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/plugins | |
| 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/plugins')
| -rw-r--r-- | src/plugins/cnat/cnat_bihash.h | 9 | ||||
| -rw-r--r-- | src/plugins/cnat/cnat_session.c | 2 |
2 files changed, 8 insertions, 3 deletions
diff --git a/src/plugins/cnat/cnat_bihash.h b/src/plugins/cnat/cnat_bihash.h index c488e61a07d..75099f6bfdb 100644 --- a/src/plugins/cnat/cnat_bihash.h +++ b/src/plugins/cnat/cnat_bihash.h @@ -44,11 +44,16 @@ typedef struct u64 value[7]; } clib_bihash_kv_40_56_t; +static inline void +clib_bihash_mark_free_40_56 (clib_bihash_kv_40_56_t *v) +{ + v->value[0] = 0xFEEDFACE8BADF00DULL; +} + static inline int clib_bihash_is_free_40_56 (const clib_bihash_kv_40_56_t *v) { - /* Free values are clib_memset to 0xff, check a bit... */ - if (v->key[0] == ~0ULL && v->value[0] == ~0ULL) + if (v->value[0] == 0xFEEDFACE8BADF00DULL) return 1; return 0; } diff --git a/src/plugins/cnat/cnat_session.c b/src/plugins/cnat/cnat_session.c index fa04de602b4..ea34d913217 100644 --- a/src/plugins/cnat/cnat_session.c +++ b/src/plugins/cnat/cnat_session.c @@ -238,7 +238,7 @@ cnat_session_scan (vlib_main_t * vm, f64 start_time, int i) { for (k = 0; k < BIHASH_KVP_PER_PAGE; k++) { - if (v->kvp[k].key[0] == ~0ULL && v->kvp[k].value[0] == ~0ULL) + if (BV (clib_bihash_is_free) (&v->kvp[k])) continue; cnat_session_t *session = (cnat_session_t *) & v->kvp[k]; |