diff options
author | Zheng Yejian <zhengyejian1@huawei.com> | 2022-11-10 05:03:19 +0300 |
---|---|---|
committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2022-11-24 03:08:31 +0300 |
commit | 96e6122cb79616c622ae0d025eb9f981120b568d (patch) | |
tree | 27a0016f9f2a0aacc103086354513c77b2f16136 /kernel/trace | |
parent | a76d4648a0bbd624a1322c15073b5032a5135f01 (diff) | |
download | linux-96e6122cb79616c622ae0d025eb9f981120b568d.tar.xz |
tracing: Optimize event type allocation with IDA
After commit 060fa5c83e67 ("tracing/events: reuse trace event ids after
overflow"), trace events with dynamic type are linked up in list
'ftrace_event_list' through field 'trace_event.list'. Then when max
event type number used up, it's possible to reuse type number of some
freed one by traversing 'ftrace_event_list'.
As instead, using IDA to manage available type numbers can make codes
simpler and then the field 'trace_event.list' can be dropped.
Since 'struct trace_event' is used in static tracepoints, drop
'trace_event.list' can make vmlinux smaller. Local test with about 2000
tracepoints, vmlinux reduced about 64KB:
before:-rwxrwxr-x 1 root root 76669448 Nov 8 17:14 vmlinux
after: -rwxrwxr-x 1 root root 76604176 Nov 8 17:15 vmlinux
Link: https://lkml.kernel.org/r/20221110020319.1259291-1-zhengyejian1@huawei.com
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r-- | kernel/trace/trace_output.c | 66 |
1 files changed, 16 insertions, 50 deletions
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 67f47ea27921..f0ba97121345 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -11,6 +11,7 @@ #include <linux/kprobes.h> #include <linux/sched/clock.h> #include <linux/sched/mm.h> +#include <linux/idr.h> #include "trace_output.h" @@ -21,8 +22,6 @@ DECLARE_RWSEM(trace_event_sem); static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly; -static int next_event_type = __TRACE_LAST_TYPE; - enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter) { struct trace_seq *s = &iter->seq; @@ -688,38 +687,23 @@ struct trace_event *ftrace_find_event(int type) return NULL; } -static LIST_HEAD(ftrace_event_list); +static DEFINE_IDA(trace_event_ida); -static int trace_search_list(struct list_head **list) +static void free_trace_event_type(int type) { - struct trace_event *e = NULL, *iter; - int next = __TRACE_LAST_TYPE; - - if (list_empty(&ftrace_event_list)) { - *list = &ftrace_event_list; - return next; - } + if (type >= __TRACE_LAST_TYPE) + ida_free(&trace_event_ida, type); +} - /* - * We used up all possible max events, - * lets see if somebody freed one. - */ - list_for_each_entry(iter, &ftrace_event_list, list) { - if (iter->type != next) { - e = iter; - break; - } - next++; - } +static int alloc_trace_event_type(void) +{ + int next; - /* Did we used up all 65 thousand events??? */ - if (next > TRACE_EVENT_TYPE_MAX) + /* Skip static defined type numbers */ + next = ida_alloc_range(&trace_event_ida, __TRACE_LAST_TYPE, + TRACE_EVENT_TYPE_MAX, GFP_KERNEL); + if (next < 0) return 0; - - if (e) - *list = &e->list; - else - *list = &ftrace_event_list; return next; } @@ -761,28 +745,10 @@ int register_trace_event(struct trace_event *event) if (WARN_ON(!event->funcs)) goto out; - INIT_LIST_HEAD(&event->list); - if (!event->type) { - struct list_head *list = NULL; - - if (next_event_type > TRACE_EVENT_TYPE_MAX) { - - event->type = trace_search_list(&list); - if (!event->type) - goto out; - - } else { - - event->type = next_event_type++; - list = &ftrace_event_list; - } - - if (WARN_ON(ftrace_find_event(event->type))) + event->type = alloc_trace_event_type(); + if (!event->type) goto out; - - list_add_tail(&event->list, list); - } else if (WARN(event->type > __TRACE_LAST_TYPE, "Need to add type to trace.h")) { goto out; @@ -819,7 +785,7 @@ EXPORT_SYMBOL_GPL(register_trace_event); int __unregister_trace_event(struct trace_event *event) { hlist_del(&event->node); - list_del(&event->list); + free_trace_event_type(event->type); return 0; } |