Re: [PATCH v2 03/10] tlsf: support on-demand requesting memory from external store

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 10/7/25 3:42 PM, Sascha Hauer wrote:
> On Mon, Oct 06, 2025 at 08:59:48PM -0400, chalianis1@gmail.com wrote:
>> From: Chali Anis <chalianis1@gmail.com>
>>
>> barebox running under an operating system (or nearly one like UEFI) does
>> not have control over all the memory and should not hog too much memory
>> upfront as that can interfere with other applications, e.g. EFI drivers
>> or the EFI firmware itself.
>>
>> To accommodate this use case, allow TLSF to dynamically request more
>> memory from an external store via tlsf_register_store().
>>
>> Signed-off-by: Ahmad Fatoum <a.fatoum@barebox.org>
>> Signed-off-by: Chali Anis <chalianis1@gmail.com>
>> ---
>>  common/tlsf.c  | 29 ++++++++++++++++++++++++++++-
>>  include/tlsf.h |  1 +
>>  2 files changed, 29 insertions(+), 1 deletion(-)
>>
>> diff --git a/common/tlsf.c b/common/tlsf.c
>> index 4ee53a9b2f20..636b57b1c642 100644
>> --- a/common/tlsf.c
>> +++ b/common/tlsf.c
>> @@ -159,6 +159,9 @@ typedef struct control_t
>>  	/* Empty lists point at this block to indicate they are free. */
>>  	block_header_t block_null;
>>  
>> +	void (*request_store)(tlsf_t, size_t);
>> +
>> +
> 
> This breaks compilation on 32bit platforms.
> 
> The reason is we have this directly under the definition of control_t:
> 
> tlsf_static_assert(sizeof(control_t) % ALIGN_SIZE == 0);
> 
> I fixed it up as follows.

Fixup looks good, thanks.

> It looks odd to me that we have to manually align the struct size each
> time we add a field to this struct. Isn't there something better?

Maybe we could hack something together with alignment or a union, but in
the end it would not be applicable to block_header_t, which is
intentionally overlayed in a misaligned manner as prev_phys_block is
part of the previous allocation...

The asserts at least work :-)

Cheers,
Ahmad

> 
> Sascha
> 
> ---------------------------8<------------------------------
> From 11fcc69bbc41954d5e28a3b082dc39171bd6cdc0 Mon Sep 17 00:00:00 2001
> From: Sascha Hauer <s.hauer@pengutronix.de>
> Date: Tue, 7 Oct 2025 15:39:38 +0200
> Subject: [PATCH] fixup! tlsf: support on-demand requesting memory from
>  external store
> 
> ---
>  common/tlsf.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/common/tlsf.c b/common/tlsf.c
> index 636b57b1c6..c4ba8259b2 100644
> --- a/common/tlsf.c
> +++ b/common/tlsf.c
> @@ -161,11 +161,9 @@ typedef struct control_t
>  
>  	void (*request_store)(tlsf_t, size_t);
>  
> -
>  	/* Bitmaps for free lists. */
>  	unsigned int fl_bitmap;
>  	unsigned int sl_bitmap[FL_INDEX_COUNT];
> -	u32 : BYTES_TO_BITS(ALIGN_SIZE - sizeof(size_t));
>  
>  	/* Head of free lists. */
>  	block_header_t* blocks[FL_INDEX_COUNT][SL_INDEX_COUNT];

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