diff options
| author |   Dave Barach <dave@barachs.net> | 2023-03-16 13:03:47 -0400 |
|---|---|---|
| committer |   Florin Coras <florin.coras@gmail.com> | 2023-03-18 18:35:46 +0000 |
| commit | b9c8c57e983246ec034bc9059b1740558c951d51 (patch) | |
| tree | cd7267591894b30cea54522fb53ffa1deca1f450 /src/vppinfra/bihash_24_16.h | |
| parent | 04bd0ea8e22dac53c09e3867cabf6256d19477fa (diff) | |
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 <dave@barachs.net>
Change-Id: I6a1aa8a2c30bc70bec4b696ce7b17c2839927065
Diffstat (limited to 'src/vppinfra/bihash_24_16.h')
| -rw-r--r-- | src/vppinfra/bihash_24_16.h | 9 |
1 files changed, 7 insertions, 2 deletions
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; } |