Re: [PATCH v5 03/10] memarea: support alloc/free/update-refcnt API

["Mattias Rönnblom" <hofors@lysator.liu.se>]

On 2022-10-05 06:09, datshan wrote:
> From: Chengwen Feng <fengchengwen@huawei.com>
> 
> This patch supports rte_memarea_alloc()/rte_memarea_free()/
> rte_memarea_update_refcnt() API.
> 
> Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
> ---
>   doc/guides/prog_guide/memarea_lib.rst |  10 ++
>   lib/memarea/memarea_private.h         |   3 +
>   lib/memarea/rte_memarea.c             | 143 ++++++++++++++++++++++++++
>   lib/memarea/rte_memarea.h             |  56 ++++++++++
>   lib/memarea/version.map               |   3 +
>   5 files changed, 215 insertions(+)
> 
> diff --git a/doc/guides/prog_guide/memarea_lib.rst b/doc/guides/prog_guide/memarea_lib.rst
> index b96dad15f6..41bc0a90cd 100644
> --- a/doc/guides/prog_guide/memarea_lib.rst
> +++ b/doc/guides/prog_guide/memarea_lib.rst
> @@ -33,6 +33,16 @@ returns the pointer to the created memarea or ``NULL`` if the creation failed.
>   
>   The ``rte_memarea_destroy()`` function is used to destroy a memarea.
>   
> +The ``rte_memarea_alloc()`` function is used to alloc one memory object from
> +the memarea.
> +
> +The ``rte_memarea_free()`` function is used to free one memory object which
> +allocated by ``rte_memarea_alloc()``.
> +
> +The ``rte_memarea_update_refcnt()`` function is used to update the memory
> +object's reference count, if the count reaches zero, the memory object will
> +be freed to memarea.
> +
>   Reference
>   ---------
>   
> diff --git a/lib/memarea/memarea_private.h b/lib/memarea/memarea_private.h
> index c76392d3e6..98406879b9 100644
> --- a/lib/memarea/memarea_private.h
> +++ b/lib/memarea/memarea_private.h
> @@ -25,6 +25,9 @@ struct rte_memarea {
>   	void                    *area_addr;
>   	struct memarea_elem_list elem_list;
>   	struct memarea_elem_list free_list;
> +
> +	uint64_t alloc_fails;
> +	uint64_t refcnt_check_fails;
>   } __rte_cache_aligned;
>   
>   #endif /* MEMAREA_PRIVATE_H */
> diff --git a/lib/memarea/rte_memarea.c b/lib/memarea/rte_memarea.c
> index 868da7661d..a072f07f20 100644
> --- a/lib/memarea/rte_memarea.c
> +++ b/lib/memarea/rte_memarea.c
> @@ -4,6 +4,7 @@
>   
>   #include <stdio.h>
>   #include <stdlib.h>
> +#include <sys/queue.h>
>   
>   #include <rte_common.h>
>   #include <rte_log.h>
> @@ -94,6 +95,8 @@ memarea_alloc_area(const struct rte_memarea_param *init)
>   		ptr = memarea_alloc_from_system_api(init->total_sz);
>   	else if (init->source == RTE_MEMAREA_SOURCE_USER_ADDR)
>   		ptr = init->user_addr;
> +	else if (init->source == RTE_MEMAREA_SOURCE_USER_MEMAREA)
> +		ptr = rte_memarea_alloc(init->user_memarea, init->total_sz, 0);
>   
>   	if (ptr == NULL)
>   		RTE_LOG(ERR, MEMAREA, "memarea: %s alloc memory area fail!\n", init->name);
> @@ -145,6 +148,8 @@ memarea_free_area(struct rte_memarea *ma)
>   		rte_free(ma->area_addr);
>   	else if (ma->init.source == RTE_MEMAREA_SOURCE_SYSTEM_API)
>   		free(ma->area_addr);
> +	else if (ma->init.source == RTE_MEMAREA_SOURCE_USER_MEMAREA)
> +		rte_memarea_free(ma->init.user_memarea, ma->area_addr);
>   }
>   
>   void
> @@ -155,3 +160,141 @@ rte_memarea_destroy(struct rte_memarea *ma)
>   	memarea_free_area(ma);
>   	rte_free(ma);
>   }
> +
> +static inline void
> +memarea_lock(struct rte_memarea *ma)
> +{
> +	if (ma->init.mt_safe)
> +		rte_spinlock_lock(&ma->lock);
> +}
> +
> +static inline void
> +memarea_unlock(struct rte_memarea *ma)
> +{
> +	if (ma->init.mt_safe)
> +		rte_spinlock_unlock(&ma->lock);
> +}
> +
> +#define memarea_roundup(val, align) ((((val) + ((align) - 1)) / (align)) * (align))
> +

You should be able to use RTE_ALIGN_CEIL() instead of your own roundup 
macro, assuming this function isn't used in a patch I'm yet to review, 
with a potentially non-power-of-2 align parameter value.

If not, change the macro to a function.

> +static inline bool
> +memarea_whether_add_node(size_t free_size, size_t need_size)
> +{
> +	size_t align_size = memarea_roundup(need_size, RTE_CACHE_LINE_SIZE);
> +	return free_size > align_size && (free_size - align_size) > sizeof(struct memarea_elem);
> +}
> +
> +static inline void
> +memarea_add_node(struct rte_memarea *ma, struct memarea_elem *elem, size_t need_size)
> +{
> +	size_t align_size = memarea_roundup(need_size, RTE_CACHE_LINE_SIZE);
> +	struct memarea_elem *new_elem;
> +	new_elem = (struct memarea_elem *)((uintptr_t)elem + sizeof(struct memarea_elem) +
> +					   align_size);

Use RTE_PTR_ADD().

> +	new_elem->size = elem->size - align_size - sizeof(struct memarea_elem);
> +	new_elem->cookie = MEMAREA_FREE_ELEM_COOKIE;
> +	new_elem->refcnt = 0;
> +	TAILQ_INSERT_AFTER(&ma->elem_list, elem, new_elem, elem_node);
> +	TAILQ_INSERT_AFTER(&ma->free_list, elem, new_elem, free_node);
> +	elem->size = align_size;
> +}
> +
> +void *
> +rte_memarea_alloc(struct rte_memarea *ma, size_t size, uint32_t cookie)
> +{
> +	struct memarea_elem *elem;
> +	void *ptr = NULL;
> +
> +	if (unlikely(ma == NULL || size == 0))
> +		return NULL;
> +
> +	memarea_lock(ma);
> +	TAILQ_FOREACH(elem, &ma->free_list, free_node) {
> +		if (elem->size < size)
> +			continue;
> +		if (memarea_whether_add_node(elem->size, size))
> +			memarea_add_node(ma, elem, size);
> +		elem->cookie = cookie;
> +		elem->refcnt = 1;
> +		TAILQ_REMOVE(&ma->free_list, elem, free_node);
> +		ptr = (void *)((uintptr_t)elem + sizeof(struct memarea_elem));

RTE_PTR_ADD() again.

> +		break;
> +	}
> +	if (unlikely(ptr == NULL))
> +		ma->alloc_fails++;
> +	memarea_unlock(ma);
> +
> +	return ptr;
> +}
> +
> +void
> +rte_memarea_free(struct rte_memarea *ma, void *ptr)
> +{
> +	rte_memarea_update_refcnt(ma, ptr, -1);
> +}
> +
> +static inline void
> +memarea_merge_node(struct rte_memarea *ma, struct memarea_elem *curr,
> +		   struct memarea_elem *next, bool del_next_from_free,
> +		   bool add_curr_to_free)
> +{
> +	curr->size += next->size + sizeof(struct memarea_elem);
> +	next->size = 0;
> +	next->cookie = 0;
> +	TAILQ_REMOVE(&ma->elem_list, next, elem_node);
> +	if (del_next_from_free)
> +		TAILQ_REMOVE(&ma->free_list, next, free_node);
> +	if (add_curr_to_free) {
> +		curr->cookie = MEMAREA_FREE_ELEM_COOKIE;
> +		TAILQ_INSERT_TAIL(&ma->free_list, curr, free_node);
> +	}
> +}
> +
> +static inline void
> +memarea_free_elem(struct rte_memarea *ma, struct memarea_elem *elem)
> +{
> +	struct memarea_elem *prev, *next;
> +	bool merged = false;
> +	prev = TAILQ_PREV(elem, memarea_elem_list, elem_node);
> +	next = TAILQ_NEXT(elem, elem_node);
> +	if (prev != NULL && prev->refcnt == 0) {
> +		memarea_merge_node(ma, prev, elem, false, false);
> +		elem = prev;
> +		merged = true;
> +	}
> +	if (next != NULL && next->refcnt == 0) {
> +		memarea_merge_node(ma, elem, next, true, !merged);
> +		merged = true;
> +	}
> +	if (!merged) {
> +		elem->cookie = MEMAREA_FREE_ELEM_COOKIE;
> +		TAILQ_INSERT_TAIL(&ma->free_list, elem, free_node);
> +	}
> +}
> +
> +void
> +rte_memarea_update_refcnt(struct rte_memarea *ma, void *ptr, int16_t value)
> +{
> +	struct memarea_elem *elem = (struct memarea_elem *)((uintptr_t)ptr -
> +							    sizeof(struct memarea_elem));
> +
> +	if (unlikely(ma == NULL || ptr == NULL))
> +		return;
> +
> +	memarea_lock(ma);
> +	if (unlikely(elem->refcnt <= 0 || elem->refcnt + value < 0)) {
> +		RTE_LOG(ERR, MEMAREA,
> +			"memarea: %s cookie: 0x%x curr refcnt: %d update refcnt: %d check fail!\n",
> +			ma->init.name, elem->cookie, elem->refcnt, value);
> +		ma->refcnt_check_fails++;
> +		if (elem->refcnt > 0)
> +			elem->refcnt += value;
> +		memarea_unlock(ma);
> +		return;
> +	}
> +
> +	elem->refcnt += value;
> +	if (elem->refcnt == 0)
> +		memarea_free_elem(ma, elem);
> +	memarea_unlock(ma);
> +}
> diff --git a/lib/memarea/rte_memarea.h b/lib/memarea/rte_memarea.h
> index 543cda4cac..10e0d6ad5a 100644
> --- a/lib/memarea/rte_memarea.h
> +++ b/lib/memarea/rte_memarea.h
> @@ -138,6 +138,62 @@ struct rte_memarea *rte_memarea_create(const struct rte_memarea_param *init);
>   __rte_experimental
>   void rte_memarea_destroy(struct rte_memarea *ma);
>   
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change without prior notice.
> + *
> + * Allocate memory from memarea.
> + *
> + * Allocate one memory object from the memarea.
> + *
> + * @param ma
> + *   The pointer of memarea.
> + * @param size
> + *   The memory size to be allocated.
> + * @param cookie
> + *   User-provided footprint which could used to debug memory leak.
> + *
> + * @return
> + *   Non-NULL on success. Otherwise NULL is returned.
> + */
> +__rte_experimental
> +void *rte_memarea_alloc(struct rte_memarea *ma, size_t size, uint32_t cookie);
> +
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change without prior notice.
> + *
> + * Free memory to memarea.
> + *
> + * Free one memory object to the memarea.
> + *
> + * @param ma
> + *   The pointer of memarea.
> + * @param ptr
> + *   The pointer of memory object which need be freed.
> + */
> +__rte_experimental
> +void rte_memarea_free(struct rte_memarea *ma, void *ptr);
> +
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change without prior notice.
> + *
> + * Update memory's refcnt.
> + *
> + * Update one memory object's refcnt.
> + * When refcnt is updated to be zero, the memory object is freed.
> + *
> + * @param ma
> + *   The pointer of memarea.
> + * @param ptr
> + *   The pointer of memory object which need be updated refcnt.
> + * @param value
> + *   The value which need be updated.
> + */
> +__rte_experimental
> +void rte_memarea_update_refcnt(struct rte_memarea *ma, void *ptr, int16_t value);
> +
>   #ifdef __cplusplus
>   }
>   #endif
> diff --git a/lib/memarea/version.map b/lib/memarea/version.map
> index f36a04d7cf..a0026fc5f9 100644
> --- a/lib/memarea/version.map
> +++ b/lib/memarea/version.map
> @@ -1,8 +1,11 @@
>   EXPERIMENTAL {
>   	global:
>   
> +	rte_memarea_alloc;
>   	rte_memarea_create;
>   	rte_memarea_destroy;
> +	rte_memarea_free;
> +	rte_memarea_update_refcnt;
>   
>   	local: *;
>   };