Messages in this thread Patch in this message | | | Date | Thu, 22 Jul 2021 09:46:38 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH v2] tracing: Allow execnames to be passed as args for synthetic events |
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On Thu, 22 Jul 2021 22:29:24 +0900 Masami Hiramatsu <mhiramat@kernel.org> wrote:
> This looks an interesting improvement. If we can do this, can we also filter > the event by 'comm' (or execname)?
We would be able to filter on the synthetic event, just like any other event with a comm (or other string) But I don't think we can filter before (that is, in the histogram code).
> > > Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> > > --- > > Changes since v1: > > - Hit a bug on freeing the histogram, found that I used "char[]" for the > > type, and it expects to be freed. Freed the old "type" and still use > > "char[]" but have the normal freeing use kfree_const() on type. > > > BTW, if we can use this technic on the hist_field->type, we can cleanup > other type = strdup("<any const type>", GFP_KERNEL) with type = "<any const type>" ? > > Anyway, that will be done in another patch (I think that should be done first, > then we can avoid an odd kfree() in update_var_execname().)
You mean like this? It was done after the patch, but I can move it first.
-- Steve
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index bb1956efd5ef..6b9e4fb70bc1 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -1590,7 +1590,7 @@ static void __destroy_hist_field(struct hist_field *hist_field) kfree(hist_field->var.name); kfree(hist_field->name); - /* execname vars use a constant type */ + /* Can likely be a const */ kfree_const(hist_field->type); kfree(hist_field->system); @@ -1648,9 +1648,7 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, if (flags & HIST_FIELD_FL_HITCOUNT) { hist_field->fn = hist_field_counter; hist_field->size = sizeof(u64); - hist_field->type = kstrdup("u64", GFP_KERNEL); - if (!hist_field->type) - goto free; + hist_field->type = "u64"; goto out; } @@ -1664,7 +1662,7 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, hist_field->fn = hist_field_log2; hist_field->operands[0] = create_hist_field(hist_data, field, fl, NULL); hist_field->size = hist_field->operands[0]->size; - hist_field->type = kstrdup(hist_field->operands[0]->type, GFP_KERNEL); + hist_field->type = kstrdup_const(hist_field->operands[0]->type, GFP_KERNEL); if (!hist_field->type) goto free; goto out; @@ -1673,18 +1671,14 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, if (flags & HIST_FIELD_FL_TIMESTAMP) { hist_field->fn = hist_field_timestamp; hist_field->size = sizeof(u64); - hist_field->type = kstrdup("u64", GFP_KERNEL); - if (!hist_field->type) - goto free; + hist_field->type = "u64"; goto out; } if (flags & HIST_FIELD_FL_CPU) { hist_field->fn = hist_field_cpu; hist_field->size = sizeof(int); - hist_field->type = kstrdup("unsigned int", GFP_KERNEL); - if (!hist_field->type) - goto free; + hist_field->type = "unsigned int"; goto out; } @@ -1697,7 +1691,7 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, flags |= HIST_FIELD_FL_STRING; hist_field->size = MAX_FILTER_STR_VAL; - hist_field->type = kstrdup(field->type, GFP_KERNEL); + hist_field->type = kstrdup_const(field->type, GFP_KERNEL); if (!hist_field->type) goto free; @@ -1710,7 +1704,7 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, } else { hist_field->size = field->size; hist_field->is_signed = field->is_signed; - hist_field->type = kstrdup(field->type, GFP_KERNEL); + hist_field->type = kstrdup_const(field->type, GFP_KERNEL); if (!hist_field->type) goto free; @@ -1796,7 +1790,7 @@ static int init_var_ref(struct hist_field *ref_field, } } - ref_field->type = kstrdup(var_field->type, GFP_KERNEL); + ref_field->type = kstrdup_const(var_field->type, GFP_KERNEL); if (!ref_field->type) { err = -ENOMEM; goto free; @@ -2165,7 +2159,7 @@ static struct hist_field *parse_unary(struct hist_trigger_data *hist_data, expr->operands[0] = operand1; expr->operator = FIELD_OP_UNARY_MINUS; expr->name = expr_str(expr, 0); - expr->type = kstrdup(operand1->type, GFP_KERNEL); + expr->type = kstrdup_const(operand1->type, GFP_KERNEL); if (!expr->type) { ret = -ENOMEM; goto free; @@ -2291,7 +2285,7 @@ static struct hist_field *parse_expr(struct hist_trigger_data *hist_data, expr->operands[1] = operand2; expr->operator = field_op; expr->name = expr_str(expr, 0); - expr->type = kstrdup(operand1->type, GFP_KERNEL); + expr->type = kstrdup_const(operand1->type, GFP_KERNEL); if (!expr->type) { ret = -ENOMEM; goto free; @@ -2679,10 +2673,10 @@ static struct hist_field *create_var(struct hist_trigger_data *hist_data, var->var.hist_data = var->hist_data = hist_data; var->size = size; var->var.name = kstrdup(name, GFP_KERNEL); - var->type = kstrdup(type, GFP_KERNEL); + var->type = kstrdup_const(type, GFP_KERNEL); if (!var->var.name || !var->type) { kfree(var->var.name); - kfree(var->type); + kfree_const(var->type); kfree(var); var = ERR_PTR(-ENOMEM); }
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