[ovs-dev] [PATCHv5] netdev-linux: Detect numa node id.

William Tu u9012063 at gmail.com
Wed Oct 23 21:08:34 UTC 2019


The patch detects the numa node id from the name of the netdev,
by reading the '/sys/class/net/<devname>/device/numa_node'.
If not available, ex: virtual device, or any error happens,
return numa id 0.  Currently only the afxdp netdev type uses it,
other linux netdev types are disabled due to no use case.

Signed-off-by: William Tu <u9012063 at gmail.com>
---
v5:
  Feedbacks from Ilya
  - reafactor the error handling
  - add mutex lock
  - Tested-at: https://travis-ci.org/williamtu/ovs-travis/builds/601947245

v4:
  Feedbacks from Eelco
  - Tested-at: https://travis-ci.org/williamtu/ovs-travis/builds/599308893

v3:
  Feedbacks from Ilya and Eelco
  - update doc, afxdp.rst
  - fix coding style
  - fix limit of numa node max, by using ovs_numa_numa_id_is_valid
  - move the function to netdev-linux
  - cache the result of numa_id
  - add security check for netdev name
  - use fscanf instead of read and convert to int
  - revise some error message content

v2:
  address feedback from Eelco
	fix memory leak of xaspintf
	log using INFO instead of WARN
---
 Documentation/intro/install/afxdp.rst |  1 -
 lib/netdev-afxdp.c                    | 11 ------
 lib/netdev-linux-private.h            |  2 ++
 lib/netdev-linux.c                    | 63 ++++++++++++++++++++++++++++++++++-
 4 files changed, 64 insertions(+), 13 deletions(-)

diff --git a/Documentation/intro/install/afxdp.rst b/Documentation/intro/install/afxdp.rst
index 820e9d993d8f..6c00c4ad1356 100644
--- a/Documentation/intro/install/afxdp.rst
+++ b/Documentation/intro/install/afxdp.rst
@@ -309,7 +309,6 @@ Below is a script using namespaces and veth peer::
 
 Limitations/Known Issues
 ------------------------
-#. Device's numa ID is always 0, need a way to find numa id from a netdev.
 #. No QoS support because AF_XDP netdev by-pass the Linux TC layer. A possible
    work-around is to use OpenFlow meter action.
 #. Most of the tests are done using i40e single port. Multiple ports and
diff --git a/lib/netdev-afxdp.c b/lib/netdev-afxdp.c
index 8eb270c150e8..cfd93fab9f45 100644
--- a/lib/netdev-afxdp.c
+++ b/lib/netdev-afxdp.c
@@ -543,17 +543,6 @@ out:
     return err;
 }
 
-int
-netdev_afxdp_get_numa_id(const struct netdev *netdev)
-{
-    /* FIXME: Get netdev's PCIe device ID, then find
-     * its NUMA node id.
-     */
-    VLOG_INFO("FIXME: Device %s always use numa id 0.",
-              netdev_get_name(netdev));
-    return 0;
-}
-
 static void
 xsk_remove_xdp_program(uint32_t ifindex, int xdpmode)
 {
diff --git a/lib/netdev-linux-private.h b/lib/netdev-linux-private.h
index a350be151147..c8f2be47b10b 100644
--- a/lib/netdev-linux-private.h
+++ b/lib/netdev-linux-private.h
@@ -96,6 +96,8 @@ struct netdev_linux {
     /* LAG information. */
     bool is_lag_master;         /* True if the netdev is a LAG master. */
 
+    int numa_id;                /* NUMA node id. */
+
 #ifdef HAVE_AF_XDP
     /* AF_XDP information. */
     struct xsk_socket_info **xsks;
diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
index f4819237370a..4dd05493b238 100644
--- a/lib/netdev-linux.c
+++ b/lib/netdev-linux.c
@@ -236,6 +236,7 @@ enum {
     VALID_VPORT_STAT_ERROR  = 1 << 5,
     VALID_DRVINFO           = 1 << 6,
     VALID_FEATURES          = 1 << 7,
+    VALID_NUMA_ID           = 1 << 8,
 };
 
 struct linux_lag_slave {
@@ -1391,6 +1392,66 @@ netdev_linux_tap_batch_send(struct netdev *netdev_,
     return 0;
 }
 
+static int
+netdev_linux_get_numa_id__(const struct netdev *netdev_)
+{
+    struct netdev_linux *netdev = netdev_linux_cast(netdev_);
+    char *numa_node_path;
+    const char *name;
+    int node_id;
+    FILE *stream;
+
+    if (netdev->cache_valid & VALID_NUMA_ID) {
+        return netdev->numa_id;
+    }
+
+    netdev->numa_id = 0;
+    netdev->cache_valid |= VALID_NUMA_ID;
+
+    name = netdev_get_name(netdev_);
+    if (strpbrk(name, "/\\")) {
+        VLOG_ERR_RL(&rl, "\"%s\" is not a valid name for a port. "
+                    "A valid name must not include '/' or '\\'."
+                    "Using numa_id 0", name);
+        return 0;
+    }
+
+    numa_node_path = xasprintf("/sys/class/net/%s/device/numa_node", name);
+
+    stream = fopen(numa_node_path, "r");
+    if (!stream) {
+        /* Virtual device does not have this info. */
+        VLOG_INFO_RL(&rl, "%s: Can't open '%s': %s, using numa_id 0",
+                     name, numa_node_path, ovs_strerror(errno));
+        free(numa_node_path);
+        return 0;
+    }
+
+    if (fscanf(stream, "%d", &node_id) != 1
+        || !ovs_numa_numa_id_is_valid(node_id))  {
+        VLOG_WARN_RL(&rl, "%s: Can't detect NUMA node, using numa_id 0", name);
+        node_id = 0;
+    }
+
+    netdev->numa_id = node_id;
+    fclose(stream);
+    free(numa_node_path);
+    return node_id;
+}
+
+static int OVS_UNUSED
+netdev_linux_get_numa_id(const struct netdev *netdev_)
+{
+    struct netdev_linux *netdev = netdev_linux_cast(netdev_);
+    int numa_id;
+
+    ovs_mutex_lock(&netdev->mutex);
+    numa_id = netdev_linux_get_numa_id__(netdev_);
+    ovs_mutex_unlock(&netdev->mutex);
+
+    return numa_id;
+}
+
 /* Sends 'batch' on 'netdev'.  Returns 0 if successful, otherwise a positive
  * errno value.  Returns EAGAIN without blocking if the packet cannot be queued
  * immediately.  Returns EMSGSIZE if a partial packet was transmitted or if
@@ -3298,7 +3359,7 @@ const struct netdev_class netdev_afxdp_class = {
     .set_config = netdev_afxdp_set_config,
     .get_config = netdev_afxdp_get_config,
     .reconfigure = netdev_afxdp_reconfigure,
-    .get_numa_id = netdev_afxdp_get_numa_id,
+    .get_numa_id = netdev_linux_get_numa_id,
     .send = netdev_afxdp_batch_send,
     .rxq_construct = netdev_afxdp_rxq_construct,
     .rxq_destruct = netdev_afxdp_rxq_destruct,
-- 
2.7.4



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