On Thu, Jan 16, 2020 at 01:04:27PM +0000, Viacheslav Ovsiienko wrote:
> The dedicated routine rte_pktmbuf_pool_create_extbuf() is
> provided to create mbuf pool with data buffers located in
> the pinned external memory. The application provides the
> external memory description and routine initializes each
> mbuf with appropriate virtual and physical buffer address.
> It is entirely application responsibility to register
> external memory with rte_extmem_register() API, map this
> memory, etc.
>
> The new introduced flag RTE_PKTMBUF_POOL_F_PINNED_EXT_BUF
> is set in private pool structure, specifying the new special
> pool type. The allocated mbufs from pool of this kind will
> have the EXT_ATTACHED_MBUF flag set and initialiazed shared
> info structure, allowing cloning with regular mbufs (without
> attached external buffers of any kind).
>
> Signed-off-by: Viacheslav Ovsiienko <viachesl...@mellanox.com>
> ---
> lib/librte_mbuf/rte_mbuf.c | 178
> ++++++++++++++++++++++++++++++++++-
> lib/librte_mbuf/rte_mbuf.h | 84 +++++++++++++++++
> lib/librte_mbuf/rte_mbuf_version.map | 1 +
> 3 files changed, 260 insertions(+), 3 deletions(-)
>
> diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
> index 8fa7f49..b9d89d0 100644
> --- a/lib/librte_mbuf/rte_mbuf.c
> +++ b/lib/librte_mbuf/rte_mbuf.c
> @@ -59,9 +59,12 @@
> }
>
> RTE_ASSERT(mp->elt_size >= sizeof(struct rte_mbuf) +
> - user_mbp_priv->mbuf_data_room_size +
> + ((user_mbp_priv->flags & RTE_PKTMBUF_POOL_F_PINNED_EXT_BUF) ?
> + sizeof(struct rte_mbuf_ext_shared_info) :
> + user_mbp_priv->mbuf_data_room_size) +
> user_mbp_priv->mbuf_priv_size);
> - RTE_ASSERT(user_mbp_priv->flags == 0);
> + RTE_ASSERT((user_mbp_priv->flags &
> + ~RTE_PKTMBUF_POOL_F_PINNED_EXT_BUF) == 0);
>
> mbp_priv = rte_mempool_get_priv(mp);
> memcpy(mbp_priv, user_mbp_priv, sizeof(*mbp_priv));
> @@ -107,6 +110,89 @@
> m->next = NULL;
> }
>
> +/*
> + * @internal
> + * The callback routine called when reference counter in shinfo for mbufs
> + * with pinned external buffer reaches zero. It means there is no more
> + * references to buffer backing mbuf and this one should be freed.
> + */
> +static void rte_pktmbuf_free_pinned_extmem(void *addr, void *opaque)
> +{
> + struct rte_mbuf *m = opaque;
> +
> + RTE_SET_USED(addr);
> + RTE_ASSERT(RTE_MBUF_HAS_EXTBUF(m));
> + RTE_ASSERT(RTE_MBUF_HAS_PINNED_EXTBUF(m));
> + RTE_ASSERT(m->shinfo->fcb_opaque == m);
> +
> + rte_mbuf_ext_refcnt_set(m->shinfo, 1);
> + rte_pktmbuf_free_seg(m);
I think it should be rte_mbuf_raw_free(m) instead.
Else, the corresponding code can fail:
- alloc packet from pinned_pool
- increase ref counter (this is legal)
- free packet on 2 cores at the same time
The refcnt will reach 0 on one of the core, then is calls
rte_pktmbuf_free_pinned_extmem(), then rte_pktmbuf_free_seg(), then
rte_pktmbuf_prefree_seg() which will do nothing because refcnt is not 1
-> mem leak
> +}
> +
> +/*
> + * pktmbuf constructor for the pool with pinned external buffer,
> + * given as a callback function to rte_mempool_obj_iter() in
> + * rte_pktmbuf_pool_create_extbuf(). Set the fields of a packet
> + * mbuf to their default values.
> + */
> +void
> +rte_pktmbuf_init_extmem(struct rte_mempool *mp,
> + void *opaque_arg,
> + void *_m,
> + __attribute__((unused)) unsigned int i)
> +{
Can it be static?
If it is public, it should be experimental and in .map
> + struct rte_mbuf *m = _m;
> + struct rte_pktmbuf_extmem_init_ctx *ctx = opaque_arg;
> + struct rte_pktmbuf_extmem *ext_mem;
> + uint32_t mbuf_size, buf_len, priv_size;
> + struct rte_mbuf_ext_shared_info *shinfo;
> +
> + priv_size = rte_pktmbuf_priv_size(mp);
> + mbuf_size = sizeof(struct rte_mbuf) + priv_size;
> + buf_len = rte_pktmbuf_data_room_size(mp);
> +
> + RTE_ASSERT(RTE_ALIGN(priv_size, RTE_MBUF_PRIV_ALIGN) == priv_size);
> + RTE_ASSERT(mp->elt_size >= mbuf_size);
> + RTE_ASSERT(buf_len <= UINT16_MAX);
> +
> + memset(m, 0, mbuf_size);
> + m->priv_size = priv_size;
> + m->buf_len = (uint16_t)buf_len;
> +
> + /* set the data buffer pointers to external memory */
> + ext_mem = ctx->ext_mem + ctx->ext;
> +
> + RTE_ASSERT(ctx->ext < ctx->ext_num);
> + RTE_ASSERT(ctx->off < ext_mem->buf_len);
> +
> + m->buf_addr = RTE_PTR_ADD(ext_mem->buf_ptr, ctx->off);
> + m->buf_iova = ext_mem->buf_iova == RTE_BAD_IOVA ?
> + RTE_BAD_IOVA : (ext_mem->buf_iova + ctx->off);
> +
> + ctx->off += ext_mem->elt_size;
> + if (ctx->off >= ext_mem->buf_len) {
> + ctx->off = 0;
> + ++ctx->ext;
> + }
> + /* keep some headroom between start of buffer and data */
> + m->data_off = RTE_MIN(RTE_PKTMBUF_HEADROOM, (uint16_t)m->buf_len);
> +
> + /* init some constant fields */
> + m->pool = mp;
> + m->nb_segs = 1;
> + m->port = MBUF_INVALID_PORT;
> + m->ol_flags = EXT_ATTACHED_MBUF;
> + rte_mbuf_refcnt_set(m, 1);
> + m->next = NULL;
> +
> + /* init external buffer shared info items */
> + shinfo = RTE_PTR_ADD(m, mbuf_size);
I think it should be
shinfo = RTE_PTR_ADD(m, mbuf_size + priv_size);
> + m->shinfo = shinfo;
> + shinfo->free_cb = rte_pktmbuf_free_pinned_extmem;
> + shinfo->fcb_opaque = m;
> + rte_mbuf_ext_refcnt_set(shinfo, 1);
To me, it is not very clear that free_cb() will only be called
for mbuf from non-pinned pools that are attached to a mbuf from
a pinned pool, i.e. the free_cb is not called at all if attach()
is not used.
> +}
> +
> /* Helper to create a mbuf pool with given mempool ops name*/
> struct rte_mempool *
> rte_pktmbuf_pool_create_by_ops(const char *name, unsigned int n,
> @@ -169,6 +255,92 @@ struct rte_mempool *
> data_room_size, socket_id, NULL);
> }
>
> +/* Helper to create a mbuf pool with pinned external data buffers. */
> +struct rte_mempool *
> +rte_pktmbuf_pool_create_extbuf(const char *name, unsigned int n,
> + unsigned int cache_size, uint16_t priv_size,
> + uint16_t data_room_size, int socket_id,
> + struct rte_pktmbuf_extmem *ext_mem, unsigned int ext_num)
struct rte_pktmbuf_extmem *ext_mem can be const
> +{
> + struct rte_mempool *mp;
> + struct rte_pktmbuf_pool_private mbp_priv;
> + struct rte_pktmbuf_extmem_init_ctx init_ctx;
> + const char *mp_ops_name;
> + unsigned int elt_size;
> + unsigned int i, n_elts = 0;
> + int ret;
> +
> + if (RTE_ALIGN(priv_size, RTE_MBUF_PRIV_ALIGN) != priv_size) {
> + RTE_LOG(ERR, MBUF, "mbuf priv_size=%u is not aligned\n",
> + priv_size);
> + rte_errno = EINVAL;
> + return NULL;
> + }
> + /* Check the external memory descriptors. */
> + for (i = 0; i < ext_num; i++) {
> + struct rte_pktmbuf_extmem *extm = ext_mem + i;
> +
> + if (!extm->elt_size || !extm->buf_len || !extm->buf_ptr) {
> + RTE_LOG(ERR, MBUF, "invalid extmem descriptor\n");
> + rte_errno = EINVAL;
> + return NULL;
> + }
> + if (data_room_size > extm->elt_size) {
> + RTE_LOG(ERR, MBUF, "ext elt_size=%u is too small\n",
> + priv_size);
> + rte_errno = EINVAL;
> + return NULL;
> + }
> + n_elts += extm->buf_len / extm->elt_size;
> + }
Maybe it's just me, but I think there is a source of confusion between:
- elt_size: the size of mempool element (i.e a sizeof(mbuf) +
priv_size + sizeof(shinfo))
- extm->elt_size: the size of data buffer in external memory
The structure fields could be renamed like this:
struct rte_pktmbuf_extmem {
void *ptr; /**< The virtual address of data buffer. */
rte_iova_t iova; /**< The IO address of the data buffer. */
size_t len; /**< External buffer length in bytes. */
uint16_t mbuf_data_size; /**< mbuf data size in bytes. */
};
> + /* Check whether enough external memory provided. */
> + if (n_elts < n) {
> + RTE_LOG(ERR, MBUF, "not enough extmem\n");
> + rte_errno = ENOMEM;
> + return NULL;
> + }
> + elt_size = sizeof(struct rte_mbuf) +
> + (unsigned int)priv_size +
> + sizeof(struct rte_mbuf_ext_shared_info);
> +
> + memset(&mbp_priv, 0, sizeof(mbp_priv));
> + mbp_priv.mbuf_data_room_size = data_room_size;
> + mbp_priv.mbuf_priv_size = priv_size;
> + mbp_priv.flags = RTE_PKTMBUF_POOL_F_PINNED_EXT_BUF;
> +
> + mp = rte_mempool_create_empty(name, n, elt_size, cache_size,
> + sizeof(struct rte_pktmbuf_pool_private), socket_id, 0);
> + if (mp == NULL)
> + return NULL;
> +
> + mp_ops_name = rte_mbuf_best_mempool_ops();
> + ret = rte_mempool_set_ops_byname(mp, mp_ops_name, NULL);
> + if (ret != 0) {
> + RTE_LOG(ERR, MBUF, "error setting mempool handler\n");
> + rte_mempool_free(mp);
> + rte_errno = -ret;
> + return NULL;
> + }
> + rte_pktmbuf_pool_init(mp, &mbp_priv);
> +
> + ret = rte_mempool_populate_default(mp);
> + if (ret < 0) {
> + rte_mempool_free(mp);
> + rte_errno = -ret;
> + return NULL;
> + }
I still think that these ~20 lines could be simplified into a call to
rte_pktmbuf_pool_create(). I don't think that using rte_mempool_obj_iter()
twice would cause a performance issue.
> +
> + init_ctx = (struct rte_pktmbuf_extmem_init_ctx){
> + .ext_mem = ext_mem,
> + .ext_num = ext_num,
> + .ext = 0,
> + .off = 0,
> + };
> + rte_mempool_obj_iter(mp, rte_pktmbuf_init_extmem, &init_ctx);
> +
> + return mp;
> +}
> +
> /* do some sanity checks on a mbuf: panic if it fails */
> void
> rte_mbuf_sanity_check(const struct rte_mbuf *m, int is_header)
7> @@ -247,7 +419,7 @@ int rte_mbuf_check(const struct rte_mbuf *m, int
is_header,
> return 0;
> }
>
> -/**
> +/*
> * @internal helper function for freeing a bulk of packet mbuf segments
> * via an array holding the packet mbuf segments from the same mempool
> * pending to be freed.
I agree with this change, but it should not go in that patch.
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> index 52d57d1..093210e 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -637,6 +637,34 @@ static inline struct rte_mbuf *rte_mbuf_raw_alloc(struct
> rte_mempool *mp)
> void rte_pktmbuf_init(struct rte_mempool *mp, void *opaque_arg,
> void *m, unsigned i);
>
> +/** The context to initialize the mbufs with pinned external buffers. */
> +struct rte_pktmbuf_extmem_init_ctx {
> + struct rte_pktmbuf_extmem *ext_mem; /* pointer to descriptor array. */
> + unsigned int ext_num; /* number of descriptors in array. */
> + unsigned int ext; /* loop descriptor index. */
> + size_t off; /* loop buffer offset. */
> +};
I think it could be private.
> +
> +/**
> + * The packet mbuf constructor for pools with pinned external memory.
> + *
> + * This function initializes some fields in the mbuf structure that are
> + * not modified by the user once created (origin pool, buffer start
> + * address, and so on). This function is given as a callback function to
> + * rte_mempool_obj_iter() called from rte_mempool_create_extmem().
> + *
> + * @param mp
> + * The mempool from which mbufs originate.
> + * @param opaque_arg
> + * A pointer to the rte_pktmbuf_extmem_init_ctx - initialization
> + * context structure
> + * @param m
> + * The mbuf to initialize.
> + * @param i
> + * The index of the mbuf in the pool table.
> + */
> +void rte_pktmbuf_init_extmem(struct rte_mempool *mp, void *opaque_arg,
> + void *m, unsigned int i);
>
Except if I missing something, it could be private too
> /**
> * A packet mbuf pool constructor.
> @@ -738,6 +766,62 @@ struct rte_mempool *
> unsigned int cache_size, uint16_t priv_size, uint16_t data_room_size,
> int socket_id, const char *ops_name);
>
> +/** A structure that describes the pinned external buffer segment. */
> +struct rte_pktmbuf_extmem {
> + void *buf_ptr; /**< The virtual address of data buffer. */
> + rte_iova_t buf_iova; /**< The IO address of the data buffer. */
> + size_t buf_len; /**< External buffer length in bytes. */
> + uint16_t elt_size; /**< mbuf element size in bytes. */
> +};
See my proposition above about fields renaming.
> +
> +/**
> + * Create a mbuf pool with external pinned data buffers.
> + *
> + * This function creates and initializes a packet mbuf pool that contains
> + * only mbufs with external buffer. It is a wrapper to rte_mempool functions.
> + *
> + * @param name
> + * The name of the mbuf pool.
> + * @param n
> + * The number of elements in the mbuf pool. The optimum size (in terms
> + * of memory usage) for a mempool is when n is a power of two minus one:
> + * n = (2^q - 1).
> + * @param cache_size
> + * Size of the per-core object cache. See rte_mempool_create() for
> + * details.
> + * @param priv_size
> + * Size of application private are between the rte_mbuf structure
> + * and the data buffer. This value must be aligned to RTE_MBUF_PRIV_ALIGN.
> + * @param data_room_size
> + * Size of data buffer in each mbuf, including RTE_PKTMBUF_HEADROOM.
> + * @param socket_id
> + * The socket identifier where the memory should be allocated. The
> + * value can be *SOCKET_ID_ANY* if there is no NUMA constraint for the
> + * reserved zone.
> + * @param ext_mem
> + * Pointer to the array of structures describing the external memory
> + * for data buffers. It is caller responsibility to register this memory
> + * with rte_extmem_register() (if needed), map this memory to appropriate
> + * physical device, etc.
> + * @param ext_num
> + * Number of elements in the ext_mem array.
> + * @return
> + * The pointer to the new allocated mempool, on success. NULL on error
> + * with rte_errno set appropriately. Possible rte_errno values include:
> + * - E_RTE_NO_CONFIG - function could not get pointer to rte_config
> structure
> + * - E_RTE_SECONDARY - function was called from a secondary process
> instance
> + * - EINVAL - cache size provided is too large, or priv_size is not
> aligned.
> + * - ENOSPC - the maximum number of memzones has already been allocated
> + * - EEXIST - a memzone with the same name already exists
> + * - ENOMEM - no appropriate memory area found in which to create memzone
> + */
> +__rte_experimental
> +struct rte_mempool *
> +rte_pktmbuf_pool_create_extbuf(const char *name, unsigned int n,
> + unsigned int cache_size, uint16_t priv_size,
> + uint16_t data_room_size, int socket_id,
> + struct rte_pktmbuf_extmem *ext_mem, unsigned int ext_num);
> +
> /**
> * Get the data room size of mbufs stored in a pktmbuf_pool
> *
> diff --git a/lib/librte_mbuf/rte_mbuf_version.map
> b/lib/librte_mbuf/rte_mbuf_version.map
> index 3bbb476..ab161bc 100644
> --- a/lib/librte_mbuf/rte_mbuf_version.map
> +++ b/lib/librte_mbuf/rte_mbuf_version.map
> @@ -44,5 +44,6 @@ EXPERIMENTAL {
> rte_mbuf_dyn_dump;
> rte_pktmbuf_copy;
> rte_pktmbuf_free_bulk;
> + rte_pktmbuf_pool_create_extbuf;
>
> };
> --
> 1.8.3.1
>
One more thing: it would be nice to have a functional test for this new
feature. I did a very minimal one to check the basic alloc/free/attach
feature, you can restart from that if you want.
static int
test_ext_pinned(int test_case)
{
struct rte_pktmbuf_extmem ext_mem;
struct rte_mempool *pinned_pool = NULL;
struct rte_mempool *std_pool = NULL;
const struct rte_memzone *mz = NULL;
struct rte_mbuf *m = NULL, *m2 = NULL;
printf("Test mbuf pool with mbufs data pinned to external buffer
(%d)\n", test_case);
std_pool = rte_pktmbuf_pool_create("std_pool",
NB_MBUF, MEMPOOL_CACHE_SIZE, 0, MBUF_DATA_SIZE,
SOCKET_ID_ANY);
if (std_pool == NULL)
GOTO_FAIL("std_pool alloc failed");
mz = rte_memzone_reserve("std_pool",
NB_MBUF * sizeof(struct rte_mbuf),
SOCKET_ID_ANY,
RTE_MEMZONE_2MB|RTE_MEMZONE_SIZE_HINT_ONLY);
if (mz == NULL)
GOTO_FAIL("memzone alloc failed");
ext_mem.buf_ptr = mz->addr;
ext_mem.buf_iova = mz->iova;
ext_mem.buf_len = mz->len;
ext_mem.elt_size = sizeof(struct rte_mbuf);
pinned_pool = rte_pktmbuf_pool_create_extbuf("pinned_pool",
NB_MBUF, MEMPOOL_CACHE_SIZE,
0, 0, SOCKET_ID_ANY, &ext_mem, 1);
if (pinned_pool == NULL)
GOTO_FAIL("pinned_pool alloc failed");
m = rte_pktmbuf_alloc(pinned_pool);
if (unlikely(m == NULL))
goto fail;
if (test_case != 0) {
m2 = rte_pktmbuf_alloc(std_pool);
if (unlikely(m == NULL))
goto fail;
rte_pktmbuf_attach(m2, m);
}
if (test_case == 0) {
rte_pktmbuf_free(m);
} else if (test_case == 1) {
rte_pktmbuf_free(m);
rte_pktmbuf_free(m2);
} else if (test_case == 2) {
rte_pktmbuf_free(m2);
rte_pktmbuf_free(m);
}
rte_mempool_free(pinned_pool);
rte_memzone_free(mz);
rte_mempool_free(std_pool);
return 0;
fail:
rte_pktmbuf_free(m2);
rte_pktmbuf_free(m);
rte_mempool_free(pinned_pool);
rte_memzone_free(mz);
rte_mempool_free(std_pool);
return -1;
}
