Hi Sean,
There was a request by teams in Oracle to decouple the HCA limited
ability to open device context and the rising amount of processes that
run on the servers.
It appear that the lowest capable HCA become the limit to all the
processes that attempt to use the library.
This patch try to decouple this by allowing the process to use the
library w/o implicitly opening the device.
Device will be opened only when needed.
BR, Shamir
>From 4e2d1aafce5d1770e81a8e0f822876aa99f58331 Mon Sep 17 00:00:00 2001
From: Shamir Rabinovitch <[email protected]>
Date: Mon, 24 Mar 2014 16:27:10 +0200
Subject: [PATCH] librdmacm: lazy initialization for ib devices
LIBRDMACM currently opens a device context per configured HCA. This is
usually done in rdma_create_event_channel() or first time whenever
ucma_init() is called. If a process is only going to use one of the
configured HCAs/RDMA IPs then the remaining device contexts are not
used/required. Opening a device context on each device apriori limits the
maximum number of processes that can be supported on a node to the maximum
number of open context supported per HCA regardless of number of HCAs present
in the system.
Signed-off-by: Shamir Rabinovitch <[email protected]>
---
src/cma.c | 152 ++++++++++++++++++++++++++++++++++++++++++++++++--------------
1 file changed, 118 insertions(+), 34 deletions(-)
diff --git a/src/cma.c b/src/cma.c
index 0cf4203..56bfa14 100644
--- a/src/cma.c
+++ b/src/cma.c
@@ -74,7 +74,7 @@ do { \
} while (0)
struct cma_device {
- struct ibv_context *verbs;
+ struct ibv_context *lverbs; /* Lazy initialization */
struct ibv_pd *pd;
uint64_t guid;
int port_cnt;
@@ -130,13 +130,20 @@ static fastlock_t idm_lock;
static void ucma_cleanup(void)
{
+ struct ibv_context *verbs;
+ struct ibv_pd *pd;
+
ucma_ib_cleanup();
if (cma_dev_cnt) {
while (cma_dev_cnt--) {
- if (cma_dev_array[cma_dev_cnt].refcnt)
- ibv_dealloc_pd(cma_dev_array[cma_dev_cnt].pd);
- ibv_close_device(cma_dev_array[cma_dev_cnt].verbs);
+ verbs = cma_dev_array[cma_dev_cnt].lverbs;
+ if (verbs) {
+ pd = cma_dev_array[cma_dev_cnt].pd;
+ if (cma_dev_array[cma_dev_cnt].refcnt)
+ ibv_dealloc_pd(pd);
+ ibv_close_device(verbs);
+ }
}
fastlock_destroy(&idm_lock);
@@ -202,11 +209,77 @@ static void ucma_set_af_ib_support(void)
rdma_destroy_id(id);
}
-int ucma_init(void)
+static int ucma_lazy_dev_init(int dev_index)
{
struct ibv_device **dev_list = NULL;
struct cma_device *cma_dev;
struct ibv_device_attr attr;
+ int ret = 0, i = dev_index, dev_cnt;
+
+ /* Quick check without lock to see if we're already initialized */
+ if (cma_dev_array[i].lverbs)
+ return 0;
+
+ pthread_mutex_lock(&mut);
+ if (cma_dev_array[i].lverbs) {
+ pthread_mutex_unlock(&mut);
+ return 0;
+ }
+
+ dev_list = ibv_get_device_list(&dev_cnt);
+ if (!dev_list) {
+ fprintf(stderr, PFX "Fatal: unable to get RDMA device list\n");
+ ret = ERR(ENODEV);
+ goto err1;
+ }
+
+ if (min(dev_cnt, cma_dev_cnt) <= i) {
+ fprintf(stderr, PFX
+ "Fatal: device index out of range, index %d, max %d\n",
+ i, min(dev_cnt, cma_dev_cnt));
+ ret = ERR(ENODEV);
+ goto err2;
+ }
+
+ cma_dev = &cma_dev_array[i];
+ cma_dev->lverbs = ibv_open_device(dev_list[i]);
+ if (!cma_dev->lverbs) {
+ fprintf(stderr, PFX "Fatal: unable to open RDMA device\n");
+ ret = ERR(ENODEV);
+ goto err2;
+ }
+
+ ret = ibv_query_device(cma_dev->lverbs, &attr);
+ if (ret) {
+ fprintf(stderr, PFX "Fatal: unable to query RDMA device\n");
+ ret = ERR(ret);
+ goto err3;
+ }
+
+ cma_dev->port_cnt = attr.phys_port_cnt;
+ cma_dev->max_qpsize = attr.max_qp_wr;
+ cma_dev->max_initiator_depth = (uint8_t) attr.max_qp_init_rd_atom;
+ cma_dev->max_responder_resources = (uint8_t) attr.max_qp_rd_atom;
+
+ pthread_mutex_unlock(&mut);
+ ibv_free_device_list(dev_list);
+ return 0;
+
+err3:
+ ibv_close_device(cma_dev->lverbs);
+ cma_dev->lverbs = NULL;
+err2:
+ ibv_free_device_list(dev_list);
+err1:
+ pthread_mutex_unlock(&mut);
+ return ret;
+}
+
+
+int ucma_init(void)
+{
+ struct ibv_device **dev_list = NULL;
+ struct cma_device *cma_dev;
int i, ret, dev_cnt;
/* Quick check without lock to see if we're already initialized */
@@ -243,29 +316,10 @@ int ucma_init(void)
goto err2;
}
- for (i = 0; dev_list[i];) {
+ for (i = 0; dev_list[i]; i++) {
cma_dev = &cma_dev_array[i];
-
cma_dev->guid = ibv_get_device_guid(dev_list[i]);
- cma_dev->verbs = ibv_open_device(dev_list[i]);
- if (!cma_dev->verbs) {
- fprintf(stderr, PFX "Fatal: unable to open RDMA device\n");
- ret = ERR(ENODEV);
- goto err3;
- }
-
- i++;
- ret = ibv_query_device(cma_dev->verbs, &attr);
- if (ret) {
- fprintf(stderr, PFX "Fatal: unable to query RDMA device\n");
- ret = ERR(ret);
- goto err3;
- }
-
- cma_dev->port_cnt = attr.phys_port_cnt;
- cma_dev->max_qpsize = attr.max_qp_wr;
- cma_dev->max_initiator_depth = (uint8_t) attr.max_qp_init_rd_atom;
- cma_dev->max_responder_resources = (uint8_t) attr.max_qp_rd_atom;
+ /* Open device only when needed... */
}
cma_dev_cnt = dev_cnt;
@@ -274,10 +328,6 @@ int ucma_init(void)
ibv_free_device_list(dev_list);
return 0;
-err3:
- while (i--)
- ibv_close_device(cma_dev_array[i].verbs);
- free(cma_dev_array);
err2:
ibv_free_device_list(dev_list);
err1:
@@ -286,6 +336,31 @@ err1:
return ret;
}
+static struct ibv_context *ucma_get_verbs_index(int dev_index)
+{
+ int ret;
+
+ ret = ucma_lazy_dev_init(dev_index);
+ assert(!ret);
+
+ if (ret)
+ return NULL;
+
+ return cma_dev_array[dev_index].lverbs;
+}
+
+static struct ibv_context *ucma_get_verbs_guid(uint64_t guid)
+{
+ int i;
+
+ for (i = 0; i < cma_dev_cnt; i++) {
+ if (cma_dev_array[i].guid == guid)
+ return ucma_get_verbs_index(i);
+ }
+
+ return NULL;
+}
+
struct ibv_context **rdma_get_devices(int *num_devices)
{
struct ibv_context **devs = NULL;
@@ -299,7 +374,7 @@ struct ibv_context **rdma_get_devices(int *num_devices)
goto out;
for (i = 0; i < cma_dev_cnt; i++)
- devs[i] = cma_dev_array[i].verbs;
+ devs[i] = ucma_get_verbs_index(i);
devs[i] = NULL;
out:
if (num_devices)
@@ -348,6 +423,7 @@ void rdma_destroy_event_channel(struct rdma_event_channel *channel)
static int ucma_get_device(struct cma_id_private *id_priv, uint64_t guid)
{
struct cma_device *cma_dev;
+ struct ibv_context *verbs;
int i, ret = 0;
for (i = 0; i < cma_dev_cnt; i++) {
@@ -358,9 +434,12 @@ static int ucma_get_device(struct cma_id_private *id_priv, uint64_t guid)
return ERR(ENODEV);
match:
+ verbs = ucma_get_verbs_index(i);
+ if (!verbs)
+ return ERR(ENODEV);
pthread_mutex_lock(&mut);
if (!cma_dev->refcnt++) {
- cma_dev->pd = ibv_alloc_pd(cma_dev_array[i].verbs);
+ cma_dev->pd = ibv_alloc_pd(verbs);
if (!cma_dev->pd) {
cma_dev->refcnt--;
ret = ERR(ENOMEM);
@@ -368,7 +447,7 @@ match:
}
}
id_priv->cma_dev = cma_dev;
- id_priv->id.verbs = cma_dev->verbs;
+ id_priv->id.verbs = verbs;
id_priv->id.pd = cma_dev->pd;
out:
pthread_mutex_unlock(&mut);
@@ -1022,11 +1101,16 @@ static int ucma_modify_qp_err(struct rdma_cm_id *id)
static int ucma_find_pkey(struct cma_device *cma_dev, uint8_t port_num,
uint16_t pkey, uint16_t *pkey_index)
{
+ struct ibv_context *verbs;
int ret, i;
uint16_t chk_pkey;
+ verbs = ucma_get_verbs_guid(cma_dev->guid);
+ if (!verbs)
+ return ERR(ENODEV);
+
for (i = 0, ret = 0; !ret; i++) {
- ret = ibv_query_pkey(cma_dev->verbs, port_num, i, &chk_pkey);
+ ret = ibv_query_pkey(verbs, port_num, i, &chk_pkey);
if (!ret && pkey == chk_pkey) {
*pkey_index = (uint16_t) i;
return 0;
--
1.8.1.2
