[PATCH] platform: recalculate heap size to support new tlb entry number

[Inochi Amaoto]

>On Fri, Nov 17, 2023 at 8:10 PM Inochi Amaoto <inochiama at outlook.com> wrote:
>>
>> Previous patch introduct a change that using hart count as the default
>> number of tlb entry in the fifo. This makes the default tlb fifo size
>> grow in square with the number of harts. So the default heap size is
>> not enough to allocate tlb fifo when the hart count is big.
>>
>> Use new formula for default heap size:
>> 0x40 * (__num_hart) ^ 2   -> handle the tlb fifo
>> 0x600 * (__num_hart)      -> remove previous static fifo allocation
>Yes, ^ 2 is not suitable for sg2042.
>

Is there any reason of unsuitability for sg2042. I think this is tight
lower bound: now we have a tlb fifo with __num_hart entries for each hart.
So I think ^ 2 is a must, otherwise a OOM will issue.

>>
>> Signed-off-by: Inochi Amaoto <inochiama at outlook.com>
>> Fixes: 52fd64b ("platform: Uses hart count as the default size of tlb info")
>> ---
>>  include/sbi/sbi_bitops.h   | 1 +
>>  include/sbi/sbi_heap.h     | 3 +++
>>  include/sbi/sbi_platform.h | 8 ++++++--
>>  lib/sbi/sbi_heap.c         | 2 --
>>  4 files changed, 10 insertions(+), 4 deletions(-)
>>
>> diff --git a/include/sbi/sbi_bitops.h b/include/sbi/sbi_bitops.h
>> index 48a2090..7d90334 100644
>> --- a/include/sbi/sbi_bitops.h
>> +++ b/include/sbi/sbi_bitops.h
>> @@ -26,6 +26,7 @@
>>  #define BIT_MASK(nr)           (1UL << ((nr) % BITS_PER_LONG))
>>  #define BIT_WORD(bit)          ((bit) / BITS_PER_LONG)
>>  #define BIT_WORD_OFFSET(bit)   ((bit) & (BITS_PER_LONG - 1))
>> +#define BIT_ALIGN(bit, align)  (((bit) + ((align) - 1)) & ~((align) - 1))
>>
>>  #define GENMASK(h, l) \
>>         (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>> diff --git a/include/sbi/sbi_heap.h b/include/sbi/sbi_heap.h
>> index 88d176e..16755ec 100644
>> --- a/include/sbi/sbi_heap.h
>> +++ b/include/sbi/sbi_heap.h
>> @@ -12,6 +12,9 @@
>>
>>  #include <sbi/sbi_types.h>
>>
>> +/* Alignment of heap base address and size */
>> +#define HEAP_BASE_ALIGN                        1024
>> +
>>  struct sbi_scratch;
>>
>>  /** Allocate from heap area */
>> diff --git a/include/sbi/sbi_platform.h b/include/sbi/sbi_platform.h
>> index 58b9069..609f608 100644
>> --- a/include/sbi/sbi_platform.h
>> +++ b/include/sbi/sbi_platform.h
>> @@ -44,8 +44,10 @@
>>
>>  #ifndef __ASSEMBLER__
>>
>> +#include <sbi/sbi_bitops.h>
>>  #include <sbi/sbi_ecall_interface.h>
>>  #include <sbi/sbi_error.h>
>> +#include <sbi/sbi_heap.h>
>>  #include <sbi/sbi_scratch.h>
>>  #include <sbi/sbi_version.h>
>>
>> @@ -146,8 +148,10 @@ struct sbi_platform_operations {
>>  #define SBI_PLATFORM_DEFAULT_HART_STACK_SIZE   8192
>>
>>  /** Platform default heap size */
>> -#define SBI_PLATFORM_DEFAULT_HEAP_SIZE(__num_hart)     \
>> -                                       (0x8000 + 0x800 * (__num_hart))
>> +#define SBI_PLATFORM_DEFAULT_HEAP_SIZE(__num_hart)             \
>> +       BIT_ALIGN((0x8000 + 0x600 * (__num_hart) +              \
>> +                  0x40 * (__num_hart) * (__num_hart)),         \
>> +                 HEAP_BASE_ALIGN)
>>
>>  /** Representation of a platform */
>>  struct sbi_platform {
>> diff --git a/lib/sbi/sbi_heap.c b/lib/sbi/sbi_heap.c
>> index 698c377..bcd404b 100644
>> --- a/lib/sbi/sbi_heap.c
>> +++ b/lib/sbi/sbi_heap.c
>> @@ -14,8 +14,6 @@
>>  #include <sbi/sbi_scratch.h>
>>  #include <sbi/sbi_string.h>
>>
>> -/* Alignment of heap base address and size */
>> -#define HEAP_BASE_ALIGN                        1024
>>  /* Minimum size and alignment of heap allocations */
>>  #define HEAP_ALLOC_ALIGN               64
>>  #define HEAP_HOUSEKEEPING_FACTOR       16
>> --
>> 2.42.1
>>
>Maybe the number of 0x600 needs more discussion. Other:

I agree with this. I have no idea about the original value "0x800", so
I only remove the static allocation of previous tlb info for minimized
heap allocation.
Maybe there should be some comment to tell why it need this size.

>Reviewed-by: Guo Ren <guoren at kernel.org>
>
>--
>Best Regards
> Guo Ren
>
>