Hi Mattias,
On 2022/10/7 3:53, Mattias Rönnblom wrote:
> On 2022-10-05 06:09, datshan wrote:
>> From: Chengwen Feng <fengcheng...@huawei.com>
>>
>> This patch supports backup memory mechanism, the memarea could use
>> another memarea as a backup.
>
> Maybe it's worth mentioning what backup means already here.
>
> "This patch adds a memarea backup mechanism, where an allocation request
> which cannot be met by a certain memarea is deferred to its backup memarea."
+1
>
> I assume they can be nested indefinitely?
Theoretically, yes.
And I'm going to add, to avoid loops
>
>>
>> Signed-off-by: Chengwen Feng <fengcheng...@huawei.com>
>> ---
>> doc/guides/prog_guide/memarea_lib.rst | 3 +++
>> lib/memarea/memarea_private.h | 2 ++
>> lib/memarea/rte_memarea.c | 22 ++++++++++++++++++++++
>> lib/memarea/rte_memarea.h | 7 +++++++
>> 4 files changed, 34 insertions(+)
>>
>> diff --git a/doc/guides/prog_guide/memarea_lib.rst
>> b/doc/guides/prog_guide/memarea_lib.rst
>> index c77012fe44..842d35f77a 100644
>> --- a/doc/guides/prog_guide/memarea_lib.rst
>> +++ b/doc/guides/prog_guide/memarea_lib.rst
>> @@ -25,6 +25,9 @@ The main features are as follows:
>> * It supports MT-safe as long as it's specified at creation time.
>> +* It provides backup memory mechanism, the memarea could use another
>> memarea
>> + as a backup.
>> +
>> Library API Overview
>> --------------------
>> diff --git a/lib/memarea/memarea_private.h b/lib/memarea/memarea_private.h
>> index 98406879b9..08735ca81f 100644
>> --- a/lib/memarea/memarea_private.h
>> +++ b/lib/memarea/memarea_private.h
>> @@ -23,11 +23,13 @@ struct rte_memarea {
>> struct rte_memarea_param init;
>> rte_spinlock_t lock;
>> void *area_addr;
>> + void *top_addr;
>> struct memarea_elem_list elem_list;
>> struct memarea_elem_list free_list;
>> uint64_t alloc_fails;
>> uint64_t refcnt_check_fails;
>> + uint64_t bak_alloc_fails;
>> } __rte_cache_aligned;
>> #endif /* MEMAREA_PRIVATE_H */
>> diff --git a/lib/memarea/rte_memarea.c b/lib/memarea/rte_memarea.c
>> index b70830d0bb..f45191aa7f 100644
>> --- a/lib/memarea/rte_memarea.c
>> +++ b/lib/memarea/rte_memarea.c
>> @@ -132,6 +132,7 @@ rte_memarea_create(const struct rte_memarea_param *init)
>> TAILQ_INIT(&ma->elem_list);
>> TAILQ_INIT(&ma->free_list);
>> ma->area_addr = addr;
>> + ma->top_addr = (void *)((uintptr_t)addr + init->total_sz - 1);
>
> RTE_PTR_ADD()
>
>> elem = addr;
>> elem->size = init->total_sz - sizeof(struct memarea_elem);
>> elem->cookie = MEMAREA_FREE_ELEM_COOKIE;
>> @@ -200,6 +201,15 @@ memarea_add_node(struct rte_memarea *ma, struct
>> memarea_elem *elem, size_t need_
>> elem->size = align_size;
>> }
>> +static inline void *
>> +memarea_alloc_backup(struct rte_memarea *ma, size_t size, uint32_t cookie)
>> +{
>> + void *ptr = rte_memarea_alloc(ma->init.bak_memarea, size, cookie);
>> + if (unlikely(ptr == NULL))
>> + ma->bak_alloc_fails++;
>> + return ptr;
>> +}
>> +
>> void *
>> rte_memarea_alloc(struct rte_memarea *ma, size_t size, uint32_t cookie)
>> {
>> @@ -221,6 +231,8 @@ rte_memarea_alloc(struct rte_memarea *ma, size_t size,
>> uint32_t cookie)
>> ptr = (void *)((uintptr_t)elem + sizeof(struct memarea_elem));
>> break;
>> }
>> + if (ptr == NULL && ma->init.bak_memarea != NULL)
>
> Maybe you want an unlikely() around the above, too. I assume using the backup
> area is an exceptional case.
+1
>
>> + ptr = memarea_alloc_backup(ma, size, cookie);
>> if (unlikely(ptr == NULL))
>> ma->alloc_fails++;
>> memarea_unlock(ma);
>> @@ -283,6 +295,12 @@ rte_memarea_update_refcnt(struct rte_memarea *ma, void
>> *ptr, int16_t value)
>> return;
>> memarea_lock(ma);
>> + if (ptr < ma->area_addr || ptr > ma->top_addr) {
>> + rte_memarea_update_refcnt(ma->init.bak_memarea, ptr, value);
>> + memarea_unlock(ma);
>> + return;
>> + }
>> +
>> 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",
>> @@ -373,10 +391,14 @@ rte_memarea_dump(struct rte_memarea *ma, FILE *f, bool
>> dump_all)
>> fprintf(f, " algorithm: %s\n", memarea_alg_name(ma->init.alg));
>> fprintf(f, " total-size: 0x%zx\n", ma->init.total_sz);
>> fprintf(f, " mt-safe: %s\n", ma->init.mt_safe ? "yes" : "no");
>> + if (ma->init.bak_memarea)
>> + fprintf(f, " backup-memarea-name: %s\n",
>> ma->init.bak_memarea->init.name);
>> fprintf(f, " total-regions: %u\n", memarea_elem_list_num(ma));
>> fprintf(f, " total-free-regions: %u\n", memarea_free_list_num(ma));
>> fprintf(f, " alloc_fails: %" PRIu64 "\n", ma->alloc_fails);
>> fprintf(f, " refcnt_check_fails: %" PRIu64 "\n",
>> ma->refcnt_check_fails);
>> + if (ma->init.bak_memarea)
>> + fprintf(f, " backup_alloc_fails: %" PRIu64 "\n",
>> ma->bak_alloc_fails);
>> if (dump_all)
>> memarea_dump_all(ma, f);
>> memarea_unlock(ma);
>> diff --git a/lib/memarea/rte_memarea.h b/lib/memarea/rte_memarea.h
>> index 10b8229c64..348febab7f 100644
>> --- a/lib/memarea/rte_memarea.h
>> +++ b/lib/memarea/rte_memarea.h
>> @@ -39,6 +39,9 @@
>> * specified, all the functions of the memarea API are lock-free, and
>> assume
>> * to not be invoked in parallel on different logical cores to work on
>> the
>> * same memarea.
>> + * - It provides backup memory mechanism, the memarea could use another
>> memarea
>> + * as a backup. It will attempts to allocate object from backup memarea
>> when
>> + * the current memarea failed to allocate.
>> */
>> #include <stdbool.h>
>> @@ -105,6 +108,10 @@ struct rte_memarea_param {
>> */
>> struct rte_memarea *user_memarea;
>> };
>> + /** Backup memarea, which is used to handle the scenario where the
>> + * current memarea allocation failure.
>> + */
>> + struct rte_memarea *bak_memarea;
>> };
>> /**
>
> .
