On Mon, Mar 2, 2020 at 9:45 PM Jerin Jacob <jerinjac...@gmail.com> wrote:
>
> On Mon, Mar 2, 2020 at 7:27 AM <xiangxia.m....@gmail.com> wrote:
> >
> > From: Tonghao Zhang <xiangxia.m....@gmail.com>
> >
> > The order of mempool initiation affects mempool index in the
> > rte_mempool_ops_table. For example, when building APPs with:
> >
> > $ gcc -lrte_mempool_bucket -lrte_mempool_ring ...
> >
> > The "bucket" mempool will be registered firstly, and its index
> > in table is 0 while the index of "ring" mempool is 1. DPDK
> > uses the mk/rte.app.mk to build APPs, and others, for example,
> > Open vSwitch, use the libdpdk.a or libdpdk.so to build it.
> > The mempool lib linked in dpdk and Open vSwitch is different.
> >
> > The mempool can be used between primary and secondary process,
> > such as dpdk-pdump and pdump-pmd/Open vSwitch(pdump enabled).
> > There will be a crash because dpdk-pdump creates the "ring_mp_mc"
> > ring which index in table is 0, but the index of "bucket" ring
> > is 0 in Open vSwitch. If Open vSwitch use the index 0 to get
> > mempool ops and malloc memory from mempool. The crash will occur:
> >
> > bucket_dequeue (access null and crash)
> > rte_mempool_get_ops (should get "ring_mp_mc",
> > but get "bucket" mempool)
> > rte_mempool_ops_dequeue_bulk
> > ...
> > rte_pktmbuf_alloc
> > rte_pktmbuf_copy
> > pdump_copy
> > pdump_rx
> > rte_eth_rx_burst
> >
> > To avoid the crash, there are some solution:
> > * constructor priority: Different mempool uses different
> > priority in RTE_INIT, but it's not easy to maintain.
> >
> > * change mk/rte.app.mk: Change the order in mk/rte.app.mk to
> > be same as libdpdk.a/libdpdk.so, but when adding a new mempool
> > driver in future, we must make sure the order.
> >
> > * register mempool orderly: Sort the mempool when registering,
> > so the lib linked will not affect the index in mempool table.
> >
> > Signed-off-by: Tonghao Zhang <xiangxia.m....@gmail.com>
> > ---
> > lib/librte_mempool/rte_mempool_ops.c | 18 ++++++++++++++++--
> > 1 file changed, 16 insertions(+), 2 deletions(-)
> >
> > diff --git a/lib/librte_mempool/rte_mempool_ops.c
> > b/lib/librte_mempool/rte_mempool_ops.c
> > index 22c5251..06dfe16 100644
> > --- a/lib/librte_mempool/rte_mempool_ops.c
> > +++ b/lib/librte_mempool/rte_mempool_ops.c
> > @@ -22,7 +22,7 @@ struct rte_mempool_ops_table rte_mempool_ops_table = {
> > rte_mempool_register_ops(const struct rte_mempool_ops *h)
> > {
> > struct rte_mempool_ops *ops;
> > - int16_t ops_index;
> > + unsigned ops_index, i;
> >
> > rte_spinlock_lock(&rte_mempool_ops_table.sl);
> >
> > @@ -50,7 +50,19 @@ struct rte_mempool_ops_table rte_mempool_ops_table = {
> > return -EEXIST;
> > }
> >
> > - ops_index = rte_mempool_ops_table.num_ops++;
> > + /* sort the rte_mempool_ops by name. the order of the mempool
> > + * lib initiation will not affect rte_mempool_ops index. */
>
> +1 for the fix.
> For the implementation, why not use qsort_r() for sorting?
The implementation is easy, and the number of mempool driver is not too large.
But we can use the qsort_r to implement it.
>
> > + ops_index = rte_mempool_ops_table.num_ops;
> > + for (i = 0; i < rte_mempool_ops_table.num_ops; i++) {
> > + if (strcmp(h->name, rte_mempool_ops_table.ops[i].name) < 0)
> > {
> > + do {
> > + rte_mempool_ops_table.ops[ops_index] =
> > + rte_mempool_ops_table.ops[ops_index
> > -1];
> > + } while (--ops_index > i);
> > + break;
> > + }
> > + }
> > +
> > ops = &rte_mempool_ops_table.ops[ops_index];
> > strlcpy(ops->name, h->name, sizeof(ops->name));
> > ops->alloc = h->alloc;
> > @@ -63,6 +75,8 @@ struct rte_mempool_ops_table rte_mempool_ops_table = {
> > ops->get_info = h->get_info;
> > ops->dequeue_contig_blocks = h->dequeue_contig_blocks;
> >
> > + rte_mempool_ops_table.num_ops++;
> > +
> > rte_spinlock_unlock(&rte_mempool_ops_table.sl);
> >
> > return ops_index;
> > --
> > 1.8.3.1
> >
--
Thanks,
Tonghao
