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_template.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_template.h')
| -rw-r--r-- | src/vppinfra/bihash_template.h | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/src/vppinfra/bihash_template.h b/src/vppinfra/bihash_template.h index c4e120e4a1f..e8a2c01cece 100644 --- a/src/vppinfra/bihash_template.h +++ b/src/vppinfra/bihash_template.h @@ -410,6 +410,7 @@ BV (clib_bihash_get_bucket) (BVT (clib_bihash) * h, u64 hash) static inline int BV (clib_bihash_search_inline_with_hash) (BVT (clib_bihash) * h, u64 hash, BVT (clib_bihash_kv) * key_result) { + BVT (clib_bihash_kv) rv; BVT (clib_bihash_value) * v; BVT (clib_bihash_bucket) * b; int i, limit; @@ -455,7 +456,10 @@ static inline int BV (clib_bihash_search_inline_with_hash) { if (BV (clib_bihash_key_compare) (v->kvp[i].key, key_result->key)) { - *key_result = v->kvp[i]; + rv = v->kvp[i]; + if (BV (clib_bihash_is_free) (&rv)) + return -1; + *key_result = rv; return 0; } } @@ -509,6 +513,7 @@ static inline int BV (clib_bihash_search_inline_2_with_hash) (BVT (clib_bihash) * h, u64 hash, BVT (clib_bihash_kv) * search_key, BVT (clib_bihash_kv) * valuep) { + BVT (clib_bihash_kv) rv; BVT (clib_bihash_value) * v; BVT (clib_bihash_bucket) * b; int i, limit; @@ -556,7 +561,10 @@ static inline int BV (clib_bihash_search_inline_2_with_hash) { if (BV (clib_bihash_key_compare) (v->kvp[i].key, search_key->key)) { - *valuep = v->kvp[i]; + rv = v->kvp[i]; + if (BV (clib_bihash_is_free) (&rv)) + return -1; + *valuep = rv; return 0; } } |