diff mbox series

[1/1] riscv: select CONFIG_ARCH_KEEP_MEMBLOCK

Message ID 20210816144728.1425121-1-heinrich.schuchardt@canonical.com (mailing list archive)
State New, archived
Headers show
Series [1/1] riscv: select CONFIG_ARCH_KEEP_MEMBLOCK | expand

Commit Message

Heinrich Schuchardt Aug. 16, 2021, 2:47 p.m. UTC
For analyzing memory blocks we can either use the memblock=debug command
line argument which creates massive output or a debug file system.

Select CONFIG_ARCH_KEEP_MEMBLOCK to provide a debugfs at
/sys/kernel/debug/memblock to analyze memory blocks. The
same is already done for arm, arm64, mips, powerpc.

The actual provisioning of the file system depends on CONFIG_DEBUG_FS.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
---
 arch/riscv/Kconfig | 1 +
 1 file changed, 1 insertion(+)

Comments

Kefeng Wang Aug. 16, 2021, 3:30 p.m. UTC | #1
On 2021/8/16 22:47, Heinrich Schuchardt wrote:
> For analyzing memory blocks we can either use the memblock=debug command
> line argument which creates massive output or a debug file system.
>
> Select CONFIG_ARCH_KEEP_MEMBLOCK to provide a debugfs at
> /sys/kernel/debug/memblock to analyze memory blocks. The
> same is already done for arm, arm64, mips, powerpc.
>
> The actual provisioning of the file system depends on CONFIG_DEBUG_FS.

Hi,for riscv, it don't use memblock(eg, no provide pfn_valid to use 
memblock),

we could call memblock_discard() to discard memblock private memory to save

some memory, right?  So I think we don't need this config for now.

>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
> ---
>   arch/riscv/Kconfig | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 4f7b70ae7c31..a6e57614c3fd 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -31,6 +31,7 @@ config RISCV
>   	select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
>   	select ARCH_HAS_STRICT_MODULE_RWX if MMU && !XIP_KERNEL
>   	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
> +	select ARCH_KEEP_MEMBLOCK
>   	select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
>   	select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
>   	select ARCH_SUPPORTS_HUGETLBFS if MMU
Heinrich Schuchardt Aug. 16, 2021, 3:52 p.m. UTC | #2
On 8/16/21 5:30 PM, Kefeng Wang wrote:
> 
> On 2021/8/16 22:47, Heinrich Schuchardt wrote:
>> For analyzing memory blocks we can either use the memblock=debug command
>> line argument which creates massive output or a debug file system.
>>
>> Select CONFIG_ARCH_KEEP_MEMBLOCK to provide a debugfs at
>> /sys/kernel/debug/memblock to analyze memory blocks. The
>> same is already done for arm, arm64, mips, powerpc.
>>
>> The actual provisioning of the file system depends on CONFIG_DEBUG_FS.
> 
> Hi,for riscv, it don't use memblock(eg, no provide pfn_valid to use 
> memblock),
> 
> we could call memblock_discard() to discard memblock private memory to save
> 
> some memory, right?  So I think we don't need this config for now.

What do you mean by "it don't use memblock?

If you boot the HiFive Unmatched with memblock=debug you will see output 
like the one below. This is the information that you can see in the 
debug file system if CONFIG_DEBUG_FS and CONFIG_ARCH_KEEP_MEMBLOCK will 
be enabled.

[    0.000000] MEMBLOCK configuration:
[    0.000000]  memory size = 0x00000003ffe00000 reserved size = 
0x000000001290fb70
[    0.000000]  memory.cnt  = 0x25
[    0.000000]  memory[0x0]     [0x0000000080200000-0x00000000fe6e2fff], 
0x000000007e4e3000 bytes flags: 0x0
[    0.000000]  memory[0x1]     [0x00000000fe6e3000-0x00000000fe6e5fff], 
0x0000000000003000 bytes flags: 0x4
[    0.000000]  memory[0x2]     [0x00000000fe6e6000-0x00000000fe709fff], 
0x0000000000024000 bytes flags: 0x0
[    0.000000]  memory[0x3]     [0x00000000fe70a000-0x00000000fe70bfff], 
0x0000000000002000 bytes flags: 0x4
[    0.000000]  memory[0x4]     [0x00000000fe70c000-0x00000000fe70ffff], 
0x0000000000004000 bytes flags: 0x0
[    0.000000]  memory[0x5]     [0x00000000fe710000-0x00000000fe710fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x6]     [0x00000000fe711000-0x00000000fe712fff], 
0x0000000000002000 bytes flags: 0x0
[    0.000000]  memory[0x7]     [0x00000000fe713000-0x00000000fe716fff], 
0x0000000000004000 bytes flags: 0x4
[    0.000000]  memory[0x8]     [0x00000000fe717000-0x00000000fe717fff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0x9]     [0x00000000fe718000-0x00000000fe71cfff], 
0x0000000000005000 bytes flags: 0x4
[    0.000000]  memory[0xa]     [0x00000000fe71d000-0x00000000fe71dfff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0xb]     [0x00000000fe71e000-0x00000000fe71efff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0xc]     [0x00000000fe71f000-0x00000000fe71ffff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0xd]     [0x00000000fe720000-0x00000000fe720fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0xe]     [0x00000000fe721000-0x00000000fe721fff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0xf]     [0x00000000fe722000-0x00000000fe722fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x10]    [0x00000000fe723000-0x00000000fe723fff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0x11]    [0x00000000fe724000-0x00000000fe724fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x12]    [0x00000000fe725000-0x00000000fe725fff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0x13]    [0x00000000fe726000-0x00000000fe726fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x14]    [0x00000000fe727000-0x00000000fe728fff], 
0x0000000000002000 bytes flags: 0x0
[    0.000000]  memory[0x15]    [0x00000000fe729000-0x00000000fe729fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x16]    [0x00000000fe72a000-0x00000000fe72afff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0x17]    [0x00000000fe72b000-0x00000000fe72cfff], 
0x0000000000002000 bytes flags: 0x4
[    0.000000]  memory[0x18]    [0x00000000fe72d000-0x00000000fe72dfff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0x19]    [0x00000000fe72e000-0x00000000fe72efff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x1a]    [0x00000000fe72f000-0x00000000fe72ffff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0x1b]    [0x00000000fe730000-0x00000000fe730fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x1c]    [0x00000000fe731000-0x00000000fe731fff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0x1d]    [0x00000000fe732000-0x00000000fe732fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x1e]    [0x00000000fe733000-0x00000000fe733fff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0x1f]    [0x00000000fe734000-0x00000000fe734fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x20]    [0x00000000fe735000-0x00000000fe736fff], 
0x0000000000002000 bytes flags: 0x0
[    0.000000]  memory[0x21]    [0x00000000fe737000-0x00000000fe737fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x22]    [0x00000000fe738000-0x00000000fff60fff], 
0x0000000001829000 bytes flags: 0x0
[    0.000000]  memory[0x23]    [0x00000000fff61000-0x00000000fff61fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x24]    [0x00000000fff62000-0x000000047fffffff], 
0x000000038009e000 bytes flags: 0x0
[    0.000000]  reserved.cnt  = 0xd
[    0.000000]  reserved[0x0]   [0x0000000080000000-0x000000008007ffff], 
0x0000000000080000 bytes flags: 0x0
[    0.000000]  reserved[0x1]   [0x0000000080200000-0x00000000815fffff], 
0x0000000001400000 bytes flags: 0x0
[    0.000000]  reserved[0x2]   [0x0000000087f00000-0x0000000087f05fff], 
0x0000000000006000 bytes flags: 0x0
[    0.000000]  reserved[0x3]   [0x00000000db0a2000-0x00000000db0a48b4], 
0x00000000000028b5 bytes flags: 0x0
[    0.000000]  reserved[0x4]   [0x00000000db2a2000-0x00000000dc709fff], 
0x0000000001468000 bytes flags: 0x0
[    0.000000]  reserved[0x5]   [0x00000000fe701000-0x00000000fe701fff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  reserved[0x6]   [0x00000000fe704040-0x00000000fe70404f], 
0x0000000000000010 bytes flags: 0x0
[    0.000000]  reserved[0x7]   [0x000000046ffe1d40-0x000000047dfe253f], 
0x000000000e000800 bytes flags: 0x0
[    0.000000]  reserved[0x8]   [0x000000047dfe2548-0x000000047dfe2578], 
0x0000000000000031 bytes flags: 0x0
[    0.000000]  reserved[0x9]   [0x000000047dfe2580-0x000000047dfe25ae], 
0x000000000000002f bytes flags: 0x0
[    0.000000]  reserved[0xa]   [0x000000047dfe25b0-0x000000047dfe25de], 
0x000000000000002f bytes flags: 0x0
[    0.000000]  reserved[0xb]   [0x000000047dfe25e0-0x000000047dfefffb], 
0x000000000000da1c bytes flags: 0x0
[    0.000000]  reserved[0xc]   [0x000000047dff0000-0x000000047fffffff], 
0x0000000002010000 bytes flags: 0x0

Best regards

Heinrich

> 
>>
>> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
>> ---
>>   arch/riscv/Kconfig | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
>> index 4f7b70ae7c31..a6e57614c3fd 100644
>> --- a/arch/riscv/Kconfig
>> +++ b/arch/riscv/Kconfig
>> @@ -31,6 +31,7 @@ config RISCV
>>       select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
>>       select ARCH_HAS_STRICT_MODULE_RWX if MMU && !XIP_KERNEL
>>       select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
>> +    select ARCH_KEEP_MEMBLOCK
>>       select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
>>       select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
>>       select ARCH_SUPPORTS_HUGETLBFS if MMU
Kefeng Wang Aug. 16, 2021, 4:03 p.m. UTC | #3
On 2021/8/16 23:52, Heinrich Schuchardt wrote:
> On 8/16/21 5:30 PM, Kefeng Wang wrote:
>>
>> On 2021/8/16 22:47, Heinrich Schuchardt wrote:
>>> For analyzing memory blocks we can either use the memblock=debug 
>>> command
>>> line argument which creates massive output or a debug file system.
>>>
>>> Select CONFIG_ARCH_KEEP_MEMBLOCK to provide a debugfs at
>>> /sys/kernel/debug/memblock to analyze memory blocks. The
>>> same is already done for arm, arm64, mips, powerpc.
>>>
>>> The actual provisioning of the file system depends on CONFIG_DEBUG_FS.
>>
>> Hi,for riscv, it don't use memblock(eg, no provide pfn_valid to use 
>> memblock),
>>
>> we could call memblock_discard() to discard memblock private memory 
>> to save
>>
>> some memory, right?  So I think we don't need this config for now.
>
> What do you mean by "it don't use memblock?

Sorry, it should be  "the riscv don't use memblock after the page 
allocator is initialized"
Mike Rapoport Aug. 16, 2021, 6:50 p.m. UTC | #4
Hi Heinrich,

On Mon, Aug 16, 2021 at 05:52:11PM +0200, Heinrich Schuchardt wrote:
> On 8/16/21 5:30 PM, Kefeng Wang wrote:
> > 
> > On 2021/8/16 22:47, Heinrich Schuchardt wrote:
> > > For analyzing memory blocks we can either use the memblock=debug command
> > > line argument which creates massive output or a debug file system.
> > > 
> > > Select CONFIG_ARCH_KEEP_MEMBLOCK to provide a debugfs at
> > > /sys/kernel/debug/memblock to analyze memory blocks. The
> > > same is already done for arm, arm64, mips, powerpc.
> > > 
> > > The actual provisioning of the file system depends on CONFIG_DEBUG_FS.
> > 
> > Hi,for riscv, it don't use memblock(eg, no provide pfn_valid to use
> > memblock),
> > 
> > we could call memblock_discard() to discard memblock private memory to save
> > 
> > some memory, right?  So I think we don't need this config for now.
> 
> What do you mean by "it don't use memblock?
> 
> If you boot the HiFive Unmatched with memblock=debug you will see output
> like the one below. This is the information that you can see in the debug
> file system if CONFIG_DEBUG_FS and CONFIG_ARCH_KEEP_MEMBLOCK will be
> enabled.

Indeed having this info in debugfs is more convenient, but it comes with a
cost of several kilobytes of code and data for *every* riscv build.

Why parsing "memblock=debug" output is not enough?
What is the use-case that justifies the costs associated with having the
debugfs entries?
 
> [    0.000000] MEMBLOCK configuration:
> [    0.000000]  memory size = 0x00000003ffe00000 reserved size =
> 0x000000001290fb70
> [    0.000000]  memory.cnt  = 0x25

BTW, it seems that the memory allocation by firmware is, well, suboptimal
and begs for fixes. I don't see why all these NOMAP areas cannot be put in
one contiguous chunk. I doubt they need to be NOMAP at all, but mysterious
the ways of ACPI.

> [    0.000000]  memory[0x0]     [0x0000000080200000-0x00000000fe6e2fff],
> 0x000000007e4e3000 bytes flags: 0x0
> [    0.000000]  memory[0x1]     [0x00000000fe6e3000-0x00000000fe6e5fff],
> 0x0000000000003000 bytes flags: 0x4
> [    0.000000]  memory[0x2]     [0x00000000fe6e6000-0x00000000fe709fff],
> 0x0000000000024000 bytes flags: 0x0
> [    0.000000]  memory[0x3]     [0x00000000fe70a000-0x00000000fe70bfff],
> 0x0000000000002000 bytes flags: 0x4
> [    0.000000]  memory[0x4]     [0x00000000fe70c000-0x00000000fe70ffff],
> 0x0000000000004000 bytes flags: 0x0
> [    0.000000]  memory[0x5]     [0x00000000fe710000-0x00000000fe710fff],
> 0x0000000000001000 bytes flags: 0x4
> [    0.000000]  memory[0x6]     [0x00000000fe711000-0x00000000fe712fff],
> 0x0000000000002000 bytes flags: 0x0
> [    0.000000]  memory[0x7]     [0x00000000fe713000-0x00000000fe716fff],
> 0x0000000000004000 bytes flags: 0x4
> [    0.000000]  memory[0x8]     [0x00000000fe717000-0x00000000fe717fff],
> 0x0000000000001000 bytes flags: 0x0
> [    0.000000]  memory[0x9]     [0x00000000fe718000-0x00000000fe71cfff],
> 0x0000000000005000 bytes flags: 0x4
> [    0.000000]  memory[0xa]     [0x00000000fe71d000-0x00000000fe71dfff],
> 0x0000000000001000 bytes flags: 0x0
> [    0.000000]  memory[0xb]     [0x00000000fe71e000-0x00000000fe71efff],
> 0x0000000000001000 bytes flags: 0x4
> [    0.000000]  memory[0xc]     [0x00000000fe71f000-0x00000000fe71ffff],
> 0x0000000000001000 bytes flags: 0x0
> [    0.000000]  memory[0xd]     [0x00000000fe720000-0x00000000fe720fff],
> 0x0000000000001000 bytes flags: 0x4
> [    0.000000]  memory[0xe]     [0x00000000fe721000-0x00000000fe721fff],
> 0x0000000000001000 bytes flags: 0x0
> [    0.000000]  memory[0xf]     [0x00000000fe722000-0x00000000fe722fff],
> 0x0000000000001000 bytes flags: 0x4
> [    0.000000]  memory[0x10]    [0x00000000fe723000-0x00000000fe723fff],
> 0x0000000000001000 bytes flags: 0x0
> [    0.000000]  memory[0x11]    [0x00000000fe724000-0x00000000fe724fff],
> 0x0000000000001000 bytes flags: 0x4
> [    0.000000]  memory[0x12]    [0x00000000fe725000-0x00000000fe725fff],
> 0x0000000000001000 bytes flags: 0x0
> [    0.000000]  memory[0x13]    [0x00000000fe726000-0x00000000fe726fff],
> 0x0000000000001000 bytes flags: 0x4
> [    0.000000]  memory[0x14]    [0x00000000fe727000-0x00000000fe728fff],
> 0x0000000000002000 bytes flags: 0x0
> [    0.000000]  memory[0x15]    [0x00000000fe729000-0x00000000fe729fff],
> 0x0000000000001000 bytes flags: 0x4
> [    0.000000]  memory[0x16]    [0x00000000fe72a000-0x00000000fe72afff],
> 0x0000000000001000 bytes flags: 0x0
> [    0.000000]  memory[0x17]    [0x00000000fe72b000-0x00000000fe72cfff],
> 0x0000000000002000 bytes flags: 0x4
> [    0.000000]  memory[0x18]    [0x00000000fe72d000-0x00000000fe72dfff],
> 0x0000000000001000 bytes flags: 0x0
> [    0.000000]  memory[0x19]    [0x00000000fe72e000-0x00000000fe72efff],
> 0x0000000000001000 bytes flags: 0x4
> [    0.000000]  memory[0x1a]    [0x00000000fe72f000-0x00000000fe72ffff],
> 0x0000000000001000 bytes flags: 0x0
> [    0.000000]  memory[0x1b]    [0x00000000fe730000-0x00000000fe730fff],
> 0x0000000000001000 bytes flags: 0x4
> [    0.000000]  memory[0x1c]    [0x00000000fe731000-0x00000000fe731fff],
> 0x0000000000001000 bytes flags: 0x0
> [    0.000000]  memory[0x1d]    [0x00000000fe732000-0x00000000fe732fff],
> 0x0000000000001000 bytes flags: 0x4
> [    0.000000]  memory[0x1e]    [0x00000000fe733000-0x00000000fe733fff],
> 0x0000000000001000 bytes flags: 0x0
> [    0.000000]  memory[0x1f]    [0x00000000fe734000-0x00000000fe734fff],
> 0x0000000000001000 bytes flags: 0x4
> [    0.000000]  memory[0x20]    [0x00000000fe735000-0x00000000fe736fff],
> 0x0000000000002000 bytes flags: 0x0
> [    0.000000]  memory[0x21]    [0x00000000fe737000-0x00000000fe737fff],
> 0x0000000000001000 bytes flags: 0x4
> [    0.000000]  memory[0x22]    [0x00000000fe738000-0x00000000fff60fff],
> 0x0000000001829000 bytes flags: 0x0
> [    0.000000]  memory[0x23]    [0x00000000fff61000-0x00000000fff61fff],
> 0x0000000000001000 bytes flags: 0x4
> [    0.000000]  memory[0x24]    [0x00000000fff62000-0x000000047fffffff],
> 0x000000038009e000 bytes flags: 0x0
> [    0.000000]  reserved.cnt  = 0xd
> [    0.000000]  reserved[0x0]   [0x0000000080000000-0x000000008007ffff],
> 0x0000000000080000 bytes flags: 0x0
> [    0.000000]  reserved[0x1]   [0x0000000080200000-0x00000000815fffff],
> 0x0000000001400000 bytes flags: 0x0
> [    0.000000]  reserved[0x2]   [0x0000000087f00000-0x0000000087f05fff],
> 0x0000000000006000 bytes flags: 0x0
> [    0.000000]  reserved[0x3]   [0x00000000db0a2000-0x00000000db0a48b4],
> 0x00000000000028b5 bytes flags: 0x0
> [    0.000000]  reserved[0x4]   [0x00000000db2a2000-0x00000000dc709fff],
> 0x0000000001468000 bytes flags: 0x0
> [    0.000000]  reserved[0x5]   [0x00000000fe701000-0x00000000fe701fff],
> 0x0000000000001000 bytes flags: 0x0
> [    0.000000]  reserved[0x6]   [0x00000000fe704040-0x00000000fe70404f],
> 0x0000000000000010 bytes flags: 0x0
> [    0.000000]  reserved[0x7]   [0x000000046ffe1d40-0x000000047dfe253f],
> 0x000000000e000800 bytes flags: 0x0
> [    0.000000]  reserved[0x8]   [0x000000047dfe2548-0x000000047dfe2578],
> 0x0000000000000031 bytes flags: 0x0
> [    0.000000]  reserved[0x9]   [0x000000047dfe2580-0x000000047dfe25ae],
> 0x000000000000002f bytes flags: 0x0
> [    0.000000]  reserved[0xa]   [0x000000047dfe25b0-0x000000047dfe25de],
> 0x000000000000002f bytes flags: 0x0
> [    0.000000]  reserved[0xb]   [0x000000047dfe25e0-0x000000047dfefffb],
> 0x000000000000da1c bytes flags: 0x0
> [    0.000000]  reserved[0xc]   [0x000000047dff0000-0x000000047fffffff],
> 0x0000000002010000 bytes flags: 0x0
> 
> Best regards
> 
> Heinrich
> 
> > 
> > > 
> > > Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
> > > ---
> > >   arch/riscv/Kconfig | 1 +
> > >   1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> > > index 4f7b70ae7c31..a6e57614c3fd 100644
> > > --- a/arch/riscv/Kconfig
> > > +++ b/arch/riscv/Kconfig
> > > @@ -31,6 +31,7 @@ config RISCV
> > >       select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
> > >       select ARCH_HAS_STRICT_MODULE_RWX if MMU && !XIP_KERNEL
> > >       select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
> > > +    select ARCH_KEEP_MEMBLOCK
> > >       select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
> > >       select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
> > >       select ARCH_SUPPORTS_HUGETLBFS if MMU
> 
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
Palmer Dabbelt Sept. 11, 2021, 6:46 a.m. UTC | #5
On Mon, 16 Aug 2021 11:50:26 PDT (-0700), rppt@kernel.org wrote:
> Hi Heinrich,
>
> On Mon, Aug 16, 2021 at 05:52:11PM +0200, Heinrich Schuchardt wrote:
>> On 8/16/21 5:30 PM, Kefeng Wang wrote:
>> >
>> > On 2021/8/16 22:47, Heinrich Schuchardt wrote:
>> > > For analyzing memory blocks we can either use the memblock=debug command
>> > > line argument which creates massive output or a debug file system.
>> > >
>> > > Select CONFIG_ARCH_KEEP_MEMBLOCK to provide a debugfs at
>> > > /sys/kernel/debug/memblock to analyze memory blocks. The
>> > > same is already done for arm, arm64, mips, powerpc.
>> > >
>> > > The actual provisioning of the file system depends on CONFIG_DEBUG_FS.
>> >
>> > Hi,for riscv, it don't use memblock(eg, no provide pfn_valid to use
>> > memblock),
>> >
>> > we could call memblock_discard() to discard memblock private memory to save
>> >
>> > some memory, right?  So I think we don't need this config for now.
>>
>> What do you mean by "it don't use memblock?
>>
>> If you boot the HiFive Unmatched with memblock=debug you will see output
>> like the one below. This is the information that you can see in the debug
>> file system if CONFIG_DEBUG_FS and CONFIG_ARCH_KEEP_MEMBLOCK will be
>> enabled.
>
> Indeed having this info in debugfs is more convenient, but it comes with a
> cost of several kilobytes of code and data for *every* riscv build.
>
> Why parsing "memblock=debug" output is not enough?
> What is the use-case that justifies the costs associated with having the
> debugfs entries?

If someone can provide a use case I'm happy to look at how to enable it.  
Otherwise I think we should just stick with the standard way of doing 
things, which according to 350e88bad496 ("mm: memblock: make keeping 
memblock memory opt-in rather than opt-out") seems to be that 
ARCH_KEEP_MEMBLOCK is for ports that need that information, not just 
those that pass it through to userspace.

>> [    0.000000] MEMBLOCK configuration:
>> [    0.000000]  memory size = 0x00000003ffe00000 reserved size =
>> 0x000000001290fb70
>> [    0.000000]  memory.cnt  = 0x25
>
> BTW, it seems that the memory allocation by firmware is, well, suboptimal
> and begs for fixes. I don't see why all these NOMAP areas cannot be put in
> one contiguous chunk. I doubt they need to be NOMAP at all, but mysterious
> the ways of ACPI.

We talked about this a bit in IRC and another thread, but it looks like 
this mess has ended up in the specs.  From my reading that was likely 
the result of a blind copy/paste from some other architecture, but it's 
in a released spec so it's cannon and I'm not really interested in 
trying to change it as I'm tired of getting yelled at by the foundation 
folks.

>> [    0.000000]  memory[0x0]     [0x0000000080200000-0x00000000fe6e2fff],
>> 0x000000007e4e3000 bytes flags: 0x0
>> [    0.000000]  memory[0x1]     [0x00000000fe6e3000-0x00000000fe6e5fff],
>> 0x0000000000003000 bytes flags: 0x4
>> [    0.000000]  memory[0x2]     [0x00000000fe6e6000-0x00000000fe709fff],
>> 0x0000000000024000 bytes flags: 0x0
>> [    0.000000]  memory[0x3]     [0x00000000fe70a000-0x00000000fe70bfff],
>> 0x0000000000002000 bytes flags: 0x4
>> [    0.000000]  memory[0x4]     [0x00000000fe70c000-0x00000000fe70ffff],
>> 0x0000000000004000 bytes flags: 0x0
>> [    0.000000]  memory[0x5]     [0x00000000fe710000-0x00000000fe710fff],
>> 0x0000000000001000 bytes flags: 0x4
>> [    0.000000]  memory[0x6]     [0x00000000fe711000-0x00000000fe712fff],
>> 0x0000000000002000 bytes flags: 0x0
>> [    0.000000]  memory[0x7]     [0x00000000fe713000-0x00000000fe716fff],
>> 0x0000000000004000 bytes flags: 0x4
>> [    0.000000]  memory[0x8]     [0x00000000fe717000-0x00000000fe717fff],
>> 0x0000000000001000 bytes flags: 0x0
>> [    0.000000]  memory[0x9]     [0x00000000fe718000-0x00000000fe71cfff],
>> 0x0000000000005000 bytes flags: 0x4
>> [    0.000000]  memory[0xa]     [0x00000000fe71d000-0x00000000fe71dfff],
>> 0x0000000000001000 bytes flags: 0x0
>> [    0.000000]  memory[0xb]     [0x00000000fe71e000-0x00000000fe71efff],
>> 0x0000000000001000 bytes flags: 0x4
>> [    0.000000]  memory[0xc]     [0x00000000fe71f000-0x00000000fe71ffff],
>> 0x0000000000001000 bytes flags: 0x0
>> [    0.000000]  memory[0xd]     [0x00000000fe720000-0x00000000fe720fff],
>> 0x0000000000001000 bytes flags: 0x4
>> [    0.000000]  memory[0xe]     [0x00000000fe721000-0x00000000fe721fff],
>> 0x0000000000001000 bytes flags: 0x0
>> [    0.000000]  memory[0xf]     [0x00000000fe722000-0x00000000fe722fff],
>> 0x0000000000001000 bytes flags: 0x4
>> [    0.000000]  memory[0x10]    [0x00000000fe723000-0x00000000fe723fff],
>> 0x0000000000001000 bytes flags: 0x0
>> [    0.000000]  memory[0x11]    [0x00000000fe724000-0x00000000fe724fff],
>> 0x0000000000001000 bytes flags: 0x4
>> [    0.000000]  memory[0x12]    [0x00000000fe725000-0x00000000fe725fff],
>> 0x0000000000001000 bytes flags: 0x0
>> [    0.000000]  memory[0x13]    [0x00000000fe726000-0x00000000fe726fff],
>> 0x0000000000001000 bytes flags: 0x4
>> [    0.000000]  memory[0x14]    [0x00000000fe727000-0x00000000fe728fff],
>> 0x0000000000002000 bytes flags: 0x0
>> [    0.000000]  memory[0x15]    [0x00000000fe729000-0x00000000fe729fff],
>> 0x0000000000001000 bytes flags: 0x4
>> [    0.000000]  memory[0x16]    [0x00000000fe72a000-0x00000000fe72afff],
>> 0x0000000000001000 bytes flags: 0x0
>> [    0.000000]  memory[0x17]    [0x00000000fe72b000-0x00000000fe72cfff],
>> 0x0000000000002000 bytes flags: 0x4
>> [    0.000000]  memory[0x18]    [0x00000000fe72d000-0x00000000fe72dfff],
>> 0x0000000000001000 bytes flags: 0x0
>> [    0.000000]  memory[0x19]    [0x00000000fe72e000-0x00000000fe72efff],
>> 0x0000000000001000 bytes flags: 0x4
>> [    0.000000]  memory[0x1a]    [0x00000000fe72f000-0x00000000fe72ffff],
>> 0x0000000000001000 bytes flags: 0x0
>> [    0.000000]  memory[0x1b]    [0x00000000fe730000-0x00000000fe730fff],
>> 0x0000000000001000 bytes flags: 0x4
>> [    0.000000]  memory[0x1c]    [0x00000000fe731000-0x00000000fe731fff],
>> 0x0000000000001000 bytes flags: 0x0
>> [    0.000000]  memory[0x1d]    [0x00000000fe732000-0x00000000fe732fff],
>> 0x0000000000001000 bytes flags: 0x4
>> [    0.000000]  memory[0x1e]    [0x00000000fe733000-0x00000000fe733fff],
>> 0x0000000000001000 bytes flags: 0x0
>> [    0.000000]  memory[0x1f]    [0x00000000fe734000-0x00000000fe734fff],
>> 0x0000000000001000 bytes flags: 0x4
>> [    0.000000]  memory[0x20]    [0x00000000fe735000-0x00000000fe736fff],
>> 0x0000000000002000 bytes flags: 0x0
>> [    0.000000]  memory[0x21]    [0x00000000fe737000-0x00000000fe737fff],
>> 0x0000000000001000 bytes flags: 0x4
>> [    0.000000]  memory[0x22]    [0x00000000fe738000-0x00000000fff60fff],
>> 0x0000000001829000 bytes flags: 0x0
>> [    0.000000]  memory[0x23]    [0x00000000fff61000-0x00000000fff61fff],
>> 0x0000000000001000 bytes flags: 0x4
>> [    0.000000]  memory[0x24]    [0x00000000fff62000-0x000000047fffffff],
>> 0x000000038009e000 bytes flags: 0x0
>> [    0.000000]  reserved.cnt  = 0xd
>> [    0.000000]  reserved[0x0]   [0x0000000080000000-0x000000008007ffff],
>> 0x0000000000080000 bytes flags: 0x0
>> [    0.000000]  reserved[0x1]   [0x0000000080200000-0x00000000815fffff],
>> 0x0000000001400000 bytes flags: 0x0
>> [    0.000000]  reserved[0x2]   [0x0000000087f00000-0x0000000087f05fff],
>> 0x0000000000006000 bytes flags: 0x0
>> [    0.000000]  reserved[0x3]   [0x00000000db0a2000-0x00000000db0a48b4],
>> 0x00000000000028b5 bytes flags: 0x0
>> [    0.000000]  reserved[0x4]   [0x00000000db2a2000-0x00000000dc709fff],
>> 0x0000000001468000 bytes flags: 0x0
>> [    0.000000]  reserved[0x5]   [0x00000000fe701000-0x00000000fe701fff],
>> 0x0000000000001000 bytes flags: 0x0
>> [    0.000000]  reserved[0x6]   [0x00000000fe704040-0x00000000fe70404f],
>> 0x0000000000000010 bytes flags: 0x0
>> [    0.000000]  reserved[0x7]   [0x000000046ffe1d40-0x000000047dfe253f],
>> 0x000000000e000800 bytes flags: 0x0
>> [    0.000000]  reserved[0x8]   [0x000000047dfe2548-0x000000047dfe2578],
>> 0x0000000000000031 bytes flags: 0x0
>> [    0.000000]  reserved[0x9]   [0x000000047dfe2580-0x000000047dfe25ae],
>> 0x000000000000002f bytes flags: 0x0
>> [    0.000000]  reserved[0xa]   [0x000000047dfe25b0-0x000000047dfe25de],
>> 0x000000000000002f bytes flags: 0x0
>> [    0.000000]  reserved[0xb]   [0x000000047dfe25e0-0x000000047dfefffb],
>> 0x000000000000da1c bytes flags: 0x0
>> [    0.000000]  reserved[0xc]   [0x000000047dff0000-0x000000047fffffff],
>> 0x0000000002010000 bytes flags: 0x0
>>
>> Best regards
>>
>> Heinrich
>>
>> >
>> > >
>> > > Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
>> > > ---
>> > >   arch/riscv/Kconfig | 1 +
>> > >   1 file changed, 1 insertion(+)
>> > >
>> > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
>> > > index 4f7b70ae7c31..a6e57614c3fd 100644
>> > > --- a/arch/riscv/Kconfig
>> > > +++ b/arch/riscv/Kconfig
>> > > @@ -31,6 +31,7 @@ config RISCV
>> > >       select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
>> > >       select ARCH_HAS_STRICT_MODULE_RWX if MMU && !XIP_KERNEL
>> > >       select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
>> > > +    select ARCH_KEEP_MEMBLOCK
>> > >       select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
>> > >       select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
>> > >       select ARCH_SUPPORTS_HUGETLBFS if MMU
>>
>>
>> _______________________________________________
>> linux-riscv mailing list
>> linux-riscv@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-riscv
diff mbox series

Patch

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 4f7b70ae7c31..a6e57614c3fd 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -31,6 +31,7 @@  config RISCV
 	select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
 	select ARCH_HAS_STRICT_MODULE_RWX if MMU && !XIP_KERNEL
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
+	select ARCH_KEEP_MEMBLOCK
 	select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
 	select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
 	select ARCH_SUPPORTS_HUGETLBFS if MMU