Re: [dpdk-dev] [PATCH v2] mem: fix cleanup when multi-process is disabled

[Ranjit Menon <ranjit.menon@intel.com>]

On 3/24/2021 12:32 PM, Dmitry Kozlyuk wrote:
> rte_eal_memory_detach() did not account for cases where multi-process
> mode is disabled: --in-memory and --no-shconf. This resulted
> in unmapping memory that had not been mapped, which caused errors:
>
>      EAL: Could not unmap memory: No error   (Windows)
>      EAL: Cannot munmap(0x1d47f40, 0x7000): Invalid argument  (Linux)
>
> Confusing "No error" was caused by using errno instead of rte_errno
> set by rte_mem_unmap().
>
> Skip detaching memory altogether when --in-memory is specified.
> Skip unmapping configuration when it's not shared.
> Fix and add error handling to produce proper log messages.
>
> Fixes: dfbc61a2f9a6 ("mem: detach memsegs on cleanup")
> Cc: Anatoly Burakov <anatoly.burakov@intel.com>
>
> Reported-by: Jie Zhou <jizh@microsoft.com>
> Suggested-by: David Marchand <david.marchand@redhat.com>
> Signed-off-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
> ---
>   lib/librte_eal/common/eal_common_memory.c | 12 ++++++++++--
>   1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/lib/librte_eal/common/eal_common_memory.c b/lib/librte_eal/common/eal_common_memory.c
> index 0e99986d3d..9495170c86 100644
> --- a/lib/librte_eal/common/eal_common_memory.c
> +++ b/lib/librte_eal/common/eal_common_memory.c
> @@ -1006,10 +1006,15 @@ rte_extmem_detach(void *va_addr, size_t len)
>   int
>   rte_eal_memory_detach(void)
>   {
> +	const struct internal_config *internal_conf =
> +		eal_get_internal_configuration();
>   	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
>   	size_t page_sz = rte_mem_page_size();
>   	unsigned int i;
>   
> +	if (internal_conf->in_memory == 1)
> +		return 0;
> +
>   	rte_rwlock_write_lock(&mcfg->memory_hotplug_lock);
>   
>   	/* detach internal memory subsystem data first */
> @@ -1032,7 +1037,7 @@ rte_eal_memory_detach(void)
>   		if (!msl->external)
>   			if (rte_mem_unmap(msl->base_va, msl->len) != 0)
>   				RTE_LOG(ERR, EAL, "Could not unmap memory: %s\n",
> -						strerror(errno));
> +						rte_strerror(rte_errno));
>   
>   		/*
>   		 * we are detaching the fbarray rather than destroying because
> @@ -1050,7 +1055,10 @@ rte_eal_memory_detach(void)
>   	 * config - we can't zero it out because it might still be referenced
>   	 * by other processes.
>   	 */
> -	rte_mem_unmap(mcfg, RTE_ALIGN(sizeof(*mcfg), page_sz));
> +	if (internal_conf->no_shconf == 0)
> +		if (rte_mem_unmap(mcfg, RTE_ALIGN(sizeof(*mcfg), page_sz)) != 0)
> +			RTE_LOG(ERR, EAL, "Could not unmap shared memory config: %s\n",
> +					rte_strerror(rte_errno));
>   	rte_eal_get_configuration()->mem_config = NULL;
>   
>   	return 0;
Acked-by: Ranjit Menon <ranjit.menon@intel.com>