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?
> + 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
>
