From b9c8c57e983246ec034bc9059b1740558c951d51 Mon Sep 17 00:00:00 2001 From: Dave Barach Date: Thu, 16 Mar 2023 13:03:47 -0400 Subject: vppinfra: fix corner-cases in bihash lookup In a case where one pounds on a single kvp in a KVP_AT_BUCKET_LEVEL table, the code would sporadically return a transitional value (junk) from a half-deleted kvp. At most, 64-bits worth of the kvp will be written atomically, so using memset(...) to smear 0xFF's across a kvp to free it left a lot to be desired. Performance impact: very mild positive, thanks to FC for doing a multi-thread host stack perf/scale test. Added an ASSERT to catch attempts to add a (key,value) pair which contains the magic "free kvp" value. Type: fix Signed-off-by: Dave Barach Change-Id: I6a1aa8a2c30bc70bec4b696ce7b17c2839927065 --- src/vppinfra/bihash_24_16.h | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'src/vppinfra/bihash_24_16.h') diff --git a/src/vppinfra/bihash_24_16.h b/src/vppinfra/bihash_24_16.h index b9279a88fab..b421ab12edc 100644 --- a/src/vppinfra/bihash_24_16.h +++ b/src/vppinfra/bihash_24_16.h @@ -43,11 +43,16 @@ typedef struct u64 value[2]; } clib_bihash_kv_24_16_t; +static inline void +clib_bihash_mark_free_24_16 (clib_bihash_kv_24_16_t *v) +{ + v->value[0] = 0xFEEDFACE8BADF00DULL; +} + static inline int clib_bihash_is_free_24_16 (const clib_bihash_kv_24_16_t * v) { - /* Free values are clib_memset to 0xff, check a bit... */ - if (v->key[0] == ~0ULL && v->value[0] == ~0ULL && v->value[1] == ~0ULL) + if (v->value[0] == 0xFEEDFACE8BADF00DULL) return 1; return 0; } -- cgit 1.2.3-korg