From 3a3d0c75b43e8d1670c5ea6bf85cb3e1e60dfa2b Mon Sep 17 00:00:00 2001 From: Olivier Matz Date: Fri, 17 Jan 2020 10:51:49 +0100 Subject: [PATCH] mempool: fix slow allocation of large pools When allocating a mempool which is larger than the largest available area, it can take a lot of time: a- the mempool calculate the required memory size, and tries to allocate it, it fails b- then it tries to allocate the largest available area (this does not request new huge pages) c- add this zone to the mempool, this triggers the allocation of a mem hdr, which request a new huge page d- back to a- until mempool is populated or until there is no more memory This can take a lot of time to finally fail (several minutes): in step a- it takes all available hugepages on the system, then release them after it fails. The problem appeared with commit eba11e364614 ("mempool: reduce wasted space on populate"), because smaller chunks are now allowed. Previously, it had to be at least one page size, which is not the case in step b-. To fix this, implement our own way to allocate the largest available area instead of using the feature from memzone: if an allocation fails, try to divide the size by 2 and retry. When the requested size falls below min_chunk_size, stop and return an error. Fixes: eba11e364614 ("mempool: reduce wasted space on populate") Cc: stable@dpdk.org Signed-off-by: Olivier Matz Acked-by: Anatoly Burakov Reviewed-by: Andrew Rybchenko Tested-by: Ali Alnubani --- lib/librte_mempool/rte_mempool.c | 29 ++++++++++++----------------- 1 file changed, 12 insertions(+), 17 deletions(-) diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c index f8d453d21f..aea597224a 100644 --- a/lib/librte_mempool/rte_mempool.c +++ b/lib/librte_mempool/rte_mempool.c @@ -463,6 +463,7 @@ rte_mempool_populate_default(struct rte_mempool *mp) unsigned mz_id, n; int ret; bool need_iova_contig_obj; + size_t max_alloc_size = SIZE_MAX; ret = mempool_ops_alloc_once(mp); if (ret != 0) @@ -542,30 +543,24 @@ rte_mempool_populate_default(struct rte_mempool *mp) if (min_chunk_size == (size_t)mem_size) mz_flags |= RTE_MEMZONE_IOVA_CONTIG; - mz = rte_memzone_reserve_aligned(mz_name, mem_size, + /* Allocate a memzone, retrying with a smaller area on ENOMEM */ + do { + mz = rte_memzone_reserve_aligned(mz_name, + RTE_MIN((size_t)mem_size, max_alloc_size), mp->socket_id, mz_flags, align); - /* don't try reserving with 0 size if we were asked to reserve - * IOVA-contiguous memory. - */ - if (min_chunk_size < (size_t)mem_size && mz == NULL) { - /* not enough memory, retry with the biggest zone we - * have - */ - mz = rte_memzone_reserve_aligned(mz_name, 0, - mp->socket_id, mz_flags, align); - } + if (mz == NULL && rte_errno != ENOMEM) + break; + + max_alloc_size = RTE_MIN(max_alloc_size, + (size_t)mem_size) / 2; + } while (mz == NULL && max_alloc_size >= min_chunk_size); + if (mz == NULL) { ret = -rte_errno; goto fail; } - if (mz->len < min_chunk_size) { - rte_memzone_free(mz); - ret = -ENOMEM; - goto fail; - } - if (need_iova_contig_obj) iova = mz->iova; else -- 2.20.1