> From: Vadim Suraev [mailto:vadim.suraev at gmail.com] > Sent: Wednesday, March 18, 2015 10:41 AM > To: Ananyev, Konstantin > Cc: dev at dpdk.org > Subject: Re: [PATCH v2] rte_mbuf: mbuf bulk alloc/free functions added + > unittest > > Hi, Konstantin, > > Got it. To make the same, nulling the next should be inside of the block as > you said. > One question raises here: If a segment in the chain has refcnt > 1 (so its > next is not assigned NULL), and the next segment has refcnt > == 1 (so it is freed), do you think this scenario is real/should be > considered? If so, the former can be safely freed only by calling > rte_pktmbuf_free_seg which does not iterate. So why to keep next pointing to > something?
I think we need it, not just to keep things the same with rte_pktmbuf_free(), but because it is a right thing to do. Let say you have a packet in 2 mbufs chained together, both mbufs have refcnt==2. Then: rte_pktmbuf_free(firs_mbuf); rte_pktmbuf_free(firs_mbuf); Would work correctly and free both mbufs back to the mempool. While after: rte_pktmbuf_free_chain(first_mbuf); rte_pktmbuf_free_chain(first_mbuf); We would have first_mbuf freed back into the mempool, while second would get lost(memory leaking). Basically free() shouldn't modify any filed inside mbuf, except refcnt if rte_mbuf_refcnt_update(m, -1) > 0 About your case, when: first_mbuf->refcnt==2 and second_mbuf->refcnt==1. Right now, rte_pktmbuf_free() can't handle such cases properly, and, as I know, such situation is not considered as valid one. Konstantin > Regards, > ?Vadim > > On Wed, Mar 18, 2015 at 11:56 AM, Ananyev, Konstantin <konstantin.ananyev at > intel.com> wrote: > > Hi Vadim, > > > > From: Vadim Suraev [mailto:vadim.suraev at gmail.com] > > Sent: Wednesday, March 18, 2015 5:19 AM > > To: Ananyev, Konstantin > > Cc: dev at dpdk.org; olivier.matz at 6wind.com; stephen at > > networkplumber.org > > Subject: Re: [PATCH v2] rte_mbuf: mbuf bulk alloc/free functions added + > > unittest > > > > Hi, Konstantin, > > > > >Shouldn't the line above be inside if (head != NULL) {...} block? > > This is removed as Olivier commented before: > > > > >> +{ > > > +? ? ?if (likely(head != NULL)) { > > > > >I think we should remove this test. The other mbuf functions do not > > >check this. > > Regards, > > ?Vadim. > > I meant that in my opinion it should be: > > while (head) { > ? ? ? ? ? ? ?next = head->next; > -? ? ? ? ? ? ?head->next = NULL; > > ? ? ? ? ? ? ?head = __rte_pktmbuf_prefree_seg(head); > ? ? ? ? ? ? ?if (likely(head != NULL)) { > +? ? ? ? ? ? ? ? ? head->next = NULL; > ? ? ? ? ? ? ? ? ? ? ?RTE_MBUF_ASSERT(rte_mbuf_refcnt_read(head) == 0); > > Same as rte_pktmbuf_free() doing. > > Konstantin > > > > > On Wed, Mar 18, 2015 at 1:46 AM, Ananyev, Konstantin <konstantin.ananyev at > > intel.com> wrote: > > Hi Vadim, > > > > > -----Original Message----- > > > From: vadim.suraev at gmail.com [mailto:vadim.suraev at gmail.com] > > > Sent: Tuesday, March 17, 2015 9:36 PM > > > To: dev at dpdk.org > > > Cc: olivier.matz at 6wind.com; stephen at networkplumber.org; Ananyev, > > > Konstantin; vadim.suraev at gmail.com > > > Subject: [PATCH v2] rte_mbuf: mbuf bulk alloc/free functions added + > > > unittest > > > > > > From: "vadim.suraev at gmail.com" <vadim.suraev at gmail.com> > > > > > > This patch adds mbuf bulk allocation/freeing functions and unittest > > > > > > Signed-off-by: Vadim Suraev > > > <vadim.suraev at gmail.com> > > > --- > > > New in v2: > > >? ? ?- function rte_pktmbuf_alloc_bulk added > > >? ? ?- function rte_pktmbuf_bulk_free added > > >? ? ?- function rte_pktmbuf_free_chain added > > >? ? ?- applied reviewers' comments > > > > > >? app/test/test_mbuf.c? ? ? ?|? ?94 > > >+++++++++++++++++++++++++++++++++++++++++++- > > >? lib/librte_mbuf/rte_mbuf.h |? ?89 > > >+++++++++++++++++++++++++++++++++++++++++ > > >? 2 files changed, 182 insertions(+), 1 deletion(-) > > > > > > diff --git a/app/test/test_mbuf.c b/app/test/test_mbuf.c > > > index 1ff66cb..b20c6a4 100644 > > > --- a/app/test/test_mbuf.c > > > +++ b/app/test/test_mbuf.c > > > @@ -77,6 +77,7 @@ > > >? #define REFCNT_RING_SIZE? ? ? ? (REFCNT_MBUF_NUM * REFCNT_MAX_REF) > > > > > >? #define MAKE_STRING(x)? ? ? ? ? # x > > > +#define MBUF_POOL_LOCAL_CACHE_SIZE 32 > > > > > >? static struct rte_mempool *pktmbuf_pool = NULL; > > > > > > @@ -405,6 +406,84 @@ test_pktmbuf_pool(void) > > >? ? ? ?return ret; > > >? } > > > > > > +/* test pktmbuf bulk allocation and freeing > > > +*/ > > > +static int > > > +test_pktmbuf_pool_bulk(void) > > > +{ > > > +? ? ?unsigned i; > > > +? ? ?/* size of mempool - size of local cache, otherwise may fail */ > > > +? ? ?unsigned mbufs_to_allocate = NB_MBUF - MBUF_POOL_LOCAL_CACHE_SIZE; > > > +? ? ?struct rte_mbuf *m[mbufs_to_allocate]; > > > +? ? ?int ret = 0; > > > +? ? ?unsigned mbuf_count_before_allocation = > > > rte_mempool_count(pktmbuf_pool); > > > + > > > +? ? ?for (i = 0; i < mbufs_to_allocate; i++) > > > +? ? ? ? ? ? ?m[i] = NULL; > > > +? ? ?/* alloc NB_MBUF-MBUF_POOL_LOCAL_CACHE_SIZE mbufs */ > > > +? ? ?ret = rte_pktmbuf_alloc_bulk(pktmbuf_pool, m, mbufs_to_allocate); > > > +? ? ?if (ret) { > > > +? ? ? ? ? ? ?printf("cannot allocate %d mbufs bulk mempool_cnt=%d > > > ret=%d\n", > > > +? ? ? ? ? ? ? ? ? ? ?mbufs_to_allocate, > > > +? ? ? ? ? ? ? ? ? ? ?rte_mempool_count(pktmbuf_pool), > > > +? ? ? ? ? ? ? ? ? ? ?ret); > > > +? ? ? ? ? ? ?return -1; > > > +? ? ?} > > > +? ? ?if ((rte_mempool_count(pktmbuf_pool) + mbufs_to_allocate) != > > > +? ? ? ? ?mbuf_count_before_allocation) { > > > +? ? ? ? ? ? ?printf("mempool count %d + allocated %d != initial %d\n", > > > +? ? ? ? ? ? ? ? ? ? ?rte_mempool_count(pktmbuf_pool), > > > +? ? ? ? ? ? ? ? ? ? ?mbufs_to_allocate, > > > +? ? ? ? ? ? ? ? ? ? ?mbuf_count_before_allocation); > > > +? ? ? ? ? ? ?return -1; > > > +? ? ?} > > > +? ? ?/* free them */ > > > +? ? ?rte_pktmbuf_bulk_free(m, mbufs_to_allocate); > > > + > > > +? ? ?if (rte_mempool_count(pktmbuf_pool)? != > > > mbuf_count_before_allocation) { > > > +? ? ? ? ? ? ?printf("mempool count %d != initial %d\n", > > > +? ? ? ? ? ? ? ? ? ? ?rte_mempool_count(pktmbuf_pool), > > > +? ? ? ? ? ? ? ? ? ? ?mbuf_count_before_allocation); > > > +? ? ? ? ? ? ?return -1; > > > +? ? ?} > > > +? ? ?for (i = 0; i < mbufs_to_allocate; i++) > > > +? ? ? ? ? ? ?m[i] = NULL; > > > + > > > +? ? ?/* alloc NB_MBUF-MBUF_POOL_LOCAL_CACHE_SIZE mbufs */ > > > +? ? ?ret = rte_pktmbuf_alloc_bulk(pktmbuf_pool, m, mbufs_to_allocate); > > > +? ? ?if (ret) { > > > +? ? ? ? ? ? ?printf("cannot allocate %d mbufs bulk mempool_cnt=%d > > > ret=%d\n", > > > +? ? ? ? ? ? ? ? ? ? ?mbufs_to_allocate, > > > +? ? ? ? ? ? ? ? ? ? ?rte_mempool_count(pktmbuf_pool), > > > +? ? ? ? ? ? ? ? ? ? ?ret); > > > +? ? ? ? ? ? ?return -1; > > > +? ? ?} > > > +? ? ?if ((rte_mempool_count(pktmbuf_pool) + mbufs_to_allocate) != > > > +? ? ? ? ?mbuf_count_before_allocation) { > > > +? ? ? ? ? ? ?printf("mempool count %d + allocated %d != initial %d\n", > > > +? ? ? ? ? ? ? ? ? ? ?rte_mempool_count(pktmbuf_pool), > > > +? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?mbufs_to_allocate, > > > +? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?mbuf_count_before_allocation); > > > +? ? ? ? ? ? ?return -1; > > > +? ? ?} > > > + > > > +? ? ?/* chain it */ > > > +? ? ?for (i = 0; i < mbufs_to_allocate - 1; i++) { > > > +? ? ? ? ? ? ?m[i]->next = m[i + 1]; > > > +? ? ? ? ? ? ?m[0]->nb_segs++; > > > +? ? ?} > > > +? ? ?/* free them */ > > > +? ? ?rte_pktmbuf_free_chain(m[0]); > > > + > > > +? ? ?if (rte_mempool_count(pktmbuf_pool)? != > > > mbuf_count_before_allocation) { > > > +? ? ? ? ? ? ?printf("mempool count %d != initial %d\n", > > > +? ? ? ? ? ? ? ? ? ? ?rte_mempool_count(pktmbuf_pool), > > > +? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?mbuf_count_before_allocation); > > > +? ? ? ? ? ? ?return -1; > > > +? ? ?} > > > +? ? ?return ret; > > > +} > > > + > > >? /* > > >? ?* test that the pointer to the data on a packet mbuf is set properly > > >? ?*/ > > > @@ -766,7 +845,8 @@ test_mbuf(void) > > >? ? ? ?if (pktmbuf_pool == NULL) { > > >? ? ? ? ? ? ? ?pktmbuf_pool = > > >? ? ? ? ? ? ? ? ? ? ? ?rte_mempool_create("test_pktmbuf_pool", NB_MBUF, > > > -? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? MBUF_SIZE, 32, > > > +? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? MBUF_SIZE, > > > +? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? MBUF_POOL_LOCAL_CACHE_SIZE, > > >? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? sizeof(struct > > >rte_pktmbuf_pool_private), > > >? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? rte_pktmbuf_pool_init, NULL, > > >? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? rte_pktmbuf_init, NULL, > > > @@ -790,6 +870,18 @@ test_mbuf(void) > > >? ? ? ? ? ? ? ?return -1; > > >? ? ? ?} > > > > > > +? ? ?/* test bulk allocation and freeing */ > > > +? ? ?if (test_pktmbuf_pool_bulk() < 0) { > > > +? ? ? ? ? ? ?printf("test_pktmbuf_pool_bulk() failed\n"); > > > +? ? ? ? ? ? ?return -1; > > > +? ? ?} > > > + > > > +? ? ?/* once again to ensure all mbufs were freed */ > > > +? ? ?if (test_pktmbuf_pool_bulk() < 0) { > > > +? ? ? ? ? ? ?printf("test_pktmbuf_pool_bulk() failed\n"); > > > +? ? ? ? ? ? ?return -1; > > > +? ? ?} > > > + > > >? ? ? ?/* test that the pointer to the data on a packet mbuf is set > > >properly */ > > >? ? ? ?if (test_pktmbuf_pool_ptr() < 0) { > > >? ? ? ? ? ? ? ?printf("test_pktmbuf_pool_ptr() failed\n"); > > > diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h > > > index 17ba791..995237d 100644 > > > --- a/lib/librte_mbuf/rte_mbuf.h > > > +++ b/lib/librte_mbuf/rte_mbuf.h > > > @@ -825,6 +825,95 @@ static inline void rte_pktmbuf_free(struct rte_mbuf > > > *m) > > >? } > > > > > >? /** > > > + * Allocate a bulk of mbufs, initiate refcnt and resets > > > + * > > > + * @param pool > > > + *? ? memory pool to allocate from > > > + * @param mbufs > > > + *? ? Array of pointers to mbuf > > > + * @param count > > > + *? ? Array size > > > + */ > > > +static inline int rte_pktmbuf_alloc_bulk(struct rte_mempool *pool, > > > +? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? struct rte_mbuf **mbufs, > > > +? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? unsigned count) > > > +{ > > > +? ? ?unsigned idx; > > > +? ? ?int rc = 0; > > > + > > > +? ? ?rc = rte_mempool_get_bulk(pool, (void **)mbufs, count); > > > +? ? ?if (unlikely(rc)) > > > +? ? ? ? ? ? ?return rc; > > > + > > > +? ? ?for (idx = 0; idx < count; idx++) { > > > +? ? ? ? ? ? ?RTE_MBUF_ASSERT(rte_mbuf_refcnt_read(mbufs[idx]) == 0); > > > +? ? ? ? ? ? ?rte_mbuf_refcnt_set(mbufs[idx], 1); > > > +? ? ? ? ? ? ?rte_pktmbuf_reset(mbufs[idx]); > > > +? ? ?} > > > +? ? ?return rc; > > > +} > > > + > > > +/** > > > + * Free a bulk of mbufs into its original mempool. > > > + * This function assumes refcnt equals 1 > > > + * as well as the freed mbufs are direct > > I think your forgot to mention in comments one more requirement for that > > function: > > all mbufs have to be from the same mempool. > > > > > + * > > > + * @param mbufs > > > + *? ? Array of pointers to mbuf > > > + * @param count > > > + *? ? Array size > > > + */ > > > +static inline void rte_pktmbuf_bulk_free(struct rte_mbuf **mbufs, > > > +? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? unsigned count) > > > +{ > > > +? ? ?unsigned idx; > > > + > > > +? ? ?RTE_MBUF_ASSERT(count > 0); > > > + > > > +? ? ?for (idx = 0; idx < count; idx++) { > > > +? ? ? ? ? ? ?rte_mbuf_refcnt_update(mbufs[idx], -1); > > > > You can do just: > > rte_mbuf_refcnt_set(m, 0); > > here and move your assert above it. > > Something like: > > RTE_MBUF_ASSERT(rte_mbuf_refcnt_read(mbufs[idx]) == 1); > > rte_mbuf_refcnt_set(m, 0); > > > > Also probably would be a good thing to add one more assert here, > > something like: > > RTE_MBUF_ASSERT(mbufs[idx]->pool == mufs[0]->pool); > > > > > +? ? ? ? ? ? ?RTE_MBUF_ASSERT(rte_mbuf_refcnt_read(mbufs[idx]) == 0); > > > +? ? ?} > > > +? ? ?rte_mempool_put_bulk(mbufs[0]->pool, (void **)mbufs, count); > > > +} > > > + > > > +/** > > > + * Free chained (scattered) mbufs into its original mempool(s). > > > + * > > > + * @param head > > > + *? ? The head of mbufs to be freed chain. Must not be NULL > > > + */ > > > +static inline void rte_pktmbuf_free_chain(struct rte_mbuf *head) > > > +{ > > > +? ? ?struct rte_mbuf *mbufs[head->nb_segs]; > > > +? ? ?unsigned mbufs_count = 0; > > > +? ? ?struct rte_mbuf *next; > > > + > > > +? ? ?while (head) { > > > +? ? ? ? ? ? ?next = head->next; > > > +? ? ? ? ? ? ?head->next = NULL; > > > > Shouldn't the line above be inside if (head != NULL) {...} block? > > > > > +? ? ? ? ? ? ?head = __rte_pktmbuf_prefree_seg(head); > > > +? ? ? ? ? ? ?if (likely(head != NULL)) { > > > +? ? ? ? ? ? ? ? ? ? ?RTE_MBUF_ASSERT(rte_mbuf_refcnt_read(head) == 0); > > > > I don't think there is any use of the assert above. > > If prefree_seg returns non-NULL value, it sets refcnt to 0 for that mbuf. > > > > > +? ? ? ? ? ? ? ? ? ? ?if (likely((!mbufs_count) || > > > +? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? (head->pool == mbufs[0]->pool))) > > > +? ? ? ? ? ? ? ? ? ? ? ? ? ? ?mbufs[mbufs_count++] = head; > > > +? ? ? ? ? ? ? ? ? ? ?else { > > > +? ? ? ? ? ? ? ? ? ? ? ? ? ? ?rte_mempool_put_bulk(mbufs[0]->pool, > > > +? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? (void **)mbufs, > > > +? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? mbufs_count); > > > +? ? ? ? ? ? ? ? ? ? ? ? ? ? ?mbufs_count = 0; > > > +? ? ? ? ? ? ? ? ? ? ?} > > > +? ? ? ? ? ? ?} > > > +? ? ? ? ? ? ?head = next; > > > +? ? ?} > > > +? ? ?if (mbufs_count > 0) > > > +? ? ? ? ? ? ?rte_mempool_put_bulk(mbufs[0]->pool, > > > +? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? (void **)mbufs, > > > +? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? mbufs_count); > > > +} > > > + > > > +/** > > >? ?* Creates a "clone" of the given packet mbuf. > > >? ?* > > >? ?* Walks through all segments of the given packet mbuf, and for each of > > >them: > > > -- > > > 1.7.9.5
