Thx applied to master~
On Fri, Nov 21, 2014 at 7:48 AM, Jarno Rajahalme <jrajaha...@nicira.com>
wrote:
> LGTM,
>
> Acked-by: Jarno Rajahalme <jrajaha...@nicira.com>
>
> Thanks,
>
> Jarno
>
>
> > On Nov 20, 2014, at 4:37 PM, Alex Wang <al...@nicira.com> wrote:
> >
> > On current master, the exact match cache entry can keep reference to
> > 'struct dp_netdev_flow' even after the flow is removed from the flow
> > table. This means the free of allocated memory of the flow is delayed
> > until the exact match cache entry is cleared or replaced.
> >
> > If the allocated memory is ahead of chunks of freed memory on heap,
> > the delay will prevent the reclaim of those freed chunks, causing
> > falsely high memory utilization.
> >
> > To fix the issue, this commit makes the owning thread conduct periodic
> > garbage collection on the exact match cache and clear dead entries.
> >
> > Signed-off-by: Alex Wang <al...@nicira.com>
> >
> > ---
> > PATCH -> V2:
> > - Adopt Jarno's suggestion and conduct slow sweep to avoid introducing
> > jitter.
> > ---
> > lib/dpif-netdev.c | 17 +++++++++++++++++
> > 1 file changed, 17 insertions(+)
> >
> > diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> > index 65df19b..265f497 100644
> > --- a/lib/dpif-netdev.c
> > +++ b/lib/dpif-netdev.c
> > @@ -129,6 +129,7 @@ struct emc_entry {
> >
> > struct emc_cache {
> > struct emc_entry entries[EM_FLOW_HASH_ENTRIES];
> > + int sweep_idx; /* For emc_cache_slow_sweep(). */
> > };
> >
> > /* Iterate in the exact match cache through every entry that might
> contain a
> > @@ -433,6 +434,7 @@ static void dp_netdev_del_pmds_on_numa(struct
> dp_netdev *dp, int numa_id);
> > static void dp_netdev_set_pmds_on_numa(struct dp_netdev *dp, int
> numa_id);
> > static void dp_netdev_reset_pmd_threads(struct dp_netdev *dp);
> >
> > +static inline bool emc_entry_alive(struct emc_entry *ce);
> > static void emc_clear_entry(struct emc_entry *ce);
> >
> > static void
> > @@ -442,6 +444,7 @@ emc_cache_init(struct emc_cache *flow_cache)
> >
> > BUILD_ASSERT(offsetof(struct miniflow, inline_values) ==
> sizeof(uint64_t));
> >
> > + flow_cache->sweep_idx = 0;
> > for (i = 0; i < ARRAY_SIZE(flow_cache->entries); i++) {
> > flow_cache->entries[i].flow = NULL;
> > flow_cache->entries[i].key.hash = 0;
> > @@ -462,6 +465,19 @@ emc_cache_uninit(struct emc_cache *flow_cache)
> > }
> > }
> >
> > +/* Check and clear dead flow references slowly (one entry at each
> > + * invocation). */
> > +static void
> > +emc_cache_slow_sweep(struct emc_cache *flow_cache)
> > +{
> > + struct emc_entry *entry =
> &flow_cache->entries[flow_cache->sweep_idx];
> > +
> > + if (!emc_entry_alive(entry)) {
> > + emc_clear_entry(entry);
> > + }
> > + flow_cache->sweep_idx = (flow_cache->sweep_idx + 1) &
> EM_FLOW_HASH_MASK;
> > +}
> > +
> > static struct dpif_netdev *
> > dpif_netdev_cast(const struct dpif *dpif)
> > {
> > @@ -2332,6 +2348,7 @@ reload:
> >
> > lc = 0;
> >
> > + emc_cache_slow_sweep(&pmd->flow_cache);
> > ovsrcu_quiesce();
> >
> > atomic_read_relaxed(&pmd->change_seq, &seq);
> > --
> > 1.7.9.5
> >
>
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