[dpdk-dev] [PATCH v2] mem: store memory mode flags in shared config

[Anatoly Burakov]

Currently, command-line switches for legacy mem mode or single-file
segments mode are only stored in internal config. This leads to a
situation where these flags have to always match between primary
and secondary, which is bad for usability.

Fix this by storing these flags in the shared config as well, so
that secondary process can know if the primary was launched in
single-file segments or legacy mem mode.

This bumps the EAL ABI, however there's an EAL deprecation notice
already in place[1] for a different feature, so that's OK.

[1] http://patches.dpdk.org/patch/43502/

Signed-off-by: Anatoly Burakov <anatoly.burakov at intel.com>
---

Notes:
    v2:
    - Added documentation on ABI break

 doc/guides/rel_notes/rel_description.rst      |  5 +++++
 doc/guides/rel_notes/release_18_11.rst        |  6 +++++-
 .../common/include/rte_eal_memconfig.h        |  4 ++++
 lib/librte_eal/linuxapp/eal/Makefile          |  2 +-
 lib/librte_eal/linuxapp/eal/eal.c             | 20 +++++++++++++++++++
 lib/librte_eal/meson.build                    |  2 +-
 6 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/doc/guides/rel_notes/rel_description.rst b/doc/guides/rel_notes/rel_description.rst
index 8f285566f..3fd289939 100644
--- a/doc/guides/rel_notes/rel_description.rst
+++ b/doc/guides/rel_notes/rel_description.rst
@@ -10,3 +10,8 @@ release version |release| and previous releases.
 It lists new features, fixed bugs, API and ABI changes and known issues.
 
 For instructions on compiling and running the release, see the :ref:`DPDK Getting Started Guide <linux_gsg>`.
+
+* eal: new ABI version for EAL library due to adding ``legacy_mem`` and
+       ``single_file_segments`` values to ``rte_config`` structure on account of
+       improving DPDK usability when using either ``--legacy-mem`` or
+       ``--single-file-segments`` flags.
diff --git a/doc/guides/rel_notes/release_18_11.rst b/doc/guides/rel_notes/release_18_11.rst
index 3ae6b3f58..34acf01d9 100644
--- a/doc/guides/rel_notes/release_18_11.rst
+++ b/doc/guides/rel_notes/release_18_11.rst
@@ -83,6 +83,10 @@ ABI Changes
    Also, make sure to start the actual text at the margin.
    =========================================================
 
+* eal: added ``legacy_mem`` and ``single_file_segments`` values to
+       ``rte_config`` structure on account of improving DPDK usability when
+       using either ``--legacy-mem`` or ``--single-file-segments`` flags.
+
 
 Removed Items
 -------------
@@ -129,7 +133,7 @@ The libraries prepended with a plus sign were incremented in this version.
      librte_compressdev.so.1
      librte_cryptodev.so.5
      librte_distributor.so.1
-     librte_eal.so.8
+   + librte_eal.so.9
      librte_ethdev.so.10
      librte_eventdev.so.4
      librte_flow_classify.so.1
diff --git a/lib/librte_eal/common/include/rte_eal_memconfig.h b/lib/librte_eal/common/include/rte_eal_memconfig.h
index aff0688dd..62a21c2dc 100644
--- a/lib/librte_eal/common/include/rte_eal_memconfig.h
+++ b/lib/librte_eal/common/include/rte_eal_memconfig.h
@@ -77,6 +77,10 @@ struct rte_mem_config {
 	 * exact same address the primary process maps it.
 	 */
 	uint64_t mem_cfg_addr;
+
+	/* legacy mem and single file segments options are shared */
+	uint32_t legacy_mem;
+	uint32_t single_file_segments;
 } __attribute__((__packed__));
 
 
diff --git a/lib/librte_eal/linuxapp/eal/Makefile b/lib/librte_eal/linuxapp/eal/Makefile
index fd92c75c2..5c16bc40f 100644
--- a/lib/librte_eal/linuxapp/eal/Makefile
+++ b/lib/librte_eal/linuxapp/eal/Makefile
@@ -10,7 +10,7 @@ ARCH_DIR ?= $(RTE_ARCH)
 EXPORT_MAP := ../../rte_eal_version.map
 VPATH += $(RTE_SDK)/lib/librte_eal/common/arch/$(ARCH_DIR)
 
-LIBABIVER := 8
+LIBABIVER := 9
 
 VPATH += $(RTE_SDK)/lib/librte_eal/common
 
diff --git a/lib/librte_eal/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
index e59ac6577..4a55d3b69 100644
--- a/lib/librte_eal/linuxapp/eal/eal.c
+++ b/lib/librte_eal/linuxapp/eal/eal.c
@@ -352,6 +352,24 @@ eal_proc_type_detect(void)
 	return ptype;
 }
 
+/* copies data from internal config to shared config */
+static void
+eal_update_mem_config(void)
+{
+	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
+	mcfg->legacy_mem = internal_config.legacy_mem;
+	mcfg->single_file_segments = internal_config.single_file_segments;
+}
+
+/* copies data from shared config to internal config */
+static void
+eal_update_internal_config(void)
+{
+	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
+	internal_config.legacy_mem = mcfg->legacy_mem;
+	internal_config.single_file_segments = mcfg->single_file_segments;
+}
+
 /* Sets up rte_config structure with the pointer to shared memory config.*/
 static void
 rte_config_init(void)
@@ -361,11 +379,13 @@ rte_config_init(void)
 	switch (rte_config.process_type){
 	case RTE_PROC_PRIMARY:
 		rte_eal_config_create();
+		eal_update_mem_config();
 		break;
 	case RTE_PROC_SECONDARY:
 		rte_eal_config_attach();
 		rte_eal_mcfg_wait_complete(rte_config.mem_config);
 		rte_eal_config_reattach();
+		eal_update_internal_config();
 		break;
 	case RTE_PROC_AUTO:
 	case RTE_PROC_INVALID:
diff --git a/lib/librte_eal/meson.build b/lib/librte_eal/meson.build
index e1fde15d1..62ef985b9 100644
--- a/lib/librte_eal/meson.build
+++ b/lib/librte_eal/meson.build
@@ -21,7 +21,7 @@ else
 	error('unsupported system type "@0@"'.format(host_machine.system()))
 endif
 
-version = 8  # the version of the EAL API
+version = 9  # the version of the EAL API
 allow_experimental_apis = true
 deps += 'compat'
 deps += 'kvargs'
-- 
2.17.1