Re: [PATCH] fib: implement RCU rule reclamation

[David Marchand <david.marchand@redhat.com>]

On Fri, Sep 27, 2024 at 6:13 PM Robin Jarry <rjarry@redhat.com> wrote:
>
> Vladimir Medvedkin, Sep 06, 2024 at 13:09:
> > Currently, for DIR24-8 algorithm, the tbl8 group is freed even though the
> > readers might be using the tbl8 group entries. The freed tbl8 group can
> > be reallocated quickly. As a result, lookup may be performed incorrectly.
> >
> > To address that, RCU QSBR is integrated for safe tbl8 group reclamation.
> >
> > Signed-off-by: Vladimir Medvedkin <vladimir.medvedkin@intel.com>
> > ---
>
> > diff --git a/lib/fib/meson.build b/lib/fib/meson.build
> > index 6795f41a0a..1895f37050 100644
> > --- a/lib/fib/meson.build
> > +++ b/lib/fib/meson.build
> > @@ -11,6 +11,7 @@ endif
> >  sources = files('rte_fib.c', 'rte_fib6.c', 'dir24_8.c', 'trie.c')
> >  headers = files('rte_fib.h', 'rte_fib6.h')
> >  deps += ['rib']
> > +deps += ['rcu']
>
> Hi Vladimir,
>
> thanks a lot for working on this!
>
> I tested with static linking and there is a missing dependency to
> static_rte_rcu:
>
> In file included from ../subprojects/dpdk/lib/fib/dir24_8_avx512.c:6:
> ../subprojects/dpdk/lib/fib/rte_fib.h:19:10: fatal error: rte_rcu_qsbr.h: No such file or directory
>    19 | #include <rte_rcu_qsbr.h>
>       |          ^~~~~~~~~~~~~~~~
>
> After adding it:
>
> @@ -45,7 +45,7 @@ if dpdk_conf.has('RTE_ARCH_X86_64') and binutils_ok
>      elif cc.has_multi_arguments('-mavx512f', '-mavx512dq')
>          dir24_8_avx512_tmp = static_library('dir24_8_avx512_tmp',
>                  'dir24_8_avx512.c',
> -                dependencies: static_rte_eal,
> +                dependencies: [static_rte_eal, static_rte_rcu],
>                  c_args: cflags + ['-mavx512f', '-mavx512dq'])
>          objs += dir24_8_avx512_tmp.extract_objects('dir24_8_avx512.c')
>          cflags += ['-DCC_DIR24_8_AVX512_SUPPORT']
>
> I get another error:
>
> In file included from /usr/lib/gcc/x86_64-redhat-linux/14/include/immintrin.h:65,
>                  from /usr/lib/gcc/x86_64-redhat-linux/14/include/x86intrin.h:32,
>                  from ../subprojects/dpdk/lib/eal/x86/include/rte_vect.h:26,
>                  from ../subprojects/dpdk/lib/fib/dir24_8_avx512.c:5:
> /usr/lib/gcc/x86_64-redhat-linux/14/include/avx512bwintrin.h: In function ‘dir24_8_vec_lookup_x16’:
> /usr/lib/gcc/x86_64-redhat-linux/14/include/avx512bwintrin.h:1947:1: error: inlining failed in call to ‘always_inline’ ‘_mm512_shuffle_epi8’: target specific option mismatch
>  1947 | _mm512_shuffle_epi8 (__m512i __A, __m512i __B)
>       | ^~~~~~~~~~~~~~~~~~~
> ../subprojects/dpdk/lib/fib/dir24_8_avx512.c:38:26: note: called from here
>    38 |                 ip_vec = _mm512_shuffle_epi8(ip_vec, bswap32);
>       |                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> /usr/lib/gcc/x86_64-redhat-linux/14/include/avx512bwintrin.h:1947:1: error: inlining failed in call to ‘always_inline’ ‘_mm512_shuffle_epi8’: target specific option mismatch
>  1947 | _mm512_shuffle_epi8 (__m512i __A, __m512i __B)
>       | ^~~~~~~~~~~~~~~~~~~
> ../subprojects/dpdk/lib/fib/dir24_8_avx512.c:38:26: note: called from here
>    38 |                 ip_vec = _mm512_shuffle_epi8(ip_vec, bswap32);
>       |                          ^~~~~~~~~

The latter issue is because you had applied the endianness change.
I replied in the other thread.


-- 
David Marchand