[dpdk-dev] [PATCH v7 1/3] lib/lpm: integrate RCU QSBR
Ruifeng Wang
Ruifeng.Wang at arm.com
Wed Jul 8 17:34:44 CEST 2020
> -----Original Message-----
> From: David Marchand <david.marchand at redhat.com>
> Sent: Wednesday, July 8, 2020 10:30 PM
> To: Ruifeng Wang <Ruifeng.Wang at arm.com>
> Cc: Bruce Richardson <bruce.richardson at intel.com>; Vladimir Medvedkin
> <vladimir.medvedkin at intel.com>; John McNamara
> <john.mcnamara at intel.com>; Marko Kovacevic
> <marko.kovacevic at intel.com>; Ray Kinsella <mdr at ashroe.eu>; Neil Horman
> <nhorman at tuxdriver.com>; dev <dev at dpdk.org>; Ananyev, Konstantin
> <konstantin.ananyev at intel.com>; Honnappa Nagarahalli
> <Honnappa.Nagarahalli at arm.com>; nd <nd at arm.com>
> Subject: Re: [dpdk-dev] [PATCH v7 1/3] lib/lpm: integrate RCU QSBR
>
> On Tue, Jul 7, 2020 at 5:16 PM Ruifeng Wang <ruifeng.wang at arm.com>
> wrote:
> > diff --git a/lib/librte_lpm/rte_lpm.h b/lib/librte_lpm/rte_lpm.h index
> > b9d49ac87..7889f21b3 100644
> > --- a/lib/librte_lpm/rte_lpm.h
> > +++ b/lib/librte_lpm/rte_lpm.h
> > @@ -1,5 +1,6 @@
> > /* SPDX-License-Identifier: BSD-3-Clause
> > * Copyright(c) 2010-2014 Intel Corporation
> > + * Copyright(c) 2020 Arm Limited
> > */
> >
> > #ifndef _RTE_LPM_H_
> > @@ -20,6 +21,7 @@
> > #include <rte_memory.h>
> > #include <rte_common.h>
> > #include <rte_vect.h>
> > +#include <rte_rcu_qsbr.h>
> >
> > #ifdef __cplusplus
> > extern "C" {
> > @@ -62,6 +64,17 @@ extern "C" {
> > /** Bitmask used to indicate successful lookup */
> > #define RTE_LPM_LOOKUP_SUCCESS 0x01000000
> >
> > +/** @internal Default RCU defer queue entries to reclaim in one go. */
> > +#define RTE_LPM_RCU_DQ_RECLAIM_MAX 16
> > +
> > +/** RCU reclamation modes */
> > +enum rte_lpm_qsbr_mode {
> > + /** Create defer queue for reclaim. */
> > + RTE_LPM_QSBR_MODE_DQ = 0,
> > + /** Use blocking mode reclaim. No defer queue created. */
> > + RTE_LPM_QSBR_MODE_SYNC
> > +};
> > +
> > #if RTE_BYTE_ORDER == RTE_LITTLE_ENDIAN
> > /** @internal Tbl24 entry structure. */ __extension__ @@ -130,6
> > +143,28 @@ struct rte_lpm {
> > __rte_cache_aligned; /**< LPM tbl24 table. */
> > struct rte_lpm_tbl_entry *tbl8; /**< LPM tbl8 table. */
> > struct rte_lpm_rule *rules_tbl; /**< LPM rules. */
> > +#ifdef ALLOW_EXPERIMENTAL_API
> > + /* RCU config. */
> > + struct rte_rcu_qsbr *v; /* RCU QSBR variable. */
> > + enum rte_lpm_qsbr_mode rcu_mode;/* Blocking, defer queue. */
> > + struct rte_rcu_qsbr_dq *dq; /* RCU QSBR defer queue. */
> > +#endif
> > +};
>
> I can see failures in travis reports for v7 and v6.
> I reproduced them in my env.
>
> 1 function with some indirect sub-type change:
>
> [C]'function int rte_lpm_add(rte_lpm*, uint32_t, uint8_t, uint32_t)'
> at rte_lpm.c:764:1 has some indirect sub-type changes:
> parameter 1 of type 'rte_lpm*' has sub-type changes:
> in pointed to type 'struct rte_lpm' at rte_lpm.h:134:1:
> type size hasn't changed
> 3 data member insertions:
> 'rte_rcu_qsbr* rte_lpm::v', at offset 536873600 (in bits) at
> rte_lpm.h:148:1
> 'rte_lpm_qsbr_mode rte_lpm::rcu_mode', at offset 536873664 (in bits)
> at rte_lpm.h:149:1
> 'rte_rcu_qsbr_dq* rte_lpm::dq', at offset 536873728 (in
> bits) at rte_lpm.h:150:1
>
Sorry, I thought if ALLOW_EXPERIMENTAL was added, ABI would be kept when experimental was not allowed by user.
ABI and ALLOW_EXPERIMENTAL should be two different things.
>
> Going back to my proposal of hiding what does not need to be seen.
>
> Disclaimer, *this is quick & dirty* but it builds and passes ABI check:
>
> $ git diff
> diff --git a/lib/librte_lpm/rte_lpm.c b/lib/librte_lpm/rte_lpm.c index
> d498ba761..7109aef6a 100644
> --- a/lib/librte_lpm/rte_lpm.c
> +++ b/lib/librte_lpm/rte_lpm.c
I understand your proposal in v5 now. A new data structure encloses rte_lpm and new members that for RCU use.
In this way, rte_lpm ABI is kept. And we can move out other members in rte_lpm that not need to be exposed in 20.11 release.
I will fix the ABI issue in next version.
> @@ -115,6 +115,15 @@ rte_lpm_find_existing(const char *name)
> return l;
> }
>
> +struct internal_lpm {
> + /* Public object */
> + struct rte_lpm lpm;
> + /* RCU config. */
> + struct rte_rcu_qsbr *v; /* RCU QSBR variable. */
> + enum rte_lpm_qsbr_mode rcu_mode;/* Blocking, defer queue. */
> + struct rte_rcu_qsbr_dq *dq; /* RCU QSBR defer queue. */
> +};
> +
> /*
> * Allocates memory for LPM object
> */
> @@ -123,6 +132,7 @@ rte_lpm_create(const char *name, int socket_id,
> const struct rte_lpm_config *config) {
> char mem_name[RTE_LPM_NAMESIZE];
> + struct internal_lpm *internal = NULL;
> struct rte_lpm *lpm = NULL;
> struct rte_tailq_entry *te;
> uint32_t mem_size, rules_size, tbl8s_size; @@ -141,12 +151,6 @@
> rte_lpm_create(const char *name, int socket_id,
>
> snprintf(mem_name, sizeof(mem_name), "LPM_%s", name);
>
> - /* Determine the amount of memory to allocate. */
> - mem_size = sizeof(*lpm);
> - rules_size = sizeof(struct rte_lpm_rule) * config->max_rules;
> - tbl8s_size = (sizeof(struct rte_lpm_tbl_entry) *
> - RTE_LPM_TBL8_GROUP_NUM_ENTRIES * config-
> >number_tbl8s);
> -
> rte_mcfg_tailq_write_lock();
>
> /* guarantee there's no existing */ @@ -170,16 +174,23 @@
> rte_lpm_create(const char *name, int socket_id,
> goto exit;
> }
>
> + /* Determine the amount of memory to allocate. */
> + mem_size = sizeof(*internal);
> + rules_size = sizeof(struct rte_lpm_rule) * config->max_rules;
> + tbl8s_size = (sizeof(struct rte_lpm_tbl_entry) *
> + RTE_LPM_TBL8_GROUP_NUM_ENTRIES *
> + config->number_tbl8s);
> +
> /* Allocate memory to store the LPM data structures. */
> - lpm = rte_zmalloc_socket(mem_name, mem_size,
> + internal = rte_zmalloc_socket(mem_name, mem_size,
> RTE_CACHE_LINE_SIZE, socket_id);
> - if (lpm == NULL) {
> + if (internal == NULL) {
> RTE_LOG(ERR, LPM, "LPM memory allocation failed\n");
> rte_free(te);
> rte_errno = ENOMEM;
> goto exit;
> }
>
> + lpm = &internal->lpm;
> lpm->rules_tbl = rte_zmalloc_socket(NULL,
> (size_t)rules_size, RTE_CACHE_LINE_SIZE, socket_id);
>
> @@ -226,6 +237,7 @@ rte_lpm_create(const char *name, int socket_id,
> void rte_lpm_free(struct rte_lpm *lpm) {
> + struct internal_lpm *internal;
> struct rte_lpm_list *lpm_list;
> struct rte_tailq_entry *te;
>
> @@ -247,8 +259,9 @@ rte_lpm_free(struct rte_lpm *lpm)
>
> rte_mcfg_tailq_write_unlock();
>
> - if (lpm->dq)
> - rte_rcu_qsbr_dq_delete(lpm->dq);
> + internal = container_of(lpm, struct internal_lpm, lpm);
> + if (internal->dq != NULL)
> + rte_rcu_qsbr_dq_delete(internal->dq);
> rte_free(lpm->tbl8);
> rte_free(lpm->rules_tbl);
> rte_free(lpm);
> @@ -276,13 +289,15 @@ rte_lpm_rcu_qsbr_add(struct rte_lpm *lpm, struct
> rte_lpm_rcu_config *cfg, {
> char rcu_dq_name[RTE_RCU_QSBR_DQ_NAMESIZE];
> struct rte_rcu_qsbr_dq_parameters params = {0};
> + struct internal_lpm *internal;
>
> - if ((lpm == NULL) || (cfg == NULL)) {
> + if (lpm == NULL || cfg == NULL) {
> rte_errno = EINVAL;
> return 1;
> }
>
> - if (lpm->v) {
> + internal = container_of(lpm, struct internal_lpm, lpm);
> + if (internal->v != NULL) {
> rte_errno = EEXIST;
> return 1;
> }
> @@ -305,20 +320,19 @@ rte_lpm_rcu_qsbr_add(struct rte_lpm *lpm, struct
> rte_lpm_rcu_config *cfg,
> params.free_fn = __lpm_rcu_qsbr_free_resource;
> params.p = lpm;
> params.v = cfg->v;
> - lpm->dq = rte_rcu_qsbr_dq_create(¶ms);
> - if (lpm->dq == NULL) {
> - RTE_LOG(ERR, LPM,
> - "LPM QS defer queue creation failed\n");
> + internal->dq = rte_rcu_qsbr_dq_create(¶ms);
> + if (internal->dq == NULL) {
> + RTE_LOG(ERR, LPM, "LPM QS defer queue creation
> failed\n");
> return 1;
> }
> if (dq)
> - *dq = lpm->dq;
> + *dq = internal->dq;
> } else {
> rte_errno = EINVAL;
> return 1;
> }
> - lpm->rcu_mode = cfg->mode;
> - lpm->v = cfg->v;
> + internal->rcu_mode = cfg->mode;
> + internal->v = cfg->v;
>
> return 0;
> }
> @@ -502,12 +516,13 @@ _tbl8_alloc(struct rte_lpm *lpm) static int32_t
> tbl8_alloc(struct rte_lpm *lpm) {
> + struct internal_lpm *internal = container_of(lpm, struct
> internal_lpm, lpm);
> int32_t group_idx; /* tbl8 group index. */
>
> group_idx = _tbl8_alloc(lpm);
> - if ((group_idx == -ENOSPC) && (lpm->dq != NULL)) {
> + if (group_idx == -ENOSPC && internal->dq != NULL) {
> /* If there are no tbl8 groups try to reclaim one. */
> - if (rte_rcu_qsbr_dq_reclaim(lpm->dq, 1, NULL, NULL, NULL) == 0)
> + if (rte_rcu_qsbr_dq_reclaim(internal->dq, 1, NULL,
> NULL, NULL) == 0)
> group_idx = _tbl8_alloc(lpm);
> }
>
> @@ -518,20 +533,21 @@ static void
> tbl8_free(struct rte_lpm *lpm, uint32_t tbl8_group_start) {
> struct rte_lpm_tbl_entry zero_tbl8_entry = {0};
> + struct internal_lpm *internal = container_of(lpm, struct
> internal_lpm, lpm);
>
> - if (!lpm->v) {
> + if (internal->v == NULL) {
> /* Set tbl8 group invalid*/
> __atomic_store(&lpm->tbl8[tbl8_group_start], &zero_tbl8_entry,
> __ATOMIC_RELAXED);
> - } else if (lpm->rcu_mode == RTE_LPM_QSBR_MODE_SYNC) {
> + } else if (internal->rcu_mode == RTE_LPM_QSBR_MODE_SYNC) {
> /* Wait for quiescent state change. */
> - rte_rcu_qsbr_synchronize(lpm->v, RTE_QSBR_THRID_INVALID);
> + rte_rcu_qsbr_synchronize(internal->v,
> + RTE_QSBR_THRID_INVALID);
> /* Set tbl8 group invalid*/
> __atomic_store(&lpm->tbl8[tbl8_group_start], &zero_tbl8_entry,
> __ATOMIC_RELAXED);
> - } else if (lpm->rcu_mode == RTE_LPM_QSBR_MODE_DQ) {
> + } else if (internal->rcu_mode == RTE_LPM_QSBR_MODE_DQ) {
> /* Push into QSBR defer queue. */
> - rte_rcu_qsbr_dq_enqueue(lpm->dq, (void *)&tbl8_group_start);
> + rte_rcu_qsbr_dq_enqueue(internal->dq, (void
> *)&tbl8_group_start);
> }
> }
>
> diff --git a/lib/librte_lpm/rte_lpm.h b/lib/librte_lpm/rte_lpm.h index
> 7889f21b3..a9568fcdd 100644
> --- a/lib/librte_lpm/rte_lpm.h
> +++ b/lib/librte_lpm/rte_lpm.h
> @@ -143,12 +143,6 @@ struct rte_lpm {
> __rte_cache_aligned; /**< LPM tbl24 table. */
> struct rte_lpm_tbl_entry *tbl8; /**< LPM tbl8 table. */
> struct rte_lpm_rule *rules_tbl; /**< LPM rules. */ -#ifdef
> ALLOW_EXPERIMENTAL_API
> - /* RCU config. */
> - struct rte_rcu_qsbr *v; /* RCU QSBR variable. */
> - enum rte_lpm_qsbr_mode rcu_mode;/* Blocking, defer queue. */
> - struct rte_rcu_qsbr_dq *dq; /* RCU QSBR defer queue. */
> -#endif
> };
>
> /** LPM RCU QSBR configuration structure. */
>
>
>
>
> --
> David Marchand
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