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mempool: fix slow allocation of large pools

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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 eba11e3646 ("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: eba11e3646 ("mempool: reduce wasted space on populate")
Cc: stable@dpdk.org

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>
Reviewed-by: Andrew Rybchenko <arybchenko@solarflare.com>
Tested-by: Ali Alnubani <alialnu@mellanox.com>
This commit is contained in:
Olivier Matz 2020-01-17 10:51:49 +01:00 committed by Thomas Monjalon
parent f159c61c35
commit 3a3d0c75b4
1 changed files with 12 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
lib/librte_mempool/rte_mempool.c
View File

@ -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