Re: [dpdk-dev] [PATCH v3 2/4] eal: add function to release internal resources

["Varghese, Vipin" <vipin.varghese@intel.com>]

> -----Original Message-----
> From: Van Haaren, Harry
> Sent: Monday, January 29, 2018 5:38 PM
> To: dev@dpdk.org
> Cc: Van Haaren, Harry <harry.van.haaren@intel.com>; thomas@monjalon.net;
> Varghese, Vipin <vipin.varghese@intel.com>
> Subject: [PATCH v3 2/4] eal: add function to release internal resources
> 
> This commit adds a new function rte_eal_cleanup().
> The function serves as a hook to allow DPDK to release internal resources (e.g.:
> hugepage allocations).
> 
> This function allows DPDK to become more like an ordinary library, where the
> library context itself can be initialized and cleaned up by the application.
> 
> The rte_exit() and rte_panic() functions must be considered, particularly if they
> should call rte_eal_cleanup() to release any resources or not. This patch adds
> the cleanup to rte_exit(), but does not clean up on rte_panic(). The reason to not
> clean up on panicing is that the developer may wish to inspect the exact internal
> state of EAL and hugepages.
> 
> Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
> 
> ---
> 
> v3:
> - Rename function to cleanup (Thomas)
> 
> v2:
> - Add eal_common.c file commit (Vipin)
> 
> Cc: thomas@monjalon.net
> Cc: vipin.varghese@intel.com
> ---
>  doc/guides/prog_guide/env_abstraction_layer.rst |  8 ++++++++
>  doc/guides/rel_notes/release_18_02.rst          |  9 +++++++++
>  lib/librte_eal/bsdapp/eal/Makefile              |  1 +
>  lib/librte_eal/bsdapp/eal/eal_debug.c           |  5 +++++
>  lib/librte_eal/common/eal_common.c              | 11 +++++++++++
>  lib/librte_eal/common/include/rte_eal.h         | 16 ++++++++++++++++
>  lib/librte_eal/linuxapp/eal/Makefile            |  1 +
>  lib/librte_eal/linuxapp/eal/eal_debug.c         |  5 +++++
>  lib/librte_eal/rte_eal_version.map              |  1 +
>  9 files changed, 57 insertions(+)
>  create mode 100644 lib/librte_eal/common/eal_common.c
> 
> diff --git a/doc/guides/prog_guide/env_abstraction_layer.rst
> b/doc/guides/prog_guide/env_abstraction_layer.rst
> index 34d871c..04bd776 100644
> --- a/doc/guides/prog_guide/env_abstraction_layer.rst
> +++ b/doc/guides/prog_guide/env_abstraction_layer.rst
> @@ -99,6 +99,14 @@ It consist of calls to the pthread library (more specifically,
> pthread_self(), p
>      The creation and initialization functions for these objects are not multi-thread
> safe.
>      However, once initialized, the objects themselves can safely be used in
> multiple threads simultaneously.
> 
> +Shutdown and Cleanup
> +~~~~~~~~~~~~~~~~~~~~
> +
> +During the initialization of EAL resources such as hugepage backed
> +memory can be allocated by core components.  The memory allocated
> +during ``rte_eal_init()`` can be released by calling the
> +``rte_eal_cleanup()`` function. Refer to the API documentation for details.
> +
>  Multi-process Support
>  ~~~~~~~~~~~~~~~~~~~~~
> 
> diff --git a/doc/guides/rel_notes/release_18_02.rst
> b/doc/guides/rel_notes/release_18_02.rst
> index 00b3224..8c3968e 100644
> --- a/doc/guides/rel_notes/release_18_02.rst
> +++ b/doc/guides/rel_notes/release_18_02.rst
> @@ -41,6 +41,15 @@ New Features
>       Also, make sure to start the actual text at the margin.
>       =========================================================
> 
> +* **Add function to allow releasing internal EAL resources on exit**
> +
> +  During ``rte_eal_init()`` EAL allocates memory from hugepages to
> + enable its  core libraries to perform their tasks. The
> + ``rte_eal_cleanup()`` function  releases these resources, ensuring
> + that no hugepage memory is leaked. It is  expected that all DPDK
> + applications call ``rte_eal_cleanup()`` before  exiting. Not calling
> + this function could result in leaking hugepages, leading  to failure during
> initialization of secondary processes.
> +
>  * **Added the ixgbe ethernet driver to support RSS with flow API.**
> 
>    Rte_flow actually defined to include RSS, but till now, RSS is out of diff --git
> a/lib/librte_eal/bsdapp/eal/Makefile b/lib/librte_eal/bsdapp/eal/Makefile
> index c694076..7480f98 100644
> --- a/lib/librte_eal/bsdapp/eal/Makefile
> +++ b/lib/librte_eal/bsdapp/eal/Makefile
> @@ -34,6 +34,7 @@ SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) +=
> eal_interrupts.c
>  SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_alarm.c
> 
>  # from common dir
> +SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common.c
>  SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_lcore.c
>  SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_timer.c
>  SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_memzone.c diff --
> git a/lib/librte_eal/bsdapp/eal/eal_debug.c
> b/lib/librte_eal/bsdapp/eal/eal_debug.c
> index b0ae2b7..f66e504 100644
> --- a/lib/librte_eal/bsdapp/eal/eal_debug.c
> +++ b/lib/librte_eal/bsdapp/eal/eal_debug.c
> @@ -14,6 +14,7 @@
>  #include <rte_log.h>
>  #include <rte_debug.h>
>  #include <rte_common.h>
> +#include <rte_eal.h>
> 
>  #define BACKTRACE_SIZE 256
> 
> @@ -79,6 +80,10 @@ rte_exit(int exit_code, const char *format, ...)
>  	va_end(ap);
> 
>  #ifndef RTE_EAL_ALWAYS_PANIC_ON_ERROR
> +	int ret = rte_eal_cleanup();
> +	if (ret)
> +		RTE_LOG(CRIT, EAL,
> +			"EAL could not release all resources, code %d\n", ret);
>  	exit(exit_code);
>  #else
>  	rte_dump_stack();
> diff --git a/lib/librte_eal/common/eal_common.c
> b/lib/librte_eal/common/eal_common.c
> new file mode 100644
> index 0000000..52771e7
> --- /dev/null
> +++ b/lib/librte_eal/common/eal_common.c
> @@ -0,0 +1,11 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(c) 2018 Intel Corporation
> + */
> +
> +#include <rte_service_component.h>
> +
> +int rte_eal_cleanup(void)
> +{
> +	rte_service_finalize();
> +	return 0;
> +}
> diff --git a/lib/librte_eal/common/include/rte_eal.h
> b/lib/librte_eal/common/include/rte_eal.h
> index 2aba2c8..8b36fea 100644
> --- a/lib/librte_eal/common/include/rte_eal.h
> +++ b/lib/librte_eal/common/include/rte_eal.h
> @@ -170,6 +170,22 @@ int rte_eal_iopl_init(void);  int rte_eal_init(int argc,
> char **argv);
> 
>  /**
> + * @warning
> + * @b EXPERIMENTAL: this API may change without prior notice
> + *
> + * Clean up the Environment Abstraction Layer (EAL)
> + *
> + * This function must be called to release any internal resources that
> +EAL has
> + * allocated during rte_eal_init(). After this call, no DPDK function
> +calls may
> + * be made. It is expected that common usage of this function is to
> +call it
> + * just before terminating the process.
> + *
> + * @return 0 Successfully released all internal EAL resources
> + * @return -EFAULT There was an error in releasing all resources.
> + */
> +int rte_eal_cleanup(void);
> +
> +/**
>   * Check if a primary process is currently alive
>   *
>   * This function returns true when a primary process is currently diff --git
> a/lib/librte_eal/linuxapp/eal/Makefile b/lib/librte_eal/linuxapp/eal/Makefile
> index 7bf278f..ad20f2f 100644
> --- a/lib/librte_eal/linuxapp/eal/Makefile
> +++ b/lib/librte_eal/linuxapp/eal/Makefile
> @@ -41,6 +41,7 @@ SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) +=
> eal_interrupts.c
>  SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_alarm.c
> 
>  # from common dir
> +SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common.c
>  SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_lcore.c
>  SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_timer.c
>  SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_memzone.c diff -
> -git a/lib/librte_eal/linuxapp/eal/eal_debug.c
> b/lib/librte_eal/linuxapp/eal/eal_debug.c
> index b0ae2b7..f66e504 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_debug.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_debug.c
> @@ -14,6 +14,7 @@
>  #include <rte_log.h>
>  #include <rte_debug.h>
>  #include <rte_common.h>
> +#include <rte_eal.h>
> 
>  #define BACKTRACE_SIZE 256
> 
> @@ -79,6 +80,10 @@ rte_exit(int exit_code, const char *format, ...)
>  	va_end(ap);
> 
>  #ifndef RTE_EAL_ALWAYS_PANIC_ON_ERROR
> +	int ret = rte_eal_cleanup();
> +	if (ret)
> +		RTE_LOG(CRIT, EAL,
> +			"EAL could not release all resources, code %d\n", ret);
>  	exit(exit_code);
>  #else
>  	rte_dump_stack();
> diff --git a/lib/librte_eal/rte_eal_version.map
> b/lib/librte_eal/rte_eal_version.map
> index 1a8b1b5..8dd4abf 100644
> --- a/lib/librte_eal/rte_eal_version.map
> +++ b/lib/librte_eal/rte_eal_version.map
> @@ -215,6 +215,7 @@ EXPERIMENTAL {
>  	rte_eal_devargs_insert;
>  	rte_eal_devargs_parse;
>  	rte_eal_devargs_remove;
> +	rte_eal_cleanup;
>  	rte_eal_hotplug_add;
>  	rte_eal_hotplug_remove;
>  	rte_service_attr_get;
> --
> 2.7.4

Thanks, Checked for Linux application.

Acked-by: Vipin Varghese <vipin.varghese@intel.com>