From patchwork Wed Apr 25 02:53:40 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yongseok Koh X-Patchwork-Id: 38853 X-Patchwork-Delegate: thomas@monjalon.net Return-Path: X-Original-To: patchwork@dpdk.org Delivered-To: patchwork@dpdk.org Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 0A7112C0C; Wed, 25 Apr 2018 04:54:01 +0200 (CEST) Received: from EUR01-VE1-obe.outbound.protection.outlook.com (mail-ve1eur01on0065.outbound.protection.outlook.com [104.47.1.65]) by dpdk.org (Postfix) with ESMTP id 7F0C12BF4 for ; Wed, 25 Apr 2018 04:53:59 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Mellanox.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version; bh=R1WZ6ORirMaX8NafyI9/7F7ZoRVb/Hp1qPq6N0DKZvU=; b=t0dhPDnuVbVmt5ATNXqzEI1auF1slnuUFL6Wp/ZHI+0F6uihRoE+06HU2Qx7yiOpyeiYjA9yFU4zfJ9oVvJpfrjtxKVo9XKemCzTAs1DjYiNnZietT3nbbj5C1vUjW1FPOkRtIjNzSS13uyMDYfxZiMFnyH3V0Ao3okmdjNCe/U= Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=yskoh@mellanox.com; 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Attaching an external buffer is quite similar to mbuf indirection in replacing buffer addresses and length of a mbuf, but a few differences: - When an indirect mbuf is attached, refcnt of the direct mbuf would be 2 as long as the direct mbuf itself isn't freed after the attachment. In such cases, the buffer area of a direct mbuf must be read-only. But external buffer has its own refcnt and it starts from 1. Unless multiple mbufs are attached to a mbuf having an external buffer, the external buffer is writable. - There's no need to allocate buffer from a mempool. Any buffer can be attached with appropriate free callback. - Smaller metadata is required to maintain shared data such as refcnt. Signed-off-by: Yongseok Koh --- ** This patch can pass the mbuf_autotest. ** Submitting only non-mlx5 patches to meet deadline for RC1. mlx5 patches will be submitted separately rebased on a differnet patchset which accommodates new memory hotplug design to mlx PMDs. v5: * rte_pktmbuf_attach_extbuf() sets headroom to 0. * if shinfo is provided when attaching, user should initialize it. * minor changes from review. v4: * rte_pktmbuf_attach_extbuf() takes new arguments - buf_iova and shinfo. user can pass memory for shared data via shinfo argument. * minor changes from review. v3: * implement external buffer attachment instead of introducing buf_off for mbuf indirection. lib/librte_mbuf/rte_mbuf.h | 303 ++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 274 insertions(+), 29 deletions(-) diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h index 43aaa9c5f..e2c12874a 100644 --- a/lib/librte_mbuf/rte_mbuf.h +++ b/lib/librte_mbuf/rte_mbuf.h @@ -344,7 +344,10 @@ extern "C" { PKT_TX_MACSEC | \ PKT_TX_SEC_OFFLOAD) -#define __RESERVED (1ULL << 61) /**< reserved for future mbuf use */ +/** + * Mbuf having an external buffer attached. shinfo in mbuf must be filled. + */ +#define EXT_ATTACHED_MBUF (1ULL << 61) #define IND_ATTACHED_MBUF (1ULL << 62) /**< Indirect attached mbuf */ @@ -584,8 +587,27 @@ struct rte_mbuf { /** Sequence number. See also rte_reorder_insert(). */ uint32_t seqn; + /** Shared data for external buffer attached to mbuf. See + * rte_pktmbuf_attach_extbuf(). + */ + struct rte_mbuf_ext_shared_info *shinfo; + } __rte_cache_aligned; +/** + * Function typedef of callback to free externally attached buffer. + */ +typedef void (*rte_mbuf_extbuf_free_callback_t)(void *addr, void *opaque); + +/** + * Shared data at the end of an external buffer. + */ +struct rte_mbuf_ext_shared_info { + rte_mbuf_extbuf_free_callback_t free_cb; /**< Free callback function */ + void *fcb_opaque; /**< Free callback argument */ + rte_atomic16_t refcnt_atomic; /**< Atomically accessed refcnt */ +}; + /**< Maximum number of nb_segs allowed. */ #define RTE_MBUF_MAX_NB_SEGS UINT16_MAX @@ -706,14 +728,33 @@ rte_mbuf_to_baddr(struct rte_mbuf *md) } /** + * Returns TRUE if given mbuf is cloned by mbuf indirection, or FALSE + * otherwise. + * + * If a mbuf has its data in another mbuf and references it by mbuf + * indirection, this mbuf can be defined as a cloned mbuf. + */ +#define RTE_MBUF_CLONED(mb) ((mb)->ol_flags & IND_ATTACHED_MBUF) + +/** * Returns TRUE if given mbuf is indirect, or FALSE otherwise. */ -#define RTE_MBUF_INDIRECT(mb) ((mb)->ol_flags & IND_ATTACHED_MBUF) +#define RTE_MBUF_INDIRECT(mb) RTE_MBUF_CLONED(mb) + +/** + * Returns TRUE if given mbuf has an external buffer, or FALSE otherwise. + * + * External buffer is a user-provided anonymous buffer. + */ +#define RTE_MBUF_HAS_EXTBUF(mb) ((mb)->ol_flags & EXT_ATTACHED_MBUF) /** * Returns TRUE if given mbuf is direct, or FALSE otherwise. + * + * If a mbuf embeds its own data after the rte_mbuf structure, this mbuf + * can be defined as a direct mbuf. */ -#define RTE_MBUF_DIRECT(mb) (!RTE_MBUF_INDIRECT(mb)) +#define RTE_MBUF_DIRECT(mb) (!(RTE_MBUF_CLONED(mb) || RTE_MBUF_HAS_EXTBUF(mb))) /** * Private data in case of pktmbuf pool. @@ -839,6 +880,58 @@ rte_mbuf_refcnt_set(struct rte_mbuf *m, uint16_t new_value) #endif /* RTE_MBUF_REFCNT_ATOMIC */ +/** + * Reads the refcnt of an external buffer. + * + * @param shinfo + * Shared data of the external buffer. + * @return + * Reference count number. + */ +static inline uint16_t +rte_mbuf_ext_refcnt_read(const struct rte_mbuf_ext_shared_info *shinfo) +{ + return (uint16_t)(rte_atomic16_read(&shinfo->refcnt_atomic)); +} + +/** + * Set refcnt of an external buffer. + * + * @param shinfo + * Shared data of the external buffer. + * @param new_value + * Value set + */ +static inline void +rte_mbuf_ext_refcnt_set(struct rte_mbuf_ext_shared_info *shinfo, + uint16_t new_value) +{ + rte_atomic16_set(&shinfo->refcnt_atomic, new_value); +} + +/** + * Add given value to refcnt of an external buffer and return its new + * value. + * + * @param shinfo + * Shared data of the external buffer. + * @param value + * Value to add/subtract + * @return + * Updated value + */ +static inline uint16_t +rte_mbuf_ext_refcnt_update(struct rte_mbuf_ext_shared_info *shinfo, + int16_t value) +{ + if (likely(rte_mbuf_ext_refcnt_read(shinfo) == 1)) { + rte_mbuf_ext_refcnt_set(shinfo, 1 + value); + return 1 + value; + } + + return (uint16_t)rte_atomic16_add_return(&shinfo->refcnt_atomic, value); +} + /** Mbuf prefetch */ #define RTE_MBUF_PREFETCH_TO_FREE(m) do { \ if ((m) != NULL) \ @@ -1213,11 +1306,127 @@ static inline int rte_pktmbuf_alloc_bulk(struct rte_mempool *pool, } /** + * Attach an external buffer to a mbuf. + * + * User-managed anonymous buffer can be attached to an mbuf. When attaching + * it, corresponding free callback function and its argument should be + * provided. This callback function will be called once all the mbufs are + * detached from the buffer. + * + * The headroom for the attaching mbuf will be set to zero and this can be + * properly adjusted after attachment. For example, ``rte_pktmbuf_adj()`` + * or ``rte_pktmbuf_reset_headroom()`` can be used. + * + * More mbufs can be attached to the same external buffer by + * ``rte_pktmbuf_attach()`` once the external buffer has been attached by + * this API. + * + * Detachment can be done by either ``rte_pktmbuf_detach_extbuf()`` or + * ``rte_pktmbuf_detach()``. + * + * Attaching an external buffer is quite similar to mbuf indirection in + * replacing buffer addresses and length of a mbuf, but a few differences: + * - When an indirect mbuf is attached, refcnt of the direct mbuf would be + * 2 as long as the direct mbuf itself isn't freed after the attachment. + * In such cases, the buffer area of a direct mbuf must be read-only. But + * external buffer has its own refcnt and it starts from 1. Unless + * multiple mbufs are attached to a mbuf having an external buffer, the + * external buffer is writable. + * - There's no need to allocate buffer from a mempool. Any buffer can be + * attached with appropriate free callback and its IO address. + * - Smaller metadata is required to maintain shared data such as refcnt. + * + * @warning + * @b EXPERIMENTAL: This API may change without prior notice. + * Once external buffer is enabled by allowing experimental API, + * ``RTE_MBUF_DIRECT()`` and ``RTE_MBUF_INDIRECT()`` are no longer + * exclusive. A mbuf can be considered direct if it is neither indirect nor + * having external buffer. + * + * @param m + * The pointer to the mbuf. + * @param buf_addr + * The pointer to the external buffer we're attaching to. + * @param buf_iova + * IO address of the external buffer we're attaching to. + * @param buf_len + * The size of the external buffer we're attaching to. If memory for + * shared data is not provided, buf_len must be larger than the size of + * ``struct rte_mbuf_ext_shared_info`` and padding for alignment. If not + * enough, this function will return NULL. + * @param shinfo + * User-provided memory for shared data. If NULL, a few bytes in the + * trailer of the provided buffer will be dedicated for shared data and + * the shared data will be properly initialized. Otherwise, user must + * initialize the content except for free callback and its argument. The + * pointer of shared data will be stored in m->shinfo. + * @param free_cb + * Free callback function to call when the external buffer needs to be + * freed. + * @param fcb_opaque + * Argument for the free callback function. + * + * @return + * A pointer to the new start of the data on success, return NULL + * otherwise. + */ +static inline char * __rte_experimental +rte_pktmbuf_attach_extbuf(struct rte_mbuf *m, void *buf_addr, + rte_iova_t buf_iova, uint16_t buf_len, + struct rte_mbuf_ext_shared_info *shinfo, + rte_mbuf_extbuf_free_callback_t free_cb, void *fcb_opaque) +{ + /* Additional attachment should be done by rte_pktmbuf_attach() */ + RTE_ASSERT(!RTE_MBUF_HAS_EXTBUF(m)); + + m->buf_addr = buf_addr; + m->buf_iova = buf_iova; + + if (shinfo == NULL) { + void *buf_end = RTE_PTR_ADD(buf_addr, buf_len); + + shinfo = RTE_PTR_ALIGN_FLOOR(RTE_PTR_SUB(buf_end, + sizeof(*shinfo)), sizeof(uintptr_t)); + if ((void *)shinfo <= buf_addr) + return NULL; + + m->buf_len = RTE_PTR_DIFF(shinfo, buf_addr); + rte_mbuf_ext_refcnt_set(shinfo, 1); + } else { + m->buf_len = buf_len; + } + + m->data_len = 0; + m->data_off = 0; + + m->ol_flags |= EXT_ATTACHED_MBUF; + m->shinfo = shinfo; + + shinfo->free_cb = free_cb; + shinfo->fcb_opaque = fcb_opaque; + + return (char *)m->buf_addr + m->data_off; +} + +/** + * Detach the external buffer attached to a mbuf, same as + * ``rte_pktmbuf_detach()`` + * + * @param m + * The mbuf having external buffer. + */ +#define rte_pktmbuf_detach_extbuf(m) rte_pktmbuf_detach(m) + +/** * Attach packet mbuf to another packet mbuf. * - * After attachment we refer the mbuf we attached as 'indirect', - * while mbuf we attached to as 'direct'. - * The direct mbuf's reference counter is incremented. + * If the mbuf we are attaching to isn't a direct buffer and is attached to + * an external buffer, the mbuf being attached will be attached to the + * external buffer instead of mbuf indirection. + * + * Otherwise, the mbuf will be indirectly attached. After attachment we + * refer the mbuf we attached as 'indirect', while mbuf we attached to as + * 'direct'. The direct mbuf's reference counter is incremented. * * Right now, not supported: * - attachment for already indirect mbuf (e.g. - mi has to be direct). @@ -1231,19 +1440,19 @@ static inline int rte_pktmbuf_alloc_bulk(struct rte_mempool *pool, */ static inline void rte_pktmbuf_attach(struct rte_mbuf *mi, struct rte_mbuf *m) { - struct rte_mbuf *md; - RTE_ASSERT(RTE_MBUF_DIRECT(mi) && rte_mbuf_refcnt_read(mi) == 1); - /* if m is not direct, get the mbuf that embeds the data */ - if (RTE_MBUF_DIRECT(m)) - md = m; - else - md = rte_mbuf_from_indirect(m); + if (RTE_MBUF_HAS_EXTBUF(m)) { + rte_mbuf_ext_refcnt_update(m->shinfo, 1); + mi->ol_flags = m->ol_flags; + } else { + /* if m is not direct, get the mbuf that embeds the data */ + rte_mbuf_refcnt_update(rte_mbuf_from_indirect(m), 1); + mi->priv_size = m->priv_size; + mi->ol_flags = m->ol_flags | IND_ATTACHED_MBUF; + } - rte_mbuf_refcnt_update(md, 1); - mi->priv_size = m->priv_size; mi->buf_iova = m->buf_iova; mi->buf_addr = m->buf_addr; mi->buf_len = m->buf_len; @@ -1259,7 +1468,6 @@ static inline void rte_pktmbuf_attach(struct rte_mbuf *mi, struct rte_mbuf *m) mi->next = NULL; mi->pkt_len = mi->data_len; mi->nb_segs = 1; - mi->ol_flags = m->ol_flags | IND_ATTACHED_MBUF; mi->packet_type = m->packet_type; mi->timestamp = m->timestamp; @@ -1268,12 +1476,52 @@ static inline void rte_pktmbuf_attach(struct rte_mbuf *mi, struct rte_mbuf *m) } /** - * Detach an indirect packet mbuf. + * @internal used by rte_pktmbuf_detach(). * + * Decrement the reference counter of the external buffer. When the + * reference counter becomes 0, the buffer is freed by pre-registered + * callback. + */ +static inline void +__rte_pktmbuf_free_extbuf(struct rte_mbuf *m) +{ + RTE_ASSERT(RTE_MBUF_HAS_EXTBUF(m)); + RTE_ASSERT(m->shinfo != NULL); + + if (rte_mbuf_ext_refcnt_update(m->shinfo, -1) == 0) + m->shinfo->free_cb(m->buf_addr, m->shinfo->fcb_opaque); +} + +/** + * @internal used by rte_pktmbuf_detach(). + * + * Decrement the direct mbuf's reference counter. When the reference + * counter becomes 0, the direct mbuf is freed. + */ +static inline void +__rte_pktmbuf_free_direct(struct rte_mbuf *m) +{ + struct rte_mbuf *md; + + RTE_ASSERT(RTE_MBUF_INDIRECT(m)); + + md = rte_mbuf_from_indirect(m); + + if (rte_mbuf_refcnt_update(md, -1) == 0) { + md->next = NULL; + md->nb_segs = 1; + rte_mbuf_refcnt_set(md, 1); + rte_mbuf_raw_free(md); + } +} + +/** + * Detach a packet mbuf from external buffer or direct buffer. + * + * - decrement refcnt and free the external/direct buffer if refcnt + * becomes zero. * - restore original mbuf address and length values. * - reset pktmbuf data and data_len to their default values. - * - decrement the direct mbuf's reference counter. When the - * reference counter becomes 0, the direct mbuf is freed. * * All other fields of the given packet mbuf will be left intact. * @@ -1282,10 +1530,14 @@ static inline void rte_pktmbuf_attach(struct rte_mbuf *mi, struct rte_mbuf *m) */ static inline void rte_pktmbuf_detach(struct rte_mbuf *m) { - struct rte_mbuf *md = rte_mbuf_from_indirect(m); struct rte_mempool *mp = m->pool; uint32_t mbuf_size, buf_len, priv_size; + if (RTE_MBUF_HAS_EXTBUF(m)) + __rte_pktmbuf_free_extbuf(m); + else + __rte_pktmbuf_free_direct(m); + priv_size = rte_pktmbuf_priv_size(mp); mbuf_size = sizeof(struct rte_mbuf) + priv_size; buf_len = rte_pktmbuf_data_room_size(mp); @@ -1297,13 +1549,6 @@ static inline void rte_pktmbuf_detach(struct rte_mbuf *m) rte_pktmbuf_reset_headroom(m); m->data_len = 0; m->ol_flags = 0; - - if (rte_mbuf_refcnt_update(md, -1) == 0) { - md->next = NULL; - md->nb_segs = 1; - rte_mbuf_refcnt_set(md, 1); - rte_mbuf_raw_free(md); - } } /** @@ -1327,7 +1572,7 @@ rte_pktmbuf_prefree_seg(struct rte_mbuf *m) if (likely(rte_mbuf_refcnt_read(m) == 1)) { - if (RTE_MBUF_INDIRECT(m)) + if (!RTE_MBUF_DIRECT(m)) rte_pktmbuf_detach(m); if (m->next != NULL) { @@ -1339,7 +1584,7 @@ rte_pktmbuf_prefree_seg(struct rte_mbuf *m) } else if (__rte_mbuf_refcnt_update(m, -1) == 0) { - if (RTE_MBUF_INDIRECT(m)) + if (!RTE_MBUF_DIRECT(m)) rte_pktmbuf_detach(m); if (m->next != NULL) {