Re: [Minios-devel] [UNIKRAFT PATCH v6 5/5] lib/ukalloc: implement new allocator helpers

[Simon Kuenzer <simon.kuenzer@xxxxxxxxx>]

On 23.01.20 16:30, Hugo Lefeuvre wrote:
> Add new allocator helpers uk_pfree_compat, uk_palloc_compat,
> uk_realloc_compat and uk_alloc_init_malloc allowing for proper
> initialization of allocators based on malloc, calloc, free and
> posix_memalign.
>
> Signed-off-by: Hugo Lefeuvre <hugo.lefeuvre@xxxxxxxxx>
>
> diff --git a/lib/ukalloc/alloc.c b/lib/ukalloc/alloc.c
> index 0e8c8d5..07d0553 100644
> --- a/lib/ukalloc/alloc.c
> +++ b/lib/ukalloc/alloc.c
> @@ -54,6 +54,7 @@
>   #include <uk/arch/limits.h>
>   
>   #define size_to_num_pages(size) ALIGN_UP((unsigned long)(size), __PAGE_SIZE) / __PAGE_SIZE
> +#define page_off(x)                    ((unsigned long)(x) & (__PAGE_SIZE - 1))
>   
>   static struct uk_alloc *uk_alloc_head;
>   
> @@ -277,6 +278,49 @@ int uk_posix_memalign_ifpages(struct uk_alloc *a,
>         return 0;
>   }
>   
> +void uk_pfree_compat(struct uk_alloc *a, void *ptr, unsigned long num_pages __unused) {
> +       UK_ASSERT(a != NULL);
You can also do here the short version: UK_ASSERT(a).

> +
> +       /* if the object is not page aligned it was clearly not from us */
> +       UK_ASSERT(page_off(ptr) == 0);
> +
> +       uk_free(a, ptr);
> +}
> +
> +void *uk_palloc_compat(struct uk_alloc *a, unsigned long num_pages) {
> +       void *ptr;
> +
> +       UK_ASSERT(a);
> +
> +       if (uk_posix_memalign(a, &ptr, __PAGE_SIZE, num_pages * __PAGE_SIZE))
> +               return NULL;
> +
> +       return ptr;
> +}
> +
> +void *uk_realloc_compat(struct uk_alloc *a, void *ptr, size_t size)
> +{
> +       void *retptr;
> +
> +       UK_ASSERT(a);
> +       if (!ptr)
> +               return uk_malloc(a, size);
> +
> +       if (ptr && !size) {
> +               uk_free(a, ptr);
> +               return NULL;
> +       }
> +
> +       retptr = uk_malloc(a, size);
> +       if (!retptr)
> +               return NULL;
> +
> +       memcpy(retptr, ptr, size);
> +
> +       uk_free(a, ptr);
> +       return retptr;
> +}
> +
>   void *uk_calloc_compat(struct uk_alloc *a, size_t nmemb, size_t size)
>   {
>         void *ptr;
> diff --git a/lib/ukalloc/exportsyms.uk b/lib/ukalloc/exportsyms.uk
> index c044705..2357501 100644
> --- a/lib/ukalloc/exportsyms.uk
> +++ b/lib/ukalloc/exportsyms.uk
> @@ -7,3 +7,6 @@ uk_realloc_ifpages
>   uk_posix_memalign_ifpages
>   uk_calloc_compat
>   uk_memalign_compat
> +uk_realloc_compat
> +uk_palloc_compat
> +uk_pfree_compat
> diff --git a/lib/ukalloc/include/uk/alloc_impl.h 
> b/lib/ukalloc/include/uk/alloc_impl.h
> index f87feb3..9d5581a 100644
> --- a/lib/ukalloc/include/uk/alloc_impl.h
> +++ b/lib/ukalloc/include/uk/alloc_impl.h
> @@ -62,9 +62,29 @@ int uk_posix_memalign_ifpages(struct uk_alloc *a, void 
> **memptr,
>                                 size_t align, size_t size);
>   void uk_free_ifpages(struct uk_alloc *a, void *ptr);
>   
> -/* Functionality that is provided based on malloc() */
> +/* Functionality that is provided based on malloc() and posix_memalign() */
>   void *uk_calloc_compat(struct uk_alloc *a, size_t num, size_t len);
> +void *uk_realloc_compat(struct uk_alloc *a, void *ptr, size_t size);
>   void *uk_memalign_compat(struct uk_alloc *a, size_t align, size_t len);
> +void *uk_palloc_compat(struct uk_alloc *a, unsigned long num_pages);
> +void uk_pfree_compat(struct uk_alloc *a, void *ptr, unsigned long num_pages);
> +
> +/* Shortcut for doing a registration of an allocator that does not implement
> + * realloc, memalign, palloc or pfree */
> +#define uk_alloc_init_malloc(a, malloc_f, calloc_f, free_f, posix_memalign_f, 
> addmem_f) \
> +       do {                                                            \
> +               (a)->malloc         = (malloc_f);                    \
> +               (a)->calloc         = (calloc_f);                    \
> +               (a)->realloc        = uk_realloc_compat;             \
> +               (a)->posix_memalign = (posix_memalign_f);            \
> +               (a)->memalign       = uk_memalign_compat;            \
> +               (a)->free           = (free_f);                              \
> +               (a)->palloc         = uk_palloc_compat;                      \
> +               (a)->pfree          = uk_pfree_compat;                       \
> +               (a)->addmem         = (addmem_f);                    \
> +                                                                       \
> +               uk_alloc_register((a));                                 \
> +       } while (0)
Hum, I am wondering if we should introduce `uk_alloc_init_malloc` as an 
helper that initializes the struct for allocators that just don't 
support palloc() and pfree(). Another wrapper based on this could add 
the additonal callbacks for posix_memalign, memalign, and maybe calloc, 
like:
#define uk_alloc_init_simple(a, malloc_f, free_f, addmem_f) \
        uk_alloc_init_malloc(.<arguments here>.)

What do you think?

>   
>   /* Shortcut for doing a registration of an allocator that only
>    * implements palloc(), pfree(), addmem() */
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