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nvmf/transport: Use mempool_get_bulk to feel pg cache

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When we try to evenly divide transport buffers between poll grouos,
e.g. when we run spdk_tgt on 8 cores, set num_shared_buffers=32768
and pg buf_cache_size=4096, the last pg can't retrieve enough
buffers to fill cache. In my case if only got 4040 buffers out of
4096. Missing 56 buffers were cached by previous poll groups.
That occurred due to mempool has per lcore cache of 512 elements
and when it becomes empty, the cache is refilled. It seems that
each poll group cached extra 8 buffers.
The issue doesn't occur when we use mempool_get_bulk.

Change-Id: I866d58aa03986a3cffe27402b12f9a2519097f83
Signed-off-by: Alexey Marchuk <alexeymar@mellanox.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/3881
Community-CI: Broadcom CI
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
This commit is contained in:
Alexey Marchuk 2020-08-21 10:19:27 +03:00 committed by Tomasz Zawadzki
parent b80667550f
commit 903fdb752b
1 changed files with 28 additions and 10 deletions
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38
lib/nvmf/transport.c
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@ -352,7 +352,8 @@ struct spdk_nvmf_transport_poll_group *
nvmf_transport_poll_group_create(struct spdk_nvmf_transport *transport)
{
struct spdk_nvmf_transport_poll_group *group;
struct spdk_nvmf_transport_pg_cache_buf *buf;
struct spdk_nvmf_transport_pg_cache_buf **bufs;
uint32_t i;
group = transport->ops->poll_group_create(transport);
if (!group) {
@ -364,17 +365,34 @@ nvmf_transport_poll_group_create(struct spdk_nvmf_transport *transport)
STAILQ_INIT(&group->buf_cache);
if (transport->opts.buf_cache_size) {
group->buf_cache_count = 0;
group->buf_cache_size = transport->opts.buf_cache_size;
while (group->buf_cache_count < group->buf_cache_size) {
buf = (struct spdk_nvmf_transport_pg_cache_buf *)spdk_mempool_get(transport->data_buf_pool);
if (!buf) {
SPDK_NOTICELOG("Unable to reserve the full number of buffers for the pg buffer cache.\n");
break;
}
STAILQ_INSERT_HEAD(&group->buf_cache, buf, link);
group->buf_cache_count++;
bufs = calloc(group->buf_cache_size, sizeof(struct spdk_nvmf_transport_pg_cache_buf *));
if (!bufs) {
SPDK_ERRLOG("Memory allocation failed, can't reserve buffers for the pg buffer cache\n");
return group;
}
if (spdk_mempool_get_bulk(transport->data_buf_pool, (void **)bufs, group->buf_cache_size)) {
group->buf_cache_size = (uint32_t)spdk_mempool_count(transport->data_buf_pool);
SPDK_NOTICELOG("Unable to reserve the full number of buffers for the pg buffer cache. "
"Decrease the number of cached buffers from %u to %u\n",
transport->opts.buf_cache_size, group->buf_cache_size);
/* Sanity check */
assert(group->buf_cache_size <= transport->opts.buf_cache_size);
/* Try again with less number of buffers */
if (spdk_mempool_get_bulk(transport->data_buf_pool, (void **)bufs, group->buf_cache_size)) {
SPDK_NOTICELOG("Failed to reserve %u buffers\n", group->buf_cache_size);
group->buf_cache_size = 0;
}
}
for (i = 0; i < group->buf_cache_size; i++) {
STAILQ_INSERT_HEAD(&group->buf_cache, bufs[i], link);
}
group->buf_cache_count = group->buf_cache_size;
free(bufs);
}
return group;
}