[ovs-dev] [PATCH 1/2] dpif-netdev: Purge all ukeys when reconfigure pmd.
Ilya Maximets
i.maximets at samsung.com
Wed Aug 12 08:10:11 UTC 2015
Ok, but why don't just put dp->dp_purge_cb(dp->dp_purge_aux) right after
dp_netdev_destroy_all_pmds(dp) in dpif_netdev_pmd_set() ? In that case,
disabling of upcalls will not be necessary.
P.S. The second letter of my name is 'L'.
On 11.08.2015 21:06, Alex Wang wrote:
> Thx, IIya for the review, please see my reply below,
>
>
>
> On Tue, Aug 11, 2015 at 4:41 AM, Ilya Maximets <i.maximets at samsung.com <mailto:i.maximets at samsung.com>> wrote:
>
> On 11.08.2015 05:47, Alex Wang 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 <mailto:i.maximets at samsung.com>>
> > Signed-off-by: Alex Wang <alexw at nicira.com <mailto: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);
> > }
>
> It is better to enable upcalls before restoring PMD threads to prevent dropping of packets.
>
>
>
> Sorry, the comments are misleading, the "dp_netdev_reset_pmd_threads()"
> is for recreating all pmd threads (not exactly restoring). If we move the
> "dp_netdev_enable_upcall()" before the function, then upcall will be enabled
> before destroying all existing pmd threads, and we will have the same issue
> again (the existing pmd threads will try installing flows/creating ukeys before
> getting destroyed).
>
> Also, since recreating pmd threads is considered a major configuration
> change and is disruptive, I think it should be okay to resume upcall handling
> right after all new pmd threads are created.
>
>
> >
> > 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
>
> double 'if' here too.
>
>
> Thx, fixed it,
>
>
>
> > + * 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)
> >
>
> Best regards, Ilya Maximets.
>
>
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