[PATCH v2 5/6] test: add file-prefix for all fast-tests on Linux

[Stephen Hemminger <stephen@networkplumber.org>]

When running tests in parallel on systems with many cores, multiple test
processes collide on the default "rte" file-prefix, causing EAL
initialization failures:

  EAL: Cannot allocate memzone list: Device or resource busy
  EAL: Cannot init memzone

This occurs because all DPDK tests (including --no-huge tests) use
file-backed arrays for memzone tracking. These files are created at
/var/run/dpdk/<prefix>/fbarray_memzone and require exclusive locking
during initialization. When multiple tests run in parallel with the
same file-prefix, they compete for this lock.

The original implementation included --file-prefix for Linux to
prevent this collision. This was later removed during test
infrastructure refactoring.

Restore the --file-prefix argument for all fast-tests on Linux,
regardless of whether they use hugepages. Tests that exercise
file-prefix functionality (like eal_flags_file_prefix_autotest)
spawn child processes with their own hardcoded prefixes and use
get_current_prefix() to verify the parent's resources, so they work
correctly regardless of what prefix the parent process uses.

Fixes: 50823f30f0c8 ("test: build using per-file dependencies")
Cc: stable@dpdk.org

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Marat Khalili <marat.khalili@huawei.com>
---
 app/test/suites/meson.build | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/app/test/suites/meson.build b/app/test/suites/meson.build
index 1010150eee..4c815ea097 100644
--- a/app/test/suites/meson.build
+++ b/app/test/suites/meson.build
@@ -85,11 +85,15 @@ foreach suite:test_suites
             if nohuge
                 test_args += test_no_huge_args
             elif not has_hugepage
-                continue  #skip this tests
+                continue  # skip this test
             endif
             if not asan and get_option('b_sanitize').contains('address')
                 continue  # skip this test
             endif
+            if is_linux
+                # use unique file-prefix to allow parallel runs
+                test_args += ['--file-prefix=' + test_name.underscorify()]
+            endif
 
             if get_option('default_library') == 'shared'
                 test_args += ['-d', dpdk_drivers_build_dir]
-- 
2.51.0