Re: [PATCH v3 1/7] tracing: Refactor hist trigger action code
From: Namhyung Kim <namhyung@kernel.org>
Date: 2018-08-10 06:59:03
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Hi Tom, On Thu, Aug 09, 2018 at 09:34:11AM -0500, Tom Zanussi wrote:
From: Tom Zanussi <redacted> The hist trigger action code currently implements two essentially hard-coded pairs of 'actions' - onmax(), which tracks a variable and saves some event fields when a max is hit, and onmatch(), which is hard-coded to generate a synthetic event. These hardcoded pairs (track max/save fields and detect match/generate synthetic event) should really be decoupled into separate components that can then be arbitrarily combined. The first component of each pair (track max/detect match) is called a 'handler' in the new code, while the second component (save fields/generate synthetic event) is called an 'action' in this scheme. This change refactors the action code to reflect this split by adding two handlers, HANDLER_ONMATCH and HANDLER_ONMAX, along with two actions, ACTION_SAVE and ACTION_TRACE. The new code combines them to produce the existing ONMATCH/TRACE and ONMAX/SAVE functionality, but doesn't implement the other combinations now possible. Future patches will expand these to further useful cases, such as ONMAX/TRACE, as well as add additional handlers and actions such as ONCHANGE and SNAPSHOT. Signed-off-by: Tom Zanussi <redacted> ---
[SNIP]
quoted hunk ↗ jump to hunk
@@ -3421,10 +3419,69 @@ static int parse_action_params(char *params, struct action_data *data) return ret; } -static struct action_data *onmax_parse(char *str) +static int action_parse(char *str, struct action_data *data, + enum handler_id handler) +{ + char *action_name; + int ret = 0; + + strsep(&str, "."); + if (!str) { + hist_err("action parsing: No action found", ""); + ret = -EINVAL; + goto out; + } + + action_name = strsep(&str, "("); + if (!action_name || !str) { + hist_err("action parsing: No action found", ""); + ret = -EINVAL; + goto out; + } + + if (strncmp(action_name, "save", strlen("save")) == 0) { + char *params = strsep(&str, ")"); + + if (!params) { + hist_err("action parsing: No params found for %s", "save"); + ret = -EINVAL; + goto out; + } + + ret = parse_action_params(params, data); + if (ret) + goto out; + + if (handler == HANDLER_ONMAX) + data->fn = onmax_save; + + data->action = ACTION_SAVE; + } else { + char *params = strsep(&str, ")"); + + if (params) { + ret = parse_action_params(params, data); + if (ret) + goto out; + } + + data->fn = action_trace; + data->action = ACTION_TRACE;
This will set action name as (synthetic) event name, right? I think it's natural to have "trace" for it with this change. Maybe it's time to change the syntax like below? onmatch(SYS.EVENT).trace(EVENT, FIELD, ...) Of course it should support old syntax too..
+ }
+
+ data->action_name = kstrdup(action_name, GFP_KERNEL);
+ if (!data->action_name) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ out:
+ return ret;
+}