[ovs-dev] [PATCH] netdev-afxdp: Detect numa node id.

William Tu u9012063 at gmail.com
Thu Sep 26 18:18:52 UTC 2019


On Thu, Sep 26, 2019 at 02:18:15PM +0200, Eelco Chaudron wrote:
> 
> 
> On 13 Sep 2019, at 19:15, William Tu wrote:
> 
> >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.
> 
> See comments below, but I think the main problem that should be fixed is
> allocating the memory pool on the correct numa.

good point.

> So replacing the xmalloc_pagealign() in xsk_configure() with something that
> is numa aware like numa_alloc_onnode().
> numa_alloc_onnode() will require libnuma.

OK! I will send v2 for this netdev_afxdp_get_numa_id() patch.
And a separate patch for using libnuma and numa_alloc_onnode()

>
> Also, you might need to update the “Limitations/Known Issues” section in the
> afxdp.rst file.

yes, thanks.

> 
> >Signed-off-by: William Tu <u9012063 at gmail.com>
> >---
> > lib/netdev-afxdp.c | 38 +++++++++++++++++++++++++++++++++-----
> > 1 file changed, 33 insertions(+), 5 deletions(-)
> >
> >diff --git a/lib/netdev-afxdp.c b/lib/netdev-afxdp.c
> >index e5b058d08a09..a94d77468cb7 100644
> >--- a/lib/netdev-afxdp.c
> >+++ b/lib/netdev-afxdp.c
> >@@ -552,11 +552,39 @@ out:
> > 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));
> >+    const char *numa_node_path;
> >+    long int node_id;
> >+    char buffer[4];
> >+    FILE *stream;
> >+    int n;
> >+
> >+    numa_node_path = xasprintf("/sys/class/net/%s/device/numa_node",
> >+                               netdev_get_name(netdev));
> 
> numa_node_path gets allocated by xasprintf() but it’s never free’ed.

yes, thanks!

> 
> >+    stream = fopen(numa_node_path, "r");
> >+    if (!stream) {
> >+        /* Virtual device does not have this info. */
> >+        VLOG_WARN_RL(&rl, "Open %s failed: %s, use numa_id 0",
> >+                     numa_node_path, ovs_strerror(errno));
> 
> Should this be a INFO? Nothing we can do about it for virtual interfaces.

agree, INFO is more appropriate.

William

> 
> >+        return 0;
> >+    }
> >+
> >+    n = fread(buffer, 1, sizeof buffer, stream);
> >+    if (!n) {
> >+        goto error;
> >+    }
> >+
> >+    node_id = strtol(buffer, NULL, 10);
> >+    if (node_id < 0 || node_id > 2) {
> >+        goto error;
> >+    }
> >+
> >+    fclose(stream);
> >+    return (int)node_id;
> >+
> >+error:
> >+    VLOG_WARN_RL(&rl, "Error detecting numa node of %s, use numa_id 0",
> >+                 numa_node_path);
> >+    fclose(stream);
> >     return 0;
> > }
> >
> >-- 
> >2.7.4


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