclusive.

Thanks,
Rafael

---
From: Rafael J. Wysocki <[email protected]>
Subject: ACPI: Drop physical_node_id_bitmap from struct acpi_device

The physical_node_id_bitmap in struct acpi_device is only used for looking up the first currently unused phyiscal dependent node ID by acpi_bind_one(). It is not really necessary, however, because acpi_bind_one() walks the entire physical_node_list of the given device object for sanity checking anyway and if that list is always sorted by node_id, it is straightforward to find the first gap between the currently used node IDs and use that number as the ID of the new list node.

This also removes the artificial limit of the maximum number of dependent physical devices per ACPI device object, which now depends only on the capacity of unsigend int.

Quoted 5 lines

Quoted 1 line

Signed-off-by Rafael J. Wysocki <[email protected]>

I like the change. Much better :-)

Acked-by Toshi Kani <[email protected]>

However, it introduces a bug in acpi_unbind_one(), because the size of the name array in there has to be increased too. Updated patch follows.

Thanks,
Rafael

---
From: Rafael J. Wysocki <[email protected]>
Subject: ACPI: Drop physical_node_id_bitmap from struct acpi_device

The physical_node_id_bitmap in struct acpi_device is only used for looking up the first currently unused dependent phyiscal node ID by acpi_bind_one(). It is not really necessary, however, because acpi_bind_one() walks the entire physical_node_list of the given device object for sanity checking anyway and if that list is always sorted by node_id, it is straightforward to find the first gap between the currently used node IDs and use that number as the ID of the new list node.

This also removes the artificial limit of the maximum number of dependent physical devices per ACPI device object, which now depends only on the capacity of unsigend int.

Quoted 1 line

Signed-off-by Rafael J. Wysocki <[email protected]>

Reviewed-by Yasuaki Ishimatsu <[email protected]>

Tested-by Yasuaki Ishimatsu <[email protected]>

I confirmed that I can add and remove a memory device correctly.

Quoted 28 lines · Toshi Kani

On Mon, 2013-08-05 at 15:14 +0200, Rafael J. Wysocki wrote:
:

Quoted 26 lines

Can you please test the appended patch? I tested it somewhat, but since the greatest number of physical nodes per ACPI device object I can get on my test machines is 2 (and even that after hacking the kernel somewhat), that was kind of unconclusive.

Thanks,
Rafael

---
From: Rafael J. Wysocki <[email protected]>
Subject: ACPI: Drop physical_node_id_bitmap from struct acpi_device

The physical_node_id_bitmap in struct acpi_device is only used for looking up the first currently unused phyiscal dependent node ID by acpi_bind_one(). It is not really necessary, however, because acpi_bind_one() walks the entire physical_node_list of the given device object for sanity checking anyway and if that list is always sorted by node_id, it is straightforward to find the first gap between the currently used node IDs and use that number as the ID of the new list node.

This also removes the artificial limit of the maximum number of dependent physical devices per ACPI device object, which now depends only on the capacity of unsigend int.

Quoted 5 lines

Quoted 1 line

Signed-off-by Rafael J. Wysocki <[email protected]>

I like the change. Much better :-)

Acked-by Toshi Kani <[email protected]>

However, it introduces a bug in acpi_unbind_one(), because the size of the name array in there has to be increased too. Updated patch follows.

Quoted 2 lines · Rafael J. Wysocki

Quoted 1 line · Toshi Kani

On Thu, 2013-08-01 at 23:43 +0200, Rafael J. Wysocki wrote:

Quoted 5 lines

Quoted 4 lines

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

Quoted 7 lines

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Right. Even bigger issue is that I do not think __add_pages() and __remove_pages() can add / delete a memory chunk that is less than 128MB. 128MB is the granularity of them. So, we may just have to fail this case gracefully.

Quoted 3 lines · Toshi Kani

Quoted 2 lines · Rafael J. Wysocki

Quoted 1 line · Toshi Kani

On Thu, 2013-08-01 at 23:43 +0200, Rafael J. Wysocki wrote:

:

Quoted 13 lines

Quoted 12 lines

Quoted 4 lines

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Quoted 4 lines

Right. Even bigger issue is that I do not think __add_pages() and __remove_pages() can add / delete a memory chunk that is less than 128MB. 128MB is the granularity of them. So, we may just have to fail this case gracefully.

FYI: I have submitted the patch blow to close this part of the issue...

https://lkml.org/lkml/2013/8/8/396

Quoted 23 lines · Toshi Kani

Quoted 3 lines · Toshi Kani

Quoted 2 lines · Rafael J. Wysocki

Quoted 1 line · Toshi Kani

On Thu, 2013-08-01 at 23:43 +0200, Rafael J. Wysocki wrote:

:

Quoted 17 lines

Quoted 5 lines

Quoted 4 lines

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

Quoted 7 lines

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Right. Even bigger issue is that I do not think __add_pages() and __remove_pages() can add / delete a memory chunk that is less than 128MB. 128MB is the granularity of them. So, we may just have to fail this case gracefully.

Quoted 3 lines

FYI: I have submitted the patch blow to close this part of the issue...

https://lkml.org/lkml/2013/8/8/396

That looks good to me, but we'd still need to make it possible to have memory blocks smaller than 128 MB ...

Quoted 24 lines · Rafael J. Wysocki

Quoted 23 lines · Toshi Kani

Quoted 3 lines · Toshi Kani

Quoted 2 lines · Rafael J. Wysocki

Quoted 1 line · Toshi Kani

On Thu, 2013-08-01 at 23:43 +0200, Rafael J. Wysocki wrote:

:

Quoted 17 lines

Quoted 5 lines

Quoted 4 lines

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

Quoted 7 lines

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Right. Even bigger issue is that I do not think __add_pages() and __remove_pages() can add / delete a memory chunk that is less than 128MB. 128MB is the granularity of them. So, we may just have to fail this case gracefully.

Quoted 6 lines

Quoted 3 lines

FYI: I have submitted the patch blow to close this part of the issue...

https://lkml.org/lkml/2013/8/8/396

That looks good to me, but we'd still need to make it possible to have memory blocks smaller than 128 MB ...

Do you mean acpi_bind_one() needs to be able to handle such case? If so, it should not be a problem since a memory block device won't be created when add_memory() fails with the change above. So, there is no binding to be done. If you mean add_memory() needs to be able to handle a smaller range, that's quite a tough one unless we make the section size smaller.

BTW, when add_memory() fails, the memory hot-add request still succeeds with no driver attached. This seems logical, but the added device is useless when no handler is attached. And it does not allow ejecting the device with no handler. I am not too worry about this since this is a rare case, but it reminded me that the framework won't handle rollback.

Quoted 39 lines · Toshi Kani

Quoted 24 lines · Rafael J. Wysocki

Quoted 23 lines · Toshi Kani

Quoted 3 lines · Toshi Kani

Quoted 2 lines · Rafael J. Wysocki

Quoted 1 line · Toshi Kani

On Thu, 2013-08-01 at 23:43 +0200, Rafael J. Wysocki wrote:

:

Quoted 17 lines

Quoted 5 lines

Quoted 4 lines

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

Quoted 7 lines

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Right. Even bigger issue is that I do not think __add_pages() and __remove_pages() can add / delete a memory chunk that is less than 128MB. 128MB is the granularity of them. So, we may just have to fail this case gracefully.

Quoted 6 lines

Quoted 3 lines

FYI: I have submitted the patch blow to close this part of the issue...

https://lkml.org/lkml/2013/8/8/396

That looks good to me, but we'd still need to make it possible to have memory blocks smaller than 128 MB ...

Do you mean acpi_bind_one() needs to be able to handle such case? If so, it should not be a problem since a memory block device won't be created when add_memory() fails with the change above. So, there is no binding to be done. If you mean add_memory() needs to be able to handle a smaller range, that's quite a tough one unless we make the section size smaller.

Quoted 5 lines

BTW, when add_memory() fails, the memory hot-add request still succeeds with no driver attached. This seems logical, but the added device is useless when no handler is attached. And it does not allow ejecting the device with no handler. I am not too worry about this since this is a rare case, but it reminded me that the framework won't handle rollback.

That is a valid observation.

Perhaps we should add a flag that will cause acpi_bus_offline_companions() to fail immediately if that flag is set for the given device?

Then, acpi_memory_enable_device() could set that flag for mem_device->device when either add_memory() or acpi_bind_memory_blocks() fails?

Quoted 24 lines · Rafael J. Wysocki

Quoted 23 lines · Toshi Kani

Quoted 3 lines · Toshi Kani

Quoted 2 lines · Rafael J. Wysocki

Quoted 1 line · Toshi Kani

On Thu, 2013-08-01 at 23:43 +0200, Rafael J. Wysocki wrote:

:

Quoted 17 lines

Quoted 5 lines

Quoted 4 lines

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

Quoted 7 lines

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Right. Even bigger issue is that I do not think __add_pages() and __remove_pages() can add / delete a memory chunk that is less than 128MB. 128MB is the granularity of them. So, we may just have to fail this case gracefully.

Quoted 6 lines

Quoted 3 lines

FYI: I have submitted the patch blow to close this part of the issue...

https://lkml.org/lkml/2013/8/8/396

That looks good to me, but we'd still need to make it possible to have memory blocks smaller than 128 MB ...

Do you mean acpi_bind_one() needs to be able to handle such case? If so, it should not be a problem since a memory block device won't be created when add_memory() fails with the change above. So, there is no binding to be done. If you mean add_memory() needs to be able to handle a smaller range, that's quite a tough one unless we make the section size smaller.

BTW, when add_memory() fails, the memory hot-add request still succeeds with no driver attached. This seems logical, but the added device is useless when no handler is attached. And it does not allow ejecting the device with no handler. I am not too worry about this since this is a rare case, but it reminded me that the framework won't handle rollback.

Quoted 39 lines · Toshi Kani

Quoted 24 lines · Rafael J. Wysocki

Quoted 23 lines · Toshi Kani

Quoted 3 lines · Toshi Kani

Quoted 2 lines · Rafael J. Wysocki

Quoted 1 line · Toshi Kani

On Thu, 2013-08-01 at 23:43 +0200, Rafael J. Wysocki wrote:

:

Quoted 17 lines

Quoted 5 lines

Quoted 4 lines

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

Quoted 7 lines

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Right. Even bigger issue is that I do not think __add_pages() and __remove_pages() can add / delete a memory chunk that is less than 128MB. 128MB is the granularity of them. So, we may just have to fail this case gracefully.

Quoted 6 lines

Quoted 3 lines

FYI: I have submitted the patch blow to close this part of the issue...

https://lkml.org/lkml/2013/8/8/396

That looks good to me, but we'd still need to make it possible to have memory blocks smaller than 128 MB ...

Do you mean acpi_bind_one() needs to be able to handle such case? If so, it should not be a problem since a memory block device won't be created when add_memory() fails with the change above. So, there is no binding to be done. If you mean add_memory() needs to be able to handle a smaller range, that's quite a tough one unless we make the section size smaller.

Quoted 5 lines

BTW, when add_memory() fails, the memory hot-add request still succeeds with no driver attached. This seems logical, but the added device is useless when no handler is attached. And it does not allow ejecting the device with no handler. I am not too worry about this since this is a rare case, but it reminded me that the framework won't handle rollback.

I'm not sure which rollback you mean. During removal?

There are two slight problems here in my view. First, even if the device cannot be ejected directly, it still will be removed when its parent is ejected, so it may be more consistent to just allow everything to be ejected regardless of whether or not it has a scan handler.

Second, I guess the
removal is undesirable for memory devices for which the registration of the scan handler failed, so it would be good to fail the "offline" of such devices regardless of how we get there. That's why I thought it would be good to have an "offline disabled" flag in struct acpi_device.

Quoted 40 lines · Rafael J. Wysocki

Quoted 39 lines · Toshi Kani

Quoted 24 lines · Rafael J. Wysocki

Quoted 23 lines · Toshi Kani

Quoted 3 lines · Toshi Kani

Quoted 2 lines · Rafael J. Wysocki

Quoted 1 line · Toshi Kani

On Thu, 2013-08-01 at 23:43 +0200, Rafael J. Wysocki wrote:

:

Quoted 17 lines

Quoted 5 lines

Quoted 4 lines

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

Quoted 7 lines

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Right. Even bigger issue is that I do not think __add_pages() and __remove_pages() can add / delete a memory chunk that is less than 128MB. 128MB is the granularity of them. So, we may just have to fail this case gracefully.

Quoted 6 lines

Quoted 3 lines

FYI: I have submitted the patch blow to close this part of the issue...

https://lkml.org/lkml/2013/8/8/396

That looks good to me, but we'd still need to make it possible to have memory blocks smaller than 128 MB ...

Do you mean acpi_bind_one() needs to be able to handle such case? If so, it should not be a problem since a memory block device won't be created when add_memory() fails with the change above. So, there is no binding to be done. If you mean add_memory() needs to be able to handle a smaller range, that's quite a tough one unless we make the section size smaller.

Quoted 7 lines

Quoted 5 lines

BTW, when add_memory() fails, the memory hot-add request still succeeds with no driver attached. This seems logical, but the added device is useless when no handler is attached. And it does not allow ejecting the device with no handler. I am not too worry about this since this is a rare case, but it reminded me that the framework won't handle rollback.

I'm not sure which rollback you mean. During removal?

I meant rollback during hot-add. Ideally, a device should be either added in usable state (success) or failed back to the original state (rollback). Added in un-usable state is not really a success for users, and creates an odd state to deal with. But it is still a LOT better than crashing the system. So, I think this outcome is reasonable on this framework because adding rollback at this point will complicate the things unnecessarily.

Quoted 4 lines

There are two slight problems here in my view. First, even if the device cannot be ejected directly, it still will be removed when its parent is ejected, so it may be more consistent to just allow everything to be ejected regardless of whether or not it has a scan handler.

Agreed.

Quoted 5 lines

Second, I guess the
removal is undesirable for memory devices for which the registration of the scan handler failed, so it would be good to fail the "offline" of such devices regardless of how we get there. That's why I thought it would be good to have an "offline disabled" flag in struct acpi_device.

I see. But when attach() failed, the memory device may not be used by the kernel. So, I think it should be safe to remove it.

Quoted 70 lines · Toshi Kani

Quoted 40 lines · Rafael J. Wysocki

Quoted 39 lines · Toshi Kani

Quoted 24 lines · Rafael J. Wysocki

Quoted 23 lines · Toshi Kani

Quoted 3 lines · Toshi Kani

Quoted 2 lines · Rafael J. Wysocki

Quoted 1 line · Toshi Kani

On Thu, 2013-08-01 at 23:43 +0200, Rafael J. Wysocki wrote:

:

Quoted 17 lines

Quoted 5 lines

Quoted 4 lines

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

Quoted 7 lines

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Right. Even bigger issue is that I do not think __add_pages() and __remove_pages() can add / delete a memory chunk that is less than 128MB. 128MB is the granularity of them. So, we may just have to fail this case gracefully.

Quoted 6 lines

Quoted 3 lines

FYI: I have submitted the patch blow to close this part of the issue...

https://lkml.org/lkml/2013/8/8/396

That looks good to me, but we'd still need to make it possible to have memory blocks smaller than 128 MB ...

Do you mean acpi_bind_one() needs to be able to handle such case? If so, it should not be a problem since a memory block device won't be created when add_memory() fails with the change above. So, there is no binding to be done. If you mean add_memory() needs to be able to handle a smaller range, that's quite a tough one unless we make the section size smaller.

Quoted 7 lines

Quoted 5 lines

BTW, when add_memory() fails, the memory hot-add request still succeeds with no driver attached. This seems logical, but the added device is useless when no handler is attached. And it does not allow ejecting the device with no handler. I am not too worry about this since this is a rare case, but it reminded me that the framework won't handle rollback.

I'm not sure which rollback you mean. During removal?

I meant rollback during hot-add. Ideally, a device should be either added in usable state (success) or failed back to the original state (rollback). Added in un-usable state is not really a success for users, and creates an odd state to deal with. But it is still a LOT better than crashing the system. So, I think this outcome is reasonable on this framework because adding rollback at this point will complicate the things unnecessarily.

Quoted 4 lines

There are two slight problems here in my view. First, even if the device cannot be ejected directly, it still will be removed when its parent is ejected, so it may be more consistent to just allow everything to be ejected regardless of whether or not it has a scan handler.

Agreed.

Quoted 5 lines

Second, I guess the
removal is undesirable for memory devices for which the registration of the scan handler failed, so it would be good to fail the "offline" of such devices regardless of how we get there. That's why I thought it would be good to have an "offline disabled" flag in struct acpi_device.

Quoted 2 lines

I see. But when attach() failed, the memory device may not be used by the kernel. So, I think it should be safe to remove it.

The failure of .attach() need not mean that the memory is not used by the kernel, though, and the ACPI device object is still there and still may be involved in some removal scenarios (through its parent).

Quoted 71 lines · Rafael J. Wysocki

Quoted 70 lines · Toshi Kani

Quoted 40 lines · Rafael J. Wysocki

Quoted 39 lines · Toshi Kani

Quoted 24 lines · Rafael J. Wysocki

Quoted 23 lines · Toshi Kani

Quoted 3 lines · Toshi Kani

Quoted 2 lines · Rafael J. Wysocki

Quoted 1 line · Toshi Kani

On Thu, 2013-08-01 at 23:43 +0200, Rafael J. Wysocki wrote:

:

Quoted 17 lines

Quoted 5 lines

Quoted 4 lines

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

Quoted 7 lines

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Right. Even bigger issue is that I do not think __add_pages() and __remove_pages() can add / delete a memory chunk that is less than 128MB. 128MB is the granularity of them. So, we may just have to fail this case gracefully.

Quoted 6 lines

Quoted 3 lines

FYI: I have submitted the patch blow to close this part of the issue...

https://lkml.org/lkml/2013/8/8/396

That looks good to me, but we'd still need to make it possible to have memory blocks smaller than 128 MB ...

Do you mean acpi_bind_one() needs to be able to handle such case? If so, it should not be a problem since a memory block device won't be created when add_memory() fails with the change above. So, there is no binding to be done. If you mean add_memory() needs to be able to handle a smaller range, that's quite a tough one unless we make the section size smaller.

Quoted 7 lines

Quoted 5 lines

BTW, when add_memory() fails, the memory hot-add request still succeeds with no driver attached. This seems logical, but the added device is useless when no handler is attached. And it does not allow ejecting the device with no handler. I am not too worry about this since this is a rare case, but it reminded me that the framework won't handle rollback.

I'm not sure which rollback you mean. During removal?

I meant rollback during hot-add. Ideally, a device should be either added in usable state (success) or failed back to the original state (rollback). Added in un-usable state is not really a success for users, and creates an odd state to deal with. But it is still a LOT better than crashing the system. So, I think this outcome is reasonable on this framework because adding rollback at this point will complicate the things unnecessarily.

Quoted 4 lines

There are two slight problems here in my view. First, even if the device cannot be ejected directly, it still will be removed when its parent is ejected, so it may be more consistent to just allow everything to be ejected regardless of whether or not it has a scan handler.

Agreed.

Quoted 5 lines

Second, I guess the
removal is undesirable for memory devices for which the registration of the scan handler failed, so it would be good to fail the "offline" of such devices regardless of how we get there. That's why I thought it would be good to have an "offline disabled" flag in struct acpi_device.

Quoted 6 lines

Quoted 2 lines

I see. But when attach() failed, the memory device may not be used by the kernel. So, I think it should be safe to remove it.

The failure of .attach() need not mean that the memory is not used by the kernel, though, and the ACPI device object is still there and still may be involved in some removal scenarios (through its parent).

As long as .attach() is failed cleanly, which I think is the case for the memory handler (if not, we need to fix it), the rest of the kernel code may not know what this device is. That is, the ACPI memory handler is the only one that knows PNP0C80 is a memory device. So, I do not think the memory can be used in such case...

Quoted 79 lines · Toshi Kani

Quoted 71 lines · Rafael J. Wysocki

Quoted 70 lines · Toshi Kani

Quoted 40 lines · Rafael J. Wysocki

Quoted 39 lines · Toshi Kani

Quoted 24 lines · Rafael J. Wysocki

Quoted 23 lines · Toshi Kani

Quoted 3 lines · Toshi Kani

Quoted 2 lines · Rafael J. Wysocki

Quoted 1 line · Toshi Kani

On Thu, 2013-08-01 at 23:43 +0200, Rafael J. Wysocki wrote:

:

Quoted 17 lines

Quoted 5 lines

Quoted 4 lines

I think it fails with -EINVAL at the place with dev_warn(dev, "ACPI handle is already set\n"). When two ACPI memory objects associate with a same memory block, the bind procedure of the 2nd ACPI memory object sees that ACPI_HANDLE(dev) is already set to the 1st ACPI memory object.

Quoted 7 lines

That sound's plausible, but I wonder how we can fix that?

There's no way for a single physical device to have two different ACPI "companions". It looks like the memory blocks should be 64 M each in that case. Or we need to create two child devices for each memory block and associate each of them with an ACPI object. That would lead to complications in the user space interface, though.

Right. Even bigger issue is that I do not think __add_pages() and __remove_pages() can add / delete a memory chunk that is less than 128MB. 128MB is the granularity of them. So, we may just have to fail this case gracefully.

Quoted 6 lines

Quoted 3 lines

FYI: I have submitted the patch blow to close this part of the issue...

https://lkml.org/lkml/2013/8/8/396

That looks good to me, but we'd still need to make it possible to have memory blocks smaller than 128 MB ...

Do you mean acpi_bind_one() needs to be able to handle such case? If so, it should not be a problem since a memory block device won't be created when add_memory() fails with the change above. So, there is no binding to be done. If you mean add_memory() needs to be able to handle a smaller range, that's quite a tough one unless we make the section size smaller.

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BTW, when add_memory() fails, the memory hot-add request still succeeds with no driver attached. This seems logical, but the added device is useless when no handler is attached. And it does not allow ejecting the device with no handler. I am not too worry about this since this is a rare case, but it reminded me that the framework won't handle rollback.

I'm not sure which rollback you mean. During removal?

I meant rollback during hot-add. Ideally, a device should be either added in usable state (success) or failed back to the original state (rollback). Added in un-usable state is not really a success for users, and creates an odd state to deal with. But it is still a LOT better than crashing the system. So, I think this outcome is reasonable on this framework because adding rollback at this point will complicate the things unnecessarily.

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There are two slight problems here in my view. First, even if the device cannot be ejected directly, it still will be removed when its parent is ejected, so it may be more consistent to just allow everything to be ejected regardless of whether or not it has a scan handler.

Agreed.

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Second, I guess the
removal is undesirable for memory devices for which the registration of the scan handler failed, so it would be good to fail the "offline" of such devices regardless of how we get there. That's why I thought it would be good to have an "offline disabled" flag in struct acpi_device.

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I see. But when attach() failed, the memory device may not be used by the kernel. So, I think it should be safe to remove it.

The failure of .attach() need not mean that the memory is not used by the kernel, though, and the ACPI device object is still there and still may be involved in some removal scenarios (through its parent).

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As long as .attach() is failed cleanly, which I think is the case for the memory handler (if not, we need to fix it), the rest of the kernel code may not know what this device is. That is, the ACPI memory handler is the only one that knows PNP0C80 is a memory device. So, I do not think the memory can be used in such case...

Yes, it can, if the kernel discovers it during boot before .attach() is first called. So say this happens and the ACPI memory device object has a parent with existing _EJ0.

The memory handler's .attach() fails, so the initial acpi_bus_scan() won't walk the namespace below the memory device, but it won't return an error code either (the root device object is always there). The parent of the failed node is regarded as operational in particular.

Now, acpi_scan_hot_remove() is called for the parent. Since the memory device object doesn't have "physical" devices associated with it, acpi_bus_offline_companions() will ignore it and acpi_scan_hot_remove() will go for acpi_bus_trim() and straight for _EJ0 for the parent. Splat!

I agree that this is a corner case, but I wonder if leaving it this way is a good idea. :-)