Sorry for the delayed reply & thx for the suggestion~
It makes sense, I'll modify the function to sweep slowly~ (one entry at a
time)
And repost the patch,
On Wed, Nov 19, 2014 at 11:22 AM, Jarno Rajahalme <jrajaha...@nicira.com>
wrote:
>
> On Nov 14, 2014, at 4:10 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 all dead entries.
> >
> > Signed-off-by: Alex Wang <al...@nicira.com>
> > ---
> > lib/dpif-netdev.c | 14 ++++++++++++++
> > 1 file changed, 14 insertions(+)
> >
> > diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> > index 65df19b..48394b3 100644
> > --- a/lib/dpif-netdev.c
> > +++ b/lib/dpif-netdev.c
> > @@ -433,6 +433,7 @@ 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
> > @@ -462,6 +463,18 @@ emc_cache_uninit(struct emc_cache *flow_cache)
> > }
> > }
> >
> > +static void
> > +emc_cache_sweep(struct emc_cache *flow_cache)
> > +{
> > + int i;
> > +
> > + for (i = 0; i < ARRAY_SIZE(flow_cache->entries); i++) {
> > + if (!emc_entry_alive(&flow_cache->entries[i])) {
> > + emc_clear_entry(&flow_cache->entries[i]);
> > + }
> > + }
> > +}
> > +
> > static struct dpif_netdev *
> > dpif_netdev_cast(const struct dpif *dpif)
> > {
> > @@ -2332,6 +2345,7 @@ reload:
> >
> > lc = 0;
> >
> > + emc_cache_sweep(&pmd->flow_cache);
>
> This may cause some jitter, maybe it would be better to sweep only a small
> portion of the cache at each invocation instead? E.g., check one entry at a
> time. That should be enough to clean out the cache.
>
> > ovsrcu_quiesce();
> >
> > atomic_read_relaxed(&pmd->change_seq, &seq);
> > --
> > 1.7.9.5
> >
> > _______________________________________________
> > dev mailing list
> > dev@openvswitch.org
> > http://openvswitch.org/mailman/listinfo/dev
>
>
_______________________________________________
dev mailing list
dev@openvswitch.org
http://openvswitch.org/mailman/listinfo/dev
