[ovs-dev] [PATCH ovn v2 3/4] expr: Evaluate the condition expression in a separate step.
Mark Michelson
mmichels at redhat.com
Wed Sep 9 13:38:53 UTC 2020
For the whole series:
Acked-by: Mark Michelson <mmichels at redhat.com>
However, there are a few nits for this particular patch that I think
should be addressed before committing:
1) The commit message says expr_simply() instead of expr_simplify()
2) The comment above expr_normalize() in expr.c needs to be updated to
mention that 'expr' must have already been simplified and had conditions
evaluated.
3) In expr_normalize(), the comment above the EXPR_T_CONDITION case
needs to be altered to say that expr_evaluate_condition resolves
conditions instead of expr_simplify.
These are all simple enough that you can just update these and then merge.
Warning: I'm also ACK-ing Han's patch series that adds some lflow-level
caching (but his patch series caches ovn_flows). So there is a chance
that whoever loses this merge race will have some extra work to get
their patch to apply cleanly.
On 9/9/20 6:09 AM, numans at ovn.org wrote:
> From: Numan Siddique <numans at ovn.org>
>
> A similar patch was committed earlier [1] and then reverted [2].
> This patch is similar to [1], but not exactly same.
>
> A new function is added - expr_evaluate_condition() which evaluates
> the condition expression - is_chassis_resident. expr_simply() will
> no longer evaluates this condition. expr_normalize() is still expected
> to be called after expr_evaluate_condition(). Otherwise it will assert
> if 'is_chassis_resident()' is not evaluated.
>
> An upcoming commit needs this in order to cache the logical flow expressions
> for logical flows having 'is_chassis_resident()' condition in their match.
> The expr tree after expr_simplify() for such logical flows is cached. Since
> we can't cache the is_chassis_resident condition, it is separated out.
> (For logical flows which do not have this condition in their match, the expr matches
> will be cached.)
>
> [1] - 99e3a145927("expr: Evaluate the condition expression in a separate step.")
> [2] - 065bcf46218("ovn-controller: Revert lflow expr caching")
>
> Signed-off-by: Numan Siddique <numans at ovn.org>
> ---
> controller/lflow.c | 3 ++-
> include/ovn/expr.h | 10 +++++----
> lib/expr.c | 50 +++++++++++++++++++++++++++++++++----------
> tests/test-ovn.c | 11 +++++-----
> utilities/ovn-trace.c | 6 ++++--
> 5 files changed, 57 insertions(+), 23 deletions(-)
>
> diff --git a/controller/lflow.c b/controller/lflow.c
> index c2f939f90f..c6e1586283 100644
> --- a/controller/lflow.c
> +++ b/controller/lflow.c
> @@ -684,7 +684,8 @@ consider_logical_flow(const struct sbrec_logical_flow *lflow,
> .lflow = lflow,
> .lfrr = l_ctx_out->lfrr
> };
> - expr = expr_simplify(expr, is_chassis_resident_cb, &cond_aux);
> + expr = expr_simplify(expr);
> + expr = expr_evaluate_condition(expr, is_chassis_resident_cb, &cond_aux);
> expr = expr_normalize(expr);
> uint32_t n_conjs = expr_to_matches(expr, lookup_port_cb, &aux,
> &matches);
> diff --git a/include/ovn/expr.h b/include/ovn/expr.h
> index b34fb0e813..ed7b054144 100644
> --- a/include/ovn/expr.h
> +++ b/include/ovn/expr.h
> @@ -432,10 +432,12 @@ void expr_destroy(struct expr *);
>
> struct expr *expr_annotate(struct expr *, const struct shash *symtab,
> char **errorp);
> -struct expr *expr_simplify(struct expr *,
> - bool (*is_chassis_resident)(const void *c_aux,
> - const char *port_name),
> - const void *c_aux);
> +struct expr *expr_simplify(struct expr *);
> +struct expr *expr_evaluate_condition(
> + struct expr *,
> + bool (*is_chassis_resident)(const void *c_aux,
> + const char *port_name),
> + const void *c_aux);
> struct expr *expr_normalize(struct expr *);
>
> bool expr_honors_invariants(const struct expr *);
> diff --git a/lib/expr.c b/lib/expr.c
> index 6fb96757ad..bff48dfd20 100644
> --- a/lib/expr.c
> +++ b/lib/expr.c
> @@ -2063,10 +2063,10 @@ expr_simplify_relational(struct expr *expr)
>
> /* Resolves condition and replaces the expression with a boolean. */
> static struct expr *
> -expr_simplify_condition(struct expr *expr,
> - bool (*is_chassis_resident)(const void *c_aux,
> +expr_evaluate_condition__(struct expr *expr,
> + bool (*is_chassis_resident)(const void *c_aux,
> const char *port_name),
> - const void *c_aux)
> + const void *c_aux)
> {
> bool result;
>
> @@ -2084,13 +2084,41 @@ expr_simplify_condition(struct expr *expr,
> return expr_create_boolean(result);
> }
>
> +struct expr *
> +expr_evaluate_condition(struct expr *expr,
> + bool (*is_chassis_resident)(const void *c_aux,
> + const char *port_name),
> + const void *c_aux)
> +{
> + struct expr *sub, *next;
> +
> + switch (expr->type) {
> + case EXPR_T_AND:
> + case EXPR_T_OR:
> + LIST_FOR_EACH_SAFE (sub, next, node, &expr->andor) {
> + ovs_list_remove(&sub->node);
> + struct expr *e = expr_evaluate_condition(sub, is_chassis_resident,
> + c_aux);
> + e = expr_fix(e);
> + expr_insert_andor(expr, next, e);
> + }
> + return expr_fix(expr);
> +
> + case EXPR_T_CONDITION:
> + return expr_evaluate_condition__(expr, is_chassis_resident, c_aux);
> +
> + case EXPR_T_CMP:
> + case EXPR_T_BOOLEAN:
> + return expr;
> + }
> +
> + OVS_NOT_REACHED();
> +}
> +
> /* Takes ownership of 'expr' and returns an equivalent expression whose
> * EXPR_T_CMP nodes use only tests for equality (EXPR_R_EQ). */
> struct expr *
> -expr_simplify(struct expr *expr,
> - bool (*is_chassis_resident)(const void *c_aux,
> - const char *port_name),
> - const void *c_aux)
> +expr_simplify(struct expr *expr)
> {
> struct expr *sub, *next;
>
> @@ -2105,8 +2133,7 @@ expr_simplify(struct expr *expr,
> case EXPR_T_OR:
> LIST_FOR_EACH_SAFE (sub, next, node, &expr->andor) {
> ovs_list_remove(&sub->node);
> - expr_insert_andor(expr, next,
> - expr_simplify(sub, is_chassis_resident, c_aux));
> + expr_insert_andor(expr, next, expr_simplify(sub));
> }
> return expr_fix(expr);
>
> @@ -2114,7 +2141,7 @@ expr_simplify(struct expr *expr,
> return expr;
>
> case EXPR_T_CONDITION:
> - return expr_simplify_condition(expr, is_chassis_resident, c_aux);
> + return expr;
> }
> OVS_NOT_REACHED();
> }
> @@ -3397,7 +3424,8 @@ expr_parse_microflow__(struct lexer *lexer,
> struct ds annotated = DS_EMPTY_INITIALIZER;
> expr_format(e, &annotated);
>
> - e = expr_simplify(e, microflow_is_chassis_resident_cb, NULL);
> + e = expr_simplify(e);
> + e = expr_evaluate_condition(e, microflow_is_chassis_resident_cb, NULL);
> e = expr_normalize(e);
>
> struct match m = MATCH_CATCHALL_INITIALIZER;
> diff --git a/tests/test-ovn.c b/tests/test-ovn.c
> index ba628288bb..544fee4c87 100644
> --- a/tests/test-ovn.c
> +++ b/tests/test-ovn.c
> @@ -312,8 +312,9 @@ test_parse_expr__(int steps)
> }
> if (!error) {
> if (steps > 1) {
> - expr = expr_simplify(expr, is_chassis_resident_cb,
> - &ports);
> + expr = expr_simplify(expr);
> + expr = expr_evaluate_condition(expr, is_chassis_resident_cb,
> + &ports);
> }
> if (steps > 2) {
> expr = expr_normalize(expr);
> @@ -914,9 +915,9 @@ test_tree_shape_exhaustively(struct expr *expr, struct shash *symtab,
> exit(EXIT_FAILURE);
> }
> } else if (operation >= OP_SIMPLIFY) {
> - modified = expr_simplify(expr_clone(expr),
> - tree_shape_is_chassis_resident_cb,
> - NULL);
> + modified = expr_simplify(expr_clone(expr));
> + modified = expr_evaluate_condition(
> + expr_clone(modified), tree_shape_is_chassis_resident_cb, NULL);
> ovs_assert(expr_honors_invariants(modified));
>
> if (operation >= OP_NORMALIZE) {
> diff --git a/utilities/ovn-trace.c b/utilities/ovn-trace.c
> index 50a32b7149..39839cb709 100644
> --- a/utilities/ovn-trace.c
> +++ b/utilities/ovn-trace.c
> @@ -931,8 +931,10 @@ read_flows(void)
> continue;
> }
> if (match) {
> - match = expr_simplify(match, ovntrace_is_chassis_resident,
> - NULL);
> + match = expr_simplify(match);
> + match = expr_evaluate_condition(match,
> + ovntrace_is_chassis_resident,
> + NULL);
> }
>
> struct ovntrace_flow *flow = xzalloc(sizeof *flow);
>
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