[ovs-dev] [PATCH 1/2] dpif-netdev: Purge all ukeys when reconfigure pmd.

Alex Wang alexw at nicira.com
Mon Aug 17 17:35:08 UTC 2015


On Mon, Aug 17, 2015 at 10:22 AM, Daniele Di Proietto <
diproiettod at vmware.com> wrote:

> The patch looks good to me.
>
> I think that losing some packets when the thread are reconfigured
> is unavoidable, considering that often the NIC must be stopped
> to change the number of rxqs.  Does this make sense?
>
>
Thx, Daniele,

Ilya, if you are also okay, I'll push this to master.



> Related to this, I've had an offline discussion with Ethan
> and we realized that ukeys are never deleted if the datapath
> flow disappear for other reasons (e.g. ovs-dpctl del-flows).
> Should we address these issues toghether?
>
>
For this issue, to be more specific, the ukeys are never deleted if:
1. datapath flow disappears,
2. && there is no userspace changes which causes increments of reval_seq.

In other words, once 'need_revalidate' is true, the obsolete ukeys should be
deleted at revaidator_sweep() stage.  Right?

This sounds to me like a different issue and may require more thinking, so
I'd
like to keep it a separate issue,

Thanks,
Alex Wang,


> Thanks
>
> On 11/08/2015 03:47, "Alex Wang" <alexw at nicira.com> wrote:
>
> >When dpdk configuration changes, all pmd threads are recreated
> >and rx queues of each port are reloaded.  After this process,
> >rx queue could be mapped to a different pmd thread other than
> >the one before reconfiguration.  However, this is totally
> >transparent to ofproto layer modules.  So, if the ofproto-dpif-upcall
> >module still holds ukeys generated before pmd thread recreation,
> >this old ukey will collide with the ukey for the new upcalls
> >from same traffic flow, causing flow installation failure.
> >
> >To fix the bug, this commit adds a new call-back function
> >in dpif layer for notifying upper layer the purging of datapath
> >(e.g. pmd threads recreation in dpif-netdev).  So, the
> >ofproto-dpif-upcall module can react properly with deleting
> >all the ukeys and with collecting all flows' last stats.
> >
> >Reported-by: Ilya Maximets <i.maximets at samsung.com>
> >Signed-off-by: Alex Wang <alexw at nicira.com>
> >---
> > lib/dpif-netdev.c             |   25 +++++++++++++++++++++++++
> > lib/dpif-netlink.c            |    1 +
> > lib/dpif-provider.h           |   11 ++++++++++-
> > lib/dpif.c                    |    8 ++++++++
> > lib/dpif.h                    |   12 ++++++++++++
> > ofproto/ofproto-dpif-upcall.c |   16 ++++++++++++++++
> > 6 files changed, 72 insertions(+), 1 deletion(-)
> >
> >diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> >index c144352..a54853f 100644
> >--- a/lib/dpif-netdev.c
> >+++ b/lib/dpif-netdev.c
> >@@ -203,6 +203,11 @@ struct dp_netdev {
> >     upcall_callback *upcall_cb;  /* Callback function for executing
> >upcalls. */
> >     void *upcall_aux;
> >
> >+    /* Callback function for notifying the purging of dp flows (during
> >+     * reseting pmd threads). */
> >+    dp_purge_callback *dp_purge_cb;
> >+    void *dp_purge_aux;
> >+
> >     /* Stores all 'struct dp_netdev_pmd_thread's. */
> >     struct cmap poll_threads;
> >
> >@@ -223,6 +228,8 @@ struct dp_netdev {
> >
> > static struct dp_netdev_port *dp_netdev_lookup_port(const struct
> >dp_netdev *dp,
> >                                                     odp_port_t);
> >+static void dp_netdev_disable_upcall(struct dp_netdev *);
> >+static void dp_netdev_enable_upcall(struct dp_netdev *);
> >
> > enum dp_stat_type {
> >     DP_STAT_EXACT_HIT,          /* Packets that had an exact match
> >(emc). */
> >@@ -2440,10 +2447,18 @@ dpif_netdev_pmd_set(struct dpif *dpif, unsigned
> >int n_rxqs, const char *cmask)
> >         free(dp->pmd_cmask);
> >         dp->pmd_cmask = cmask ? xstrdup(cmask) : NULL;
> >
> >+        /* Disables upcall and notifies higher layer about the incoming
> >+         * datapath purging. */
> >+        dp_netdev_disable_upcall(dp);
> >+        dp->dp_purge_cb(dp->dp_purge_aux);
> >+
> >         /* Restores the non-pmd. */
> >         dp_netdev_set_nonpmd(dp);
> >         /* Restores all pmd threads. */
> >         dp_netdev_reset_pmd_threads(dp);
> >+
> >+        /* Enables upcall after pmd reconfiguration. */
> >+        dp_netdev_enable_upcall(dp);
> >     }
> >
> >     return 0;
> >@@ -3419,6 +3434,15 @@ struct dp_netdev_execute_aux {
> > };
> >
> > static void
> >+dpif_netdev_register_dp_purge_cb(struct dpif *dpif, dp_purge_callback
> >*cb,
> >+                                 void *aux)
> >+{
> >+    struct dp_netdev *dp = get_dp_netdev(dpif);
> >+    dp->dp_purge_aux = aux;
> >+    dp->dp_purge_cb = cb;
> >+}
> >+
> >+static void
> > dpif_netdev_register_upcall_cb(struct dpif *dpif, upcall_callback *cb,
> >                                void *aux)
> > {
> >@@ -3665,6 +3689,7 @@ const struct dpif_class dpif_netdev_class = {
> >     NULL,                       /* recv */
> >     NULL,                       /* recv_wait */
> >     NULL,                       /* recv_purge */
> >+    dpif_netdev_register_dp_purge_cb,
> >     dpif_netdev_register_upcall_cb,
> >     dpif_netdev_enable_upcall,
> >     dpif_netdev_disable_upcall,
> >diff --git a/lib/dpif-netlink.c b/lib/dpif-netlink.c
> >index 8884a9f..f8f3092 100644
> >--- a/lib/dpif-netlink.c
> >+++ b/lib/dpif-netlink.c
> >@@ -2314,6 +2314,7 @@ const struct dpif_class dpif_netlink_class = {
> >     dpif_netlink_recv,
> >     dpif_netlink_recv_wait,
> >     dpif_netlink_recv_purge,
> >+    NULL,                       /* register_dp_purge_cb */
> >     NULL,                       /* register_upcall_cb */
> >     NULL,                       /* enable_upcall */
> >     NULL,                       /* disable_upcall */
> >diff --git a/lib/dpif-provider.h b/lib/dpif-provider.h
> >index 28ea86f..8f2690f 100644
> >--- a/lib/dpif-provider.h
> >+++ b/lib/dpif-provider.h
> >@@ -361,13 +361,22 @@ struct dpif_class {
> >      * return. */
> >     void (*recv_purge)(struct dpif *dpif);
> >
> >+    /* When 'dpif' is about to purge the datapath, the higher layer may
> >want
> >+     * to be notified so that it could try reacting accordingly (e.g.
> >grabbing
> >+     * all flow stats before they are gone).
> >+     *
> >+     * Registers an upcall callback function with 'dpif'.  This is only
> >used if
> >+     * if 'dpif' needs to notify the purging of datapath.  'aux' is
> >passed to
> >+     * the callback on invocation. */
> >+    void (*register_dp_purge_cb)(struct dpif *, dp_purge_callback *,
> >void *aux);
> >+
> >     /* For datapaths that run in userspace (i.e. dpif-netdev), threads
> >polling
> >      * for incoming packets can directly call upcall functions instead of
> >      * offloading packet processing to separate handler threads.
> >Datapaths
> >      * that directly call upcall functions should use the functions
> >below to
> >      * to register an upcall function and enable / disable upcalls.
> >      *
> >-     * Registers an upcall callback function with 'dpif'. This is only
> >used if
> >+     * Registers an upcall callback function with 'dpif'. This is only
> >used
> >      * if 'dpif' directly executes upcall functions. 'aux' is passed to
> >the
> >      * callback on invocation. */
> >     void (*register_upcall_cb)(struct dpif *, upcall_callback *, void
> >*aux);
> >diff --git a/lib/dpif.c b/lib/dpif.c
> >index 6e26f30..9a67a24 100644
> >--- a/lib/dpif.c
> >+++ b/lib/dpif.c
> >@@ -1346,6 +1346,14 @@ dpif_handlers_set(struct dpif *dpif, uint32_t
> >n_handlers)
> > }
> >
> > void
> >+dpif_register_dp_purge_cb(struct dpif *dpif, dp_purge_callback *cb, void
> >*aux)
> >+{
> >+    if (dpif->dpif_class->register_dp_purge_cb) {
> >+        dpif->dpif_class->register_dp_purge_cb(dpif, cb, aux);
> >+    }
> >+}
> >+
> >+void
> > dpif_register_upcall_cb(struct dpif *dpif, upcall_callback *cb, void
> >*aux)
> > {
> >     if (dpif->dpif_class->register_upcall_cb) {
> >diff --git a/lib/dpif.h b/lib/dpif.h
> >index ea9caf8..dca5d00 100644
> >--- a/lib/dpif.h
> >+++ b/lib/dpif.h
> >@@ -787,6 +787,18 @@ struct dpif_upcall {
> >     struct nlattr *actions;    /* Argument to OVS_ACTION_ATTR_USERSPACE.
> >*/
> > };
> >
> >+/* A callback to notify higher layer of dpif about to be purged, so that
> >+ * higher layer could try reacting to this (e.g. grabbing all flow stats
> >+ * before they are gone).  This function is currently implemented only by
> >+ * dpif-netdev.
> >+ *
> >+ * The caller only needs to provide the 'aux' pointer passed down by
> >higher
> >+ * layer from the dpif_register_notify_cb() function.
> >+ */
> >+typedef void dp_purge_callback(void *aux);
> >+
> >+void dpif_register_dp_purge_cb(struct dpif *, dp_purge_callback *, void
> >*aux);
> >+
> > /* A callback to process an upcall, currently implemented only by
> >dpif-netdev.
> >  *
> >  * The caller provides the 'packet' and 'flow' to process, the
> >corresponding
> >diff --git a/ofproto/ofproto-dpif-upcall.c b/ofproto/ofproto-dpif-upcall.c
> >index 0f2e186..6385abc 100644
> >--- a/ofproto/ofproto-dpif-upcall.c
> >+++ b/ofproto/ofproto-dpif-upcall.c
> >@@ -306,6 +306,7 @@ static int upcall_receive(struct upcall *, const
> >struct dpif_backer *,
> > static void upcall_uninit(struct upcall *);
> >
> > static upcall_callback upcall_cb;
> >+static dp_purge_callback dp_purge_cb;
> >
> > static atomic_bool enable_megaflows = ATOMIC_VAR_INIT(true);
> > static atomic_bool enable_ufid = ATOMIC_VAR_INIT(true);
> >@@ -358,6 +359,7 @@ udpif_create(struct dpif_backer *backer, struct dpif
> >*dpif)
> >     }
> >
> >     dpif_register_upcall_cb(dpif, upcall_cb, udpif);
> >+    dpif_register_dp_purge_cb(dpif, dp_purge_cb, udpif);
> >
> >     return udpif;
> > }
> >@@ -1110,6 +1112,20 @@ out:
> >     return error;
> > }
> >
> >+/* In reaction to dpif purge, purges all 'ukey's. */
> >+static void
> >+dp_purge_cb(void *aux)
> >+{
> >+    struct udpif *udpif = aux;
> >+    size_t i;
> >+
> >+    for (i = 0; i < udpif->n_revalidators; i++) {
> >+        struct revalidator *revalidator = &udpif->revalidators[i];
> >+
> >+        revalidator_purge(revalidator);
> >+    }
> >+}
> >+
> > static int
> > process_upcall(struct udpif *udpif, struct upcall *upcall,
> >                struct ofpbuf *odp_actions, struct flow_wildcards *wc)
> >--
> >1.7.9.5
> >
>
>



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