[PATCH RFC 1/3] lib: add talloc for overlaying a tree onto allocations

[Sascha Hauer]

On Tue, Oct 28, 2025 at 11:26:02AM +0100, Ahmad Fatoum wrote:
> Hi,
> 
> On 10/28/25 10:42 AM, Sascha Hauer wrote:
> > On Mon, Oct 27, 2025 at 08:54:32AM +0100, Ahmad Fatoum wrote:
> >> +#ifndef __TALLOC_H__
> >> +#define __TALLOC_H__
> >> +
> >> +#include <linux/types.h>
> >> +
> >> +struct talloc {
> >> +	struct talloc *child;
> >> +	struct talloc *next;
> >> +	union {
> >> +		struct talloc *prev;
> >> +		struct talloc *parent; /* Valid only when is_first(mem) */
> >> +	};
> >> +};
> > 
> > Currently tlsf allocations are 8 byte aligned. On 32bit architectures
> > struct talloc will be 12 bytes, so talloc allocations will only have 4
> > byte alignment.
> 
> Good catch. On 32-bit, there is 4 bytes of unused padding inside TLSF
> and feels bad sacrificing 4 more bytes here. :/

I find the memory leak checker extremly useful and it becomes even more
useful with the memory leaks in hush fixed.

I suggest we add an __aligned(8) here and be done with it for now.

We can still think about it when widening the talloc use for
dev_kmalloc(), but as long as it's only used by hush we shouldn't hold
this series up.

Sascha

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