[ovs-dev] [PATCH v9 2/2] netdev-afxdp: NUMA-aware memory allocation for XSK related memory

Yi-Hung Wei yihung.wei at gmail.com
Sat Jan 4 01:13:26 UTC 2020


Currently, the AF_XDP socket (XSK) related memory are allocated by main
thread in the main thread's NUMA domain.  With the patch that detects
netdev-linux's NUMA node id, the PMD thread of AF_XDP port will be run on
the AF_XDP netdev's NUMA domain.  If the net device's NUMA domain
is different from the main thread's NUMA domain, we will have two
cross-NUMA memory accesses (netdev <-> memory, memory <-> CPU).

This patch addresses the aforementioned issue by allocating
the memory in the net device's NUMA domain.

Signed-off-by: Yi-Hung Wei <yihung.wei at gmail.com>
---
v9:
  - Addreess review comments from Ilya in patch 2.
    * Add check on numa_available()
    * Properly restore memory policy with get/set_mempolicy.

v8:
  - Addreess review comments from Eelco and Ilya in patch 2.
    * Use OVS_FIND_DEPENDENCY().
    * Avoid the locking issue when calling netdev_get_numa_id().
    * Check NETDEV_NUMA_UNSPEC.
    * Use return value from netdev_get_numa_id() directly, and
      check NETDEV_NUMA_UNSPEC case.
    * Use numa_set_preferred().

---
 Documentation/intro/install/afxdp.rst |  2 +-
 acinclude.m4                          |  2 ++
 include/sparse/automake.mk            |  1 +
 include/sparse/numa.h                 | 27 +++++++++++++++++++++++++++
 lib/netdev-afxdp.c                    | 26 ++++++++++++++++++++++++++
 5 files changed, 57 insertions(+), 1 deletion(-)
 create mode 100644 include/sparse/numa.h

diff --git a/Documentation/intro/install/afxdp.rst b/Documentation/intro/install/afxdp.rst
index 7b0736c96114..c4685fa7ebac 100644
--- a/Documentation/intro/install/afxdp.rst
+++ b/Documentation/intro/install/afxdp.rst
@@ -164,7 +164,7 @@ If a test case fails, check the log at::
 
 Setup AF_XDP netdev
 -------------------
-Before running OVS with AF_XDP, make sure the libbpf and libelf are
+Before running OVS with AF_XDP, make sure the libbpf, libelf, and libnuma are
 set-up right::
 
   ldd vswitchd/ovs-vswitchd
diff --git a/acinclude.m4 b/acinclude.m4
index 542637ac8cb8..f73dc9bf7e3c 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -286,6 +286,8 @@ AC_DEFUN([OVS_CHECK_LINUX_AF_XDP], [
     AC_CHECK_FUNCS([pthread_spin_lock], [],
       [AC_MSG_ERROR([unable to find pthread_spin_lock for AF_XDP support])])
 
+    OVS_FIND_DEPENDENCY([numa_alloc_onnode], [numa], [libnuma])
+
     AC_DEFINE([HAVE_AF_XDP], [1],
               [Define to 1 if AF_XDP support is available and enabled.])
     LIBBPF_LDADD=" -lbpf -lelf"
diff --git a/include/sparse/automake.mk b/include/sparse/automake.mk
index 073631e8c082..974ad3fe55f7 100644
--- a/include/sparse/automake.mk
+++ b/include/sparse/automake.mk
@@ -5,6 +5,7 @@ noinst_HEADERS += \
         include/sparse/bits/floatn.h \
         include/sparse/assert.h \
         include/sparse/math.h \
+        include/sparse/numa.h \
         include/sparse/netinet/in.h \
         include/sparse/netinet/ip6.h \
         include/sparse/netpacket/packet.h \
diff --git a/include/sparse/numa.h b/include/sparse/numa.h
new file mode 100644
index 000000000000..3691a0eaf729
--- /dev/null
+++ b/include/sparse/numa.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2019 Nicira, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __CHECKER__
+#error "Use this header only with sparse.  It is not a correct implementation."
+#endif
+
+/* Avoid sparse warning: non-ANSI function declaration of function" */
+#define numa_get_membind_compat() numa_get_membind_compat(void)
+#define numa_get_interleave_mask_compat() numa_get_interleave_mask_compat(void)
+#define numa_get_run_node_mask_compat() numa_get_run_node_mask_compat(void)
+
+/* Get actual <numa.h> definitions for us to annotate and build on. */
+#include_next<numa.h>
diff --git a/lib/netdev-afxdp.c b/lib/netdev-afxdp.c
index 426dce944977..fad0aab9d550 100644
--- a/lib/netdev-afxdp.c
+++ b/lib/netdev-afxdp.c
@@ -26,6 +26,8 @@
 #include <linux/rtnetlink.h>
 #include <linux/if_xdp.h>
 #include <net/if.h>
+#include <numa.h>
+#include <numaif.h>
 #include <poll.h>
 #include <stdlib.h>
 #include <sys/resource.h>
@@ -669,6 +671,24 @@ netdev_afxdp_reconfigure(struct netdev *netdev)
     struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
     int err = 0;
 
+    /* Allocate all the xsk related memory in the netdev's NUMA domain. */
+    struct bitmask *old_bm = NULL;
+    int old_policy, numa_id;
+    if (numa_available() != -1) {
+        numa_id = netdev_get_numa_id(netdev);
+        if (numa_id != NETDEV_NUMA_UNSPEC) {
+            old_bm = numa_allocate_nodemask();
+            if (get_mempolicy(&old_policy, old_bm->maskp, old_bm->size + 1,
+                              NULL, 0)) {
+                VLOG_INFO("Failed to get NUMA memory policy.");
+                numa_bitmask_free(old_bm);
+                old_bm = NULL;
+            } else {
+                numa_set_preferred(numa_id);
+            }
+        }
+    }
+
     ovs_mutex_lock(&dev->mutex);
 
     if (netdev->n_rxq == dev->requested_n_rxq
@@ -700,6 +720,12 @@ netdev_afxdp_reconfigure(struct netdev *netdev)
     netdev_change_seq_changed(netdev);
 out:
     ovs_mutex_unlock(&dev->mutex);
+    if (old_bm) {
+        if (set_mempolicy(old_policy, old_bm->maskp, old_bm->size + 1)) {
+            VLOG_WARN("Failed to restore NUMA memory policy.");
+        }
+        numa_bitmask_free(old_bm);
+    }
     return err;
 }
 
-- 
2.17.1



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